New textures for the lepton mass matrices
P. M. Ferreira; L. Lavoura
2014-12-02T23:59:59.000Z
We study predictive textures for the lepton mass matrices in which the charged-lepton mass matrix has either four or five zero matrix elements while the neutrino Majorana mass matrix has, respectively, either four or three zero matrix elements. We find that all the viable textures of these two kinds share many predictions: the neutrino mass spectrum is inverted, the sum of the light-neutrino masses is close to 0.1 eV, the Dirac phase $\\delta$ in the lepton mixing matrix is close to either $0$ or $\\pi$, and the mass term responsible for neutrinoless double-beta decay lies in between 12 and 22 meV.
Lepton Mass Hierarchy and Neutrino Oscillations
H. Fritzsch; Z. Z Xing
1995-09-26T23:59:59.000Z
Starting from the symmetry of lepton flavor democracy, we propose and discuss a simple pattern for the mass generation and flavor mixing of the charged leptons and neutrinos. The three neutrino masses are nearly degenerate, and the flavor mixing angles can be calculated. The observed deficit of solar and atmospheric neutrinos can be interpreted as a consequence of the near degeneracy and large oscillations of $\
Parallel hybrid textures of lepton mass matrices
S. Dev; Shivani Gupta; Radha Raman Gautam
2010-09-28T23:59:59.000Z
We analyse the parallel hybrid texture structures in the charged lepton and the neutrino sector. These parallel hybrid texture structures have physical implications as they cannot be obtained from arbitrary lepton mass matrices through weak basis transformations. The total sixty parallel hybrid texture structures can be grouped into twelve classes, and all the hybrid textures in the same class have identical physical implications. We examine all the twelve classes under the assumption of non-factorizable phases in the neutrino mass matrix. Five out of the total twelve classes are found to be phenomenologically disallowed. We study the phenomenological implications of the allowed classes for 1-3 mixing angle, Majorana and Dirac-type $CP$ violating phases. Interesting constraints on effective Majorana mass are obtained for all the allowed classes.
Parallel hybrid textures of lepton mass matrices
Dev, S.; Gupta, Shivani; Gautam, Radha Raman [Department of Physics, Himachal Pradesh University, Shimla 171005 (India)
2010-10-01T23:59:59.000Z
We analyze the parallel hybrid texture structures in the charged lepton and the neutrino sector. These parallel hybrid texture structures have physical implications as they cannot be obtained from arbitrary lepton mass matrices through weak basis transformations. The total 60 parallel hybrid texture structures can be grouped into 12 classes, and all the hybrid textures in the same class have identical physical implications. We examine all 12 classes under the assumption of nonfactorizable phases in the neutrino mass matrix. Five out of the total 12 classes are found to be phenomenologically disallowed. We study the phenomenological implications of the allowed classes for 1-3 mixing angle, Majorana and Dirac-type CP violating phases. Interesting constraints on effective Majorana mass are obtained for all the allowed classes.
Parallel hybrid textures of lepton mass matrices
Dev, S; Gautam, Radha Raman
2010-01-01T23:59:59.000Z
We analyse the parallel hybrid texture structures in the charged lepton and the neutrino sector. These parallel hybrid texture structures have physical implications as they cannot be obtained from arbitrary lepton mass matrices through weak basis transformations. The total sixty parallel hybrid texture structures can be grouped into twelve classes, and all the hybrid textures in the same class have identical physical implications. We examine all the twelve classes under the assumption of non-factorizable phases in the neutrino mass matrix. Five out of the total twelve classes are found to be phenomenologically disallowed. We study the phenomenological implications of the allowed classes for 1-3 mixing angle, Majorana and Dirac-type $CP$ violating phases. Interesting constraints on effective Majorana mass are obtained for all the allowed classes.
Universal Mass Texture, CP violation and Quark-Lepton Complementarity
Canales, F Gonzalez; Barranco, J
2010-01-01T23:59:59.000Z
Recent measurements of the neutrino and quark mixing angles satisfy the empirical relations called quark-lepton complementarity. These empirical relations suggests the existence of a correlation between the mixing matrices of leptons and quarks. In this work, we examine the possibility that this correlation between the mixing angles of quarks and leptons originates in the similar hierarchy of quarks and charged lepton masses and the seesaw mechanism type I, that gives mass to the Majorana neutrinos. We asssume that the similar mass hierarchies of charged lepton and quark masses allows us to represent all the mass matrices of Dirac fermions in terms of a two zeroes Fritzsch texture.
Universal mass matrix for quarks and leptons and CP violation
Barranco, J.; Gonzalez Canales, F.; Mondragon, A. [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut), Am Muehlenberg 1, D-14476 Golm (Germany); Instituto de Fisica, Universidad Nacional Autonoma de Mexico, 04510, Mexico D.F. (Mexico)
2010-10-01T23:59:59.000Z
The measurements of the neutrino and quark mixing angles satisfy the empirical relations called quark-lepton complementarity. These empirical relations suggest the existence of a correlation between the mixing matrices of leptons and quarks. In this work, we examine the possibility that this correlation between the mixing angles of quarks and leptons originates in the similar hierarchy of quarks and charged lepton masses and the seesaw mechanism type I, that gives mass to the Majorana neutrinos. We assume that the similar mass hierarchies of charged lepton and quark masses allows us to represent all the mass matrices of Dirac fermions in terms of a universal form with four texture zeroes.
Investigating texture six zero lepton mass matrices
Mahajan, Neelu; Gupta, Manmohan; Gill, P S
2013-01-01T23:59:59.000Z
All possible hermitian texture 6 zero Fritzsch like as well as non Fritzsch like lepton mass matrices (144 combinations in all) have been investigated for both Majorana and Dirac neutrinos for their compatibility with the current neutrino oscillation data, keeping in mind the hierarchy of neutrino masses. All the combinations considered here are ruled out by the existing data in the case of inverted hierarchy and degenerate scenario of Majorana neutrino masses. For Majorana neutrinos with normal hierarchy, we find that out of 144 combinations, only 16 possibilities can accommodate the experimental data. Assuming neutrinos to be Dirac particles, normal hierarchy, inverted hierarchy as well as degenerate neutrinos are ruled out for all the combinations.
Texture 4 zero Fritzsch-like lepton mass matrices
Gulsheen Ahuja; Sanjeev Kumar; Monika Randhawa; Manmohan Gupta; S. Dev
2008-02-20T23:59:59.000Z
For Majorana or Dirac neutrinos, using Fritzsch-like texture 4 zero mass matrices with parallel texture structures for the charged leptons and the Dirac neutrino mass matrix (M_{\
Limits on tau lepton flavor violating decays in three charged leptons
Cervelli, Alberto
2010-04-29T23:59:59.000Z
A search for the neutrinoless, lepton-flavor violating decay of the {tau} lepton into three charged leptons has been performed using an integrated luminosity of 468 fb{sup -1} collected with the BABAR detector at the PEP-II collider. In all six decay modes considered, the numbers of events found in data are compatible with the background expectations. Upper limits on the branching fractions are set in the range (1.8-3.3) x 10{sup -8} at 90% confidence level.
Search for Low Mass Exotic leptonic or bosonic structures
B. Tatischeff; E. Tomasi-Gustafsson
2007-07-09T23:59:59.000Z
Recently, several papers discussed the existence of a low mass leptonic structure. It was suggested that the $\\Sigma^{+}$ disintegration: $\\Sigma^{+}\\to$pP$^{0}$, P$^{0}\\to\\mu^{-}\\mu^{+}$ proceeds through an intermediate particle P$^{0}$ having a mass close to M$\\approx$~214.3 MeV. The present work intends to look at other available data, in order to observe the eventual existence of a small peak or shoulder, at a mass close to M=214.3 MeV, which can strengthen the existence of a state produced by two leptons of opposite electric charge.
Permutation symmetry for neutrino and charged-lepton mass matrices
Ma, Ernest [Physics Department, Univeristy of California, Riverside, California 92521 (United States)] [Physics Department, Univeristy of California, Riverside, California 92521 (United States)
2000-02-01T23:59:59.000Z
Permutation symmetry S{sub 3} is applied to obtain two equal Majorana neutrino masses, while maintaining three different charged-lepton masses and suppressing neutrinoless double beta decay. The resulting radiative splitting of the two neutrinos is shown to be suitable for solar neutrino vacuum oscillations. (c) 2000 The American Physical Society.
Electroweak model of lepton mass and mixing hierarchies
E. M. Lipmanov
2009-04-06T23:59:59.000Z
Flavor physics, like cosmology, is likely in need of new basic ideas; the puzzles of elementary particle mass hierarchies and in particular the e-mu-tau and neutrino ones still remain mysteries. In this paper a new idea of dynamical connection between low energy 3-flavor particle mass hierarchies and electroweak charges is studied with restriction to the simplest case of lepton flavor phenomenology. The main inference is that it can be only two types of lepton 3-flavor particle-copy groups: 1) with large and strongly hierarchical mass ratios and 2) with close to 1 mass ratios. From experimental data definitely follows that the three charged leptons belong to the first type whereas the three neutrinos belong to the second type and so are quasi-degenerate. The inferences of QD-neutrinos with realistic small masses and oscillation hierarchy parameter and quark-QD-neutrino mixing angle complementarity follow from the fact of small EW charges and their relation to the concept of benchmark flavor pattern.
Statistical Understanding of Quark and Lepton Masses in Gaussian Landscapes
Lawrence J. Hall; Michael P. Salem; Taizan Watari
2007-08-10T23:59:59.000Z
The fundamental theory of nature may allow a large landscape of vacua. Even if the theory contains a unified gauge symmetry, the 22 flavor parameters of the Standard Model, including neutrino masses, may be largely determined by the statistics of this landscape, and not by any symmetry. Then the measured values of the flavor parameters do not lead to any fundamental symmetries, but are statistical accidents; their precise values do not provide any insights into the fundamental theory, rather the overall pattern of flavor reflects the underlying landscape. We investigate whether random selection from the statistics of a simple landscape can explain the broad patterns of quark, charged lepton, and neutrino masses and mixings. We propose Gaussian landscapes as simplified models of landscapes where Yukawa couplings result from overlap integrals of zero-mode wavefunctions in higher-dimensional supersymmetric gauge theories. In terms of just five free parameters, such landscapes can account for all gross features of flavor, including: the hierarchy of quark and charged lepton masses; small quark mixing angles, with 13 mixing less than 12 and 23 mixing; very light Majorana neutrino masses, with the solar to atmospheric neutrino mass ratio consistent with data; distributions for leptonic 12 and 23 mixings that are peaked at large values, while the distribution for 13 mixing is peaked at low values; and order unity CP violating phases in both the quark and lepton sectors. While the statistical distributions for flavor parameters are broad, the distributions are robust to changes in the geometry of the extra dimensions. Constraining the distributions by loose cuts about observed values leads to narrower distributions for neutrino measurements of 13 mixing, CP violation, and neutrinoless double beta decay.
Texture-zero model for the lepton mass matrices
Ferreira, P M
2012-01-01T23:59:59.000Z
We suggest a simple model, based on the type-I seesaw mechanism, for the lepton mass matrices. The model hinges on an Abelian symmetry which leads to mass matrices with some vanishing matrix elements. The model predicts one massless neutrino and $M_{e\\mu} = 0$ ($M$ is the effective light-neutrino Majorana mass matrix). We show that these predictions perfectly agree with the present experimental data if the neutrino mass spectrum is inverted, i.e. if $m_3 = 0$, provided the Dirac phase $\\delta$ is very close to maximal ($\\pm \\pi / 2$). In the case of a normal neutrino mass spectrum, i.e. when $m_1 = 0$, the agreement of our model with the data is less than optimal---the reactor mixing angle $\\theta_{13}$ is too small in our model. Minimal leptogenesis is not an option in our model due to the vanishing elements in the Yukawa-coupling matrices.
Texture-zero model for the lepton mass matrices
P. M. Ferreira; L. Lavoura
2012-10-01T23:59:59.000Z
We suggest a simple model, based on the type-I seesaw mechanism, for the lepton mass matrices. The model hinges on an Abelian symmetry which leads to mass matrices with some vanishing matrix elements. The model predicts one massless neutrino and $M_{e\\mu} = 0$ ($M$ is the effective light-neutrino Majorana mass matrix). We show that these predictions perfectly agree with the present experimental data if the neutrino mass spectrum is inverted, i.e. if $m_3 = 0$, provided the Dirac phase $\\delta$ is very close to maximal ($\\pm \\pi / 2$). In the case of a normal neutrino mass spectrum, i.e. when $m_1 = 0$, the agreement of our model with the data is less than optimal---the reactor mixing angle $\\theta_{13}$ is too small in our model. Minimal leptogenesis is not an option in our model due to the vanishing elements in the Yukawa-coupling matrices.
Implications of theta_13 on Fritzsch-like lepton mass matrices
Fakay, Priyanka; Verma, Rohit; Ahuja, Gulsheen; Gupta, Manmohan
2013-01-01T23:59:59.000Z
Implications of the lepton mixing angles, in particular of theta_13, have been investigated for minimal as well as non-minimal Fritzsch-like textures for the case of Majorana neutrinos. Both, in minimal texture (texture 6 zero lepton mass matrices) and non-minimal textures (two cases of texture 5 zero lepton mass matrices), inverted hierarchy and degenerate scenario of neutrino masses have been ruled out. The implications of theta_13 have been investigated on the lightest neutrino mass m_\
Implications of theta_13 on Fritzsch-like lepton mass matrices
Priyanka Fakay; Samandeep Sharma; Rohit Verma; Gulsheen Ahuja; Manmohan Gupta
2013-01-25T23:59:59.000Z
Implications of the lepton mixing angles, in particular of theta_13, have been investigated for minimal as well as non-minimal Fritzsch-like textures for the case of Majorana neutrinos. Both, in minimal texture (texture 6 zero lepton mass matrices) and non-minimal textures (two cases of texture 5 zero lepton mass matrices), inverted hierarchy and degenerate scenario of neutrino masses have been ruled out. The implications of theta_13 have been investigated on the lightest neutrino mass m_\
Dark Matter and Lepton Flavour Violation in a Hybrid Neutrino Mass Model
Deppisch, Frank F
2014-01-01T23:59:59.000Z
We describe a hybrid model in which the light neutrino mass matrix receives both tree-level seesaw and loop-induced contributions. An additional U(1) gauge symmetry is used to stabilize the lightest right-handed neutrino as the Dark Matter candidate. After fitting the experimental neutrino data, we analyze and correlate the phenomenological consequences of the model, namely its impact on electroweak precision measurements, the Dark Matter relic abundance, lepton flavour violating rare decays and neutrinoless double beta decay. We find that natural realizations of the model characterized by large Yukawa couplings are compatible with and close to the current experimental limits.
Upper limits on electric dipole moments of tau-lepton, heavy quarks, and W-boson
A. G. Grozin; I. B. Khriplovich; A. S. Rudenko
2009-03-04T23:59:59.000Z
We discuss upper limits on the electric dipole moments (EDM) of the tau-lepton, heavy quarks, and W-boson, which follow from the precision measurements of the electron and neutron EDM.
Upper limits on electric dipole moments of tau-lepton, heavy quarks, and W-boson
Grozin, A G; Rudenko, A S
2009-01-01T23:59:59.000Z
We discuss upper limits on the electric dipole moments (EDM) of the tau-lepton, heavy quarks, and W-boson, which follow from the precision measurements of the electron and neutron EDM.
Photon and graviton mass limits
Nieto, Michael [Los Alamos National Laboratory; Goldhaber Scharff, Alfred [SUNY
2008-01-01T23:59:59.000Z
We review past and current studies of possible long-distance, low-frequency deviations from Maxwell electrodynamics and Einstein gravity. Both have passed through three phases: (1) Testing the inverse-square laws of Newton and Coulomb, (2) Seeking a nonzero value for the rest mass of photon or graviton, and (3) Considering more degrees of freedom, allowing mass while preserving gauge or general-coordinate invariance. For electrodynamics there continues to be no sign of any deviation. Since our previous review the lower limit on the photon Compton wavelength (associated with weakening of electromagnetic fields in vacuum over large distance scale) has improved by four orders of magnitude, to about one astronomical unit. Rapid current progress in astronomical observations makes it likely that there will be further advances. These ultimately could yield a bound exceeding galactic dimensions, as has long been contemplated. Meanwhile, for gravity there have been strong arguments about even the concept of a graviton rest mass. At the same time there are striking observations, commonly labeled 'dark matter' and 'dark energy' that some argue imply modified gravity. This makes the questions for gravity much more interesting. For dark matter, which involves increased attraction at large distances, any explanation by modified gravity would be qualitatively different from graviton mass. Because dark energy is associated with reduced attraction at large distances, it might be explained by a graviton-mass-like effect.
Neutrino Mixing Angles from Texture Zeros of the Lepton Mass Matrices
Fritzsch, Harald
2012-01-01T23:59:59.000Z
Taking into account the latest neutrino oscillation data, we study texture zeros of the lepton mass matrices. Assuming the Dirac neutrino mass matrix M_D, the charged-lepton mass matrix M_l and the mass matrix of heavy right-handed Majorana neutrinos M_R to have three texture zeros, we show that the observed neutrino mixing angles can naturally be obtained. The phenomenological implications for the neutrino mass spectrum, the CP-violating phases, the tritium beta decay and the neutrinoless double-beta decay are explored.
Neutrino Mixing Angles from Texture Zeros of the Lepton Mass Matrices
Harald Fritzsch; Shun Zhou
2012-12-03T23:59:59.000Z
Taking into account the latest neutrino oscillation data, we study texture zeros of the lepton mass matrices. Assuming the Dirac neutrino mass matrix M_D, the charged-lepton mass matrix M_l and the mass matrix of heavy right-handed Majorana neutrinos M_R to have three texture zeros, we show that the observed neutrino mixing angles can naturally be obtained. The phenomenological implications for the neutrino mass spectrum, the CP-violating phases, the tritium beta decay and the neutrinoless double-beta decay are explored.
Updated values of running quark and lepton masses at GUT scale in SM, 2HDM and MSSM
Kalpana Bora
2012-06-26T23:59:59.000Z
Updated values of running quark and lepton masses at GUT (Grand unified theories) scales are important for fermion mass model building, and to calculate neutrino masses, in GUTs . We present their values at GUT scales, in SM, MSSM and 2HDM theories, using the latest values of running quark and lepton masses.
Texture Zero Mass Matrices and Flavor Mixing of Quarks and Leptons
Fritzsch, Harald
2015-01-01T23:59:59.000Z
We discuss mass matrices with four texture zeros for the quarks and leptons. The three mixing angles for the quarks and leptons are functions of the fermion masses. The results agree with the experimental data. The ratio of the masses of the first two neutrinos is given by the solar mixing angle. The neutrino masses are calculated: $m_1$ $\\approx$ 0.003 eV , $m_2$ $\\approx$ 0.012 eV , $m_3$ $\\approx$ 0.048 eV.
Confronting predictive texture zeros in lepton mass matrices with current data
Luís M. Cebola; David Emmanuel-Costa; Ricardo González Felipe
2015-04-24T23:59:59.000Z
Several popular Ans\\"atze of lepton mass matrices that contain texture zeros are confronted with current neutrino observational data. We perform a systematic $\\chi^2$-analysis in a wide class of schemes, considering arbitrary Hermitian charged lepton mass matrices and symmetric mass matrices for Majorana neutrinos or Hermitian mass matrices for Dirac neutrinos. Our study reveals that several patterns are still consistent with all the observations at 68.27% confidence level, while some others are disfavored or excluded by the experimental data. The well-known Frampton-Glashow-Marfatia two-zero textures, hybrid textures and parallel structures, among others, are considered.
Confronting predictive texture zeros in lepton mass matrices with current data
Cebola, Luís M; Felipe, Ricardo González
2015-01-01T23:59:59.000Z
Several popular Ans\\"atze of lepton mass matrices that contain texture zeros are confronted with current neutrino observational data. We perform a systematic $\\chi^2$-analysis in a wide class of schemes, considering arbitrary Hermitian charged lepton mass matrices and symmetric mass matrices for Majorana neutrinos or Hermitian mass matrices for Dirac neutrinos. Our study reveals that several patterns are still consistent with all the observations at 68.27% confidence level, while some others are disfavored or excluded by the experimental data. The well-known Frampton-Glashow-Marfatia two-zero textures, hybrid textures and parallel structures, among others, are considered.
Top Quark Mass in Events with two Charged Leptons at the D0 Experiment
Boline, Daniel Dooley; /Boston U.
2010-01-01T23:59:59.000Z
The top quark is the most massive observed fundamental subatomic particle, and at the Tevatron accelerator is produced mostly in top-antitop (t{bar t}) quark pairs from the collisions of protons and anti-protons. Each top quark decays into a bottom quark and a W boson. The W boson can then decay into a pair of quarks, or into a charged lepton and a neutrino. The various decays can be broken up into three different channels based on the number of leptons from the decay of the W bosons: all-jets (with no leptons), lepton+jets (with one lepton), and dilepton (with two leptons). This dissertation will present a measurement of the top quark mass in the dilepton channel. The dilepton channel is characterized by two leptons, two neutrinos and two b-quarks. The neutrinos are not directly observed, but their absence is felt as missing transverse momentum (p{sub T}) in the detector. The combination of two leptons and large p{sub T} produces an easily isolated signal, giving the dilepton channel a high signal over background ratio. Having two neutrinos means that we cannot know what the transverse momenta of either neutrino is. This means that even if we knew the momenta of the leptons and b-quarks perfectly, we would be unable to reconstruct the mass of the top quark. This measurement gets around this problem by scanning over all possible values of the top mass, finding all consistent t{bar t} combinations, assigning a kinematic weight to each, and then adding the weights for each combination at a given possible top mass. The lepton momenta, jet momenta, and p{sub T} are only known to within some finite precision, so for a given top mass, I also vary each of these momenta within their resolutions and add the weights for a given possible top mass. After scanning over possible top masses, I choose the top mass with the largest sum of weights m{sub t}{sup max} as an observable for the event. I then perform a template based likelihood fit of m{sub t} using m{sub t}{sup max}. I analyze 322 candidate events collected by the D0 detector, and obtain a top quark mass of: m{sub t} = 174.8 {+-} 3.1 GeV.
Measurement of the Mass of the W Boson in $e^+ e^-$ collisions using the Fully Leptonic Channel
Abbiendi, G; Ĺkesson, P F; Alexander, Gideon; Allison, J; Anagnostou, G; Anderson, K J; Asai, S; Axen, D A; Azuelos, Georges; Bailey, I; Barberio, E; Barlow, R J; Batley, J Richard; Bechtle, P; Behnke, T; Bell, K W; Bell, P J; Bella, G; Bellerive, A; Benelli, G; Bethke, Siegfried; Biebel, O; Bloodworth, Ian J; Boeriu, O; Bock, P; Bonacorsi, D; Boutemeur, M; Braibant, S; Brigliadori, L; Brown, R M; Büsser, K; Burckhart, H J; Cammin, J; Campana, S; Carnegie, R K; Caron, B; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Cohen, I; Csilling, Akos; Cuffiani, M; Dado, S; Dallavalle, G M; Dallison, S; de Roeck, A; De Wolf, E A; Desch, Klaus; Donkers, M; Dubbert, J; Duchovni, E; Duckeck, G; Duerdoth, I P; Etzion, E; Fabbri, Franco Luigi; Feld, L; Ferrari, P; Fiedler, F; Fleck, I; Ford, M; Frey, A; Fürtjes, A; Gagnon, P; Gary, J W; Gaycken, G; Geich-Gimbel, C; Giacomelli, G; Giacomelli, P; Giunta, M; Goldberg, J; Gross, E; Gruwé, M; Günther, P O; Sen-Gupta, A; Hajdu, C; Hamann, M; Hanson, G G; Harder, K; Harel, A; Harin-Dirac, M; Hauschild, M; Hauschildt, J; Hawkes, C M; Hawkings, R; Hemingway, Richard J; Hensel, C; Herten, G; Heuer, R D; Hill, J C; Hoffman, K; Homer, R James; Horváth, D; Howard, R; Hüntemeyer, P; Igo-Kemenes, P; Ishii, K; Jeremie, H; Jones, C R; Jovanovic, P; Junk, T R; Kanaya, N; Kanzaki, J; Karapetian, G V; Karlen, D A; Kartvelishvili, V G; Kawagoe, K; Kawamoto, T; Keeler, Richard K; Kellogg, R G; Kennedy, B W; Kim, D H; Klein, K; Klier, A; Kluth, S; Kobayashi, T; Kobel, M; Kokott, T P; Komamiya, S; Kormos, L L; Kowalewski, R V; Krämer, T; Kress, T; Krieger, P; Von Krogh, J; Krop, D; Kühl, T; Kupper, M; Kyberd, P; Lafferty, G D; Landsman, Hagar Yaël; Lanske, D; Layter, J G; Leins, A; Lellouch, Daniel; Letts, J; Levinson, L; Lillich, J; Littlewood, C; Lloyd, S L; Loebinger, F K; Lü, J; Ludwig, J; Macchiolo, A; MacPherson, A L; Mader, W; Marcellini, S; Marchant, T E; Martin, A J; Martin, J P; Masetti, G; Mashimo, T; Mättig, P; McDonald, W J; McKenna, J A; McMahon, T J; McPherson, R A; Meijers, F; Méndez-Lorenzo, P; Menges, W; Merritt, F S; Mes, H; Michelini, Aldo; Mihara, S; Mikenberg, G; Miller, D J; Moed, S; Mohr, W; Mori, T; Mutter, A; Nagai, K; Nakamura, I; Neal, H A; Nisius, R; O'Neale, S W; Oh, A; Okpara, A N; Oreglia, M J; Orito, S; Pahl, C; Pásztor, G; Pater, J R; Patrick, G N; Pilcher, J E; Pinfold, James L; Plane, D E; Poli, B; Polok, J; Pooth, O; Quadt, A; Rabbertz, K; Rembser, C; Renkel, P; Rick, Hartmut; Roney, J M; Rosati, S; Rozen, Y; Runge, K; Rust, D R; Sachs, K; Saeki, T; Sahr, O; Sarkisyan-Grinbaum, E; Schaile, A D; Schaile, O; Scharff-Hansen, P; Schröder, M; Schumacher, M; Schwick, C; Scott, W G; Seuster, R; Shears, T G; Shen, B C; Shepherd-Themistocleous, C H; Sherwood, P; Siroli, G P; Skuja, A; Smith, A M; Sobie, Randall J; Söldner-Rembold, S; Spagnolo, S; Spanó, F; Stahl, A; Stephens, K; Strom, D; Ströhmer, R; Tarem, S; Tasevsky, M; Taylor, R J; Teuscher, R; Thomson, M A; Torrence, E; Toya, D; Tran, P; Trefzger, T M; Tricoli, A; Trigger, I; Trócsányi, Z L; Tsur, E; Turner-Watson, M F; Ueda, I; Ujvári, B; Vachon, B; Vollmer, C F; Vannerem, P; Verzocchi, M; Voss, H; Vossebeld, Joost Herman; Waller, D; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wengler, T; Wermes, N; Wetterling, D; Wilson, G W; Wilson, J A; Wyatt, T R; Yamashita, S; Zacek, V; Zer-Zion, D
2003-01-01T23:59:59.000Z
A novel method of determining the mass of the W boson in the W+W- -> lnu lnu channel is presented and applied to 667pb^-1 of data recorded at the center-of- mass energies in the range 183-207 GeV with the OPAL detector at LEP. The Measured energies of charged leptons and the results of a new procedure based on an approximate kinematic reconstruction of the events are combined to give: Mw=80.41+-0.41+-0.13 GeV, when the first error is statistical and the second is systematic. The systematic error is dominated by the uncertainty on the lepton energy, which is calibrated using data, and the parameterization of the variables used in the fitting, which is obtained using Monte Carlo events. Both of these are limited by statistics.
Measurement of the Top Quark Mass Simultaneously in Dilepton and Lepton + Jets Decay Channels
Fedorko, Wojciech T.; /Chicago U.
2008-09-01T23:59:59.000Z
The authors present the first measurement of the top quark mass using simultaneously data from two decay channels. They use a data sample of {radical}s = 1.96 TeV collisions with integrated luminosity of 1.9 fb{sup -1} collected by the CDF II detector. They select dilepton and lepton + jets channel decays of t{bar t} pairs and reconstruct two observables in each topology. They use non-parametric techniques to derive probability density functions from simulated signal and background samples. The observables are the reconstructed top quark mass and the scalar sum of transverse energy of the event in the dilepton topology and the reconstructed top quark mass and the invariant mass of jets from the W boson decay in lepton + jets channel. They perform a simultaneous fit for the top quark mass and the jet energy scale which is constrained in situ by the hadronic W boson resonance from the lepton + jets channel. Using 144 dilepton candidate events and 332 lepton + jets candidate events they measure: M{sub top} = 171.9 {+-} 1.7 (stat. + JES) {+-} 1.1 (other sys.) GeV/c{sup 2} = 171.9 {+-} 2.0 GeV/c{sup 2}. The measurement features a robust treatment of the systematic uncertainties, correlated between the two channels and develops techniques for a future top quark mass measurement simultaneously in all decay channels. Measurements of the W boson mass and the top quark mass provide a constraint on the mass of the yet unobserved Higgs boson. The Higgs boson mass implied by measurement presented here is higher than Higgs boson mass implied by previously published, most precise CDF measurements of the top quark mass in lepton + jets and dilepton channels separately.
Leptogenesis in a seesaw model with Fritzsch-type lepton mass matrices
Ahn, Y. H.; Kim, C. S.; Lee, Jake [Department of Physics, Yonsei University, Seoul 120-749 (Korea, Republic of); Kang, Sin Kyu [School of Liberal Arts, Seoul National University of Technology, Seoul 139-743 (Korea, Republic of)
2008-04-01T23:59:59.000Z
We investigate how the baryon asymmetry of our Universe via leptogenesis can be achieved within the framework of the seesaw model with Fritzsch-type lepton mass matrices proposed by Fukugita et al. We study the cases with CP-violating phases in charged-lepton Yukawa matrix, however, with and without Dirac neutrino Yukawa phases. We consider both flavor-independent and flavor-dependent leptogenesis, and demonstrate how they lead to different amounts of lepton asymmetries in detail. In particular, it is shown that flavor-dependent leptogenesis in this model can be achieved only for very tiny or zero values of CP phases in Dirac neutrino Yukawa matrix at the grand unified theory scale. In addition to the CP phases, for successful leptogenesis in the model it is required that the degeneracy of the heavy Majorana neutrino mass spectrum should be broken and we also show that the breakdown of the degeneracy can be radiatively induced.
Lyuboshitz, V. L.; Lyuboshitz, V. V., E-mail: Valery.Lyuboshitz@jinr.ru [Joint Institute for Nuclear Research (Russian Federation)
2013-08-15T23:59:59.000Z
The lepton-charge (L{sub e}, L{sub {mu}}, L{sub {tau}}) nonconserving interaction leads to the mixing of the electron, muon, and tau neutrinos, which manifests itself in spatial oscillations of a neutrino beam, and also to the mixing of the electron, negative muon, and tau lepton, which, in particular, may be the cause of the 'forbidden' radiative decay of the negative muon into the electron and {gamma} quantum. Under the assumption that the nondiagonal elements of the mass matrices for neutrinos and ordinary leptons, connected with the lepton charge nonconservation, are the same, and by performing the joint analysis of the experimental data on neutrino oscillations and experimental restriction for the probability of the decay Micro-Sign {sup -} {yields} e{sup -} + {gamma} per unit time, the following estimate for the lower bound of neutrino mass has been obtained: m{sup ({nu})} > 1.5 eV/c{sup 2}.
A complete survey of texture zeros in the lepton mass matrices
Ludl, Patrick Otto
2014-01-01T23:59:59.000Z
We perform a systematic and complete analysis of texture zeros in the lepton mass matrices and identify all viable and maximally restrictive cases of pairs (M_\\ell, M_D) and (M_\\ell, M_L), where M_\\ell, M_D and M_L are the charged-lepton, Dirac neutrino and Majorana neutrino mass matrices, respectively. To this end, we perform a thorough analysis of textures which are equivalent through weak-basis permutations. Furthermore, we introduce numerical measures for the predictivity of textures and apply them to the viable and maximally restrictive texture zero models. It turns out that for Dirac neutrinos these models can at most predict the smallest neutrino mass and the CKM-type phase of the mixing matrix. For Majorana neutrinos most models can, in addition, predict the effective neutrino mass for neutrinoless double beta decay.
Neutrino masses and mixing, quark-lepton symmetry, and strong right-handed neutrino hierarchy
Dermisek, Radovan [Davis Institute for High Energy Physics, University of California, Davis, California 95616 (United States)
2004-10-01T23:59:59.000Z
Assuming the same form of all mass matrices as motivated by quark-lepton symmetry, we discuss conditions under which bilarge mixing in the lepton sector can be obtained with a minimal amount of fine-tuning requirements for possible models. We assume hierarchical mass matrices, dominated by the 3-3 element, with off-diagonal elements much smaller than the larger neighboring diagonal element. Characteristic features of this scenario are strong hierarchy in masses of right-handed neutrinos, and comparable contributions of both lighter right-handed neutrinos to the resulting left-handed neutrino Majorana mass matrix. Because of obvious quark-lepton symmetry, this approach can be embedded into grand unified theories. The mass of the lightest neutrino does not depend on details of a model in the leading order. The right-handed neutrino scale can be identified with the GUT scale in which case the mass of the lightest neutrino is given as (m{sub top}{sup 2}/M{sub GUT}) vertical bar U{sub {tau}}{sub 1} vertical bar{sup 2}.
W. J. Huo
2003-01-27T23:59:59.000Z
By using the anomalous magnetic and electric dipole moments of the $\\tau$ lepton in an effective lagrangian approach to the new physics, we investigate the lepton flavor violation (LFV) decays, $l\\to l'\\gamma$, and $\\mu,\\tau$ anomalous magnetic and electric dipole moments in a lepton mass matrices ansatz which induced by SUSY GUT. We put very stringent constraints LFV decays and $\\tau$ anomalous magnetic and electric dipole moments.
Neutrino mass hierarchy and the origin of leptonic flavor mixing from the righthanded sector
Leser, Philipp
2011-01-01T23:59:59.000Z
We consider a neutrino mass model where all leptonic mixing is induced by a heavy Majorana sector through the seesaw type I mechanism, while the Dirac mass matrices are diagonal. Such a pattern occurs naturally in Grand Unified Theories (GUTs). Constraints on the parameters of the models are considered and it is shown that a normal neutrino mass hierarchy is preferred. The lightest neutrino mass is typically small, leading to non-observable rates for neutrinoless double beta decay in the normal hierarchy case.
Monika Sinha; Banibrata Mukhopadhyay
2007-11-21T23:59:59.000Z
We study the consequences of CPT and lepton number violation in neutrino sector. For CPT violation we take gravity with which neutrino and antineutrino couple differently. Gravity mixes neutrino and antineutrino in an unequal ratio to give two mass eigenstates. Lepton number violation interaction together with CPT violation gives rise to neutrino-antineutrino oscillation. Subsequently, we study the neutrino flavor mixing and oscillation under the influence of gravity. It is found that gravity changes flavor oscillation significantly which influences the relative abundance of different flavors in present universe. We show that the neutrinoless double beta decay rate is modified due to presence of gravity- the origin of CPT violation, as the mass of the flavor state is modified.
PHYSICAL REVIEW D VOLUME 53,NUMBER 1 Measurement of the mass of the T lepton
Olsen, Stephen L.
PHYSICAL REVIEW D VOLUME 53,NUMBER 1 Measurement of the mass of the T lepton 1JANUARY 1996 J. Z,4 .I. Chen,5 S. J. Chen,l S. M. Chen,l Y. Chen,' Y. B. Chen,' Y. Q. Chen,' B. S. Cheng,' R. F. Cowan,e H. C. Cu&l X. Z. Cui,' H. L. Ding,' Z. Z. Du,' W. Dunwoodie,e X. L. Fan,' J. Fang, 1 C. S. Gao,' M
New precise determination of the $\\tau$ lepton mass at KEDR detector
Anashin, V V; Baldin, E M; Barladyan, A K; Barnyakov, A Y; Barnyakov, M Y; Baru, S E; Bedny, I V; Beloborodova, O L; Blinov, A E; Blinov, V E; Bobrov, A B; Bobrovnikov, V S; Bogomyagkov, A V; Bondar, A E; Bondarev, D V; Buzykaev, A R; Cherepanov, V P; Eidelman, S I; Glukhovchenko, Yu M; Gulevich, V V; Karnaev, S E; Karpov, G V; Karpov, S V; Kiselev, V A; Kononov, S A; Kotov, K Yu; Kravchenko, E A; Kremyanskaya, E V; Kulikov, V F; Kurkin, G Ya; Kuper, E A; Levichev, E B; Maksimov, D A; Malyshev, V M; Maslennikov, A L; Medvedko, A S; Meshkov, O I; Mishnev, S E; Morozov, I I; Muchnoi, N Yu; Neufeld, V V; Nikitin, S A; Nikolaev, I B; Onuchin, A P; Oreshkin, S B; Orlov, I O; Osipov, A A; Peleganchuk, S V; Petrosyan, S S; Pivovarov, S G; Piminov, P; Petrov, V V; Poluektov, A O; Pospelov, G E; Prisekin, V G; Ruban, A A; Sandyrev, V K; Savinov, G A; Shamov, A G; Shatilov, D N; Shubin, E I; Shwartz, B A; Sidorov, V A; Simonov, E A; Sinyatkin, S V; Skovpen, Y I; Skrinsky, A N; Smaluk, V V; Soukharev, A M; Struchalin, M V; Talyshev, A A; Tayursky, V A; Telnov, V I; Tikhonov, Yu A; Todyshev, K Y; Tumaikin, G M; Usov, Yu V; Vorobiov, A I; Yushkov, A N; Zhilich, V N; Zhuravlev, A N
2007-01-01T23:59:59.000Z
The status of the experiment on the precise $\\tau$ lepton mass measurement running at the VEPP-4M collider with the KEDR detector is reported. The mass value is evaluated from the $\\tau^+\\tau^-$ cross section behaviour around the production threshold. The preliminary result based on 6.7 pb$^{-1}$ of data is $m_{\\tau}=1776.80^{+0.25}_{-0.23} \\pm 0.15$ MeV. Using 0.8 pb$^{-1}$ of data collected at the $\\psi'$ peak the preliminary result is also obtained: $\\Gamma_{ee}B_{\\tau\\tau}(\\psi') = 7.2 \\pm 2.1$ eV.
A complete survey of texture zeros in the lepton mass matrices
Patrick Otto Ludl; Walter Grimus
2014-10-16T23:59:59.000Z
We perform a systematic and complete analysis of texture zeros in the lepton mass matrices and identify all viable and maximally restrictive cases of pairs (M_\\ell, M_D) and (M_\\ell, M_L), where M_\\ell, M_D and M_L are the charged-lepton, Dirac neutrino and Majorana neutrino mass matrices, respectively. To this end, we perform a thorough analysis of textures which are equivalent through weak-basis permutations. Furthermore, we introduce numerical measures for the predictivity of textures and apply them to the viable and maximally restrictive texture zero models. It turns out that for Dirac neutrinos these models can at most predict the smallest neutrino mass and the CKM-type phase of the mixing matrix. For Majorana neutrinos most models can, in addition, predict the effective neutrino mass for neutrinoless double beta decay. Apart from one model, which has marginal predictive power with respect to sin^2(theta_23), no other model can predict any of the already measured observables.
Mass and temperature limits for blackbody radiation
Alessandro Pesci
2006-03-24T23:59:59.000Z
A spherically symmetric distribution of classical blackbody radiation is considered, at conditions in which gravitational self-interaction effects become not negligible. Static solutions to Einstein field equations are searched for, for each choice of the assumed central energy density. Spherical cavities at thermodynamic equilibrium, i.e. filled with blackbody radiation, are then studied, in particular for what concerns the relation among the mass M of the ball of radiation contained in them and their temperature at center and at the boundary. For these cavities it is shown, in particular, that: i) there is no absolute limit to M as well to their central and boundary temperatures; ii) when radius R is fixed, however, limits exist both for mass and for boundary energy density rho_B: M temperature) of the ball of radiation.
Neutrino Masses, Lepton Flavor Mixing and Leptogenesis in the Minimal Seesaw Model
Wan-lei Guo; Zhi-zhong Xing; Shun Zhou
2006-12-05T23:59:59.000Z
We present a review of neutrino phenomenology in the minimal seesaw model (MSM), an economical and intriguing extension of the Standard Model with only two heavy right-handed Majorana neutrinos. Given current neutrino oscillation data, the MSM can predict the neutrino mass spectrum and constrain the effective masses of the tritium beta decay and the neutrinoless double-beta decay. We outline five distinct schemes to parameterize the neutrino Yukawa-coupling matrix of the MSM. The lepton flavor mixing and baryogenesis via leptogenesis are investigated in some detail by taking account of possible texture zeros of the Dirac neutrino mass matrix. We derive an upper bound on the CP-violating asymmetry in the decay of the lighter right-handed Majorana neutrino. The effects of the renormalization-group evolution on the neutrino mixing parameters are analyzed, and the correlation between the CP-violating phenomena at low and high energies is highlighted. We show that the observed matter-antimatter asymmetry of the Universe can naturally be interpreted through the resonant leptogenesis mechanism at the TeV scale. The lepton-flavor-violating rare decays, such as $\\mu \\to e + \\gamma$, are also discussed in the supersymmetric extension of the MSM.
Precise measurement of the top-quark mass from lepton+jets events at D0
Abazov, Victor Mukhamedovich [Dubna, JINR; Abbott, Braden Keim [Oklahoma U.; Acharya, Bannanje Sripath [Tata Inst.; Adams, Mark Raymond [Illinois U., Chicago; Adams, Todd [Florida State U.; Alexeev, Guennadi D [Dubna, JINR; Alkhazov, Georgiy D [St. Petersburg, INP; Alton, Andrew K [Michigan U.; Augustana Coll., Sioux Falls; Alverson, George O [Northeastern U.; Alves, Gilvan Augusto [Rio de Janeiro, CBPF; Ancu, Lucian Stefan [Nijmegen U.; Fermilab
2011-08-09T23:59:59.000Z
We report a measurement of the mass of the top quark in lepton+jets final states of pp&3772; ? tt? data corresponding to 2.6 fb^{-1} of integrated luminosity collected at the D0 experiment at the Fermilab Tevatron Collider. Using a matrix element method, we combine an in situ jet energy calibration with the standard jet energy scale derived in studies of ? + jet and dijet events and employ a novel flavor-dependent jet response correction to measure a top-quark mass of m_{t} = 176.01 ą 1.64 GeV. Combining this result with a previous result obtained on an independent data set, we measure a top-quark mass of m_{t} = 174.94 ą 1.49 GeV for a total integrated luminosity of 3.6 fb^{-1}.
Precise measurement of the top-quark mass from lepton+jets events at D0
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Alexeev, Guennadi D; Alkhazov, Georgiy D; Alton, Andrew K; Alverson, George O; Alves, Gilvan Augusto; et al
2011-08-09T23:59:59.000Z
We report a measurement of the mass of the top quark in lepton+jets final states of pp&3772; ? tt? data corresponding to 2.6 fb-1 of integrated luminosity collected at the D0 experiment at the Fermilab Tevatron Collider. Using a matrix element method, we combine an in situ jet energy calibration with the standard jet energy scale derived in studies of ? + jet and dijet events and employ a novel flavor-dependent jet response correction to measure a top-quark mass of mt = 176.01 ą 1.64 GeV. Combining this result with a previous result obtained on an independent data set, wemore ťmeasure a top-quark mass of mt = 174.94 ą 1.49 GeV for a total integrated luminosity of 3.6 fb-1.Ť less
Precise measurement of the top-quark mass from lepton+jets events at D0
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Abazov, Victor Mukhamedovich [Dubna, JINR; Abbott, Braden Keim [Oklahoma U.; Acharya, Bannanje Sripath [Tata Inst.; Adams, Mark Raymond [Illinois U., Chicago; Adams, Todd [Florida State U.; Alexeev, Guennadi D [Dubna, JINR; Alkhazov, Georgiy D [St. Petersburg, INP; Alton, Andrew K [Michigan U.; Augustana Coll., Sioux Falls; Alverson, George O [Northeastern U.; Alves, Gilvan Augusto [Rio de Janeiro, CBPF; Ancu, Lucian Stefan [Nijmegen U.; Fermilab
2011-08-09T23:59:59.000Z
We report a measurement of the mass of the top quark in lepton+jets final states of pp&3772; ? tt? data corresponding to 2.6 fb-1 of integrated luminosity collected at the D0 experiment at the Fermilab Tevatron Collider. Using a matrix element method, we combine an in situ jet energy calibration with the standard jet energy scale derived in studies of ? + jet and dijet events and employ a novel flavor-dependent jet response correction to measure a top-quark mass of mt = 176.01 ą 1.64 GeV. Combining this result with a previous result obtained on an independent data set, we measure a top-quark mass of mt = 174.94 ą 1.49 GeV for a total integrated luminosity of 3.6 fb-1.
Finding the Lower Stellar Mass Limit Observationally Justin Cantrell
Wiita, Paul J.
saying: "1. Objects with true masses below the limiting mass for thermonuclear fusion of deuterium masses above the limiting mass for thermonuclear fusion of deuterium are "brown dwarfs", no matter how below the limiting mass for thermonuclear fusion of deuterium are not "planets", but are "sub
Neutrino Mass, Sneutrino Dark Matter and Signals of Lepton Flavor Violation in the MRSSM
Kumar, Abhishek; Weiner, Neal
2009-01-01T23:59:59.000Z
We study the phenomenology of mixed-sneutrino dark matter in the Minimal R-Symmetric Supersymmetric Standard Model (MRSSM). Mixed sneutrinos fit naturally within the MRSSM, as the smallness (or absence) of neutrino Yukawa couplings singles out sneutrino A-terms as the only ones not automatically forbidden by R-symmetry. We perform a study of randomly generated sneutrino mass matrices and find that (i) the measured value of $\\Omega_{DM}$ is well within the range of typical values obtained for the relic abundance of the lightest sneutrino, (ii) with small lepton-number-violating mass terms $m_{nn}^{2} {\\tilde n} {\\tilde n}$ for the right-handed sneutrinos, random matrices satisfying the $\\Omega_{DM}$ constraint have a decent probability of satisfying direct detection constraints, and much of the remaining parameter space will be probed by upcoming experiments, (iii) the $m_{nn}^{2} {\\tilde n} {\\tilde n}$ terms radiatively generate appropriately small Majorana neutrino masses, with neutrino oscillation data favo...
CDF/PHYS/TOP/PUBLIC/7245 Top Quark Mass Measurement in Non-tagged Lepton+Jets Events at CDF
Quigg, Chris
CDF/PHYS/TOP/PUBLIC/7245 Top Quark Mass Measurement in Non-tagged Lepton+Jets Events at CDF The CDF of the top quark mass in non-tagged sample of lep- ton+4 jet events from p#22;p collisions at p s=1.96 Te as a superposition of top and W+jet events. The signal-constrained #12;t imposing a signal of 15.5#6;3.2 events
Neutrino mass limit from tritium beta decay
E. W. Otten; C. Weinheimer
2009-09-11T23:59:59.000Z
The paper reviews recent experiments on tritium beta spectroscopy searching for the absolute value of the electron neutrino mass $m(\
Search for Lepton-Flavor and Lepton-Number Violation in the Decay tau to lhh'
Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Tisserand, V.; Zghiche, A.; /Annecy, LAPP; Grauges, E.; /Barcelona, IFAE; Palano, A.; Pappagallo, M.; Pompili, A.; /Bari U. /INFN, Bari; Chen, J.C.; Qi, N.D.; Rong, G.; Wang, P.; Zhu, Y.S.; /Beijing, Inst. High Energy Phys.; Eigen, G.; Ofte, I.; Stugu, B. /Bergen U. /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /Bristol U. /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San
2005-06-29T23:59:59.000Z
A search for lepton-flavor and lepton-number violation in the decay of the tau lepton into one charged lepton and two charged hadrons is performed using 221.4 fb{sup -1} of data collected at an e{sup +}e{sup -} center-of-mass energy of 10.58 GeV with the BABAR detector at the PEP-II storage ring. In all 14 decay modes considered, the observed data are compatible with background expectations, and upper limits are set in the range {Beta}({tau} {yields} {ell}hh') < (0.7-4.8) x 10{sup -7} at 90% confidence level.
Precise Nucleosynthesis Limits on Neutrino Masses
Kimmo Kainulainen
1996-08-02T23:59:59.000Z
A computation of nucleosynthesis bounds on the masses of long-lived Dirac and Majorana neutrinos is reviewed. In particular an explicit treatment of the ``differential heating'' of the $\
Measurement of the Top Quark Mass at CDF Using the Template Method in the Lepton + Jets Channel
Adelman, Jahred A.; /Chicago U.
2008-05-01T23:59:59.000Z
A measurement of the top quark mass in p{bar p} collisions at {radical}s = 1.96 TeV is presented. The analysis uses a template method, in which the overconstrained kinematics of the Lepton+Jets channel of the t{bar t} system are used to measure a single quantity, the reconstructed top quark mass, that is strongly correlated with the true top quark mass. in addition, the dijet mass of the hadronically decaying W boson is used to constrain in situ the uncertain jet energy scale in the CDF detector. Two-dimensional probability density functions are derived using a kernel density estimate-based machinery. Using 1.9 fb{sup -1} of data, the top quark mass is measured to be 171.8{sub -1.9}{sup +1.9}(stat.) {+-} 1.0(syst.)GeV/c{sup 2}.
A. E. Blinov; A. S. Rudenko
2009-03-23T23:59:59.000Z
The total cross-sections measured at LEP for e+e- annihilation into tau+tau-, c\\bar{c} and b\\bar{b} at 2E ~ 200 GeV are used to derive the upper limits 3*10^{-17}, 5*10^{-17}, 2*10^{-17} e*cm for the electric dipole moments and 4*10^{-17}, 7*10^{-17}, 2.5*10^{-17} e*cm for the weak dipole moments of the tau-lepton, c-, and b-quarks, respectively. Some of the existing limits on these moments are improved and for the b-quark the improvement is rather significant.
Aspects of Neutrino Masses and Lepton-Number Violation in the light of the Super-Kamiokande data
Smaragda Lola
1999-03-01T23:59:59.000Z
We discuss aspects of neutrino masses and lepton-number violation, in the light of the observations of Super-Kamiokande. As a first step, we use the data from various experiments, in order to obtain a phenomenological understanding of neutrino mass textures. We then investigate how the required patterns of neutrino masses and mixings are related to the flavour structure of the underlying theory. In supersymmetric extensions of the Standard Model, renormalisation group effects can have important implications: for small tanb, bottom-tau unification indicates the presence of significant muon-tau flavour mixing. The evolution of the neutrino mixing may be described by simple semi-analytic expressions, which confirm that, for large tanb, very small mixing at the GUT scale may be amplified to maximal mixing at low energies, and vice versa. Passing to specific models, we first discuss the predictions for neutrino masses in different GUT models (including superstring-embedded solutions). Imposing the requirement for successful leptogenesis may give additional constraints on the generic structure of the neutrino mass textures. Finally, we discuss direct ways to look for lepton-number violation in ultra-high energy neutrino interactions.
Constraints on the relic neutrino abundance and implications for cosmological neutrino mass limits
Bell, Nicole F.; /Fermilab
2004-01-01T23:59:59.000Z
The authors examine a mechanism which can lead to flavor transformation of neutrino-antineutrino asymmetries in the early universe, a process which is unavoidable when the neutrino mixing angles are large. This sets the best limit on the lepton number of the universe, and hence on the relic neutrino abundance. They also consider the consequences for the relic neutrino abundance if extra neutrino interactions are allowed, e.g., the coupling of the neutrinos to a light (compared to m{sub {nu}}) boson. For a wide range of couplings not excluded by other considerations, the relic neutrinos would annihilate to bosons at late times, and thus make a negligible contribution to the matter density today. This mechanism evades the neutrino mass limits arising from large scale structure.
Quigg, Chris
/CDF/PHYS/TOP/PUBLIC/7781 First Measurement of the Top Quark Mass in the Lepton+Jets channel using a novel method to measure the top quark mass using the transverse decay length of b-hadrons from top a competitive measurement of the top quark mass by itself, since the decay length technique is uncorrelated
Dalchenko, Mykhailo; Charlot, Claude
This thesis document reports measurements of the mass and width of the new boson re- cently discovered at the Large Hadron Collider (LHC), candidating to be the Standard Model Higgs boson. The analysis uses proton-proton collision data recorded by the Compact Muon Solenoid (CMS) detector at the LHC, corresponding to integrated luminosities of $5.1~fb^{?1}$ at $7~$TeV center of mass energy and $19.7~fb^{?1}$ at $8~$TeV center of mass energy. Set of events selecting Higgs boson via the $H\\to ZZ$ decay channel, where both $Z$ bosons decay to electron or muon lepton pairs, is used for the Higgs boson properties measurements. A precise measurement of its mass has been performed and gives $125.6\\pm0.4\\mbox{(stat)}\\pm0.2\\mbox{(syst)}~$GeV. Constraints on the Higgs boson width were established using its off-shell production and decay to a pair of $Z$ bosons, where one $Z$ boson decays to an electron or muon pair, and the other to an electron, muon, or neutrino pair. The obtained result is an upper limit on the Hi...
Quigg, Chris
/CDF/PHYS/TOP/PUBLIC/8133 Measurement of the Top Quark Mass in the Lepton+Jets channel using present an updated measurement of the top quark mass using the transverse decay length of b- hadrons from top decays. This technique relies solely on tracking and thus avoids the jet energy scale uncertainty
Mondragon, A.; Mondragon, M.; Peinado, E. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apdo. Postal 20-364, 01000 Mexico D.F. (Mexico)
2007-10-01T23:59:59.000Z
The mass matrices of the charged leptons and neutrinos, previously derived in a minimal S{sub 3}-invariant extension of the standard model, were reparametrized in terms of their eigenvalues. We obtained explicit, analytical expressions for all entries in the neutrino mixing matrix, V{sub PMNS}, the neutrino mixing angles, and the Majorana phases as functions of the masses of charged leptons and neutrinos in excellent agreement with the latest experimental values. The resulting V{sub PMNS} matrix is very close to the tribimaximal form of the neutrino mixing matrix. We also derived explicit, analytical expressions for the matrices of the Yukawa couplings and computed the branching ratios of some selected flavor-changing neutral current processes as functions of the masses of the charged leptons and the neutral Higgs bosons. We find that the S{sub 3}xZ{sub 2} flavor symmetry and the strong mass hierarchy of the charged leptons strongly suppress the FCNC processes in the leptonic sector well below the present experimental upper bounds by many orders of magnitude.
Matsuda, Koichi; Nishiura, Hiroyuki [Center for High Energy Physics, Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Faculty of Information Science and Technology, Osaka Institute of Technology, Hirakata, Osaka 573-0196 (Japan)
2006-08-01T23:59:59.000Z
We reconsider a universal mass matrix model which has a seesaw-invariant structure with four-zero texture common to all quarks and leptons. The Cabibbo-Kobayashi-Maskawa (CKM) quark and Maki-Nakagawa-Sakata (MNS) lepton mixing matrices of the model are analyzed analytically. We show that the model can be consistent with all the experimental data of neutrino oscillation and quark mixings by tuning free parameters of the model. It is also shown that the model predicts a relatively large value for the (1, 3) element of the MNS lepton mixing matrix (U{sub MNS}){sub 13}{sup 2}{approx_equal}(0.041-9.6)x10{sup -2}. Using the seesaw mechanism, we also discuss the conditions for the components of the Dirac and the right-handed Majorana neutrino mass matrices which lead to the neutrino mass matrix consistent with the experimental data.
Leptonic decay constants fK, fD and fDs with Nf = 2+1+1 twisted-mass lattice QCD
N. Carrasco; P. Dimopoulos; R. Frezzotti; P. Lami; V. Lubicz; F. Nazzaro; E. Picca; L. Riggio; G. C. Rossi; F. Sanfilippo; S. Simula; C. Tarantino
2015-02-25T23:59:59.000Z
We present a lattice QCD calculation of the pseudoscalar decay constants fK, fD and fDs performed using the gauge configurations produced by the European Twisted Mass Collaboration with Nf = 2 + 1 + 1 dynamical quarks, which include in the sea, besides two light mass degenerate quarks, also the strange and charm quarks with masses close to their values in the real world. The simulations are based on a unitary setup for the two light mass-degenerate quarks and on a mixed action approach for the strange and charm quarks. We use data simulated at three different values of the lattice spacing in the range 0.06 - 0.09 fm and at pion masses in the range 210 - 450 MeV. Our main results are: fK+ / fpi+ = 1.184 (16), fK+ = 154.4 (2.0) MeV, which incorporate the leading strong isospin breaking correction due to the up- and down-quark mass difference, and fK = 155.0 (1.9) MeV, fD = 207.4 (3.8) MeV, fDs = 247.2 (4.1) MeV, fDs / fD = 1.192 (22) and (fDs / fD) / (fK / fpi) = 1.003 (14) obtained in the isospin symmetric limit of QCD. Combined with the experimental measurements of the leptonic decay rates of kaon, pion, D- and Ds-mesons our results lead to the following determination of the CKM matrix elements: |Vus| = 0.2269 (29), |Vcd| = 0.2221 (67) and |Vcs| = 1.014 (24). Using the latest value of |Vud| from superallowed nuclear beta decays the unitarity of the first row of the CKM matrix is fulfilled at the permille level.
Measurement of the Top Quark Mass in the Di-lepton Channel using the Dalitz-Goldstein Method
Hare, Matthew Frederick; /Tufts U.
2010-10-01T23:59:59.000Z
This dissertation describes a measurement of the mass of the top quark using a method developed by G. Goldstein and R.H. Dalitz. It is based on 2.0 fb{sup -1} of data collected by the Collider Detector Facility at Fermi National Accelerator Laboratories. Di-lepton events were observed from colliding protons with anti-protons with {radical}s = 1.96 TeV in the Tevatron Collider. A total of 145 candidate events were observed with 49 expected to be from background. These events include two neutrinos which elude detection. The method begins by assuming an initial top quark mass and solves for the neutrino momenta using a geometrical construction. The method samples over a range of likely top quark masses choosing the most consistent mass via a likelihood function. An important distinguishing feature of this method from others is its lack of dependence on the missing transverse energy, a quantity that is poorly measured by the experiment. This analysis determines the top quark mass to be M{sub top} = 172.3 {+-} 3.4(stat.) {+-} 2.0(syst.) GeV/c{sup 2} (M{sub top} = 170.5 {+-} 3.7(stat.) {+-} 1.8(syst.) GeV/c{sup 2} with b-tagging).
Intra-Aggregate Mass Transport-Limited Bioavailability of
Rockne, Karl J.
and high octanol-water partition coef- ficients (1). In aquatic environments PAHs tend to partition Brunswick, New Jersey 08901 Biodegradation kinetics for three- and four-ring PAHs by Mycobacterium sp-aggregate mass transport limitations were compared with abiotic PAH desorption kinetics. The results indicate
Measurement of the top quark mass in $p \\bar{p}$ collisions using events with two leptons
Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; /Oklahoma U.; Acharya, Bannanje Sripath; /Tata Inst.; Adams, Mark Raymond; /Illinois U., Chicago; Adams, Todd; /Florida State U.; Alexeev, Guennadi D.; /Dubna, JINR; Alkhazov, Georgiy D.; /St. Petersburg, INP; Alton, Andrew K.; /Michigan U. /Augustana Coll., Sioux Falls; Alverson, George O.; /Northeastern U.; Aoki, Masato; /Fermilab; Askew, Andrew Warren; /Florida State U. /Stockholm U.
2012-01-01T23:59:59.000Z
We present a measurement of the top quark mass (m{sub t}) in p{bar p} collisions at {radical}s = 1.96 TeV using t{bar t} events with two leptons (ee, e{mu} or {mu}{mu}) in the final state in 4.3 fb{sup -1} of data collected with the D0 detector at the Fermilab Tevatron collider. We analyze the kinematically underconstrained dilepton events by integrating over the neutrino rapidity distributions. We reduce the dominant systematic uncertainties from jet energy calibration using a correction obtained from t{bar t} {yields} {ell} + jets events. We also correct jets in simulated events to replicate the quark flavor dependence of the jet response in data. In combination with our previous analysis, we measure m{sub t} = 174.0 {+-} 2.4(stat) {+-} 1.4(syst) GeV.
Tu, Yanjun; /Pennsylvania U.
2008-10-01T23:59:59.000Z
We present a search for high-mass resonances decaying into two leptons of different flavor: e{mu}, e{tau}, and {mu}{tau}. These resonances are predicted by several models beyond the standard model, such as the R-parity-violating MSSM. The search is based on 1 fb{sup -1} of data collected at the Collider Detector at Fermilab (CDF II) in proton anti-proton collisions. Our observations are consistent with the standard model expectations. The results are interpreted to set 95% C.L. upper limits on {sigma} x BR of {tilde {nu}}{sub {tau}} {yields} e{mu}, e{tau}, {mu}{tau}.
CMS Collaboration
2015-01-01T23:59:59.000Z
A search for heavy states decaying into the e$\\mu$ final state has been performed using an integrated luminosity of $19.7~\\text{fb}^{-1}$ of $8\\,\\text{TeV}$ proton-proton collision data recorded with the CMS detector at the LHC. No evidence for physics beyond the Standard Model is observed in the invariant mass spectrum of selected e$\\mu$ pairs. 95$\\%$ CL upper limits are set on the cross section times branching ratio of different signals arising in theories of new physics with lepton flavour violation in interactions involving charged leptons. In the framework of TeV-scale quantum gravity from a renormalization of Newton's constant, exclusion limits are set on the production threshold of quantum black holes for threshold masses below $1.99\\,\\text{TeV}$, and in extra-dimensional models the bounds range from $2.36\\,\\text{TeV}$ for one extra dimension to $3.63\\,\\text{TeV}$ for six extra dimensions. Scenarios of resonant tau sneutrino LSP production in R-parity violating supersymmetry are excluded for LSP masses...
Lepton textures and neutrino oscillations
Verma, Rohit
2014-01-01T23:59:59.000Z
Systematic analyses of the textures arising in lepton mass matrices have been carried out using unitary transformations and condition of naturalness for the Dirac and Majorana neutrino possibilities. It is observed that the recent three neutrino oscillation data together with the effective mass in neutrinoless double beta decay provide vital clues in predicting the general structures of these lepton mass matrices.
Lepton textures and neutrino oscillations
Rohit Verma
2014-06-03T23:59:59.000Z
Systematic analyses of the textures arising in lepton mass matrices have been carried out using unitary transformations and condition of naturalness for the Dirac and Majorana neutrino possibilities. It is observed that the recent three neutrino oscillation data together with the effective mass in neutrinoless double beta decay provide vital clues in predicting the general structures of these lepton mass matrices.
Aad, Georges; Abbott, Brad; Abdallah, Jalal; Abdelalim, Ahmed Ali; Abdesselam, Abdelouahab; Abdinov, Ovsat; Abi, Babak; Abolins, Maris; Abramowicz, Halina; Abreu, Henso; Acerbi, Emilio; Acharya, Bobby Samir; Adams, David; Addy, Tetteh; Adelman, Jahred; Aderholz, Michael; Adomeit, Stefanie; Adragna, Paolo; Adye, Tim; Aefsky, Scott; Aguilar-Saavedra, Juan Antonio; /Freiburg U. /Oklahoma U. /Barcelona, IFAE /Geneva U. /Oxford U. /Baku, Inst. Phys. /Oklahoma State U. /Michigan State U. /Tel Aviv U. /Orsay, LAL /INFN, Milan /Milan U. /INFN, Udine /ICTP, Trieste /Brookhaven /Hampton U. /Yale U. /Heidelberg, Max Planck Inst. /Munich U. /Queen Mary, U. of London /Rutherford
2012-06-20T23:59:59.000Z
The ATLAS detector is used to search for high-mass states, such as heavy charged gauge bosons (W{prime},W*), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of ppcollisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 36 pb{sup -1}. No excess beyond standard model expectations is observed. A W{prime} with sequential standard model couplings is excluded at 95% confidence level for masses below 1.49 TeV, and a W* (charged chiral boson) for masses below 1.35 TeV.
Measurement of the Higgs Boson Mass in Decays into Four Leptons with the ATLAS Detector
Röhrig, Rainer
This master thesis presents a measurement of the mass of the observed Higgs boson candidate in the decay channel $H \\rightarrow ZZ^* \\rightarrow \\ell^+\\ell^-\\ell^{'+}\\ell^{'-}$, with $\\ell,\\ell' = e$ or $\\mu$. The result is based on the full 2011 and 2012 proton-proton collision dataset recorded with the ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosity of $4.5~\\mathrm{fb}^{-1}$ and $20.3~\\mathrm{fb}^{-1}$ at a center-of-mass energy of $\\sqrt{s} = 7~\\mathrm{TeV}$ and $8~\\mathrm{TeV}$, respectively. The mass is measured to be $m_H = 124.58 ^{+0.53}_{-0.47}{\\rm{~(stat)~}}\\pm0.06{\\rm{~(syst)~}} ~\\mathrm{GeV}$ using an analytical parametrization of the expected mass distribution on an event-by-event basis.
Bauer, Gerry P.
We present the first measurement of the mass of the top quark in a sample of tt? ???? bb? qq? events (where ?=e,?) selected by identifying jets containing a muon candidate from the semileptonic decay of heavy-flavor hadrons ...
Yue-Liang Wu
2012-07-12T23:59:59.000Z
A model for the lepton-flavor mixing and CP violation is proposed based on the SU$_F$(3) gauge family symmetry and the Majorana feature of neutrinos. A consistent prediction for the lepton-flavor mixing and masses is shown to be resulted from the appropriate vacuum structure of SU$_F$(3) gauge symmetry breaking. By choosing the SU$_F$(3) gauge fixing condition to possess a residual $Z_2$ symmetry and requiring the vacuum structure of spontaneous symmetry breaking to have approximate global U(1) family symmetries, we obtain naturally the tri-bimaximal mixing matrix and largely degenerate neutrino masses in the neutrino sector and the small mixing matrix in the charged-lepton sector. With a simple ansatz that all the smallness due to the approximate global U(1) family symmetries is characterized by a single Wolfenstein parameter $\\lambda \\simeq 0.22$, and the charged-lepton mixing matrix has a similar hierarchy structure as the CKM quark mixing matrix, we arrive at a consistent prediction for the MNSP lepton-flavor mixing with a maximal spontaneous CP violation: $\\delta =\\pi/2$, $\\sin^2\\theta_{13} \\simeq 1/2\\lambda^2 \\simeq 0.024$ ($\\sin^22\\theta_{13} \\simeq 0.094$), $\\sin^2\\theta_{12} \\simeq 1/3{3}(1 - 2\\lambda^3) \\simeq 0.326$ and $\\sin^2\\theta_{23} \\simeq 1/2(1 - \\lambda^2) \\simeq 0.48$, which agree well with the current experimental data. The CP-violating Jarlskog-invariant is obtained to be $J_{CP} \\simeq 1/6\\lambda(1-\\lambda^2/2-\\lambda^3)\\sin\\delta \\simeq 0.035$, which is detectable in next generation neutrino experiment. The largely degenerate neutrino masses with the normal hierarchy and inverse hierarchy are discussed and found be at the order $m_{\
Top quark mass measurement in the lepton plus jets channel using a modified matrix element method
Xie, Si
We report a measurement of the top quark mass, m_t, obtained from pp? collisions at ?s=1.96??TeV at the Fermilab Tevatron using the CDF II detector. We analyze a sample corresponding to an integrated luminosity of ...
The Mass-Function of Low Mass Halo Stars: Limits on Baryonic Halo Dark Matter
David S. Graff; Katherine Freese
1996-06-18T23:59:59.000Z
We derive mass functions (MF) for halo red dwarfs (the faintest hydrogen burning stars) and then extrapolate to place limits on the total mass of halo brown dwarfs (stars not quite massive enough to burn hydrogen). The mass functions are obtained from the luminosity function of a sample of 114 local halo stars in the USNO parallax survey (Dahn \\etal 1995). We use stellar models of Alexander \\etal (1996) and make varying assumptions about metallicity and about possible unresolved binaries in the sample. We find that the MF for halo red dwarfs cannot rise more quickly than $1/m^2$ as one approaches the hydrogen burning limit. Using recent results from star formation theory, we extrapolate the MF into the brown-dwarf regime. We see that likely extrapolations imply that the total mass of brown dwarfs in the halo is less than $\\sim 3\\%$ of the local mass density of the halo ($\\sim 0.3\\%$ for the more realistic models we consider). Our limits apply to brown dwarfs in the halo that come from the same stellar population as the red dwarfs.
Top Quark Mass Measurement in the Lepton plus Jets Channel Using a Modified Matrix Element Method
Aaltonen, T.; /Helsinki Inst. of Phys.; Adelman, J.; /Chicago U., EFI; Akimoto, T.; /Tsukuba U.; Alvarez Gonzalez, B.; /CSIC, Catalunya; Amerio, S.; /INFN, Padua; Amidei, D.; /Michigan U.; Anastassov, A.; /Northwestern U.; Annovi, A.; /Frascati; Antos, J.; /Comenius U.; Apollinari, G.; /Fermilab; Apresyan, A.; /Purdue U. /Waseda U.
2008-12-01T23:59:59.000Z
The authors report a measurement of the top quark mass, m{sub t}, obtained from p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron using the CDF II detector. They analyze a sample corresponding to an integrated luminosity of 1.9 rfb{sup -1}. They select events with an electron or muon, large missing transverse energy, and exactly four high-energy jets in the central region of the detector, at least one of which is tagged as coming from a b quark. They calculate a signal likelihood using a matrix element integration method, where the matrix element is modified by using effective propagators to take into account assumptions on event kinematics. The event likelihood is a function of m{sub t} and a parameter JES that determines in situ the calibration of the jet energies. They use a neural network discriminant to distinguish signal from background events. They also apply a cut on the peak value of each event likelihood curve to reduce the contribution of background and badly reconstructed events. Using the 318 events that pass all selection criteria, they find m{sub t} = 172.7 {+-} 1.8 (stat. + JES) {+-} 1.2(syst.) GeV/c{sup 2}.
Search for quark-lepton compositeness using the Drell-Yan process at D-Zero
NONE
1998-09-01T23:59:59.000Z
We present preliminary results on the search for quark-lepton compositeness using the Drell-Yan process in p{anti p} collisions at {radical}s = 1.8 TeV. If quarks and leptons were composite with common substructure, the dielectron mass spectrum would show an excess in the high mass region relative to the Standard model. We observe no such excess. We set a 95% confidence level lower limit on the compositness scale using a contact interaction model.
Aaltonen, T [Helsinki Inst. of Phys.; Alvarez Gonzalez, B [Oviedo U., Cantabria Inst. of Phys.; Amerio, S [INFN, Padua; Amidei, D [Michigan U.; Anastassov, A [Northwestern U.; Annovi, A [Frascati
2011-10-14T23:59:59.000Z
A measurement of the top-quark mass is presented using Tevatron data from proton-antiproton collisions at center-of-mass energy ?s = 1.96 TeV collected with the CDF II detector. Events are selected from a sample of candidates for production of tt? pairs that decay into the lepton+jets channel. The top-quark mass is measured with an unbinned maximum likelihood method where the event probability density functions are calculated using signal and background matrix elements, as well as a set of parameterized jet-to-parton transfer functions. The likelihood function is maximized with respect to the top-quark mass, the signal fraction in the sample, and a correction to the jet energy scale (JES) calibration of the calorimeter jets. The simultaneous measurement of the JES correction ({Delta}{sub JES}) amounts to an additional in situ jet energy calibration based on the known mass of the hadronically decaying W boson. Using the data sample of 578 lepton+jets candidate events, corresponding to 3.2 fb^{-1} of integrated luminosity, the top-quark mass is measured to be m_{t} = 172.4ą 1.4 (stat + ?_{JES}) ą 1.3 (syst) GeV/c^{2}.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aaltonen, T; Alvarez Gonzalez, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A
2011-10-14T23:59:59.000Z
A measurement of the top-quark mass is presented using Tevatron data from proton-antiproton collisions at center-of-mass energy ?s = 1.96 TeV collected with the CDF II detector. Events are selected from a sample of candidates for production of tt? pairs that decay into the lepton+jets channel. The top-quark mass is measured with an unbinned maximum likelihood method where the event probability density functions are calculated using signal and background matrix elements, as well as a set of parameterized jet-to-parton transfer functions. The likelihood function is maximized with respect to the top-quark mass, the signal fraction in the sample, and amore ťcorrection to the jet energy scale (JES) calibration of the calorimeter jets. The simultaneous measurement of the JES correction ({Delta}{sub JES}) amounts to an additional in situ jet energy calibration based on the known mass of the hadronically decaying W boson. Using the data sample of 578 lepton+jets candidate events, corresponding to 3.2 fb-1 of integrated luminosity, the top-quark mass is measured to be mt = 172.4ą 1.4 (stat + ?JES) ą 1.3 (syst) GeV/c2.Ť less
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aaltonen, T [Helsinki Inst. of Phys.; Alvarez Gonzalez, B [Oviedo U., Cantabria Inst. of Phys.; Amerio, S [INFN, Padua; Amidei, D [Michigan U.; Anastassov, A [Northwestern U.; Annovi, A [Frascati
2011-10-14T23:59:59.000Z
A measurement of the top-quark mass is presented using Tevatron data from proton-antiproton collisions at center-of-mass energy ?s = 1.96 TeV collected with the CDF II detector. Events are selected from a sample of candidates for production of tt? pairs that decay into the lepton+jets channel. The top-quark mass is measured with an unbinned maximum likelihood method where the event probability density functions are calculated using signal and background matrix elements, as well as a set of parameterized jet-to-parton transfer functions. The likelihood function is maximized with respect to the top-quark mass, the signal fraction in the sample, and a correction to the jet energy scale (JES) calibration of the calorimeter jets. The simultaneous measurement of the JES correction ({Delta}{sub JES}) amounts to an additional in situ jet energy calibration based on the known mass of the hadronically decaying W boson. Using the data sample of 578 lepton+jets candidate events, corresponding to 3.2 fb-1 of integrated luminosity, the top-quark mass is measured to be mt = 172.4ą 1.4 (stat + ?JES) ą 1.3 (syst) GeV/c2.
On quark-lepton complementarity
F. Gonzalez-Canales; A. Mondragon
2006-06-16T23:59:59.000Z
Recent measurements of the neutrino solar mixing angle and the Cabibbo angle satisfy the empirical relation theta_{sol} + theta_{C} ~ 45^{o}. This relation suggests the existence of a correlation between the mixing matrices of leptons and quarks, the so called quark-lepton complementarity. Here, we examine the possibility that this correlation originates in the strong hierarchy in the mass spectra of quarks and charged leptons, and the seesaw mechanism that gives mass to the Majorana neutrinos. In a unified treatment of quarks and leptons in which the mass matrices of all fermions have a similar Fritzsch texture, we calculate the mixing matrices V_{CKM} and U_{MNSP} as functions of quark and lepton masses and only two free parameters, in very good agreement with the latest experimental values on masses and mixings. Three essential ingredients to explain the quark-lepton complementarity relation are identified: the strong hierarchy in the mass spectra of quarks and charged leptons, the normal seesaw mechanism and the assumption of maximal CP violation in the lepton sector.
On quark-lepton complementarity
Gonzalez Canales, F.; Mondragon, A. [Instituto de Fisica, UNAM, 04510, Mexico D.F. (Mexico)
2006-09-25T23:59:59.000Z
Recent measurements of the neutrino solar mixing angle and the Cabibbo angle satisfy the empirical relation {theta}{sub sol} + {theta}{sub C} {approx_equal} ({pi}/4). This relation suggests the existence of a correlation between the mixing matrices of leptons and quarks, the so called quark-lepton complementarity. Here, we examine the possibility that this correlation originates in the strong hierarchy in the mass spectra of quarks and charged leptons, and the seesaw mechanism that gives mass to the Majorana neutrinos. In a unified treatment of quarks and leptons in which the mass matrices of all fermions have a similar Fritzsch texture, we calculate the mixing matrices VCKM and UMNSP as functions of quark and lepton masses and only two free parameters, in very good agreement with the latest experimental values on masses and mixings. Three essential ingredients to explain the quark-lepton complementarity relation are identified: the strong hierarchy in the mass spectra of quarks and charged leptons, the normal seesaw mechanism and the assumption of maximal CP violation in the lepton sector.
A. Hernandez-Galeana; N. S. Mankoc Borstnik
2011-12-19T23:59:59.000Z
The {\\it theory unifying spin and charges and predicting families}, proposed by N.S.M.B., predicts at the low energy regime two (in the mixing matrix elements decoupled) groups of four families. There are two kinds of contributions to mass matrices in this theory. One kind distinguishes on the tree level only among the members of one family, that is among the $u$-quark, $d$-quark, neutrino and electron, the left and right handed, while the other kind distinguishes only among the families. Mass matrices for $d$-quarks and electrons are on the tree level correspondingly strongly correlated and so are mass matrices for $u$-quarks and neutrinos, up to the term, the Majorana term, which is nonzero only for right handed neutrinos. Beyond the tree level both kinds of contributions start to contribute coherently and it is expected that a detailed study of properties of mass matrices beyond the tree level explains drastic differences in masses and mixing matrices between quarks and leptons. We report in this paper on analysis of one loop corrections to the tree level fermion masses and mixing matrices. Loop diagrams are mediated by the gauge bosons and the two kinds of scalar fields. A detailed numerical analysis of fermion masses and mixing, including neutrinos, within this scenario is in progress and preparation.
Seesaw enhancement of lepton mixing
Smirnov, A.Y. (Institute for Advanced Study, Princeton, New Jersey 08540 (United States) International Centre for Theoretical Physics, 34100 Trieste (Italy) Institute for Nuclear Research, 117312 Moscow (Russian Federation))
1993-10-01T23:59:59.000Z
The seesaw mechanism of neutrino mass generation may enhance lepton mixing up to maximal even if the Dirac mass matrices of leptons have a structure similar to that in the quark sector. Two sets of conditions for such an enhancement are found. The first one includes the seesaw generation of heavy Majorana masses for right-handed neutrinos and a universality of Yukawa couplings which can follow from the unification of neutrinos with new superheavy neutral leptons. The second set is related to the lepton number symmetry of the Yukawa interactions in the Dirac basis of neutrinos. Models which realize these conditions have a strong hierarchy or strong degeneration of Majorana masses of the right-handed neutrinos.
Statistical Confirmation of a Stellar Upper Mass Limit
M. S. Oey; C. J. Clarke
2005-01-07T23:59:59.000Z
We derive the expectation value for the maximum stellar mass (m_max) in an ensemble of N stars, as a function of the IMF upper-mass cutoff (m_up) and N. We statistically demonstrate that the upper IMF of the local massive star census observed thus far in the Milky Way and Magellanic Clouds clearly exhibits a universal upper mass cutoff around 120 - 200 M_sun for a Salpeter IMF, although the result is more ambiguous for a steeper IMF.
On the robustness of cosmological axion mass limits
Di Valentino, Eleonora; Giusarma, Elena; Mena, Olga
2015-01-01T23:59:59.000Z
We present cosmological bounds on the thermal axion mass in an extended cosmological scenario in which the primordial power spectrum of scalar perturbations differs from the usual power-law shape predicted by the simplest inflationary models. The power spectrum is instead modeled by means of a "piecewise cubic Hermite interpolating polynomial" (PCHIP). When using Cosmic Microwave Background measurements combined with other cosmological data sets, the thermal axion mass constraints are degraded only slightly. The addition of the measurements of $\\sigma_8$ and $\\Omega_m$ from the 2013 Planck cluster catalogue on galaxy number counts relaxes the bounds on the thermal axion mass, mildly favouring a $\\sim 1$~eV axion mass, regardless of the model adopted for the primordial power spectrum.
Hernandez-Galeana, A
2011-01-01T23:59:59.000Z
The {\\it theory unifying spin and charges and predicting families}, proposed by N.S.M.B., predicts at the low energy regime two (in the mixing matrix elements decoupled) groups of four families. There are two kinds of contributions to mass matrices in this theory. One kind distinguishes on the tree level only among the members of one family, that is among the $u$-quark, $d$-quark, neutrino and electron, the left and right handed, while the other kind distinguishes only among the families. Mass matrices for $d$-quarks and electrons are on the tree level correspondingly strongly correlated and so are mass matrices for $u$-quarks and neutrinos, up to the term, the Majorana term, which is nonzero only for right handed neutrinos. Beyond the tree level both kinds of contributions start to contribute coherently and it is expected that a detailed study of properties of mass matrices beyond the tree level explains drastic differences in masses and mixing matrices between quarks and leptons. We report in this paper on ...
Kubo, Taichi; /Tsukuba U.
2008-02-01T23:59:59.000Z
We have measured the top quark mass with the dynamical likelihood method. The data corresponding to an integrated luminosity of 1.7fb{sup -1} was collected in proton antiproton collisions at a center of mass energy of 1.96 TeV with the CDF detector at Fermilab Tevatron during the period March 2002-March 2007. We select t{bar t} pair production candidates by requiring one high energy lepton and four jets, in which at least one of jets must be tagged as a b-jet. In order to reconstruct the top quark mass, we use the dynamical likelihood method based on maximum likelihood method where a likelihood is defined as the differential cross section multiplied by the transfer function from observed quantities to parton quantities, as a function of the top quark mass and the jet energy scale(JES). With this method, we measure the top quark mass to be 171.6 {+-} 2.0 (stat.+ JES) {+-} 1.3(syst.) = 171.6 {+-} 2.4 GeV/c{sup 2}.
Gomez-Ceballos, Guillelmo
We present an analysis of top-antitop quark production and decay into a tau lepton, tau neutrino, and bottom quark using data from 9??fb[superscript ?1] of integrated luminosity at the Collider Detector at Fermilab. Dilepton ...
Mass and Weak Field Limit of Boson Stars in Brans Dicke Gravity
A. W. Whinnett
1999-06-14T23:59:59.000Z
We study boson stars in Brans Dicke gravity and use them to illustrate some of the properties of three different mass definitions: the Schwarzschild mass, the Keplerian mass and the Tensor mass. We analyse the weak field limit of the solutions and show that only the Tensor mass leads to a physically reasonable definition of the binding energy. We examine numerically strong field $\\omega=-1$ solutions and show how, in this extreme case, the three mass values and the conserved particle number behave as a function of the central boson field amplitude. The numerical studies imply that for $\\omega=-1$, solutions with extremal Tensor mass also have extremal particle number. This is a property that a physically reasonable definition of the mass of a boson star must have, and we prove analytically that this is true for all values of $\\omega$. The analysis supports the conjecture that the Tensor mass uniquely describes the total energy of an asymptotically flat solution in BD gravity.
Tabares Velasco, P. C.
2011-04-01T23:59:59.000Z
This presentation discusses estimating heat and mass transfer processes in green roof systems: current modeling capabilities and limitations. Green roofs are 'specialized roofing systems that support vegetation growth on rooftops.'
Intramolecular Isotope Effects for the Study of Reactions with MassTransfer Limitations
Wagner, Joshua G.
2010-01-16T23:59:59.000Z
The research presented provides a method to use the comparison of intermolecular isotope effects vs. the intramolecular isotope effects for the study of reactions in which study of the rate limiting step is ambiguous due to interfering mass transfer...
Quasidegeneracy of Majorana Neutrinos and the Origin of Large Leptonic Mixing
G. C. Branco; M. N. Rebelo; J. I. Silva-Marcos; Daniel Wegman
2015-02-20T23:59:59.000Z
We propose that the observed large leptonic mixing may just reflect a quasidegeneracy of three Majorana neutrinos. The limit of exact degeneracy of Majorana neutrinos is not trivial, as leptonic mixing and even CP violation may occur. We conjecture that the smallness of $|U_{13}|$, when compared to the other elements of $U_{PMNS}$, may just reflect the fact that, in the limit of exact mass degeneracy, the leptonic mixing matrix necessarily has a vanishing element. We show that the lifting of the mass degeneracy can lead to the measured value of $|U_{13}|$ while at the same time accommodating the observed solar and atmospheric mixing angles. In the scenario we consider for the breaking of the mass degeneracy there is only one CP violating phase, already present in the limit of exact degeneracy, which upon the lifting of the degeneracy generates both Majorana and Dirac-type CP violation in the leptonic sector. We analyse some of the correlations among physical observables and point out that in most of the cases considered, the implied strength of leptonic Dirac-type CP violation is large enough to be detected in the next round of experiments.
Nuclear structure aspects of neutrinoless {beta}{beta} decay: limits on the electron neutrino mass
Civitarese, O. [Department of Physics. University of La Plata, 1900 La Plata (Argentina); Suhonen, J. [Department of Physics. University of Jyvaeskyla, (Finland)
2007-02-12T23:59:59.000Z
We discuss some features of the nuclear structure elements participant in the calculation of the mass sector of the half-life of the neutrinoless double beta decay, and the consequences upon the adopted limits of the electron-neutrino mass.
Capps, R.H.; Strobel, E.L.
1985-07-01T23:59:59.000Z
It is assumed that the Dirac mass matrix for the neutrinos (..nu../sub e/,..nu../sub ..mu../,..nu../sub tau/) is similar in form to those for the quarks and charged leptons, and that the smallness of the observed ..nu.. masses results from the Gell-Mann--Ramond--Slansky mechanism. It is shown that if certain tentative experimental results concerning the ..nu.. masses and mixing angles are confirmed, significant limitations may be placed on the Majorana mass matrix. The most satisfactory simple assumption concerning the Majorana mass matrix is that it is approximately proportional to the Dirac mass matrix. Some general properties of the Dirac matrices are discussed.
Freeman, John; /Fermilab
2004-12-01T23:59:59.000Z
The authors measure the mass of the top quark using 162 pb{sup -1} of data collected by the CDF experiment at FNAL in Run II. The decay chain t{bar t} {yields} bq{bar q}{bar b}lv is studied using a novel technique called the Multivariate Template Method (MTM). Using this technique they obtain a result of M{sub top} = 179.6{sub -6.3}{sup +6.4} {+-} 6.8 GeV/c{sup 2} for the top quark.
Lepton Number Violation within the Conformal Inverse Seesaw
Humbert, Pascal; Patra, Sudhanwa; Smirnov, Juri
2015-01-01T23:59:59.000Z
We present a novel framework within the conformal inverse seesaw scheme allowing large lepton number violation while the neutrino mass formula is still governed by the low-scale inverse seesaw mechanism. This model includes new contributions to rare low-energy lepton number violating processes like neutrinoless double beta decay. We find that the lifetime for this rare process due to heavy sterile neutrinos can saturate current experimental limits. The characteristic collider signature of the present conformal inverse seesaw scheme includes, same-sign dilepton plus two jets and same-sign dilepton plus four jets. Finally, we comment on the testability of the model at the Large Hadron Collider since there are new scalars, new fermions and an extra neutral gauge boson with masses around few 100 GeV to few TeV.
Strobel, E.L.
1985-01-01T23:59:59.000Z
Given the many conflicting experimental results, examination is made of the neutrino mass matrix in order to determine possible masses and mixings. It is assumed that the Dirac mass matrix for the electron, muon, and tau neutrinos is similar in form to those of the quarks and charged leptons, and that the smallness of the observed neutrino masses results from the Gell-Mann-Ramond-Slansky mechanism. Analysis of masses and mixings for the neutrinos is performed using general structures for the Majorana mass matrix. It is shown that if certain tentative experimental results concerning the neutrino masses and mixing angles are confirmed, significant limitations may be placed on the Majorana mass matrix. The most satisfactory simple assumption concerning the Majorana mass matrix is that it is approximately proportional to the Dirac mass matrix. A very recent experimental neutrino mass result and its implications are discussed. Some general properties of matrices with structure similar to the Dirac mass matrices are discussed.
McGivern, Dustin; /University Coll. London
2005-12-01T23:59:59.000Z
Measurements of the production cross section of W{sup +}W{sup -} pairs in p{bar p} collisions at 1.96 TeV and limits on trilinear gauge boson coupling (TGC) parameters are presented. The data were recorded with the CDF experiment at Tevatron during the 2001 and 2002 data taking periods in which a total integrated luminosity of 184 pb{sup -1} was collected. The data sample was filtered for events with two leptonic w boson decays where the charged leptons can be either electrons or muons. 17 events are observed against an expected background of 5.0{sub -0.8}{sup +2.2} events. The resulting cross-section is found to be {sigma}(p{bar p} {yields} W{sup +}W{sup -}) = 14.5{sub -5.1}{sup +5.8}(stat){sub -3.0}{sup +1.8}(syst) {+-} 0.9(lum) pb and agrees well with the Standard Model expectation. Limits on the TGC parameters {Delta}{kappa} and {lambda} are set under both the equal coupling scheme, that assumes the W boson couples identically to the Z and {gamma}, and the HISZ coupling scheme, that requires the couplings to respect SU(2){sub L} x &(1){sub Y} gauge symmetry. In both cases this is achieved by using a likelihood fit to the lepton-P{sub T} distribution of the 17 candidate events. The resulting limits are found to be: -0.4 < {Delta}{kappa} < +0.6({lambda} = 0); -0.3 < {lambda} < +0.4 ({Delta}{kappa} = 0) for the EQUAL couplings and -0.7 < {Delta}{kappa} < +0.9 ({lambda} = 0); -0.4 < {lambda} < +0.4 ({Delta}{kappa} = 0) for the HISZ couplings.
Continuum limit for three-dimensional mass-spring networks and discrete Korn's inequality.
Berlyand, Leonid
) and the domain sizes (large scale)), which represents local energy in the neighborhood of a point. For periodic a discrete network of a large number of concen- trated masses (particles) connected by elastic springs. We. For generic non-periodic arrays of particles we describe continuum limit in terms of local energy
Photon mass new limits from strong photon-torsion coupling generation of primordial magnetic fields
Garcia de Andrade
2011-12-21T23:59:59.000Z
Recently Adelberger et al [Phys Rev Lett 98: 010402, (2007)] have placed a limit to photon mass by investigating the primordial magnetic fields. Earlier Bertolami et al [Phys Lett \\textbf{B} 455, 96(1999)] showed that massive photons in a spontaneous Lorentz breaking may generate primordial magnetic fields consistent with galactic dynamo seeds. Torsion coupling constant of order $10^{-5}$, much higher than the previously obtained by de Sabbata and Sivaram of $10^{-24}$, leads to strong amplification of magnetic field able to seed galactic dynamo at recombination era contrary to what happens in general relativistic dynamos. This results in $B\\sim{10^{-5}{\\beta}G}$ where ${\\beta}$ is the massive photon-torsion coupling. Thus in order to obtain the observed galaxy field of $B_{G}\\sim{{\\mu}G}$ one should have a coupling $\\beta\\sim{10^{-1}}$, never observed in the universe. Thus we may conclude that the weaker couplings for torsion to e.m fields shall only produce magnetic fields without dynamos starting from extremely strong magnetic seeds. From the strongest photon-torsion considered one obtains the best CMB estimate for torsion generated magnetic fields $\\frac{{\\delta}B}{B}\\le{10^{-4}}$. By making use of the strong photon-torsion limits obtained here, photon mass limit of $m_{\\gamma}\\sim{10^{-24}eV}$, well-within limits found in literature, which allows us to conclude that a stronger massive photon-torsion limit is physically consistent. Actually this last limit is also graviton mass limit. This results differs from Adelberger et al by two orders of magnitude.
Extending the CRESST-II commissioning run limits to lower masses
Andrew Brown; Sam Henry; Hans Kraus; Christopher McCabe
2012-01-23T23:59:59.000Z
Motivated by the recent interest in light WIMPs of mass ~O(10 GeV), an extension of the elastic, spin-independent WIMP-nucleon cross-section limits resulting from the CRESST-II commissioning run (2007) are presented. Previously, these data were used to set cross-section limits from 1000 GeV down to ~17 GeV, using tungsten recoils, in 47.9 kg-days of exposure of calcium tungstate. Here, the overlap of the oxygen and calcium bands with the acceptance region of the commissioning run data set is reconstructed using previously published quenching factors. The resulting elastic WIMP cross section limits, accounting for the additional exposure of oxygen and calcium, are presented down to 5 GeV.
Natural fourth generation of leptons
Oleg Antipin; Matti Heikinheimo; Kimmo Tuominen
2009-09-14T23:59:59.000Z
We consider implications of a fourth generation of leptons, allowing for the most general mass patterns for the fourth generation neutrino. We determine the constraints due to the precision electroweak measurements and outline the signatures to search for at the LHC experiments. As a concrete framework to apply these results we consider the minimal walking technicolor (MWTC) model where the matter content, regarding the electroweak quantum numbers, corresponds to a fourth generation.
Performance of intact and partially degraded concrete barriers in limiting mass transport
Walton, J.C. (EG and G Idaho, Inc., Idaho Falls, ID (United States))
1992-06-01T23:59:59.000Z
Mass transport through concrete barriers and release rate from concrete vaults are quantitatively evaluated. The thorny issue of appropriate diffusion coefficients for use in performance assessment calculations is covered, with no ultimate solution found. Release from monolithic concrete vaults composed of concrete waste forms is estimated with a semi-analytical solution. A parametric study illustrates the importance of different parameters on release. A second situation of importance is the role of a concrete shell or vault placed around typical waste forms in limiting mass transport. In both situations, the primary factor controlling concrete performance is cracks. The implications of leaching behavior on likely groundwater concentrations is examined. Frequently, lower groundwater concentrations can be expected in the absence of engineered covers that reduce infiltration.
Guzowski, Pawel; Evans, Justin; Karagiorgi, Georgia; McCabe, Nathan; Soldner-Rembold, Stefan
2015-01-01T23:59:59.000Z
We present a framework to combine data from the latest neutrinoless double-beta decay experiments for multiple isotopes and derive a limit on the effective neutrino mass using the experimental energy distributions. The combined limits on the effective mass range between 130-310 meV, where the spread is due to different model calculations of nuclear matrix elements (NMEs). The statistical consistency (p values) between this result and the signal observation claimed by the Heidelberg-Moscow experiment is derived. The limits on the effective mass are also evaluated in a (3+1) sterile neutrino model, assuming all neutrinos are Majorana particles.
Search for the Higgs boson in lepton, tau and jets final states
D0 Collaboration
2013-01-28T23:59:59.000Z
We present a search for the standard model Higgs boson in final states with an electron or muon and a hadronically decaying tau lepton in association with two or more jets using 9.7 fb^{-1} of Run II Fermilab Tevatron Collider data collected with the D0 detector. The analysis is sensitive to Higgs boson production via gluon fusion, associated vector boson production, and vector boson fusion, followed by the Higgs boson decay to tau lepton pairs or to W boson pairs. The ratios of 95% C.L. upper limits on the cross section times branching ratio to those predicted by the standard model are obtained for orthogonal subsamples that are enriched in either H -> tau tau decays or H -> WW decays, and for the combination of these subsample limits. The observed and expected limit ratios for the combined subsamples at a Higgs boson mass of 125 GeV are 11.3 and 9.0 respectively.
Search for the Higgs boson in lepton, tau, and jets final states
Abazov, V. M.; et al.
2013-09-01T23:59:59.000Z
We present a search for the standard model Higgs boson in final states with an electron or muon and a hadronically decaying tau lepton in association with two or more jets using 9.7 fb?1 of Run II Fermilab Tevatron Collider data collected with the D0 detector. The analysis is sensitive to Higgs boson production via gluon fusion, associated vector boson production, and vector boson fusion, followed by the Higgs boson decay to tau lepton pairs or to W boson pairs. The ratios of 95% C.L. upper limits on the cross section times branching ratio to those predicted by the standard model are obtained for orthogonal subsamples that are enriched in either H ? ? ? decays or H ? WW decays, and for the combination of these subsample limits. The observed and expected limit ratios for the combined subsamples at a Higgs boson mass of 125 GeV are 11.3 and 9.0 respectively.
A METHODOLOGY FOR DETERMINING THE DOSE RATE FOR BOUNDING MASS LIMITS IN A 9977 PACKAGING
Abramczyk, G.; Bellamy, S.; Nathan, S.; Loftin, B.
2012-05-24T23:59:59.000Z
The Small Gram Quantity (SGQ) concept is based on the understanding that the hazards associated with the shipment of a radioactive material are directly proportional to its mass. This study describes a methodology that estimates the acceptable masses for several neutron and gamma emitting isotopes that can be shipped in a 9977 Package compliant with the Title 10 of the Code of Federal Regulations, Part 71 (10CFR71) external radiation level limits. 10CFR71.33 states that a shipping application identifies the radioactive and fissile materials at their maximum quantity and provides an evaluation demonstrating compliance with the external radiation standards. Since rather small amounts of some isotopes emit sufficiently strong radiation to produce a large external dose rate, quantifying of the dose rate for a proposed content is a challenging issue for the SGQ approach. It is essential to quantify external radiation levels from several common gamma and neutron sources that can be safely placed in a specific packaging, to ensure compliance with federal regulations. A methodology was established for determining the dose rate for bounding mass limits for a set of isotopes in the Model 9977 Shipping Package. Calculations were performed to estimate external radiation levels using the MCNP radiation transport code to develop a set of response multipliers (Green's functions) for 'dose per source particle' for each neutron and photon spectral group. The source spectrum from one gram of each isotope was folded with the response multipliers to generate the dose rate per gram of each isotope in the 9977 shipping package and its associated shielded containers. The maximum amount of a single isotope that could be shipped within the regulatory limits for dose rate at the surface was determined. For a package containing a mixture of isotopes, the acceptability for shipment can be determined by a sum of fractions approach. Furthermore, the results of this analysis can be easily extended to additional radioisotopes by simply evaluating the neutron and/or photon spectra of those isotopes and folding the spectral data with the Green's functions provided.
Michele Redi
2014-07-21T23:59:59.000Z
We study the lepton sector of composite Higgs models with partial compositeness. The standard anarchic scenario is in conflict with the absence of observable charged lepton flavor violation. This tension can be completely solved in MFV scenarios that require either left-handed or right-handed SM leptons to be equally composite. Constraints on this scenario are weak and the composite lepton partners could be as light as few hundreds GeVs with interesting LHC signatures. The contribution to the muon (g-2) in theories where the Higgs is a pseudo Nambu-Goldstone boson is also discussed.
Lindner, Manfred; Merle, Alexander; Rodejohann, Werner [Physik-Department, Technische Universitaet Muenchen, James-Franck-Strasse, D-85748 Garching (Germany)
2006-03-01T23:59:59.000Z
We analyze the impact of a measurement, or of an improved bound, on {theta}{sub 13} for the determination of the effective neutrino mass in neutrinoless double beta decay and cosmology. In particular, we discuss how an improved limit on (or a specific value of) {theta}{sub 13} can influence the determination of the neutrino mass spectrum via neutrinoless double beta decay. We also discuss the interplay with improved cosmological neutrino mass searches.
Electroweak phase transition in a model with gauged lepton number
Alfredo Aranda; Enrique Jiménez; Carlos A. Vaquera-Araujo
2015-01-16T23:59:59.000Z
In this work we study the electroweak phase transition in a model with gauged lepton number. Here, a family of vector-like leptons is required in order to cancel the gauge anomalies. Furthermore, these leptons can play an important role in the transition process. We find that this framework is able to provide a strong transition, but only for a very limited number of cases.
Modular Invariant Soft Breaking, WMAP, Dark Matter and Sparticle Mass Limits
Chattopadhyay, Utpal; Chattopadhyay, Utpal; Nath, Pran
2004-01-01T23:59:59.000Z
An analysis of soft breaking under the constraint of modular invariance is given. The role of dilaton and moduli dependent front factors in achieving a modular invariant $V_{soft}$ is emphasized. Further, it is shown that in string models $\\tan\\beta$ is no longer a free parameter but is determined in terms of $\\alpha_{string}$ and the other soft parameters by the constraints of modular invariance and radiative electroweak symmetry breaking. The above framework is then used to analyze the neutralino relic density consistent with the WMAP data at self dual points in the Kahler and complex structure moduli. One finds that the combined set of constraints arising from modular invariant soft breaking, radiative electroweak symmetry breaking and WMAP lead to upper limits on sparticle masses for $\\mu>0$. These limits are investigated for a class of models and found to lie within reach of the Tevatron and of the Large Hadron Collider (LHC). Further, an analysis of the neutralino-proton cross section shows that dark ma...
Wu, Zhenbin
2012-01-01T23:59:59.000Z
We present a measurement of the single top quark cross section in the lepton plus jets final state using an integrated luminosity corresponding to 7.5~\\text{fb}^{-1} of p\\bar p collision data collected by the Collider Detector at Fermilab. The single top candidate events are identified by the signature of a charged lepton, large missing transverse energy, and two or three jets with at least one of them identified as originating from a bottom quark. A new Monte Carlo generator \\textsc{powheg} is used to model the single top quark production processes, which include {s}-channel, {t}-channel, and {Wt}-channel. A neural network multivariate method is exploited to discriminate the single top quark signal from the comparatively large backgrounds. We measure a single top production cross section of $3.04^{+0.57}_{-0.53}$ (\\mathrm{stat.~+~syst.}) pb assuming $m_{\\rm top}=172.5$~GeV/$c^2$. In addition, we extract the CKM matrix element value $|V_{tb}|=0.96\\pm 0.09~(\\mathrm{stat.~+~syst.})\\pm 0.05~(\\mathrm{theory})$ and set a lower limit of |V_{tb}|>0.78 at the 95\\% credibility level.
The Lepton Sector of a Fourth Generation
Gustavo Burdman; Leandro Da Rold; Ricardo D. Matheus
2010-05-10T23:59:59.000Z
In extensions of the standard model with a heavy fourth generation one important question is what makes the fourth-generation lepton sector, particularly the neutrinos, so different from the lighter three generations. We study this question in the context of models of electroweak symmetry breaking in warped extra dimensions, where the flavor hierarchy is generated by the localization of the zero-mode fermions in the extra dimension. In this setup the Higgs sector is localized near the infrared brane, whereas the Majorana mass term is localized at the ultraviolet brane. As a result, light neutrinos are almost entirely Majorana particles, whereas the fourth generation neutrino is mostly a Dirac fermion. We show that it is possible to obtain heavy fourth-generation leptons in regions of parameter space where the light neutrino masses and mixings are compatible with observation. We study the impact of these bounds, as well as the ones from lepton flavor violation, on the phenomenology of these models.
Search for the standard model Higgs boson in tau lepton pair final states
D0 Collaboration
2012-05-16T23:59:59.000Z
We present a search for the standard model Higgs boson in final states with an electron or muon and a hadronically decaying tau lepton in association with zero, one, or two or more jets using data corresponding to an integrated luminosity of up to 7.3 fb^{-1} collected with the D0 detector at the Fermilab Tevatron collider. The analysis is sensitive to Higgs boson production via gluon gluon fusion, associated vector boson production, and vector boson fusion, and to Higgs boson decays to tau lepton pairs or W boson pairs. Observed (expected) limits are set on the ratio of 95% C.L. upper limits on the cross section times branching ratio, relative to those predicted by the Standard Model, of 14 (22) at a Higgs boson mass of 115 GeV and 7.7 (6.8) at 165 GeV.
Search for the standard model Higgs boson in tau lepton final states
Abazov, Victor Mukhamedovich; et al.
2012-08-01T23:59:59.000Z
We present a search for the standard model Higgs boson in final states with an electron or muon and a hadronically decaying tau lepton in association with zero, one, or two or more jets using data corresponding to an integrated luminosity of up to 7.3 fb{sup -1} collected with the D0 detector at the Fermilab Tevatron collider. The analysis is sensitive to Higgs boson production via gluon gluon fusion, associated vector boson production, and vector boson fusion, and to Higgs boson decays to tau lepton pairs or W boson pairs. Observed (expected) limits are set on the ratio of 95% C.L. upper limits on the cross section times branching ratio, relative to those predicted by the Standard Model, of 14 (22) at a Higgs boson mass of 115 GeV and 7.7 (6.8) at 165 GeV.
Addition of First Generation Leptons to the External Flux Model
Aaron J. Roy
2009-11-28T23:59:59.000Z
In an extra dimensional EW model in M_4 X S_1 there is no distinction mathematically with the standard model analog as far as the degrees of freedom of the two models along with the masses and more importantly the mass ratio relation in the zero mode limit. In this paper we present a theoretical construct of the same geometry but with the addition of an external magnetic flux permeating the extra coordinate. This will give all of the charged fields in the model an additional phase with nontrivial periodicity. This rather important addition leads to very interesting and mathematically rich physics. Here we will present the generalized theory for the addition of first generation leptons to this theory.
Phenomenology of a leptonic goldstino and invisible Higgs boson decays
Ignatios Antoniadis; Marc Tuckmantel; Fabio Zwirner
2005-03-23T23:59:59.000Z
Non-linearly realized supersymmetry, combined with the Standard Model field content and SU(3)XSU(2)XU(1) gauge invariance, permits local dimension-six operators involving a goldstino, a lepton doublet and a Higgs doublet. These interactions preserve total lepton number if the left-handed goldstino transforms as an antilepton. We discuss the resulting phenomenology, in the simple limit where the new couplings involve only one lepton family, thus conserving also lepton flavour. Both the Z boson and the Higgs boson can decay into a neutrino and a goldstino: the present limits from the invisible Z width and from other observables leave room for the striking possibility of a Higgs boson decaying dominantly, or at least with a sizable branching ratio, via such an invisible mode. We finally comment on the perspectives at hadron and lepton colliders, and on possible extensions of our analysis.
Relating quarks and leptons with the T7 flavour group
Bonilla, Cesar; Peinado, Eduardo; Valle, Jose W F
2014-01-01T23:59:59.000Z
In this letter we present a model for quarks and leptons based on T7 as flavour symmetry, predicting a canonical mass relation between charged leptons and down-type quarks proposed earlier. Neutrino masses are generated through a Type-I seesaw mechanism, with predicted correlations between the atmospheric mixing angle and neutrino masses. Compatibility with oscillation results lead to lower bounds for the lightest neutrino mass as well as for the neutrinoless double beta decay rates, even for normal neutrino mass hierarchy.
Bauer, Gerry P.
A precision measurement of the top quark mass mt [m subscript t] is obtained using a sample of tt? events from pp? collisions at the Fermilab Tevatron with the CDF II detector. Selected events require an electron or muon, ...
Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, Anthony A.; Akimoto, T.; Albrow, M.G.; Ambrose, D.; Amerio, S.; Amidei, D.; Anastassov, A.; Anikeev, K.; /Taiwan,
2005-12-01T23:59:59.000Z
This report describes a measurement of the top quark mass, M{sub top}, with the dynamical likelihood method (DLM) using the CDF II detector at the Fermilab Tevatron. The Tevatron produces top/anti-top (t{bar t}) pairs in p{bar p} collisions at a center-of-mass energy of 1.96 TeV. The data sample used in this analysis was accumulated from March 2002 through August 2004, which corresponds to an integrated luminosity of 318 pb{sup -1}. They use the t{bar t} candidates in the ''lepton+jets'' decay channel, requiring at least one jet identified as a b quark by finding an displaced secondary vertex. The DLM defines a likelihood for each event based on the differential cross section as a function of M{sub top} per unit phase space volume of the final partons, multiplied by the transfer functions from jet to parton energies. The method takes into account all possible jet combinations in an event, and the likelihood is multiplied event by event to derive the top quark mass by the maximum likelihood method. Using 63 t{bar t} candidates observed in the data, with 9.2 events expected from background, they measure the top quark mass to be 173.2{sub -2.4}{sup +2.6}(stat.) {+-} 3.2(syst.) GeV/c{sup 2}, or 173.2{sub -4.0}{sup +4.1} GeV/c{sup 2}.
California at Berkeley, University of
MAGNETOHYDRODYNAMIC SIMULATIONS OF THE SOLAR CORONA AND SOLAR WIND USING A BOUNDARY TREATMENT TO LIMIT SOLAR WIND MASS FLUX Keiji Hayashi W. W. Hansen Experimental Physics Laboratory, Stanford ABSTRACT Magnetohydrodynamic simulations of the solar corona and solar wind are sensitive to conditions
Harilal, S. S.
Optimization of extreme ultraviolet photons emission and collection in mass-limited laser produced in DPP or with pre-pulsing in LPP provide wide area for optimization in regards to conversion efficiency and collection as well as calculating photons source location and size. We optimized several parameters of dual
Search for a High-Mass Diphoton State and Limits on Randall-Sundrum Gravitons at CDF
Aaltonen, T; Adelman, J; Affolder, T; Akimoto, T; Albrow, M G; Amerio, S; Amidei, D; Anastassov, A; Anikeev, K; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Azzi-Bacchetta, P; Azzurri, P; Bacchetta, N; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Bartsch, V; Bauer, G; Beauchemin, P H; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Belloni, A; Benjamin, D; Beretvas, A; Beringer, J; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bölla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, Yu; Budd, H S; Budd, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carrillo, S; Carlsmith, D; Carosi, R; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, I; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Cilijak, M; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Coca, M; Compostella, G; Convery, M E; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Crescioli, F; Cuenca-Almenar, C; Cuevas-Maestro, J; Culbertson, R; Cully, J C; Da Ronco, S; Datta, M; D'Auria, S; Davies, T; Dagenhart, D; De Barbaro, P; De Cecco, S; Deisher, A; De Lentdecker, G; De Lorenzo, G; Dell'Orso, Mauro; Delli Paoli, F; Demortier, L; Deng, J; Deninno, M; De Pedis, D; Derwent, P F; Di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Dorr, C; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, I; Fedorko, W T; Feild, R G; Feindt, M; Fernández, J P; Field, R; Flanagan, G; Forrest, R; Forrester, S; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; García, J E; Garberson, F; Garfinkel, A F; Gay, C; Gerberich, H; Gerdes, D; Giagu, S; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Goldstein, J; Golossanov, A; Gómez, G; Gómez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Group, R C; Grundler, U; Guimarăes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Hamilton, A; Han, B Y; Han, J Y; Handler, R; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hauser, J; Hays, C; Heck, M; Heijboer, A; Heinemann, B; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hidas, D; Hill, C S; Hirschbuehl, D; Höcker, A; Holloway, A; Hou, S; Houlden, M; Hsu, S C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; Iyutin, B; James, E; Jang, D; Jayatilaka, B; Jeans, D; Jeon, E J; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Karchin, P E; Kato, Y; Kemp, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kraan, A C; Kraus, J; Kreps, M; Kroll, J; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhlmann, S E; Kuhr, T; Kulkarni, N P; Kusakabe, Y; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; LeCompte, T; Lee, J; Lee, J; Lee, Y J; Lee, S W; Lefčvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Lin, C; Lin, C S; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Lu, R S; Lucchesi, D; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Mack, P; MacQueen, D; Madrak, R; Maeshima, K; Makhoul, K; Mäki, T; Maksimovic, P; Malde, S; Malik, S; Manca, G; Manousakis, A; Margaroli, F; Marginean, R; Marino, C; Marino, C P; Martin, A; Martin, M; Martin, V; Martínez, M; Martinez-Ballarin, R; Maruyama, T; Mastrandrea, P; Masubuchi, T; Matsunaga, H; Mattson, M E; Mazini, R; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtälä, P; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; Miao, T; Miladinovic, N; Miles, J; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyamoto, A; Moed, S; Moggi, N; Mohr, B; Moon, C S; Moore, R; Morello, M; Movilla-Fernández, P A; Mülmenstädt, J; Mukherjee, A; Müller, T; Mumford, R; Murat, P; Mussini, M; Nachtman, J; Nagano, A; Naganoma, J; Nakamura, K; Nakano, I; Napier, A; Necula, V
2007-01-01T23:59:59.000Z
We have performed a search for new particles which decay to two photons using 1.2/fb of integrated luminosity from p-pbar collisions at sqrt(s) = 1.96 TeV collected using the CDF II Detector at the Fermilab Tevatron. We find the diphoton mass spectrum to be in agreement with the standard model expectation, and set limits on the cross section times branching ratio for the Randall-Sundrum graviton, as a function of diphoton mass. We subsequently derive lower limits for the graviton mass of 230 GeV/c2 and 850 GeV/c2, at the 95% confidence level, for coupling parameters (k/M_Pl) of 0.01 and 0.1 respectively.
The ATLAS collaboration
2015-01-01T23:59:59.000Z
A search for the associated production of the Higgs boson with a top quark pair is performed in multi-lepton final states using 20.3 fb$^{-1}$ of proton-proton collision data recorded by the ATLAS experiment at $\\sqrt{s}=8$ TeV at the Large Hadron Collider. Five final states, targeting the decays $H\\to WW^*$, $\\tau\\tau$, and $ZZ^*$, are examined for the presence of the Standard Model (SM) Higgs boson: two same-charged light leptons ($e$ or $\\mu$) without an additional hadronically decaying tau; three light leptons; two same-charged light leptons with an additional hadronically decaying tau; four light leptons; and one light lepton and two hadronically decaying taus. No significant excess of events is observed above the background expectation. The best fit for the $t\\bar t H$ production cross section, assuming a Higgs boson mass of 125 GeV, is $2.1 ^{+1.4}_{-1.2}$ times the SM expectation, and the observed (expected) upper limit at the 95% confidence level is 4.7 (2.4) times the SM rate. The $p$-value for comp...
Little Flavor: Heavy Leptons, Z' and Higgs Phenomenology
Sichun Sun
2014-12-01T23:59:59.000Z
The Little Flavor model is a close cousin of the Little Higgs theory which aims to generate flavor structure around TeV scale. While the original Little Flavor only included the quark sector, here we build the lepton part of the Little Flavor model and explore its phenomenology. The model produces the neutrino mixing matrix and Majorana masses of the Standard Model neutrinos through coupling to heavy lepton partners and Little Higgses. We combine the usual right-handed seesaw mechanism with global symmetry protection to suppress the Standard Model neutrino masses, and identify the TeV partners of leptons as right-handed Majorana neutrinos. The lepton masses and mixing matrix are calculated perturbatively in the theory. The TeV new gauge bosons have suppressed decay width in dilepton channels. Even assuming the Standard Model couplings, the branching ratios to normal dilepton channels are largely reduced in the model, to evade the bound from current $Z'$ search. It also opens up the new search channels for exotic gauge bosons, especially Z' -> E_{t missing} + multi L. The multiple lepton partners will create new chain decay signals in flavor related processes in colliders, which also give rise to flavor anomalies. The lepton flavor violation process can be highly suppressed in charged lepton sector and happens only through neutrinos.
QCD thermodynamics with $N_f=2+1$ near the continuum limit at realistic quark masses
Takashi Umeda
2006-10-03T23:59:59.000Z
We report on our study of QCD thermodynamics with 2+1 flavors of dynamical quarks. In this proceeding we present several thermodynamic quantities and our recent calculation of the critical temperature. In order to investigate the thermodynamic properties of QCD near the continuum limit we adopt improved staggered (p4) quarks coupled with tree-level Symanzik improved glue on $N_t=4$ and 6 lattices. The simulations are performed with a physical value of the strange quark mass and light quark masses which are in the range of $m_q/m_s=0.05-0.4$. The lightest quark mass corresponds to a pion mass of about 150 MeV.
Choudalakis, Georgios
We present a measurement of the top quark mass with tt? dilepton events produced in pp? collisions at the Fermilab Tevatron (?s=1.96??TeV) and collected by the CDF II detector. A sample of 328 events with a charged ...
Differentiating neutrino models on the basis of $\\theta_{13}$ and lepton flavor violation
Albright, Carl H.; /Northern Illinois U. /Fermilab
2008-03-01T23:59:59.000Z
The authors show how models of neutrino masses and mixings can be differentiated on the basis of their predictions for {theta}{sub 13} and lepton flavor violation in radiative charged lepton decays and {mu} - e conversion. They illustrate the lepton flavor violation results for five predictive SO(10) SUSY GUT models and point out the relative importance of their heavy right-handed neutrino mass spectra and {theta}{sub 13} predictions.
Chou, P
2011-12-14T23:59:59.000Z
This work establishes the criticality safety technical basis to increase the fissile mass limit from 120 grams to 200 grams for Type A 55-gallon drums and their equivalents. Current RHWM fissile mass limit is 120 grams Pu for Type A 55-gallon containers and their equivalent. In order to increase the Type A 55-gallon drum limit to 200 grams, a few additional criticality safety control requirements are needed on moderators, reflectors, and array controls to ensure that the 200-gram Pu drums remain criticality safe with inadvertent criticality remains incredible. The purpose of this work is to analyze the use of 200-gram Pu drum mass limit for waste storage operations in Radioactive and Hazardous Waste Management (RHWM) Facilities. In this evaluation, the criticality safety controls associated with the 200-gram Pu drums are established for the RHWM waste storage operations. With the implementation of these criticality safety controls, the 200-gram Pu waste drum storage operations are demonstrated to be criticality safe and meet the double-contingency-principle requirement per DOE O 420.1.
Vakamudi, Ashoak Kumar
1975-01-01T23:59:59.000Z
of the solute remaining in the body. The dialyzer effiency in- turn depends on the design characteristics of the dialyzer. The solute removal process is limited in some instances by biological rather than dialyzer system processes. For example, erythrocytes...
Ricco, Antonio J.; Staton, Alan W.; Yelton, W. Graham
1999-06-10T23:59:59.000Z
The sensitivity of surface acoustic wave (SAW) sensors has been enhanced by increasing the active surface area of these devices. Electrodepositions of Ni, Pd, and Pt in a mass-transport-limited mode with trace foreign metals yield highly dendritic crystal structures of uniform macroscopic thickness. The concentration of metal ions, supporting electrolyte, agitation, and additives greatly impact the crystal morphology of the deposit. This methodology can be used simply and economically to provide high-area films in selective regions.
Ricco, A.J.; Staton, A.W.; Yelton, W.G.
1999-06-07T23:59:59.000Z
The sensitivity of surface acoustic wave (SAW) sensors has been enhanced by increasing the active surface area of these devices, Electrodepositions of Ni, Pd, and Pt in a mass-transport-limited mode with trace foreign metals yield highly dendritic crystal structures of uniform macroscopic thickness. The concentration of metal ions, supporting electrolyte, agitation, and additives greatly impact the crystal morphology of the deposit. This methodology can be used simply and economically to provide high-area films in selective regions.
G. Quznetsov
2008-11-10T23:59:59.000Z
In this paper I cite p.p. 100-117 of book G. Quznetsov, Probabilistic Treatment of Gauge Theories, in series Contemporary Fundamental Physics,ed. V. Dvoeglazov, Nova Sci. Publ., NY (2007). There I research a bound between neutrino and it's lepton.
Ion funnel with extended mass range and reduced conductance limit aperture
Tolmachev, Aleksey V. (Richland, WA); Smith, Richard D. (Richland, WA)
2008-04-01T23:59:59.000Z
An improved ion funnel design is disclosed that decreases the axial RF (parasite) fields at the ion funnel exit. This is achieved by addition of one or more compensation electrodes after the conductance limit electrode. Various RF voltage profiles may be applied to the various electrodes minimizing the parasite axial potential wells. The smallest RF aperture that serves as the conductance limiting electrode is further reduced over standard designs. Overall, the ion funnel improves transmission ranges of both low m/z and high m/z ions, reducing RF activation of ions and decreasing the gas load to subsequent differential pumping stages.
Survey of lepton number violation via effective operators
Gouvea, Andre de; Jenkins, James [Northwestern University, Department of Physics and Astronomy, 2145 Sheridan Road, Evanston, Illinois 60208 (United States)
2008-01-01T23:59:59.000Z
We survey 129 lepton number violating effective operators, consistent with the minimal standard model gauge group and particle content, of mass dimension up to and including 11. Upon requiring that each one radiatively generates the observed neutrino masses, we extract an associated characteristic cutoff energy scale which we use to calculate other observable manifestations of these operators for a number of current and future experimental probes, concentrating on lepton number violating phenomena. These include searches for neutrinoless double-beta decay and rare meson, lepton, and gauge boson decays. We also consider searches at hadron/lepton collider facilities in anticipation of the CERN LHC and the future ILC. We find that some operators are already disfavored by current data, while more are ripe to be probed by next-generation experiments. We also find that our current understanding of lepton mixing disfavors a subset of higher dimensional operators. While neutrinoless double-beta decay is the most promising signature of lepton number violation for the majority of operators, a handful is best probed by other means. We argue that a combination of constraints from various independent experimental sources will help to pinpoint the ''correct'' model of neutrino mass, or at least aid in narrowing down the set of possibilities.
A Survey of Lepton Number Violation Via Effective Operators
Andre de Gouvea; James Jenkins
2007-08-09T23:59:59.000Z
We survey 129 lepton number violating effective operators, consistent with the minimal Standard Model gauge group and particle content, of mass dimension up to and including eleven. Upon requiring that each one radiatively generates the observed neutrino masses, we extract an associated characteristic cutoff energy scale which we use to calculate other observable manifestations of these operators for a number of current and future experimental probes, concentrating on lepton number violating phenomena. These include searches for neutrinoless double-beta decay and rare meson, lepton, and gauge boson decays. We also consider searches at hadron/lepton collider facilities in anticipation of the LHC and the future ILC. We find that some operators are already disfavored by current data, while more are ripe to be probed by next-generation experiments. We also find that our current understanding of lepton mixing disfavors a subset of higher dimensional operators. While neutrinoless double-beta decay is the most promising signature of lepton number violation for the majority of operators, a handful is best probed by other means. We argue that a combination of constraints from various independent experimental sources will help to pinpoint the ``correct'' model of neutrino mass, or at least aid in narrowing down the set of possibilities.
An independent limit on the axion mass from the variable white dwarf star R548
Córsico, A.H.; Althaus, L.G. [Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, (1900) La Plata (Argentina); Romero, A.D.; Kepler, S.O. [Departamento de Astronomia, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, Porto Alegre 91501-970, RS (Brazil); Mukadam, A.S. [Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States); García-Berro, E. [Departament de Física Aplicada, Universitat Politčcnica de Catalunya, c/Esteve Terrades 5, 08860 Castelldefels (Spain); Isern, J. [Institut de Cičncies de l'Espai (CSIC), Campus UAB, 08193 Bellaterra (Spain); Corti, M.A., E-mail: acorsico@fcaglp.unlp.edu.ar, E-mail: althaus@fcaglp.unlp.edu.ar, E-mail: aromero@fcaglp.unlp.edu.ar, E-mail: anjum@astro.washington.edu, E-mail: enrique.garcia-berro@upc.edu, E-mail: isern@ice.cat, E-mail: kepler@if.ufrgs.br, E-mail: mariela@fcaglp.fcaglp.unlp.edu.ar [Instituto Argentino de Radioastronomía (CCT-La Plata, CONICET), C.C. No. 5, 1894 Villa Elisa (Argentina)
2012-12-01T23:59:59.000Z
Pulsating white dwarfs with hydrogen-rich atmospheres, also known as DAV stars, can be used as astrophysical laboratories to constrain the properties of fundamental particles like axions. Comparing the measured cooling rates of these stars with the expected values from theoretical models allows us to search for sources of additional cooling due to the emission of weakly interacting particles. In this paper, we present an independent inference of the mass of the axion using the recent determination of the evolutionary cooling rate of R548, the DAV class prototype. We employ a state-of-the-art code which allows us to perform a detailed asteroseismological fit based on fully evolutionary sequences. Stellar cooling is the solely responsible of the rates of change of period with time (.?)) for the DAV class. Thus, the inclusion of axion emission in these sequences notably influences the evolutionary timescales, and also the expected pulsational properties of the DAV stars. This allows us to compare the theoretical .?) values to the corresponding empirical rate of change of period with time of R548 to discern the presence of axion cooling. We found that if the dominant period at 213.13 s in R548 is associated with a pulsation mode trapped in the hydrogen envelope, our models indicate the existence of additional cooling in this pulsating white dwarf, consistent with axions of mass m{sub a}cos {sup 2}? ? 17.1 meV at a 2? confidence level. This determination is in agreement with the value inferred from another well-studied DAV, G117-B15A. We now have two independent and consistent estimates of the mass of the axion obtained from DAVs, although additional studies of other pulsating white dwarfs are needed to confirm this value of the axion mass.
Search for Lepton Flavor Violation in the Decay tau -> electron gamma
Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Tisserand, V.; Zghiche, A.; /Annecy, LAPP; Grauges, E.; /Barcelona, IFAE; Palano, A.; Pappagallo, M.; Pompili, A.; /Bari U. /INFN, Bari; Chen, J.C.; Qi, N.D.; Rong, G.; Wang, P.; Zhu, Y.S.; /Beijing, Inst. High Energy Phys.; Eigen, G.; Ofte, I.; Stugu, B. /Bergen U. /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /Bristol U. /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San
2005-08-26T23:59:59.000Z
A search for the non-conservation of lepton flavor in the decay {tau}{sup {+-}} {yields} e{sup {+-}}{gamma} has been performed with 2.07 x 10{sup 8} e{sup +}e{sup -} {yields} {tau}{sup +}{tau}{sup -} events collected by the BABAR detector at the PEP-II storage ring at a center-of-mass energy near 10.58 GeV. They find no evidence for a signal and set an upper limit on the branching ratio of {Beta}({tau}{sup {+-}} {yields} e{sup {+-}}{gamma}) < 1.1 x 10{sup -7} at 90% confidence level.
Taylor, Frank E.
Measurements of four-lepton (4?, ? = e,?) production cross sections at the Z resonance in pp collisions at the LHC with the ATLAS detector are presented. For dilepton and four-lepton invariant mass regions m[subscript ?+??] ...
Detecting exotic heavy leptons at the large hadron collider.
Allanach, B C; Harris, Chris M; Parker, Michael A; Richardson, P; Webber, Bryan R
the cuts actually slightly increases with mass due to the longer time delays. 0.01 0.1 1 10 100 1000 100 200 300 400 500 600 700 800 900 1000 Cr os s se ct io n (fb ) Mass of heavy lepton (GeV) Before applying cuts After applying cuts Figure 5: Cross...
Chatrchyan, Serguei; et al.
2012-03-01T23:59:59.000Z
A search for a Higgs boson in the four-lepton decay channel H to ZZ, with each Z boson decaying to an electron or muon pair, is reported. The search covers Higgs boson mass hypotheses in the range 110 < mH < 600 GeV. The analysis uses data corresponding to an integrated luminosity of 4.7 inverse femtobarns recorded by the CMS detector in pp collisions at sqrt(s) = 7 TeV from the LHC. Seventy-two events are observed with four-lepton invariant mass m[4 leptons] > 100 GeV (with thirteen below 160 GeV), while 67.1 +/- 6.0 (9.5 +/-1.3) events are expected from background. The four-lepton mass distribution is consistent with the expectation of standard model background production of ZZ pairs. Upper limits at 95% confidence level exclude the standard model Higgs boson in the ranges 134-158 GeV, 180-305 GeV, and 340 -465 GeV. Small excesses of events are observed around masses of 119, 126, and 320 GeV, making the observed limits weaker than expected in the absence of a signal.
Leptonic CP Violation Phases, Quark-Lepton Similarity and Seesaw Mechanism
Basudeb Dasgupta; Alexei Yu. Smirnov
2014-05-20T23:59:59.000Z
We explore generic features of the leptonic CP violation in the framework of the seesaw type I mechanism with similarity of the Dirac lepton and quarks mass matrices $m_D$. For this, we elaborate on the standard parametrization conditions which allow to simultaneously obtain the Dirac and Majorana phases. If the only origin of CP violation is the left-handed (LH) transformation which diagonalizes $m_D$ (similar to quarks), the leptonic CP violation is suppressed and the Dirac phase is close to $\\pi$ or to $0$ with $\\sin \\delta_{CP} \\approx (\\sin \\theta_{13}^q /\\sin \\theta_{13}) \\cos \\theta_{23} \\sin \\delta_q \\sim \\lambda^2 \\sin \\delta_q$. Here $\\lambda \\sim \\theta_C$, is the Cabibbo mixing angle, and $\\theta_{13}^q$ and $\\theta_{13}$ are the 1-3 mixing angles of quarks and leptons respectively. The Majorana phases $\\beta_1$ and $\\beta_2$ are suppressed as $\\lambda^3\\sin\\delta_q$. For Majorana neutrinos implied by seesaw, the right-handed (RH) transformations are important. We explore the simplest extension inspired by Left-Right (L-R) symmetry with small CKM-type CP violation. In this case, seesaw enhancement of the CP violation occurs due to strong hierarchy of the eigenvalues of $m_D$ leading to $\\delta_{CP} \\sim 1$. The enhancement is absent under the phase factorization conditions which require certain relations between parameters of the Majorana mass matrix of RH neutrinos.
New PVLAS model independent limit for the axion coupling to $??$ for axion masses above 1meV
F. Della Valle; A. Ejlli; U. Gastaldi; G. Messineo; E. Milotti; R. Pengo; L. Piemontese; G. Ruoso; G. Zavattini
2014-10-15T23:59:59.000Z
During 2014 the PVLAS experiment has started data taking with a new apparatus installed at the INFN Section of Ferrara, Italy. The main target of the experiment is the observation of magnetic birefringence of vacuum. According to QED, the ellipticity generated by the magnetic birefringence of vacuum in the experimental apparatus is expected to be $\\psi^{\\rm(QED)} \\approx 5\\times10^{-11}$. No ellipticity signal is present so far with a noise floor $\\psi^{\\rm(noise)} \\approx 2.5\\times10^{-9}$ after 210 hours of data taking. The resulting ellipticity limit provides the best model independent upper limit on the coupling of axions to $\\gamma\\gamma$ for axion masses above $10^{-3}$eV.
Lepton sector of a fourth generation
Burdman, G. [Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo (Brazil); Da Rold, L. [Centro Atomico Bariloche, Bariloche (Argentina); Matheus, R. D. [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo (Brazil)
2010-09-01T23:59:59.000Z
In extensions of the standard model with a heavy fourth generation, one important question is what makes the fourth-generation lepton sector, particularly the neutrinos, so different from the lighter three generations. We study this question in the context of models of electroweak symmetry breaking in warped extra dimensions, where the flavor hierarchy is generated by choosing the localization of the zero-mode fermions in the extra dimension. In this setup the Higgs sector is localized near the infrared brane, whereas the Majorana mass term is localized at the ultraviolet brane. As a result, light neutrinos are almost entirely Majorana particles, whereas the fourth-generation neutrino is mostly a Dirac fermion. We show that it is possible to obtain heavy fourth-generation leptons in regions of parameter space where the light neutrino masses and mixings are compatible with observation. We study the impact of these bounds, as well as the ones from lepton flavor violation, on the phenomenology of these models.
Axion mass limit from observations of the neutron star in Cassiopeia A
Lev B. Leinson
2014-08-14T23:59:59.000Z
Direct Chandra observations of a surface temperature of isolated neutron star in Cassiopeia A (Cas A NS) and its cooling scenario which has been recently simultaneously suggested by several scientific teams put stringent constraints on poorly known properties of the superfluid neutron star core. It was found also that the thermal energy losses from Cas A NS are approximately twice more intensive than it can be explained by the neutrino emission. We use these unique data and well-defined cooling scenario to estimate the strength of KSVZ axion interactions with neutrons. We speculate that enlarged energy losses occur owing to emission of axions from superfluid core of the neutron star. If the axion and neutrino losses are comparable we find $c_{n}^{2}m_{a}^{2}\\sim 5.7\\times 10^{-6}\\,\\text{eV}^2$, where $m_{a}$ is the axion mass, and $c_{n}$ is the effective Peccei-Quinn charge of the neutron. (Given the QCD uncertainties of the hadronic axion models, the dimensionless constant $c_{n}$ could range from $-0.05$ to $ 0.14$.)
Search for Lepton Flavor Violation in Upsilon Decays
Love, W.; Savinov, V. [University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Lopez, A.; Mehrabyan, S.; Mendez, H.; Ramirez, J. [University of Puerto Rico, Mayaguez, Puerto Rico 00681 (Puerto Rico); Huang, G. S.; Miller, D. H.; Pavlunin, V.; Sanghi, B.; Shipsey, I. P. J.; Xin, B. [Purdue University, West Lafayette, Indiana 47907 (United States); Adams, G. S.; Anderson, M.; Cummings, J. P.; Danko, I.; Hu, D.; Moziak, B.; Napolitano, J. [Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); He, Q. [University of Rochester, Rochester, New York 14627 (United States)] (and others)
2008-11-14T23:59:59.000Z
In this Letter, we describe a search for lepton flavor violation (LFV) in the bottomonium system. We search for leptonic decays {upsilon}(nS){yields}{mu}{tau} (n=1, 2, and 3) using the data collected with the CLEO III detector. We identify the {tau} lepton using its leptonic decay {nu}{sub {tau}}{nu}{sub e}e and utilize multidimensional likelihood fitting with probability density function shapes measured from independent data samples. We report our estimates of 95% C.L. upper limits on LFV branching fractions of {upsilon} mesons. We interpret our results in terms of the exclusion plot for the energy scale of a hypothetical new interaction versus its effective LFV coupling in the framework of effective field theory.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aad, G.; Abajyan, T.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdelalim, A. A.; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Addy, T. N.; Adelman, J.; Adomeit, S.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J. A.; Agustoni, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahsan, M.; Aielli, G.; Ĺkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Alam, M. A.; Albert, J.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Allbrooke, B. M. M.; Allison, L. J.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alonso, F.; Altheimer, A.; Alvarez Gonzalez, B.; Alviggi, M. G.; Amako, K.; Amelung, C.; Ammosov, V. V.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amram, N.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Anduaga, X. S.; Angelidakis, S.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Arfaoui, S.; Arguin, J-F.; Argyropoulos, S.; Arik, E.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Artamonov, A.; Artoni, G.; Arutinov, D.; Asai, S.; Ask, S.; Ĺsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Astbury, A.; Atkinson, M.; Auerbach, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Avolio, G.; Axen, D.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Baccaglioni, G.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Backus Mayes, J.; Badescu, E.; Bagnaia, P.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, S.; Balek, P.; Balli, F.; Banas, E.; Banerjee, P.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Bardin, D. Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarăes da Costa, J.; Bartoldus, R.; Barton, A. E.; Bartsch, V.; Basye, A.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battaglia, A.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beale, S.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, S.; Beckingham, M.; Becks, K. H.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behar Harpaz, S.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellomo, M.; Belloni, A.; Beloborodova, O.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernat, P.; Bernhard, R.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Bertella, C.; Bertin, A.; Bertolucci, F.; Besana, M. I.; Besjes, G. J.; Besson, N.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biscarat, C.; Bittner, B.; Black, C. W.; Black, J. E.; Black, K. M.; Blair, R. E.; Blanchard, J.-B.; Blazek, T.; Bloch, I.; Blocker, C.; Blocki, J.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boek, T. T.; Boelaert, N.; Bogaerts, J. A.; Bogdanchikov, A.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Bolnet, N. M.; Bomben, M.; Bona, M.; Boonekamp, M.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borri, M.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boutouil, S.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozovic-Jelisavcic, I.; Bracinik, J.; Branchini, P.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brazzale, S. F.; Brelier, B.; Bremer, J.; Brendlinger, K.; Brenner, R.; Bressler, S.; Bristow, T. M.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Broggi, F.; Bromberg, C.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brown, G.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.; Bruschi, M.; Bryngemark, L.
2013-07-01T23:59:59.000Z
A search for new particles that decay into top quark pairs (ttŻ) is performed with the ATLAS experiment at the LHC using an integrated luminosity of 4.7 fb?š of protonproton (pp ) collision data collected at a center-of-mass energy ?s =7 TeV . In the ttŻ ?WbWb decay, the lepton plus jets final state is used, where one W boson decays leptonically and the other hadronically. The ttŻ system is reconstructed using both small-radius and large-radius jets, the latter being supplemented by a jet substructure analysis. A search for local excesses in the number of data events compared to the Standard Model expectation in the ttŻ invariant mass spectrum is performed. No evidence for a ttŻ resonance is found and 95% credibility-level limits on the production rate are determined for massive states predicted in two benchmark models. The upper limits on the cross section times branching ratio of a narrow Z' resonance range from 5.1 pb for a boson mass of 0.5 TeV to 0.03 pb for a mass of 3 TeV. A narrow leptophobic topcolor Z' resonance with a mass below 1.74 TeV is excluded. Limits are also derived for a broad color-octet resonance with ?/m=15.3% . A KaluzaKlein excitation of the gluon in a RandallSundrum model is excluded for masses below 2.07 TeV.
ATLAS Collaboration
2015-03-06T23:59:59.000Z
A search for new charged massive gauge bosons, called $W'$, is performed with the ATLAS detector at the LHC, in proton-proton collisions at a centre-of-mass energy of $\\sqrt{s}$ = 8 TeV, using a dataset corresponding to an integrated luminosity of 20.3 fb$^{-1}$. This analysis searches for $W'$ bosons in the $W' \\to t\\bar{b}$ decay channel in final states with electrons or muons, using a multivariate method based on boosted decision trees. The search covers masses between 0.5 and 3.0 TeV, for right-handed or left-handed $W'$ bosons. No significant deviation from the Standard Model expectation is observed and limits are set on the $W' \\to t\\bar{b}$ cross-section times branching ratio and on the $W'$-boson effective couplings as a function of the $W'$-boson mass using the CL$_s$ procedure. For a left-handed (right-handed) $W'$ boson, masses below 1.70 (1.92) TeV are excluded at 95% confidence level.
Charged-Lepton-Flavour Violation in the Light of the Super-Kamiokande Data
John Ellis; M. E. Gomez; G. K. Leontaris; S. Lola; D. V. Nanopoulos
1999-12-18T23:59:59.000Z
Motivated by the data from Super-Kamiokande and elsewhere indicating oscillations of atmospheric and solar neutrinos, we study charged-lepton-flavour violation, in particular the radiative decays mu -> e gamma and tau -> mu gamma, but also commenting on mu -> 3e and tau -> 3 mu/e decays, as well as mu - e conversion on nuclei. We first show how the renormalization group may be used to calculate flavour-violating soft supersymmetry-breaking masses for charged sleptons and sneutrinos in models with universal input parameters. Subsequently, we classify possible patterns of lepton-flavour violation in the context of phenomenological neutrino mass textures that accommodate the Super-Kamiokande data, giving examples based on Abelian flavour symmetries. Then we calculate in these examples rates for mu -> e gamma and tau ->mu gamma, which may be close to the present experimental upper limits, and show how they may distinguish between the different generic mixing patterns. The rates are promisingly large when the soft supersymmetry-breaking mass parameters are chosen to be consistent with the cosmological relic-density constraints. In addition, we discuss mu -> e conversion on Titanium, which may also be accessible to future experiments.
Unveiling neutrino mixing and leptonic CP violation
Mena, Olga; /Fermilab
2005-01-01T23:59:59.000Z
We review the present understanding of neutrino masses and mixings, discussing what are the unknowns in the three family oscillation scenario. Despite the anticipated success coming from the planned long baseline neutrino experiments in unraveling the leptonic mixing sector, there are two important unknowns which may remain obscure: the mixing angle {theta}{sub 13} and the CP-phase {delta}. The measurement of these two parameters has led us to consider the combination of superbeams and neutrino factories as the key to unveil the neutrino oscillation picture.
Lepton Flavor Violation in Predictive SUSY-GUT Models
Albright, Carl H.; /Northern Illinois U. /Fermilab; Chen, Mu-Chun; /UC, Irvine
2008-02-01T23:59:59.000Z
There have been many theoretical models constructed which aim to explain the neutrino masses and mixing patterns. While many of the models will be eliminated once more accurate determinations of the mixing parameters, especially sin{sup 2} 2{theta}{sub 13}, are obtained, charged lepton flavor violation (LFV) experiments are able to differentiate even further among the models. In this paper, they investigate various rare LFV processes, such as {ell}{sub i} {yields} {ell}{sub j} + {gamma} and {mu} - e conversion, in five predictive SUSY SO(10) models and their allowed soft SUSY breaking parameter space in the constrained minimal SUSY standard model (CMSSM). Utilizing the WMAP dark matter constraints, they obtain lower bounds on the branching ratios of these rare processes and find that at least three of the five models they consider give rise to predictions for {mu} {yields} e + {gamma} that will be tested by the MEG collaboration at PSI. in addition, the next generation {mu} - e conversion experiment has sensitivity to the predictions of all five models, making it an even more robust way to test these models. While generic studies have emphasized the dependence of the branching ratios of these rare processes on the reactor neutrino angle, {theta}{sub 13}, and the mass of the heaviest right-handed neutrino, M{sub 3}, they find very massive M{sub 3} is more significant than large {theta}{sub 13} in leading to branching ratios near to the present upper limits.
Renormalization group invariant of lepton Yukawa couplings
Tsuyuki, Takanao
2015-01-01T23:59:59.000Z
By using quark Yukawa matrices only, we can construct renormalization invariants that are exact at the one-loop level in the standard model. One of them $I^q$ is accidentally consistent with unity, even though quark masses are strongly hierarchical. We calculate a lepton version of the invariant $I^l$ for Dirac and Majorana neutrino cases and find that $I^l$ can be also close to unity. For the Dirac neutrino case, if we assume $I^q=I^l$, we can deduce that the hierarchy of neutrino masses is inverted, and the lightest neutrino mass is 3.0 meV to 8.8 meV.
Polarisation Observables in Antiproton Proton to Lepton Antilepton Reactions
Jennings, Elise [School of Mathematics, Trinity College Dublin (Ireland)
2007-06-13T23:59:59.000Z
The electromagnetic form factors of hadrons as measured both in the space like and time like domains provide fundamental information on the nucleon structure and internal dynamics. General expressions, including the lepton mass, for the spin averaged differential cross section for the annihilation reaction lepton antilepton to proton antiproton are given, as well as general formulae for the single and double spin asymmetries. The time reversed reaction would involve a kinematic factor. We also present general expressions for the helicity amplitudes for this reaction.
Neutrinoless Double Beta Decay and Lepton Flavor Violation
V. Cirigliano; A. Kurylov; M. J. Ramsey-Musolf; P. Vogel
2004-06-17T23:59:59.000Z
We point out that extensions of the Standard Model with low scale (~TeV) lepton number violation (LNV) generally lead to a pattern of lepton flavor violation (LFV) experimentally distinguishable from the one implied by models with GUT scale LNV. As a consequence, muon LFV processes provide a powerful diagnostic tool to determine whether or not the effective neutrino mass can be deduced from the rate of neutrinoless double beta decay. We discuss the role of \\mu -> e \\gamma and \\mu -> e conversion in nuclei, which will be studied with high sensitivity in forthcoming experiments.
Hu, Jian Zhi; Rommereim, Donald N.; Wind, Robert A.; Minard, Kevin R.; Sears, Jesse A.
2006-11-01T23:59:59.000Z
A simple approach is reported that yields high resolution, high sensitivity šH NMR spectra of biofluids with limited mass supply. This is achieved by spinning a capillary sample tube containing a biofluid at the magic angle at a frequency of about 80Hz. A 2D pulse sequence called šH PASS is then used to produce a high-resolution šH NMR spectrum that is free from magnetic susceptibility induced line broadening. With this new approach a high resolution šH NMR spectrum of biofluids with a volume less than 1.0 ľl can be easily achieved at a magnetic field strength as low as 7.05T. Furthermore, the methodology facilitates easy sample handling, i.e., the samples can be directly collected into inexpensive and disposable capillary tubes at the site of collection and subsequently used for NMR measurements. In addition, slow magic angle spinning improves magnetic field shimming and is especially suitable for high throughput investigations. In this paper first results are shown obtained in a magnetic field of 7.05T on urine samples collected from mice using a modified commercial NMR probe.
Search for neutral MSSM Higgs bosons decaying to a pair of tau leptons in pp collisions
Khachatryan, V. [Yerevan Physics Institute (Armenia); et al.,
2014-10-01T23:59:59.000Z
A search for neutral Higgs bosons in the minimal supersymmetric extension of the standard model (MSSM) decaying to tau-lepton pairs in pp collisions is performed, using events recorded by the CMS experiment at the LHC. The dataset corresponds to an integrated luminosity of 24.6 fb$^{?1}$, with 4.9 fb$^{?1}$ at 7 TeV and 19.7 fb$^{?1}$ at 8 TeV. To enhance the sensitivity to neutral MSSM Higgs bosons, the search includes the case where the Higgs boson is produced in association with a b-quark jet. No excess is observed in the tau-lepton-pair invariant mass spectrum. Exclusion limits are presented in the MSSM parameter space for different benchmark scenarios, m$_{h}^{max}$ , m$_{h}^{mod?+}$ , m$_{h}^{mod??}$ , light-stop, light-stau, ?-phobic, and low-m$_{H}$. Upper limits on the cross section times branching fraction for gluon fusion and b-quark associated Higgs boson production are also given.
Classification of lepton mixing patterns from finite flavour symmetries
Renato M. Fonseca; Walter Grimus
2014-10-15T23:59:59.000Z
Flavour symmetries have been used to constrain both quark and lepton mixing parameters. In particular, they can be used to completely fix the mixing angles. For the lepton sector, assuming that neutrinos are Majorana particles, we have derived the complete list of mixing patterns achievable in this way, as well as the symmetry groups associated to each case. Partial computer scans done in the past have hinted that such list is limited, and this does indeed turn out to be the case. In addition, most mixing patterns are already 3-sigma excluded by neutrino oscillation data.
Renormalization group invariant of lepton Yukawa couplings
Takanao Tsuyuki
2015-04-20T23:59:59.000Z
By using quark Yukawa matrices only, we can construct renormalization invariants that are exact at the one-loop level in the standard model. One of them $I^q$ is accidentally consistent with unity, even though quark masses are strongly hierarchical. We calculate a lepton version of the invariant $I^l$ for Dirac and Majorana neutrino cases and find that $I^l$ can also be close to unity. For the Dirac neutrino and inverted hierarchy case, if the lightest neutrino mass is 3.0 meV to 8.8 meV, an equality $I^q=I^l$ can be satisfied. These invariants are not changed even if new particles couple to the standard model particles, as long as those couplings are generation independent.
A minimal and predictive $T_7$ lepton flavor 331 model
Hernández, A E Cárcamo
2015-01-01T23:59:59.000Z
We present a model based on the $SU(3)_{C}\\otimes SU(3)_{L}\\otimes U(1)_{X}$ gauge group having an extra $T_{7}\\otimes Z_{3}\\otimes Z_{14}$ flavor group, where the light active neutrino masses arise via double seesaw mechanism and the observed charged lepton mass hierarchy is a consequence of the $Z_{14}$ symmetry breaking at very high energy. In our minimal and predictive $T_7$ lepton flavor 331 model, the spectrum of neutrinos includes very light active neutrinos and heavy and very heavy sterile neutrinos. The obtained neutrino mixing parameters and neutrino mass squared splittings are compatible with the neutrino oscillation experimental data, for both normal and inverted hierarchies. The model predicts CP conservation in neutrino oscillations.
Energy or Mass and Interaction
Gustavo R Gonzalez-Martin
2010-07-19T23:59:59.000Z
A review. Problems: 1-Many empirical parameters and large dimension number; 2-Gravitation and Electrodynamics are challenged by dark matter and energy. Energy and nonlinear electrodynamics are fundamental in a unified nonlinear interaction. Nuclear energy appears as nonlinear SU(2) magnetic energy. Gravitation and electromagnetism are unified giving Einstein's equation and a geometric energy momentum tensor. A solution energy in the newtonian limit gives the gravitational constant G. Outside of this limit G is variable. May be interpreted as dark matter or energy. In vacuum, known gravitational solutions are obtained. Electromagnetism is an SU(2) subgroup. A U(1) limit gives Maxwell's equations. Geometric fields determine a generalized Dirac equation and are the germ of quantum physics. Planck's h and of Einstein's c are given by the potential and the metric. Excitations have quanta of charge, flux and spin determining the FQHE. There are only three stable 1/2 spin fermions. Mass is a form of energy. The rest energies of the fermions give the proton/electron mass ratio. Potential excitations have energies equal to the weak boson masses allowing a geometric interpretation of Weinberg's angle. SU(2) gives the anomalous magnetic moments of proton, electron, neutron and generates nuclear range attractive potentials strong enough to produce the binding energies of the deuteron and other nuclides. Lepton and meson masses are due to topological excitations. The geometric mass spectrum is satisfactory. The proton has a triple structure. The alpha constant is a geometric number.
Search for a Narrow Resonance in e e- to Four Lepton Final States
Aubert, B.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E.; /Barcelona U., ECM; Martinelli, M.; Palano, A.; Pappagallo, M.; /INFN, Bari /Bari U.; Eigen, G.; Stugu, B.; Sun, L.; /Bergen U.; Battaglia, M.; Brown, D.N.; Hooberman, B.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G. /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT, LNS /McGill U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /Mt. Holyoke Coll. /INFN, Naples /Naples U. /INFN, Naples /INFN, Naples /Naples U. /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /Pennsylvania U. /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas U. /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U., IFIC /Victoria U. /Warwick U. /Wisconsin U., Madison
2009-10-17T23:59:59.000Z
Motivated by recent models proposing a hidden sector with {approx} GeV scale force carriers, we present a search for a narrow dilepton resonance in 4 lepton final states using 536 fb{sup -1} collected by the BABAR detector. We search for the reaction, e{sup +}e{sup -} {yields} W{prime}W{prime} {yields} (l{sup +}l{sup -})(l{prime}{sup +}l{prime}{sup -}), where the leptons carry the full 4-momentum and the two dilepton pair invariant masses are equal. We do not observe a significant signal and we set 90% upper limits of {sigma}(e{sup +}e{sup -} {yields} W{prime}W{prime} {yields} e{sup +}e{sup -}e{sup +}e{sup -}) < (15-70) ab, {sigma}(e{sup +}e{sup -} {yields} W{prime}W{prime} {yields} e{sup +}e{sup -}{mu}{sup +}{mu}{sup -} < (15-40) ab, and {sigma}(e{sup +}e{sup -} {yields} W{prime}W{prime} {yields} {mu}{sup +}{mu}{sup -}{mu}{sup +}{mu}{sup -}) < 11-17) ab in the W{prime} mass range between 0.24 and 5.3GeV/c{sup 2}. Under the assumption that the W{prime} coupling to electrons and muons is the same, we obtain a combined upper limit of {sigma}e{sup +}e{sup -} {yields} W{prime}W{prime} {yields} l{sup +}l{sup -}l{prime}{sup +}l{prime}{sup -} < (25-60) ab. Using these limits, we constrain the product of the SM-dark sector mixing and the dark coupling constant in the case of a non-Abelian Higgsed dark sector.
P. Lundqvist; C. Kozma; J. Sollerman; C. Fransson
2001-05-23T23:59:59.000Z
ISO/SWS observations of SN 1987A on day 3425 show no emission in [Fe I] 24.05 microns and [Fe II] 25.99 microns down to the limits of roughly 0.39 Jy and 0.64 Jy, respectively. Assuming a homogeneous distribution of Ti-44 inside 2000 km/s and negligible dust cooling, we have made time dependent theoretical models to estimate an upper limit on the mass of ejected Ti-44. Assessing various uncertainties of the model, and checking the late optical emission it predicts, we obtain an upper limit of 1.1EE-4 solar masses. This is lower than in our previous estimate using other ISO data, and we compare our new result with other models for the late emission, as well as with expected yields from explosion models. We also show that steady-state models for the optical emission are likely to overestimate the mass of ejected Ti-44. The low limit we find for the mass of ejected Ti-44 could be higher if dust cooling is important. A direct check on this is provided by the gamma-ray emission at 1.157 Mev as a result of the radioactive decay of Ti-44.
Search for neutrinoless decays of the ? lepton
Baringer, Philip S.
1990-02-01T23:59:59.000Z
We have searched for neutrinoless ? decays into three charged particles. Evidence of such decays would demonstrate nonconservation of lepton flavor and, in some cases, lepton number. We see no signal for any such neutrinoless ? decays and set upper...
Chatrchyan, S. [Yerevan Physics Institute (Armenia); et al.,
2014-08-01T23:59:59.000Z
A search for physics beyond the standard model in events with at least three leptons is presented. The data sample, corresponding to an integrated luminosity of 19.5 inverse femtobarns of proton-proton collisions with center-of-mass energy sqrt(s) = 8 TeV, was collected by the CMS experiment at the LHC during 2012. The data are divided into exclusive categories based on the number of leptons and their flavor, the presence or absence of an opposite-sign, same-flavor lepton pair (OSSF), the invariant mass of the OSSF pair, the presence or absence of a tagged bottom-quark jet, the number of identified hadronically decaying tau leptons, and the magnitude of the missing transverse energy and of the scalar sum of jet transverse momenta. The numbers of observed events are found to be consistent with the expected numbers from standard model processes, and limits are placed on new-physics scenarios that yield multilepton final states. In particular, scenarios that predict Higgs boson production in the context of supersymmetric decay chains are examined. We also place a 95% confidence level upper limit of 1.3% on the branching fraction for the decay of a top quark to a charm quark and a Higgs boson (t to c H), which translates to a bound on the left- and right-handed top-charm flavor-violating Higgs Yukawa couplings, lambda[H, tc] and lambda[H, ct], respectively, of sqrt(abs(lambda[H, tc])^2 + abs(lambda[H, ct])^2) < 0.21.
Mikhail A. Samokhvalov
2014-04-01T23:59:59.000Z
The work is based on the equation of relativistic dynamics, the law of mass conservation of material body moving in gravitational field and the influence of gravitation on time passage discovered by Einstein. The formulae describing changes of inert and gravitational masses of material body were found. A new formula for the power of gravitational interaction of material bodies was derived. Newtons formula was shown to be the approximation of the new formula. It was determined that the equivalence principle of inert and gravitational masses is not universal. This principle is true with definite accuracy within the Solar system, when the sum of kinetic and potential energies of a material body is equal to zero. Limitation of the equivalence principle of inert and gravitational masses for galactic star systems erases the problem of dark matter.
Zhi-zhong Xing
2001-07-02T23:59:59.000Z
We point out two simple but instructive possibilities to construct the charged lepton and neutrino mass matrices, from which the nearly bi-maximal neutrino mixing with large T violation can naturally emerge. The two lepton mixing scenarios are compatible very well with current experimental data on solar and atmospheric neutrino oscillations, and one of them may lead to an observable T-violating asymmetry between \
Bowler, Brendan P; Shkolnik, Evgenya L; Dupuy, Trent J
2013-01-01T23:59:59.000Z
We report the discovery of an L-type companion to the young M3.5V star 2MASS J01225093-2439505 at a projected separation of 1.45" (~52 AU) as part of our adaptive optics imaging search for extrasolar giant planets around young low-mass stars. 2MASS 0122-2439 B has very red near-infrared colors similar to the HR 8799 planets and the reddest known young/dusty L dwarfs in the field. Moderate-resolution (R~3800) 1.5-2.4 $\\mu$m spectroscopy reveals a near-infrared spectral type of L4-L6 and an angular H-band shape, confirming its cool temperature and young age. The kinematics of 2MASS 0122-2439 AB are marginally consistent with members of the ~120 Myr AB Dor young moving group based on the photometric distance to the primary (36 +/- 4 pc) and our radial velocity measurement of 2MASS 0122-2439 A from Keck/HIRES. We adopt the AB Dor group age for the system, but the high energy emission, lack of Li I $\\lambda$6707 absorption, and spectral shape of 2MASS 0122-2439 B suggest a range of ~10-120 Myr is possible. The age...
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Kile, Jennifer; Kobach, Andrew; Soni, Amarjit
2015-05-01T23:59:59.000Z
In this work, we address two paradoxes. The first is that the measured dark-matter relic density can be satisfied with new physics at O(100 GeV1 TeV), while the null results from direct-detection experiments place lower bounds of O(10 TeV) on a new-physics scale. The second puzzle is that the severe suppression of lepton-flavor-violating processes involving electrons, e.g. ? ? 3e, ? ? e??, etc., implies that generic new-physics contributions to lepton interactions cannot exist below O(10100 TeV), whereas the 3.6? deviation of the muon g 2 from the standard model can be explained by a new physics scale
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Kile, Jennifer; Kobach, Andrew; Soni, Amarjit
2015-05-01T23:59:59.000Z
In this work, we address two paradoxes. The first is that the measured dark-matter relic density can be satisfied with new physics at O(100 GeV1 TeV), while the null results from direct-detection experiments place lower bounds of O(10 TeV) on a new-physics scale. The second puzzle is that the severe suppression of lepton-flavor-violating processes involving electrons, e.g. ? ? 3e, ? ? e??, etc., implies that generic new-physics contributions to lepton interactions cannot exist below O(10100 TeV), whereas the 3.6? deviation of the muon g 2 from the standard model can be explained by a new physics scale more ťTeV). Here, we suggest that it may not be a coincidence that both the muon g 2 and the relic density can be satisfied by a new-physics scale ?1 TeV. We consider the possibility of a gauged lepton-flavor interaction that couples at tree level only to ?- and ?-flavored leptons and the dark sector. Dark matter thus interacts appreciably only with particles of ? and ? flavor at tree level and has loop-suppressed couplings to quarks and electrons. Remarkably, if such a gauged flavor interaction exists at a scale O(100 GeV1 TeV), it allows for a consistent phenomenological framework, compatible with the muon g 2, the relic density, direct detection, indirect detection, charged-lepton decays, neutrino trident production, and results from hadron and e?e? colliders. We suggest experimental tests for these ideas at colliders and for low-energy observables. (author)Ť less
Artigau, Étienne; Faherty, Jacqueline; Malo, Lison; Naud, Marie-Eve; Doyon, René; Lafreničre, David; Beletsky, Yuri
2015-01-01T23:59:59.000Z
We report the discovery of a substellar companion to 2MASS J02192210-3925225, a young M6 $\\gamma$ candidate member of the Tucana-Horologium association (30 - 40 Myr). This L4 $\\gamma$ companion has been discovered with seeing-limited direct imaging observations; at a 4" separation (160AU) and a modest contrast ratio, it joins the very short list of young low-mass companions amenable to study without the aid of adaptive optics, enabling its characterization with a much wider suite of instruments than is possible for companions uncovered by high-contrast imaging surveys. With a model-dependent mass of 12-15MJup, it straddles the boundary between the planet and brown dwarf mass regimes. We present near-infrared spectroscopy of this companion and compare it to various similar objects uncovered in the last few years. The J0219-3925 system falls in a sparsely populated part of the host mass versus mass ratio diagram for binaries; the dearth of known similar companions may be due to observational biases in previous ...
Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; /Oklahoma U.; Abolins, Maris A.; /Michigan State U.; Acharya, Bannanje Sripath; /Tata Inst.; Adams, Mark Raymond; /Illinois U., Chicago; Adams, Todd; /Florida State U.; Alexeev, Guennadi D.; /Dubna, JINR; Alkhazov, Georgiy D.; /St. Petersburg, INP; Alton, Andrew K.; /Michigan U. /Augustana Coll., Sioux Falls; Alverson, George O.; /Northeastern U.; Alves, Gilvan Augusto; /Rio de Janeiro, CBPF /Nijmegen U.
2010-08-01T23:59:59.000Z
We present the first search for pair production of isolated jets of charged leptons in association with a large imbalance in transverse energy in p{bar p} collisions using 5.8 fb{sup -1} of integrated luminosity collected by the D0 detector at the Fermilab Tevatron Collider. No excess is observed above Standard Model background, and the result is used to set upper limits on the production cross section of pairs of supersymmetric chargino and neutralino particles as a function of 'dark-photon' mass, where the dark photon is produced in the decay of the lightest supersymmetric particle.
Clues for flavor from rare lepton and quark decays
Varzielas, Ivo de Medeiros
2015-01-01T23:59:59.000Z
Flavor symmetries successfully explain lepton and quark masses and mixings yet it is usually hard to distinguish different models that predict the same mixing angles. Further experimental input could be available, if the agents of flavor breaking are sufficiently low in mass and detectable or if new physics with non-trivial flavor charges is sufficiently low in mass and detectable. The recent hint for lepton-nonuniversality in the ratio of branching fractions $B \\to K \\mu \\mu$ over $B \\to K e e$, $R_K$, suggests the latter, at least for indirect detection via rare decays. We demonstrate the discriminating power of the rare decay data on flavor model building taking into account viable leptonic mixings and show how correlations with other observables exist in leptoquark models. We give expectations for branching ratios $B \\to K \\ell \\ell^\\prime, B_{(s)} \\to \\ell \\ell^\\prime$ and $\\ell \\to \\ell^\\prime \\gamma$, and Higgs decays $h \\to \\ell \\ell^\\prime$.
Renormalization of a two-loop neutrino mass model
Babu, K. S. [Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078 (United States); Julio, J. [Fisika LIPI, Kompleks Puspiptek Serpong, Tangerang 15310, Indonesia and Joef Stefan Institute, Jamova Cesta 39, 1001 Ljubljana (Slovenia)
2014-01-01T23:59:59.000Z
We analyze the renormalization group structure of a radiative neutrino mass model consisting of a singly charged and a doubly charged scalar fields. Small Majorana neutrino masses are generated by the exchange of these scalars via two-loop diagrams. We derive boundedness conditions for the Higgs potential and show how they can be satisfied to energies up to the Planck scale. Combining boundedness and perturbativity constraints with neutrino oscillation phenomenology, new limits on the masses and couplings of the charged scalars are derived. These in turn lead to lower limits on the branching ratios for certain lepton flavor violating (LFV) processes such as ??e?, ??3e and ? e conversion in nuclei. Improved LFV measurements could test the model, especially in the case of inverted neutrino mass hierarchy where these are more prominent.
Guever, Tolga; Oezel, Feryal; Psaltis, Dimitrios [Department of Astronomy, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
2012-03-01T23:59:59.000Z
Time-resolved X-ray spectroscopy of thermonuclear bursts observed from low-mass X-ray binaries offer a unique tool to measure neutron-star masses and radii. In this paper, we continue our systematic analysis of all the X-ray bursts observed with Rossi X-ray Timing Explorer from X-ray binaries. We determine the events that show clear evidence for photospheric radius expansion and measure the Eddington limits for these accreting neutron stars using the bolometric fluxes attained at the touchdown moments of each X-ray burst. We employ a Bayesian technique to investigate the degree to which the Eddington limit for each source remains constant between bursts. We find that for sources with a large number of radius expansion bursts, systematic uncertainties are at a 5%-10% level. Moreover, in six sources with only pairs of Eddington-limited bursts, the distribution of fluxes is consistent with a {approx}10% fractional dispersion. This indicates that the spectroscopic measurements of neutron-star masses and radii using thermonuclear X-ray bursts can reach the level of accuracy required to distinguish between different neutron-star equations of state, provided that uncertainties related to the overall flux calibration of X-ray detectors are of comparable magnitude.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Aben, R.; Abolins, M.; AbouZeid, O.?S.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B.?S.; Adamczyk, L.; Adams, D.?L.; Adelman, J.; Adomeit, S.; Adye, T.; Affolder, A.?A.; Agatonovic-Jovin, T.; Aguilar-Saavedra, J.?A.; Agustoni, M.; Ahlen, S.?P.; Ahmadov, F.; Aielli, G.; Akerstedt, H.; Ĺkesson, T.?P.?A.; Akimoto, G.; Akimov, A.?V.; Alberghi, G.?L.; Albert, J.; Albrand, S.; Alconada Verzini, M.?J.; Aleksa, M.; Aleksandrov, I.?N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Alkire, S.?P.; Allbrooke, B.?M.?M.; Allport, P.?P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Alvarez Gonzalez, B.; Álvarez Piqueras, D.; Alviggi, M.?G.; Amako, K.; Amaral Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S.?P.; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L.?S.; Andari, N.; Andeen, T.; Anders, C.?F.; Anders, G.; Anderson, K.?J.; Andreazza, A.; Andrei, V.; Angelidakis, S.; Angelozzi, I.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A.?V.; Anjos, N.; Annovi, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Arabidze, G.; Arai, Y.; Araque, J.?P.; Arce, A.?T.?H.; Arduh, F.?A.; Arguin, J-F.; Argyropoulos, S.; Arik, M.; Armbruster, A.?J.; Arnaez, O.; Arnal, V.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Ĺsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N.?B.; Auerbach, B.; Augsten, K.; Aurousseau, M.; Avolio, G.; Axen, B.; Ayoub, M.?K.; Azuelos, G.; Baak, M.?A.; Baas, A.?E.; Bacci, C.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Badescu, E.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bain, T.; Baines, J.?T.; Baker, O.?K.; Balek, P.; Balestri, T.; Balli, F.; Banas, E.; Banerjee, Sw.; Bannoura, A.?A.?E.; Bansil, H.?S.; Barak, L.; Baranov, S.?P.; Barberio, E.?L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnes, S.?L.; Barnett, B.?M.; Barnett, R.?M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A.?J.; Barreiro, F.; Barreiro Guimarăes da Costa, J.; Bartoldus, R.; Barton, A.?E.; Bartos, P.; Bassalat, A.; Basye, A.; Bates, R.?L.; Batista, S.?J.; Batley, J.?R.; Battaglia, M.; Bauce, M.; Bauer, F.; Bawa, H.?S.; Beacham, J.?B.; Beattie, M.?D.; Beau, T.; Beauchemin, P.?H.; Beccherle, R.; Bechtle, P.; Beck, H.?P.; Becker, K.; Becker, M.; Becker, S.; Beckingham, M.; Becot, C.; Beddall, A.?J.; Beddall, A.; Bednyakov, V.?A.; Bee, C.?P.; Beemster, L.?J.; Beermann, T.?A.; Begel, M.; Behr, J.?K.; Belanger-Champagne, C.; Bell, P.?J.; Bell, W.?H.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bender, M.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J.?A.; Benjamin, D.?P.; Bensinger, J.?R.; Bentvelsen, S.; Beresford, L.; Beretta, M.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Beringer, J.; Bernard, C.; Bernard, N.?R.; Bernius, C.; Bernlochner, F.?U.; Berry, T.; Berta, P.; Bertella, C.; Bertoli, G.; Bertolucci, F.; Bertsche, C.; Bertsche, D.; Besana, M.?I.; Besjes, G.?J.; Bessidskaia Bylund, O.; Bessner, M.; Besson, N.; Betancourt, C.; Bethke, S.; Bevan, A.?J.; Bhimji, W.; Bianchi, R.?M.; Bianchini, L.; Bianco, M.; Biebel, O.; Bieniek, S.?P.; Biglietti, M.; Bilbao De Mendizabal, J.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Black, C.?W.; Black, J.?E.; Black, K.?M.; Blackburn, D.; Blair, R.?E.; Blanchard, J.-B.; Blanco, J.?E.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Bobbink, G.?J.; Bobrovnikov, V.?S.; Bocchetta, S.?S.; Bocci, A.; Bock, C.; Boehler, M.; Bogaerts, J.?A.; Bogdanchikov, A.?G.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A.?S.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E.?V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boveia, A.; Boyd, J.; Boyko, I.?R.; Bozic, I.; Bracinik, J.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J.?E.; Braun, H.?M.; Brazzale, S.?F.; Brendlinger, K.; Brennan, A.?J.; Brenner, L.; Brenner, R.; Bressler, S.; Bristow, K.; Bristow, T.?M.; Britton, D.; Britzger, D.; Brochu, F.?M.; Brock, I.; Brock, R.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W.?K.; Brosamer, J.; Brost, E.; Brown, J.
2015-06-01T23:59:59.000Z
A search has been performed for pair production of heavy vectorlike down-type (B) quarks. The analysis explores the lepton-plus-jets final state, characterized by events with one isolated charged lepton (electron or muon), significant missing transverse momentum, and multiple jets. One or more jets are required to be tagged as arising from b quarks, and at least one pair of jets must be tagged as arising from the hadronic decay of an electroweak boson. The analysis uses the full data sample of pp collisions recorded in 2012 by the ATLAS detector at the LHC, operating at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3??fb?š. No significant excess of events is observed above the expected background. Limits are set on vectorlike B production, as a function of the B branching ratios, assuming the allowable decay modes are B ? Wt/Zb/Hb. In the chiral limit with a branching ratio of 100% for the decay B ? Wt, the observed (expected) 95% C.L. lower limit on the vectorlike B mass is 810 GeV (760 GeV). In the case where the vectorlike B quark has branching ratio values corresponding to those of an SU(2) singlet state, the observed (expected) 95% C.L. lower limit on the vectorlike B mass is 640 GeV (505 GeV). The same analysis, when used to investigate pair production of a colored, charge 5/3 exotic fermion T5/3, with subsequent decay T5/3 ? Wt, sets an observed (expected) 95% C.L. lower limit on the T5/3 mass of 840 GeV (780 GeV).
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Aben, R.; Abolins, M.; AbouZeid, O.?S.; Abramowicz, H.; Abreu, H.; Abreu, R.; et al
2015-06-01T23:59:59.000Z
A search has been performed for pair production of heavy vectorlike down-type (B) quarks. The analysis explores the lepton-plus-jets final state, characterized by events with one isolated charged lepton (electron or muon), significant missing transverse momentum, and multiple jets. One or more jets are required to be tagged as arising from b quarks, and at least one pair of jets must be tagged as arising from the hadronic decay of an electroweak boson. The analysis uses the full data sample of pp collisions recorded in 2012 by the ATLAS detector at the LHC, operating at a center-of-mass energy of 8more ťTeV, corresponding to an integrated luminosity of 20.3 fb?š. No significant excess of events is observed above the expected background. Limits are set on vectorlike B production, as a function of the B branching ratios, assuming the allowable decay modes are B ? Wt/Zb/Hb. In the chiral limit with a branching ratio of 100% for the decay B ? Wt, the observed (expected) 95% C.L. lower limit on the vectorlike B mass is 810 GeV (760 GeV). In the case where the vectorlike B quark has branching ratio values corresponding to those of an SU(2) singlet state, the observed (expected) 95% C.L. lower limit on the vectorlike B mass is 640 GeV (505 GeV). The same analysis, when used to investigate pair production of a colored, charge 5/3 exotic fermion T5/3, with subsequent decay T5/3 ? Wt, sets an observed (expected) 95% C.L. lower limit on the T5/3 mass of 840 GeV (780 GeV).Ť less
Electroweak Penguin and Leptonic Decays at BaBar
Bucci, F.; /Pisa U. /INFN, Pisa
2005-08-26T23:59:59.000Z
Recent BABAR results on electroweak penguin and leptonic decays are reviewed. In particular, the measurements of B {yields} K{sup (*)}l{sup +}l{sup -} and the preliminary results on B {yields} X{sub s}l{sup +}l{sup -} are presented. Also summarized are the preliminary limits on B{sup +} {yields} l{sup +}{nu} (l = e,{mu}) and B{sup +} {yields} K{sup +}{nu}{bar {nu}}.
Rabatel, Antoine
measurements. A recent time series of images from optical and SAR data are selected on 3 outlet glaciers well-scale areas. The limitations are cloudiness for optical data and high slope distortion on SAR images. I resolution, repeat coverage, radiometric calibration and stereo capabilities (automatic generation of DEM
Small Neutrino Masses from Supersymmetry Breaking
Arkani-Hamed, Nima
2009-01-01T23:59:59.000Z
neutrino mass matrices. The above Majorana and Dirac casesMajorana mass for N of the order F/M ? 100GeV, yielding a LR neutrino mass matrixMajorana masses M and couplings to the lepton doublets: L = M NN + ?LNH where M and ? are mass matrices.
Rephasing Invariants of Quark and Lepton Mixing Matrices
Elizabeth Jenkins; Aneesh V. Manohar
2007-11-14T23:59:59.000Z
Rephasing invariants of quark and lepton mixing matrices are obtained in the standard model extended by the seesaw mechanism, and in its low-energy effective theory with the dimension-five Majorana mass operator. We classify the basic invariants, discuss non-trivial relations between them, and determine the independent invariants which characterize all the information in the mixing matrices in a basis-independent way. We also discuss the restrictions on the allowed ranges for the mixing phases, and on the rephasing invariants, which follow from a discrete invariance of the Majorana mass matrix.
Impact of Lepton Number Violation at the LHC on Models of Leptogenesis
Frank F. Deppisch; Julia Harz
2014-08-22T23:59:59.000Z
The discovery of lepton number violation (LNV) at the LHC would have profound consequences for the viability of high-scale leptogenesis models. As an example, we discuss the case of observing a signal with two same-sign leptons, two jets and no missing energy. This would imply a large washout factor for the lepton number density in the early Universe, which leads to a significant constraint on any high-scale model for the generation of the observed baryon asymmetry. In a standard leptogenesis scenario, the corresponding washout factor would strongly decrease a pre-existing lepton asymmetry and thus would render leptogenesis models that generate a (B-L) asymmetry far above the LHC scale ineffective. Therefore, LHC searches focused on LNV processes without missing energy are powerful probes for high-scale leptogenesis models and correspondingly shed light on the nature of baryogenesis and neutrino masses.
Chatrchyan, Serguei; et al.
2011-06-01T23:59:59.000Z
A search is performed for an excess of events, over the standard model expectations, with a photon, a lepton, and large missing transverse energy in pp collisions at sqrt(s) = 7 TeV. Such events are expected in many new physics models, in particular a supersymmetric theory that is broken via a gauge-mediated mechanism, when the lightest charged and neutral gauginos are mass degenerate. The data sample used in this search corresponds to an integrated luminosity of 35 inverse picobarns collected with the CMS detector at the LHC. No evidence of such an excess above the standard model backgrounds, dominated by W-gamma production, is found. The results are presented as 95% confidence level upper limits on the cross section for a benchmark gauge-mediated scenario, and are then converted into exclusion limits on the squark, gluino, and wino masses.
Lepton flavor violating Higgs boson decays from massive seesaw neutrinos
Arganda, Ernesto; Curiel, Ana M.; Herrero, Maria J.; Temes, David [Departamento de Fisica Teorica, Universidad Autonoma de Madrid (Spain); Laboratoire de Physique Theorique, LAPTH (France)
2005-02-01T23:59:59.000Z
Lepton flavor violating Higgs boson decays are studied within the context of seesaw models with Majorana massive neutrinos. Two models are considered: the SM-seesaw, with the standard model particle content plus three right-handed neutrinos, and the MSSM-seesaw, with the minimal supersymmetric standard model particle content plus three right-handed neutrinos and their supersymmetric partners. The widths for these decays are derived from a full one-loop diagrammatic computation in both models, and they are analyzed numerically in terms of the seesaw parameters, namely, the Dirac and Majorana mass matrices. Several possible scenarios for these mass matrices that are compatible with neutrino data are considered. In the SM-seesaw case, very small branching ratios are found for all studied scenarios. These ratios are explained as a consequence of the decoupling behavior of the heavy right-handed neutrinos. In contrast, in the MSSM-seesaw case, sizable branching ratios are found for some of the leptonic flavor violating decays of the MSSM neutral Higgs bosons and for some choices of the seesaw matrices and MSSM parameters. The relevance of the two competing sources of lepton flavor changing interactions in the MSSM-seesaw case is also discussed. The nondecoupling behavior of the supersymmetric particles contributing in the loop diagrams is finally shown.
Yuuiti Sendouda; Shigehiro Nagataki; Katsuhiko Sato
2006-06-07T23:59:59.000Z
The mass spectrum of the primordial black holes formed by density perturbation in the radiation-dominated era of the Randall-Sundrum type-2 cosmology is given. The spectrum coincides with standard four-dimensional one on large scales but the deviation is apparent on smaller scales. The mass spectrum is initially softer than standard four-dimensional one, while after accretion during the earliest era it becomes harder than that. We also show expected extragalactic diffuse photon background spectra varying the initial perturbation power-law power spectrum and give constraints on the blue spectra and/or the reheating temperature. The most recent observations on the small scale density perturbation from WMAP, SDSS and Lyman-\\alpha Forest are used. What we get are interpreted as constraints on the smaller scale inflation on the brane connected to the larger one at the scale of Lyman-\\alpha Forest. If we set the bulk curvature radius to be 0.1 mm and assume the reheating temperature is higher than 10^6 GeV, the scalar spectral index from the smaller scale inflation is constrained to be n \\lesssim 1.3. Typically, the constraints are tighter than standard four-dimensional one, which is also revised by us using the most recent observations.
Leptogenesis within a generalized quark-lepton symmetry
Buccella, F.; Falcone, D.; Oliver, L. [Dipartimento di Scienze Fisiche, Universita di Napoli, Via Cintia, Naples (Italy) and INFN, Sezione di Napoli (Italy); Dipartimento di Scienze Fisiche, Universita di Napoli, Via Cintia, Naples (Italy); Laboratoire de Physique Theorique, Universite de Paris XI, Batiment 210, Orsay Cedex (France)
2008-02-01T23:59:59.000Z
We reexamine the question of baryogenesis via leptogenesis in schemes of the seesaw mechanism with quark-lepton symmetry. Within the phenomenological approach of textures, we propose to relax this strict symmetry and propose weaker conditions, namely, models of the neutrino Dirac mass matrix M{sub D} which have the same hierarchy as the matrix elements of M{sub u}. We call this guideline generalized hierarchical quark-lepton symmetry. We consider in detail particular cases in which the moduli of the matrix elements of M{sub D} are equal to those of M{sub u}. We try for the heavy Majorana mass matrix diagonal and off-diagonal forms. We find that an ansatz for M{sub D} preserving the hierarchy, together with an off-diagonal model for the heavy Majorana neutrino mass, is consistent with neutrino masses, neutrino mixing, and baryogenesis via leptogenesis for an intermediate mass scale m{sub R}{approx}10{sup 12} GeV. The preservation of the hierarchical structure could come from a possible symmetry scheme.
Baringer, Philip S.
1999-06-01T23:59:59.000Z
the Drell-Yan Monte Carlo model and MRSsA 0 d [11] parton distribution func- tions, is ?53% and does not depend strongly on mass above m ee ? 250 GeVyc 2 . This makes the analysis rela- tively model independent. The systematic uncertainty on the acceptance... (negative sign for constructive interference) LR 1 RL LL 2 LR RL 2 RR VV AA 3.9 3.9 4.0 4.9 4.7 4.4 4.5 4.3 6.1 5.5 [16,17], LL 2 LR, RL 2 RR [18], vector-vector sVV ? LL 1 RR 1 LR 1 RLd [19], and axial vector-axial vector sAA ? LL 1 RR 2 LR 2 RLd [19...
Perturbations to $?-?$ Symmetry, Leptogenesis and Lepton Flavour Violation with Type II Seesaw
Manikanta Borah; Debasish Borah; Mrinal Kumar Das; Sudhanwa Patra
2014-10-17T23:59:59.000Z
We study the possibility of generating non-zero reactor mixing angle $\\theta_{13}$ by perturbing the $\\mu-\\tau$ symmetric neutrino mass matrix. The leading order $\\mu-\\tau$ symmetric neutrino mass matrix originates from type I seesaw mechanism whereas the perturbations to $\\mu-\\tau$ symmetry originate from type II seesaw term. We consider four different realizations of $\\mu-\\tau$ symmetry: Bimaximal Mixing(BM), Tri-bimaximal Mixing (TBM), Hexagonal Mixing (HM) and Golden Ratio Mixing (GRM) all giving rise to $\\theta_{13} = 0, \\theta_{23} = \\frac{\\pi}{4}$ but different non-zero values of solar mixing angle $\\theta_{12}$. We assume a minimal $\\mu-\\tau$ symmetry breaking type II seesaw mass matrix as a perturbation and calculate the neutrino oscillation parameters as a function of type II seesaw strength. We then consider the origin of non-trivial leptonic CP phase in the charged lepton sector and calculate the lepton asymmetry arising from the lightest right handed neutrino decay by incorporating the presence of both type I and type II seesaw. We constrain the type II seesaw strength as well as leptonic CP phase (and hence the charged lepton sector) by comparing our results with experimental neutrino oscillation parameters as well as Planck bound on baryon to photon ratio. Finally, we extend our analysis on lepton flavour violating decays like $\\mu \\to e \\gamma$ and $\\mu \\to eee$ due to exchange of TeV scale Higgs triplet scalar within the low scale type II seesaw framework. The branching ratios for these lepton flavour processes are examined with the small type II perturbation term $\\omega$ and the estimated values are very close to the experimental bound coming from current search experiments.
E. O. Iltan
2001-05-17T23:59:59.000Z
We calculate the electric dipole moment of electron using the experimental result of muon electric dipole moment and upper limit of the BR(\\mu --> e\\gamma) in the framework of the general two Higgs doublet model. Our prediction is 10^{-32} e-cm, which lies in the experimental current limits. Further, we obtain constraints for the Yukawa couplings \\bar{\\xi}^{D}_{N,\\tau e} and \\bar{\\xi}^{D}_{N,\\tau\\mu}. Finally we present an expression which connects the BR(\\tau\\to \\mu\\gamma) and the electric dipole moment of \\tau-lepton and study the relation between these physical quantities.
Search for lepton-family-number nonconservation
Hoffman, C.M.
1986-01-01T23:59:59.000Z
A review of the status of lepton-family-number nonconservation is given. After a brief historical and theoretical discussion, a description of how experimental searches for lepton-family-number nonconservation are performed is presented. Finally, a summary of the results from past experiments and prospects for future experiments is given.
Symmetrical parametrizations of the lepton mixing matrix
Rodejohann, W. [Max-Planck-Institut fuer Kernphysik, Postfach 103980, 69029 Heidelberg (Germany); Valle, J. W. F. [AHEP Group, Institut de Fisica Corpuscular--C.S.I.C./Universitat de Valencia, Edificio Institutos de Paterna, Apt 22085, E-46071 Valencia (Spain)
2011-10-01T23:59:59.000Z
Advantages of the original symmetrical form of the parametrization of the lepton mixing matrix are discussed. It provides a conceptually more transparent description of neutrino oscillations and lepton number violating processes like neutrinoless double beta decay, clarifying the significance of Dirac and Majorana phases. It is also ideal for parametrizing scenarios with light sterile neutrinos.
Christian Weinheimer; Kai Zuber
2013-09-04T23:59:59.000Z
The various experiments on neutrino oscillation evidenced that neutrinos have indeed non-zero masses but cannot tell us the absolute neutrino mass scale. This scale of neutrino masses is very important for understanding the evolution and the structure formation of the universe as well as for nuclear and particle physics beyond the present Standard Model. Complementary to deducing constraints on the sum of all neutrino masses from cosmological observations two different methods to determine the neutrino mass scale in the laboratory are pursued: the search for neutrinoless double $\\beta$-decay and the direct neutrino mass search by investigating single $\\beta$-decays or electron captures. The former method is not only sensitive to neutrino masses but also probes the Majorana character of neutrinos and thus lepton number violation with high sensitivity. Currently quite a few experiments with different techniques are being constructed, commissioned or are even running, which aim for a sensitivity on the neutrino mass of {\\cal O}(100) meV. The principle methods and these experiments will be discussed in this short review.
Masses of Fundamental Particles
Hidezumi Terazawa
2014-06-11T23:59:59.000Z
In the original paper entitled, "Masses of Fundamental Particles"(arXiv:1109.3705v5, 10 Feb 2012), not only the masses of fundamental particles including the weak bosons, Higgs boson, quarks, and leptons, but also the mixing angles of quarks and those of neutrinos are all explained and/or predicted in the unified composite models of quarks and leptons successfully. In this addendum entitled, "Higgs Boson Mass in the Minimal Unified Subquark Model", it is emphasized that the Higgs boson mass is predicted to be about 130Gev in the minimal unified subquark model, which agrees well with the experimental values of 125-126GeV recently found by the ATLAS and CMS Collaborations at the LHC.
Kalman filter based tracker study for lepton flavor violation experiments
Rashid M. Djilkibaev; Rostislav V. Konoplich
2009-08-19T23:59:59.000Z
A tracking detector is proposed for lepton flavor violation experiments ($\\mu \\to e$ conversion, $\\mu \\to e + \\gamma$, $\\mu \\to 3e $) consisting of identical chambers which can be reconfigured to meet the requirements for all three experiments. A pattern recognition and track reconstruction procedure based on the Kalman filter technique is presented for this detector. The pattern recognition proceeds in two stages. At the first stage only hit straw tube center coordinates, without drift time information, are used to reduce the background to a manageable level. At the second stage the drift time information is incorporated and a deterministic annealing filter is applied to reach the final level of background suppression. The final track momentum reconstruction is provided by a combinatorial drop filter which is effective in hit-to-track assignment. The momentum resolution of the tracker in measuring monochromatic leptons is found to be $\\sigma_{p}$ = 0.17 and 0.26 MeV for the $\\mu \\to e$ conversion and $\\mu^+ \\to e^+ + \\gamma$ processes, respectively. The tracker reconstruction resolution for the total scalar lepton momentum is $\\sigma_{p} = $ 0.33 MeV for the $\\mu \\to 3e$ process. The obtained tracker resolutions allow an increase in sensitivity to the branching ratios for these processes by a few orders of magnitude over current experimental limits.
Higgs Boson Creation in Laser-Boosted Lepton Collisions
Sarah J. Müller; Christoph H. Keitel; Carsten Müller
2014-02-26T23:59:59.000Z
Electroweak processes in high-energy lepton collisions are considered in a situation where the incident center-of-mass energy lies below the reaction threshold, but is boosted to the required level by subsequent laser acceleration. Within the framework of laser-dressed quantum field theory, we study the laser-boosted process $\\ell^+ \\ell^- \\to HZ^0$ in detail and specify the technical demands needed for its experimental realization. Further, we outline possible qualitative differences to field-free processes regarding the detection of the produced Higgs bosons.
Lepton number violating processes mediated by Majorana neutrinos at hadron colliders
Kovalenko, Sergey; Lu Zhun; Schmidt, Ivan [Departamento de Fisica, Universidad Tecnica Federico, Santa Maria, Casilla 110-V, Valparaiso (Chile) and Center of Subatomic Physics, Valparaiso (Chile)
2009-10-01T23:59:59.000Z
We study the lepton number violating like-sign dilepton processes h{sub 1}h{sub 2}{yields}l{sup {+-}}l{sup '{+-}}jjX and h{sub 1}h{sub 2}{yields}l{sup {+-}}l{sup '{+-}}W{sup {+-}}X, mediated by heavy GeV scale Majorana neutrinos. We focus on the resonantly enhanced contributions with a nearly on-mass-shell Majorana neutrino in the s channel. We study the constraints on like-sign dilepton production at the Tevatron and the LHC on the basis of the existing experimental limits on the masses of heavy neutrinos and their mixings U{sub {alpha}}{sub N} with {alpha}={nu}{sub e}, {nu}{sub {mu}}, {nu}{sub {tau}}. Special attention is paid to the constraints from neutrinoless double beta decay. We note that searches for like-sign e{sup {+-}}e{sup {+-}} events at Tevatron and LHC may provide evidence of CP violation in the neutrino sector. We also discuss the conditions under which it is possible to extract individual constraints on the mixing matrix elements in a model independent way.
Top quark mass measurements at the LHC
Fuster, Juan; The ATLAS collaboration
2015-01-01T23:59:59.000Z
The latest measurements of the top quark mass using the ATLAS and CMS experiments at the LHC are presented. The discussion includes the results obtained using the conventional methods (Template/Ideogram) and those derived from the so called alternative methods. Results from the conventional methods using the various top final states (lepton+jets, di-lepton and full hadronic) are reviewed. Determinations using the inclusive ttbar production, the ttbar production with an additional jet and the lepton-b-jet invariant mass distribution are also discussed.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
del Amo Sanchez, P.; Lees, J. P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Milanes, D. A.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Brown, D. N.; Kerth, L. T.; Kolomensky, Yu. G.; Lynch, G.; Osipenkov, I. L.; Koch, H.; Schroeder, T.; Asgeirsson, D. J.; Hearty, C.; Mattison, T. S.; McKenna, J. A.; Khan, A.; Blinov, V. E.; Buzykaev, A. R.; Druzhinin, V. P.; Golubev, V. B.; Kravchenko, E. A.; Onuchin, A. P.; Serednyakov, S. I.; Skovpen, Yu. I.; Solodov, E. P.; Todyshev, K. Yu.; Yushkov, A. N.; Bondioli, M.; Curry, S.; Kirkby, D.; Lankford, A. J.; Mandelkern, M.; Martin, E. C.; Stoker, D. P.; Atmacan, H.; Gary, J. W.; Liu, F.; Long, O.; Vitug, G. M.; Campagnari, C.; Hong, T. M.; Kovalskyi, D.; Richman, J. D.; West, C. A.; Eisner, A. M.; Heusch, C. A.; Kroseberg, J.; Lockman, W. S.; Martinez, A. J.; Schalk, T.; Schumm, B. A.; Seiden, A.; Winstrom, L. O.; Cheng, C. H.; Doll, D. A.; Echenard, B.; Hitlin, D. G.; Ongmongkolkul, P.; Porter, F. C.; Rakitin, A. Y.; Andreassen, R.; Dubrovin, M. S.; Meadows, B. T.; Sokoloff, M. D.; Bloom, P. C.; Ford, W. T.; Gaz, A.; Nagel, M.; Nauenberg, U.; Smith, J. G.; Wagner, S. R.; Ayad, R.; Toki, W. H.; Jasper, H.; Petzold, A.; Spaan, B.; Kobel, M. J.; Schubert, K. R.; Schwierz, R.; Bernard, D.; Verderi, M.; Clark, P. J.; Playfer, S.; Watson, J. E.; Andreotti, M.; Bettoni, D.; Bozzi, C.; Calabrese, R.; Cecchi, A.; Cibinetto, G.; Fioravanti, E.; Franchini, P.; Garzia, I.; Luppi, E.; Munerato, M.; Negrini, M.; Petrella, A.; Piemontese, L.; Baldini-Ferroli, R.; Calcaterra, A.; de Sangro, R.; Finocchiaro, G.; Nicolaci, M.; Pacetti, S.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Rama, M.; Zallo, A.; Contri, R.; Guido, E.; Lo Vetere, M.; Monge, M. R.; Passaggio, S.; Patrignani, C.; Robutti, E.; Bhuyan, B.; Prasad, V.; Lee, C. L.; Morii, M.; Edwards, A. J.; Adametz, A.; Marks, J.; Uwer, U.; Bernlochner, F. U.; Ebert, M.; Lacker, H. M.; Lueck, T.; Volk, A.; Dauncey, P. D.; Tibbetts, M.; Behera, P. K.; Mallik, U.; Chen, C.; Cochran, J.; Crawley, H. B.; Meyer, W. T.; Prell, S.; Rosenberg, E. I.; Rubin, A. E.; Gritsan, A. V.; Guo, Z. J.; Arnaud, N.; Davier, M.; Derkach, D.; Firmino da Costa, J.; Grosdidier, G.; Le Diberder, F.; Lutz, A. M.; Malaescu, B.; Perez, A.; Roudeau, P.; Schune, M. H.; Serrano, J.; Sordini, V.; Stocchi, A.; Wang, L.; Wormser, G.; Lange, D. J.; Wright, D. M.; Bingham, I.; Chavez, C. A.; Coleman, J. P.; Fry, J. R.; Gabathuler, E.; Hutchcroft, D. E.; Payne, D. J.; Touramanis, C.; Bevan, A. J.; Di Lodovico, F.; Sacco, R.; Sigamani, M.; Cowan, G.; Paramesvaran, S.; Wren, A. C.; Brown, D. N.; Davis, C. L.; Denig, A. G.; Fritsch, M.; Gradl, W.; Hafner, A.; Alwyn, K. E.; Bailey, D.; Barlow, R. J.; Jackson, G.; Lafferty, G. D.; Anderson, J.; Cenci, R.; Jawahery, A.; Roberts, D. A.; Simi, G.; Tuggle, J. M.; Dallapiccola, C.; Salvati, E.; Cowan, R.; Dujmic, D.; Sciolla, G.; Zhao, M.; Lindemann, D.; Patel, P. M.; Robertson, S. H.; Schram, M.; Biassoni, P.; Lazzaro, A.; Lombardo, V.; Palombo, F.; Stracka, S.; Cremaldi, L.; Godang, R.; Kroeger, R.; Sonnek, P.; Summers, D. J.; Nguyen, X.; Simard, M.; Taras, P.; De Nardo, G.; Monorchio, D.; Onorato, G.; Sciacca, C.; Raven, G.; Snoek, H. L.; Jessop, C. P.; Knoepfel, K. J.; LoSecco, J. M.; Wang, W. F.; Corwin, L. A.; Honscheid, K.; Kass, R.; Blount, N. L.; Brau, J.; Frey, R.; Igonkina, O.; Kolb, J. A.; Rahmat, R.; Sinev, N. B.; Strom, D.; Strube, J.; Torrence, E.; Castelli, G.; Feltresi, E.; Gagliardi, N.; Margoni, M.; Morandin, M.; Posocco, M.; Rotondo, M.; Simonetto, F.; Stroili, R.; Ben-Haim, E.; Bomben, M.; Bonneaud, G. R.; Briand, H.; Calderini, G.; Chauveau, J.; Hamon, O.; Leruste, Ph.; Marchiori, G.; Ocariz, J.; Prendki, J.; Sitt, S.; Biasini, M.; Manoni, E.; Rossi, A.; Angelini, C.; Batignani, G.; Bettarini, S.; Carpinelli, M.; Casarosa, G.; Cervelli, A.; Forti, F.; Giorgi, M. A.; Lusiani, A.; Neri, N.; Paoloni, E.; Rizzo, G.; Walsh, J. J.; Lopes Pegna, D.; Lu, C.; Olsen, J.; Smith, A. J. S.; Telnov, A. V.; Anulli, F.; Baracchini, E.; Cavoto, G.; Faccini, R.; Ferrarotto, F.; Ferroni, F.; Gaspero, M.; Li Gioi, L.; Mazzoni, M. A.; Piredda, G.; Renga, F.; Buenger, C.; Hartmann, T.; Leddig, T.; Schröder, H.; Waldi, R.; Adye, T.; Olaiya, E. O.; Wilson, F. F.; Emery, S.; Hamel de Monchenault, G.; Vasseur, G.; Yčche, Ch.; Allen, M. T.; Aston, D.; Bard, D. J.; Bartoldus, R.; Benitez, J. F.; Cartaro, C.; Convery, M. R.; Dorfan, J.; Dubois-Felsmann, G. P.; Dunwoodie, W.; Field, R. C.; Franco Sevilla, M.; Fulsom, B. G.; Gabareen, A. M.; Graham, M. T.; Grenier, P.; Hast, C.; Innes, W. R.; Kelsey, M. H.; Kim, H.; Kim, P.; Kocian, M. L.; Leith, D. W. G. S.; Lewis, P.; Li, S.; Lindquist, B.; Luitz, S.; Luth, V.; Lynch, H. L.; MacFarlane, D. B.; Muller, D. R.
2011-05-01T23:59:59.000Z
Searches for B mesons decaying to final states containing a baryon and a lepton are performed, where the baryon is either ?c or ? and the lepton is a muon or an electron. These decays violate both baryon and lepton number and would be a signature of physics beyond the standard model. No significant signal is observed in any of the decay modes, and upper limits in the range (3.2520)×10?? are set on the branching fractions at the 90% confidence level.
New limit on the mass of 14.4-keV solar axions emitted in an M1 transition in {sup 57}Fe nuclei
Derbin, A. V., E-mail: derbin@pnpi.spb.ru; Muratova, V. N.; Semenov, D. A.; Unzhakov, E. V. [Russian Academy of Sciences, Petersburg Nuclear Physics Institute (Russian Federation)
2011-04-15T23:59:59.000Z
Axions of energy 14.4 keV that originated from the M1 transition in {sup 57}Fe nuclei in the Sun were sought by using the resonance-absorption reaction A+{sup 57}Fe {yields} {sup 57}Fe* {yields} {sup 57}Fe+{gamma} (14.4 keV). Asectioned Si(Li) detector arranged in a low-background facility was used to record photons from this reaction. This resulted in setting a new limit on the axion couplings to nucleons, vertical bar -1.19g{sub AN}{sup 0} + g{sub AN}{sup 3} vertical bar {<=} 3.0 Multiplication-Sign 10{sup -6}. Within the hadronic-axion model, the respective constraint on the axion mass is m{sub A} {<=} 145 eV (at a 95% C.L.).
Inclusive Higgs Boson Searches in Four-Lepton Final States at the LHC
Evelyne Delmeire
2007-05-15T23:59:59.000Z
The inclusive search for the Standard Model Higgs boson in four-lepton final states with the ATLAS and CMS detectors at the LHC pp collider is presented. The discussion focusses on the H-> ZZ^(*)->4l+X decay mode for a Higgs boson in the mass range 120 ~Higgs boson properties is also given.
A wave equation including leptons and quarks for the standard model of quantum physics in
Boyer, Edmond
A wave equation including leptons and quarks for the standard model of quantum physics in Clifford-m@orange.fr August 27, 2014 Abstract A wave equation with mass term is studied for all particles and an- tiparticles of color and antiquarks u and d. This wave equation is form invariant under the Cl 3 group generalizing
Measurement of leptonic asymmetries and top-quark polarization in tt-bar production
Baringer, Philip S.; Bean, Alice; Chen, G.; Clutter, Justace Randall; Sekaric, Jadranka; Wilson, Graham Wallace; Abazov, V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Alverson, G.; Askew, A.; Atkins, S.
2013-01-24T23:59:59.000Z
We present measurements of lepton (?) angular distributions in top-quark (t) pair production and tt-bar?W+bW?b-bar??+?b???-b-ar b-bar decays produced in pp-bar collisions at a center-of-mass energy of s?=1.96??TeV, where ...
CDF/ANAL/TOP/PUB/7680 Measurement of the Top Quark Mass using the Template Method
Quigg, Chris
CDF/ANAL/TOP/PUB/7680 Measurement of the Top Quark Mass using the Template Method in the Lepton, 2005) We report a measurement of the top quark mass in the lepton plus jets channel of tÂŻt events from, which brings 138 tÂŻt candidates separated into four subsamples. A top quark mass is reconstructed
Leptonic CP Violation from a New Perspective
David Emmanuel-Costa; Nuno Rosa Agostinho; J. I. Silva-Marcos; Daniel Wegman
2015-04-27T23:59:59.000Z
We study leptonic CP violation from a new perspective. For Majorana neutrinos, a new parametrization for leptonic mixing of the form $V=O_{23} O_{12} K_{a}^{i}\\cdot O$ reveals interesting aspects that are less clear in the standard parametrization. We identify several important scenario-cases with mixing angles in agreement with experiment and leading to large leptonic CP violation. If neutrinos happen to be quasi-degenerate, this new parametrization might be very useful, e.g., in reducing the number of relevant parameters of models.
Leptonic CP Violation from a New Perspective
Emmanuel-Costa, David; Silva-Marcos, J I; Wegman, Daniel
2015-01-01T23:59:59.000Z
We study leptonic CP violation from a new perspective. For Majorana neutrinos, a new parametrization for leptonic mixing of the form $V=O_{23} O_{12} K_{a}^{i}\\cdot O$ reveals interesting aspects that are less clear in the standard parametrization. We identify several important scenario-cases with mixing angles in agreement with experiment and leading to large leptonic CP violation. If neutrinos happen to be quasi-degenerate, this new parametrization might be very useful, e.g., in reducing the number of relevant parameters of models.
Matrŕ, L; Wyatt, M C; Dent, W R F
2014-01-01T23:59:59.000Z
In recent years, gas has been observed in an increasing number of debris discs, though its nature remains to be determined. Here, we analyse CO molecular excitation in optically thin debris discs, and search ALMA Cycle-0 data for CO J=3-2 emission in the Fomalhaut ring. No significant line emission is observed; we set a 3-$\\sigma$ upper limit on the integrated line flux of 0.16 Jy km s$^{-1}$. We show a significant dependency of the CO excitation on the density of collisional partners $n$, on the gas kinetic temperature $T_k$ and on the ambient radiation field $J$, suggesting that assumptions widely used for protoplanetary discs (e.g. LTE) do not necessarily apply to their low density debris counterparts. When applied to the Fomalhaut ring, we consider a primordial origin scenario where H$_2$ dominates collisional excitation of CO, and a secondary origin scenario dominated by e$^-$ and H$_2$O. In either scenario, we obtain a strict upper limit on the CO mass of 4.9 $\\times$ 10$^{-4}$ M$_{\\oplus}$. This arises...
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Khachatryan, Vardan [Yerevan Physics Inst. (YerPhI) (Armenia)
2014-11-01T23:59:59.000Z
A search is presented for standard model (SM) production of four top quarks (t?tt?t) in pp collisions in the lepton + jets channel. The data correspond to an integrated luminosity of 19.6?š recorded at a centre-of-mass energy of 8 TeV with the CMS detector at the CERN LHC. The expected cross section for SM (t?tt?t) production is ?SM(t?tt?t). A combination of kinematic reconstruction and multivariate techniques is used to distinguish between the small signal and large background. The data are consistent with expectations of the SM, and an upper limit of 32 fb is set at a 95% confidence level on the cross section for producing four top quarks in the SM, where a limit of 32 ą 17 fb is expected.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Khachatryan, Vardan
2014-11-01T23:59:59.000Z
A search is presented for standard model (SM) production of four top quarks (t?tt?t) in pp collisions in the lepton + jets channel. The data correspond to an integrated luminosity of 19.6?š recorded at a centre-of-mass energy of 8 TeV with the CMS detector at the CERN LHC. The expected cross section for SM (t?tt?t) production is ?SM(t?tt?t). A combination of kinematic reconstruction and multivariate techniques is used to distinguish between the small signal and large background. The data are consistent with expectations of the SM, and an upper limit of 32 fb is set at a 95% confidence levelmore ťon the cross section for producing four top quarks in the SM, where a limit of 32 ą 17 fb is expected.Ť less
Khachatryan, Vardan [Yerevan Physics Inst. (YerPhI) (Armenia)
2014-11-01T23:59:59.000Z
A search is presented for standard model (SM) production of four top quarks (t?tt?t) in pp collisions in the lepton + jets channel. The data correspond to an integrated luminosity of 19.6?š recorded at a centre-of-mass energy of 8 TeV with the CMS detector at the CERN LHC. The expected cross section for SM (t?tt?t) production is ?^{SM}_{(t?tt?t)}. A combination of kinematic reconstruction and multivariate techniques is used to distinguish between the small signal and large background. The data are consistent with expectations of the SM, and an upper limit of 32 fb is set at a 95% confidence level on the cross section for producing four top quarks in the SM, where a limit of 32 ą 17 fb is expected.
Testing Radiative Neutrino Mass Models at the LHC
Yi Cai; Jackson D. Clarke; Michael A. Schmidt; Raymond R. Volkas
2015-02-07T23:59:59.000Z
The Large Hadron Collider provides us new opportunities to search for the origin of neutrino mass. Beyond the minimal see-saw models a plethora of models exist which realise neutrino mass at tree- or loop-level, and it is important to be sure that these possibilities are satisfactorily covered by searches. The purpose of this paper is to advance a systematic approach to this problem. Majorana neutrino mass models can be organised by SM-gauge-invariant operators which violate lepton number by two units. In this paper we write down the minimal ultraviolet completions for all of the mass-dimension 7 operators. We predict vector-like quarks, vector-like leptons, scalar leptoquarks, a charged scalar, and a scalar doublet, whose properties are constrained by neutrino oscillation data. A detailed collider study is presented for $O_3=LLQ\\bar dH$ and $O_8 = L\\bar d\\bar e^\\dagger \\bar u^\\dagger H$ completions with a vector-like quark $\\chi\\sim(3, 2, -\\frac{5}{6})$ and a leptoquark $\\phi\\sim(\\bar 3,1,\\frac{1}{3})$. The existing LHC limits extracted from searches for vector-like fermions and sbottoms/stops are $m_\\chi \\gtrsim 620$ GeV and $m_\\phi\\gtrsim 600$ GeV.
ATLAS Collaboration
2015-05-26T23:59:59.000Z
A search for new particles that decay into top quark pairs is reported. The search is performed with the ATLAS experiment at the LHC using an integrated luminosity of 20.3 fb$^{-1}$ of proton-proton collision data collected at a centre-of-mass energy of $\\sqrt{s}=8$ TeV. The lepton-plus-jets final state is used, where the top pair decays to $W^+bW^-\\bar{b}$, with one $W$ boson decaying leptonically and the other hadronically. The invariant mass spectrum of top quark pairs is examined for local excesses or deficits that are inconsistent with the Standard Model predictions. No evidence for a top quark pair resonance is found, and 95% confidence-level limits on the production rate are determined for massive states in benchmark models. The upper limits on the cross-section times branching ratio of a narrow $Z'$ boson decaying to top pairs range from 4.2 pb to 0.03 pb for resonance masses from 0.4 TeV to 3.0 TeV. A narrow leptophobic topcolour $Z'$ boson with mass below 1.8 TeV is excluded. Upper limits are set on the cross-section times branching ratio for a broad colour-octet resonance with $\\Gamma/m =$ 15% decaying to $t\\bar{t}$. These range from 2.5 pb to 0.03 pb for masses from 0.4 TeV to 3.0 TeV. A Kaluza-Klein excitation of the gluon in a Randall-Sundrum model is excluded for masses below 2.2 TeV.
J. Q. Zhang; X. C. Song; W. J. Huo; T. F. Feng
2002-06-17T23:59:59.000Z
In an effective lagrangian approach [EM97] to new physics, the authors in ref. [HL99] pushed tau anomalous magnetic and electric dipole moments (AMDM and EDM) down to $10^{-11}$ and $10^{-25} e cm$ by using a Fritzsch-Xing lepton mass matrix ansatz. In this note, we find that, in this approach, there exists the connection between $\\tau$ AMDM and EDM and the lepton flavor mixing matrix. By using the current neutrino oscillation experimental results, we investigate the parameter space of lepton mixing angles to $\\tau$ AMDM and EDM. We can obtain the same or smaller bounds of $\\delta a_\\tau$ and $d_\\tau$ acquired in ref. [HL99] and constrain $\\theta_l$ (the mixing angle obtained by long-baseline neutrino oscillation experiments) from $\\tau$ AMDM and EDM.
Bryan W. Lynn; Glenn D. Starkman; Katherine Freese; Dmitry I. Podolsky
2013-01-23T23:59:59.000Z
More than four decades ago, Lee and Symanzik proved that, in the Gell Mann-Levy (GML) model with partially conserved axial-vector currents (PCAC), tadpole renormalization (a Higgs Vacuum Stability Condition) forces all S-matrix ultra-violet quadratic divergences (UVQD) to be absorbed into the physical renormalized pseudo-scalar pion (pole) mass squared. We show that this includes "new" UVQD (widely unfamiliar to modern audiences). We also show that tadpole renormalization is an automatic consequence of Ward-Takahashi identities. We prove that all UVQD therefore vanish identically in the Goldstone-mode limit, where pions are Nambu-Goldstone Bosons (NGB), and where Lee and Symanzik's Goldstone Symmetry Restoration Condition (a renormalization prescription) enforces spontaneous symmetry breaking and the massless-ness of NGB. Axial-vector current conservation is restored as is SU(2)(L-R) chiral symmetry: the vanishing of UVQD is therefore achieved in the Goldstone-mode by restoration of an exact symmetry, and therefore (by definition) without fine-tuning! A weak-scale Higgs mass is therefore not UVQD fine-tuned in the spontaneously broken GML LSM. That is simply another (albeit unfamiliar) consequence of the Goldstone Theorem. Hence Goldstone-mode O(4) LSM symmetries are sufficient to ensure that the theory does not suffer from the Higgs Fine Tuning Problem. This is contrary to the widely accepted belief that UVQD in the Higgs mass lead to such problems in the O(4) LSM, which are then presumed to be inherited by the Standard Model (SM). The key observation is to regard the spontaneously broken O(4) LSM as the Goldstone-mode limit of the GML LSM. We prove this first at 1-loop then at all loop orders for the pure scalar GML model. We then break the O(4) symmetry to SU(2)L with SM Yukawa couplings, and show that the above remains true.
Shu Luo
2011-12-14T23:59:59.000Z
Enlightened by the idea of the 3 times 3 CKM angle matrix proposed recently by Harrison et al., we introduce the Dirac angle matrix Phi and the Majorana angle matrix Psi in the lepton sector for Dirac and Majorana neutrinos respectively. We show that in presence of the CP violation, the angle matrix Phi or Psi is entirely equivalent to the complex MNS matrix V itself, but has the advantage of being real, phase rephasing invariant, directly associated to the leptonic unitarity triangles (UTs) and do not depend on any particular parametrization of V. In this paper, we further analyzed how the angle matrices evolve with the energy scale. The one-loop Renormalization Group Equations (RGEs) of Phi, Psi and some other rephasing invariant parameters are derived and the numerical analysis is performed to compare between the case of Dirac and Majorana neutrinos. Different neutrino mass spectra are taken into account in our calculation. We find that apparently different from the case of Dirac neutrinos, for Majorana neutrinos the RG-evolutions of Phi, Psi and the Jarlskog strongly depend on the Majorana-type CP-violating parameters and are quite sensitive to the sign of Delta m^{2}_{31}. They may receive significant radiative corrections in the MSSM if three neutrino masses are nearly degenerate.
Generalized lepton number and dark left-right gauge model
Khalil, Shaaban [Center for Theoretical Physics, British University in Egypt, El Sherouk City, Postal No. 11837, P.O. Box 43 (Egypt); Department of Mathematics, Ain Shams University, Faculty of Science, Cairo 11566 (Egypt); Lee, Hye-Sung; Ma, Ernest [Department of Physics and Astronomy, University of California, Riverside, California 92521 (United States)
2009-02-15T23:59:59.000Z
In a left-right gauge model of particle interactions, the left-handed fermion doublet ({nu},e){sub L} is connected to its right-handed counterpart (n,e){sub R} through a scalar bidoublet so that e{sub L} pairs with e{sub R}, and {nu}{sub L} with n{sub R} to form mass terms. Suppose the latter link is severed without affecting the former, then n{sub R} is not the mass partner of {nu}{sub L}, and as we show in this paper, becomes a candidate for dark matter which is relevant for the recent PAMELA and ATIC observations. We accomplish this in a specific nonsupersymmetric model, where a generalized lepton number can be defined, so that n{sub R} and W{sub R}{sup {+-}} are odd under R{identical_to}(-1){sup 3B+L+2j}. Fermionic leptoquarks are also predicted.
Neutrino Masses and Flavor Mixing
Fritzsch, Harald
2015-01-01T23:59:59.000Z
We discuss the neutrino oscillations, using texture zero mass matrices for the leptons. The reactor mixing angle $\\theta^{}_{l}$ is calculated. The ratio of the masses of two neutrinos is determined by the solar mixing angle. We can calculate the masses of the three neutrinos: $m_1$ $\\approx$ 0.003 eV - $m_2$ $\\approx$ 0.012 eV - $m_3$ $\\approx$ 0.048 eV.
Neutrino Masses and Flavor Mixing
Harald Fritzsch
2015-03-06T23:59:59.000Z
We discuss the neutrino oscillations, using texture zero mass matrices for the leptons. The reactor mixing angle $\\theta^{}_{l}$ is calculated. The ratio of the masses of two neutrinos is determined by the solar mixing angle. We can calculate the masses of the three neutrinos: $m_1$ $\\approx$ 0.003 eV - $m_2$ $\\approx$ 0.012 eV - $m_3$ $\\approx$ 0.048 eV.
Baraffe, I; Allard, F; Chabrier, G
2015-01-01T23:59:59.000Z
We present new models for low-mass stars down to the hydrogen-burning limit that consistently couple atmosphere and interior structures, thereby superseding the widely used BCAH98 models. The new models include updated molecular linelists and solar abundances, as well as atmospheric convection parameters calibrated on 2D/3D radiative hydrodynamics simulations. Comparison of these models with observations in various colour-magnitude diagrams for various ages shows significant improvement over previous generations of models. The new models can solve flaws that are present in the previous ones, such as the prediction of optical colours that are too blue compared to M dwarf observations. They can also reproduce the four components of the young quadruple system LkCa 3 in a colour-magnitude diagram with one single isochrone, in contrast to any presently existing model. In this paper we also highlight the need for consistency when comparing models and observations, with the necessity of using evolutionary models and...
Neutrino mass, lepton number, and the origin of matter
antiparticles? And many other things% Do neutrinos violate CP? #12;Neutrinoless Double Beta Decay W. Rodejohann? #12;Neutrinoless Double Beta Decay 1 sigma W. Rodejohann, 1206.2560 #12;14 F. Iachello #12;15 Regions
Subluminal and Superluminal Electromagnetic Waves and the Lepton Mass Spectrum
Rodríguez, W A
1996-01-01T23:59:59.000Z
Maxwell equation $\\dirac F = 0$ for $F \\in \\sec \\bwe^2 M \\subset \\sec \\clif (M)$, where $\\clif (M)$ is the Clifford bundle of differential forms, have subluminal and superluminal solutions characterized by $F^2 \
Leptonic Decays of the Charged B Meson
Corwin, Luke A.; /Ohio State U.; ,
2010-06-11T23:59:59.000Z
The authors present a search for the decay B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}} ({ell} = {tau}, {mu}, or e) in (458.9 {+-} 5.1) x 10{sup 6} {Upsilon}(4S) decays recorded with the BABAR detector at the SLAC PEP-II B-Factory. A sample of events with one reconstructed exclusive semi-leptonic B decay (B{sup -} {yields} D{sup 0}{ell}{sup -}{bar {nu}}X) is selected, and in the recoil a search for B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}} signal is performed. The {tau} is identified in the following channels: {tau}{sup +} {yields} e{sup +}{nu}{sub e}{bar {nu}}{sub {tau}}, {tau}{sup +} {yields} {mu}{sup +}{nu}{sub {mu}}{bar {nu}}{sub {tau}}, {tau}{sup +} {yields} {pi}{sup +}{bar {nu}}{sub {tau}}, and {tau}{sup +} {yields} {pi}{sup +}{pi}{sup 0}{bar {nu}}{sub {tau}}. The analysis strategy and the statistical procedure is set up for branching fraction extraction or upper limit determination. They determine from the dataset a preliminary measurement of {Beta}(B{sup +} {yields} {tau}{sup +}{nu}{sub {tau}}) = (1.8 {+-} 0.8 {+-} 0.1) x 10{sup -4}, which excludes zero at 2.4{sigma}, and f{sub B} = 255 {+-} 58 MeV. Combination with the hadronically tagged measurement yields {Beta}(B{sup +} {yields} {tau}{sup +}{nu}{sub {tau}}) = (1.8 {+-} 0.6) x 10{sup -4}. They also set preliminary limits on the branching fractions at {Beta}(B{sup +} {yields} e{sup +}{nu}{sub e}) < 7.7 x 10{sup -6} (90% C.L.), {Beta}(B{sup +} {yields} {mu}{sup +}{nu}{sub {mu}}) < 11 x 10{sup -6} (90% C.L.), and {Beta}(B{sup +} {yields} {tau}{sup +}{nu}{sub {tau}}) < 3.2 x 10{sup -4} (90% C.L.).
Two-Higgs Leptonic Minimal Flavour Violation
Botella, F J; Nebot, M; Rebelo, M N
2011-01-01T23:59:59.000Z
We construct extensions of the Standard Model with two Higgs doublets, where there are flavour changing neutral currents both in the quark and leptonic sectors, with their strength fixed by the fermion mixing matrices $V_{CKM}$ and $V_{PMNS}$. These models are an extension to the leptonic sector of the class of models previously considered by Branco, Grimus and Lavoura, for the quark sector. We consider both the cases of Dirac and Majorana neutrinos and identify the minimal discrete symmetry required in order to implement the models in a natural way.
Probing lepton number violation on three frontiers
Deppisch, Frank F. [Department of Physics and Astronomy, University College London (United Kingdom)
2013-12-30T23:59:59.000Z
Neutrinoless double beta decay constitutes the main probe for lepton number violation at low energies, motivated by the expected Majorana nature of the light but massive neutrinos. On the other hand, the theoretical interpretation of the (non-)observation of this process is not straightforward as the Majorana neutrinos can destructively interfere in their contribution and many other New Physics mechanisms can additionally mediate the process. We here highlight the potential of combining neutrinoless double beta decay with searches for Tritium decay, cosmological observations and LHC physics to improve the quantitative insight into the neutrino properties and to unravel potential sources of lepton number violation.
Luo, Shu
2011-01-01T23:59:59.000Z
Enlightened by the idea of the 3 times 3 CKM angle matrix proposed recently by Harrison et al., we introduce the Dirac angle matrix Phi and the Majorana angle matrix Psi in the lepton sector for Dirac and Majorana neutrinos respectively. We show that in presence of the CP violation, the angle matrix Phi or Psi is entirely equivalent to the complex MNS matrix V itself, but has the advantage of being real, phase rephasing invariant, directly associated to the leptonic unitarity triangles (UTs) and do not depend on any particular parametrization of V. In this paper, we further analyzed how the angle matrices evolve with the energy scale. The one-loop Renormalization Group Equations (RGEs) of Phi, Psi and some other rephasing invariant parameters are derived and the numerical analysis is performed to compare between the case of Dirac and Majorana neutrinos. Different neutrino mass spectra are taken into account in our calculation. We find that apparently different from the case of Dirac neutrinos, for Majorana ne...
Gomez-Ceballos, Guillelmo
We measure the inclusive forwardbackward asymmetry of the charged-lepton pseudorapidities from top-quark pairs produced in protonantiproton collisions and decaying to final states that contain two charged leptons (electrons ...
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aaltonen, T.; Álvarez González, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J. A.; Apresyan, A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Auerbach, B.; Aurisano, A.; Azfar, F.; Badgett, W.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Barria, P.; Bartos, P.; Bauce, M.; Bauer, G.; Bedeschi, F.; Beecher, D.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Bhatti, A.; Binkley, M.; Bisello, D.; Bizjak, I.; Bland, K. R.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brau, B.; Brigliadori, L.; Brisuda, A.; Bromberg, C.; Brucken, E.; Bucciantonio, M.; Budagov, J.; Budd, H. S.; Budd, S.; Burkett, K.; Busetto, G.; Bussey, P.; Buzatu, A.; Calancha, C.; Camarda, S.; Campanelli, M.; Campbell, M.; Canelli, F.; Canepa, A.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Carron, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Chlebana, F.; Cho, K.; Chokheli, D.; Chou, J. P.; Chung, W. H.; Chung, Y. S.; Ciobanu, C. I.; Ciocci, M. A.; Clark, A.; Clarke, C.; Compostella, G.; Convery, M. E.; Conway, J.; Corbo, M.; Cordelli, M.; Cox, C. A.; Cox, D. J.; Crescioli, F.; Cuenca Almenar, C.; Cuevas, J.; Culbertson, R.; Dagenhart, D.; dAscenzo, N.; Datta, M.; de Barbaro, P.; De Cecco, S.; De Lorenzo, G.; DellOrso, M.; Deluca, C.; Demortier, L.; Deng, J.; Deninno, M.; Devoto, F.; dErrico, M.; Di Canto, A.; Di Ruzza, B.; Dittmann, J. R.; DOnofrio, M.; Donati, S.; Dong, P.; Dorigo, M.; Dorigo, T.; Ebina, K.; Elagin, A.; Eppig, A.; Erbacher, R.; Errede, D.; Errede, S.; Ershaidat, N.; Eusebi, R.; Fang, H. C.; Farrington, S.; Feindt, M.; Fernandez, J. P.; Ferrazza, C.; Field, R.; Flanagan, G.; Forrest, R.; Frank, M. J.; Franklin, M.; Freeman, J. C.; Funakoshi, Y.; Furic, I.; Gallinaro, M.; Galyardt, J.; Garcia, J. E.; Garfinkel, A. F.; Garosi, P.; Gerberich, H.; Gerchtein, E.; Giagu, S.; Giakoumopoulou, V.; Giannetti, P.; Gibson, K.; Ginsburg, C. M.; Giokaris, N.; Giromini, P.; Giunta, M.; Giurgiu, G.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldin, D.; Goldschmidt, N.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; González, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Grinstein, S.; Grosso-Pilcher, C.; Group, R. C.; Guimaraes da Costa, J.; Gunay-Unalan, Z.; Haber, C.; Hahn, S. R.; Halkiadakis, E.; Hamaguchi, A.; Han, J. Y.; Happacher, F.; Hara, K.; Hare, D.; Hare, M.; Harr, R. F.; Hatakeyama, K.; Hays, C.; Heck, M.; Heinrich, J.; Herndon, M.; Hewamanage, S.; Hidas, D.; Hocker, A.; Hopkins, W.; Horn, D.; Hou, S.; Hughes, R. E.; Hurwitz, M.; Husemann, U.; Hussain, N.; Hussein, M.; Huston, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E. J.; Jha, M. K.; Jindariani, S.; Johnson, W.; Jones, M.; Joo, K. K.; Jun, S. Y.; Junk, T. R.; Kamon, T.; Karchin, P. E.; Kasmi, A.; Kato, Y.; Ketchum, W.; Keung, J.; Khotilovich, V.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, H. W.; Kim, J. E.; Kim, M. J.; Kim, S. B.; Kim, S. H.; Kim, Y. K.; Kimura, N.; Kirby, M.; Klimenko, S.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Kotwal, A. V.; Kreps, M.; Kroll, J.; Krop, D.; Krumnack, N.; Kruse, M.; Krutelyov, V.; Kuhr, T.; Kurata, M.; Kwang, S.; Laasanen, A. T.; Lami, S.; Lammel, S.; Lancaster, M.; Lander, R. L.; Lannon, K.; Lath, A.; Latino, G.; LeCompte, T.; Lee, E.; Lee, H. S.; Lee, J. S.; Lee, S. W.; Leo, S.; Leone, S.; Lewis, J. D.; Limosani, A.; Lin, C.-J.; Linacre, J.; Lindgren, M.; Lipeles, E.; Lister, A.; Litvintsev, D. O.; Liu, C.; Liu, Q.; Liu, T.; Lockwitz, S.; Loginov, A.; Lucchesi, D.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lys, J.; Lysak, R.; Madrak, R.; Maeshima, K.; Maestro, P.; Makhoul, K.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Margaroli, F.; Marino, C.; Martínez, M.; Martínez-Ballarín, R.; Mastrandrea, P.; Mattson, M. E.; Mazzanti, P.; McFarland, K. S.; McIntyre, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Menzione, A.; Mesropian, C.; Miao, T.; Mietlicki, D.; Mitra, A.; Miyake, H.; Moed, S.; Moggi, N.; Mondragon, M. N.; Moon, C. S.; Moore, R.; Morello, M. J.; Morlock, J.; Movilla Fernandez, P.; Mukherjee, A.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Naganoma, J.; Nakano, I.; Napier, A.; Nett, J.; Neu, C.; Neubauer, M. S.; Nielsen, J.; Nodulman, L.; Norniella, O.; Nurse, E.; Oakes, L.; Oh, S. H.; Oh, Y. D.; Oksuzian, I.; Okusawa, T.; Orava, R.; Ortolan, L.; Pagan Griso, S.; Pagliarone, C.; Palencia, E.; Papadimitriou, V.; Paramonov, A. A.; Patrick, J.; Pauletta, G.; Paulini, M.; Paus, C.; Pellett, D. E.; Penzo, A.; Phillips, T. J.; Piacentino, G.; Pianori, E.; Pilot, J.; Pitts, K.; Plager, C.
2012-05-01T23:59:59.000Z
We report on a search for the standard model Higgs boson decaying into pairs of ? leptons in pp? collisions produced by the Tevatron at ?s=1.96 TeV. The analyzed data sample was recorded by the CDFII detector and corresponds to an integrated luminosity of 6.0 fb?š. The search is performed in the final state with one ? decaying leptonically and the second one identified through its semihadronic decay. Since no significant excess is observed, a 95% credibility level upper limit on the production cross section times branching ratio to the ?? final state is set for hypothetical Higgs boson masses between 100 and 150 GeV/c˛. For a Higgs boson of 120 GeV/c˛ the observed (expected) limit is 14.6 (15.3) the predicted value.
Hill, Christopher S.; /UC, Santa Barbara
2004-12-01T23:59:59.000Z
The top quark, with its extraordinarily large mass (nearly that of a gold atom), plays a significant role in the phenomenology of EWSB in the Standard Model. In particular, the top quark mass when combined with the W mass constrains the mass of the as yet unobserved Higgs boson. Thus, a precise determination of the mass of the top quark is a principal goal of the CDF and D0 experiments. With the data collected thus far in Runs 1 and 2 of the Tevatron, CDF and D0 have measured the top quark mass in both the lepton+jets and dilepton decay channels using a variety of complementary experimental techniques. The author presents an overview of the most recent of the measurements.
Chatrchyan, Serguei; et al.
2011-08-01T23:59:59.000Z
Results are reported from a search for physics beyond the standard model in proton-proton collisions at a center-of-mass energy of 7 TeV, focusing on the signature with a single, isolated, high-transverse-momentum lepton (electron or muon), energetic jets, and large missing transverse momentum. The data sample comprises an integrated luminosity of 36 inverse picobarns, recorded by the CMS experiment at the LHC. The search is motivated by models of new physics, including supersymmetry. The observed event yields are consistent with standard model backgrounds predicted using control samples obtained from the data. The characteristics of the event sample are consistent with those expected for the production of t t-bar and W +jets events. The results are interpreted in terms of limits on the parameter space for the constrained minimal supersymmetric extension of the standard model.
Pasham, Dheeraj R; Mushotzky, Richard F
2015-01-01T23:59:59.000Z
M82 X-1, the brightest X-ray source in the galaxy M82, has been thought to be an intermediate-mass black hole (100 to 10,000 solar masses) because of its extremely high luminosity and variability characteristics, although some models suggest that its mass may be only about 20 solar masses. The previous mass estimates were based on scaling relations that use low-frequency characteristic timescales which have large intrinsic uncertainties. For stellar-mass black holes, we know that the high-frequency quasi-periodic oscillations (100-450 hertz) in the X-ray emission that occur in a 3:2 frequency ratio are stable and scale in frequency inversely with black hole mass with a reasonably small dispersion. The discovery of such stable oscillations thus potentially offers an alternative and less ambiguous means of mass determination for intermediate-mass black holes, but has hitherto not been realized. Here we report stable, twin-peak (3:2 frequency ratio) X-ray quasi-periodic oscillations from M82 X-1 at frequencies o...
Further evidence for narrow exotic low mass baryons
B. Tatischeff
2004-04-29T23:59:59.000Z
Although narrow low mass baryonic structures, observed mainly in SPES3 (Saturne) data, were not confirmed in recent experiments using lepton probes, their existence is confirmed in other data, where hadronic probes were used.
airborne particle mass: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Feb 2012), not only the masses of fundamental particles including the weak bosons, Higgs boson, quarks, and leptons, but also the mixing angles of quarks and those of neutrinos...
Classification of lepton mixing matrices from finite residual symmetries
Renato M. Fonseca; Walter Grimus
2014-08-19T23:59:59.000Z
Assuming that neutrinos are Majorana particles, we perform a complete classification of all possible mixing matrices which are fully determined by residual symmetries in the charged-lepton and neutrino mass matrices. The classification is based on the assumption that the residual symmetries originate from a finite flavour symmetry group. The mathematical tools which allow us to accomplish this classification are theorems on sums of roots of unity. We find 17 sporadic cases plus one infinite series of mixing matrices associated with three-flavour mixing, all of which have already been discussed in the literature. Only the infinite series contains mixing matrices which are compatible with the data at the 3 sigma level.
Alexander Mann
2012-05-22T23:59:59.000Z
This thesis consists of three closely related parts. An analysis of data recorded by the ATLAS detector in 2010 in proton-proton collisions at a center-of-mass energy of 7 TeV with an integrated luminosity of 33.4/pb is performed, searching for supersymmetric final states containing jets and missing transverse energy and no electrons or muons (zero-lepton channel). No excess over the Standard Model background expectation is observed. Using the CLs and PLR methods, exclusion limits are set in two different supergravity models. These considerably extend the excluded parameter ranges from earlier experiments. The rates and efficiencies of triggers based on combined signatures with jets plus missing transverse energy in ATLAS are studied, which are the primary triggers for the search for Supersymmetry in the zero-lepton channel. For the measurement of the efficiencies in data collected in 2010 and 2011, the bootstrap method is applied. Different sample triggers based on jets and missing transverse energy are compared and their efficiencies are measured. A reweighting approach is used to correct for the bias from the propagation of the uncertainties in the bootstrap method. A universal model is developed to describe the contribution of fake missing transverse energy from resolution effects to the rates of missing transverse energy triggers as function of the level of in-time pile-up, i.e. the number of concurrent proton-proton interactions. The input parameters are tuned to the properties of the ATLAS trigger system, and the model predictions are compared to measurements of trigger rates in ATLAS. Good agreement is found for low thresholds for which the rates are dominated by resolution effects, whereas the rates for higher thresholds are underestimated due to additional sources of fake and real missing transverse energy, which are not incorporated in the model.
Standard model high mass Higgs search at CDF
Lucchesi, Donatella; /INFN, Padua
2010-01-01T23:59:59.000Z
The CDF collaboration has analyzed almost 6 f b{sup -1} of data collected at the Tevatron Collider at {radical}{ovr s} = 1.96 TeV to search for Standard Model Higgs boson through the decay into W{sup +}W{sup -}*. Starting from events with two leptons, advanced analysis techniques are applied to better discriminate signal from background. The Higgs sensitivity is maximized combining together analysis that exploit different event topologies. No significant excess over the expected background is observed and data is used to set a limit in units of Standard Model expectations. The limit plays a fundamental role in the Higgs search excluding the existence of this particle with mass between 158 and 175 GeV/c{sup 2} when combined with D0, the other Tevatron experiment.
Khachatryan, Vardan [Yerevan Phys. Inst. (Armenia); et al.,
2014-08-01T23:59:59.000Z
A search for new resonances decaying to WW, ZZ, or WZ is presented. Final states are considered in which one of the vector bosons decays leptonically and the other hadronically. Results are based on data corresponding to an integrated luminosity of 19.7 inverse femtobarns recorded in proton-proton collisions at $\\sqrt{s}$ = 8 TeV with the CMS detector at the CERN LHC. Techniques aiming at identifying jet substructures are used to analyze signal events in which the hadronization products from the decay of highly boosted W or Z bosons are contained within a single reconstructed jet. Upper limits on the production of generic WW, ZZ, or WZ resonances are set as a function of the resonance mass and width. We increase the sensitivity of the analysis by statistically combining the results of this search with a complementary study of the all-hadronic final state. Upper limits at 95% confidence level are set on the bulk graviton production cross section in the range from 700 to 10 femtobarns for resonance masses between 600 and 2500 GeV, respectively. These limits on the bulk graviton model are the most stringent to date in the diboson final state.
Badertscher, A; Degunda, U; Epprecht, L; Horikawa, S; Knecht, L; Lazzaro, C; Lussi, D; Marchionni, A; Natterer, G; Otiougova, P; Resnati, F; Rubbia, A; Strabel, C; Ulbricht, J; Viant, T
2010-01-01T23:59:59.000Z
GLACIER (Giant Liquid Argon Charge Imaging ExpeRiment) is a large underground observatory for proton decay search, neutrino astrophysics and CP-violation studies in the lepton sector. Possible underground sites are studied within the FP7 LAGUNA project (Europe) and along the JPARC neutrino beam in collaboration with KEK (Japan). The concept is scalable to very large masses.
New limits for neutrinoless tau decays
Ammar, Raymond G.; Baringer, Philip S.; Bean, Alice; Besson, David Zeke; Coppage, Don; Darling, C.; Davis, Robin E. P.; Kotov, S.; Kravchenko, I.; Kwak, Nowhan; Zhou, L.
1998-05-01T23:59:59.000Z
double beta decays, neutrino oscillations, Z!l11l22 decays, and other rare pro- cesses. In particular, there are strict limits on muon neutrino- less decays: B(m!eg),4.9310211 and B(m!eee),2.4 310212 at 90% confidence level @18#. However, lepton num- ber... particles and on the new coupling constants. The most optimistic branching fraction predictions are at the level of about 1026. Constraints on lepton flavor violation come from studies of rare and forbidden K , p, and m decays, e-m conversions, neutrinoless...
Istvan Danko; for the CLEO Collaboration
2006-01-18T23:59:59.000Z
We present the analysis technique and preliminary results of two ongoing analyses at CLEO which put lepton universality and lepton flavor conservation to the test in Upsilon decays.
Limits on Low-Mass WIMP Dark Matter with an Ultra-Low-Energy Germanium Detector at 220 eV Threshold
Shin-Ted Lin; H. T. Wong; for the TEXONO Collaboration
2008-10-20T23:59:59.000Z
An energy threshold of (220$\\pm$10) eV was achieved at an efficiency of 50% with a four-channel ultra-low-energy germanium detector each with an active mass of 5 g\\cite{wimppaper}. This provides a unique probe to WIMP dark matter with mass below 10 GeV. With low background data taken at the Kuo-Sheng Laboratory, constraints on WIMPs in the galactic halo were derived. Both spin-independent WIMP-nucleon and spin-dependent WIMP-neutron bounds improve over previous results for WIMP mass between 3$-$6 GeV. These results, together with those on spin-dependent couplings, will be presented. Sensitivities for full-scale experiments were projected. This detector technique makes the unexplored sub-keV energy window accessible for new neutrino and dark matter experiments.
Lepton Flavor Violation in Flavored Gauge Mediation
Lorenzo Calibbi; Paride Paradisi; Robert Ziegler
2014-08-04T23:59:59.000Z
We study the anatomy and phenomenology of Lepton Flavor Violation (LFV) in the context of Flavored Gauge Mediation (FGM). Within FGM, the messenger sector couples directly to the MSSM matter fields with couplings controlled by the same dynamics that explains the hierarchies in the SM Yukawas. Although the pattern of flavor violation depends on the particular underlying flavor model, FGM provides a built-in flavor suppression similar to wave function renormalization or SUSY Partial Compositeness. Moreover, in contrast to these models, there is an additional suppression of left-right (LR) flavor transitions by third-generation Yukawas that in particular provides an extra protection against flavor-blind phases. We exploit the consequences of this setup for lepton flavor phenomenology, assuming that the new couplings are controlled by simple U(1) flavor models that have been proposed to accommodate large neutrino mixing angles. Remarkably, it turns out that in the context of FGM these models can pass the impressive constraints from LFV processes and leptonic EDMs even for light superpartners, therefore offering the possibility of resolving the longstanding muon g-2 anomaly.
On the minimum and maximum mass of neutron stars and the delayed collapse
Strobel, K; Strobel, Klaus; Weigel, Manfred K.
2001-01-01T23:59:59.000Z
The minimum and maximum mass of protoneutron stars and neutron stars are investigated. The hot dense matter is described by relativistic (including hyperons) and non-relativistic equations of state. We show that the minimum mass ($\\sim$ 0.88 - 1.28 $M_{\\sun}$) of a neutron star is determined by the earliest stage of its evolution and is nearly unaffected by the presence of hyperons. The maximum mass of a neutron star is limited by the protoneutron star or hot neutron star stage. Further we find that the delayed collapse of a neutron star into a black hole during deleptonization is not only possible for equations of state with softening components, as for instance, hyperons, meson condensates etc., but also for neutron stars with a pure nucleonic-leptonic equation of state.
On the minimum and maximum mass of neutron stars and the delayed collapse
Klaus Strobel; Manfred K. Weigel
2000-12-14T23:59:59.000Z
The minimum and maximum mass of protoneutron stars and neutron stars are investigated. The hot dense matter is described by relativistic (including hyperons) and non-relativistic equations of state. We show that the minimum mass ($\\sim$ 0.88 - 1.28 $M_{\\sun}$) of a neutron star is determined by the earliest stage of its evolution and is nearly unaffected by the presence of hyperons. The maximum mass of a neutron star is limited by the protoneutron star or hot neutron star stage. Further we find that the delayed collapse of a neutron star into a black hole during deleptonization is not only possible for equations of state with softening components, as for instance, hyperons, meson condensates etc., but also for neutron stars with a pure nucleonic-leptonic equation of state.
Further Evidence of Narrow Baryonic Structures with Hadronic as Well as Leptonic Probes
B. Tatischeff; E. Tomasi-Gustafsson
2004-11-22T23:59:59.000Z
Although extracted from several experiments using hadronic probes \\cite{bor1}, narrow baryonic structures have been sometimes met with disbelief. New signatures are presented, which appear from already published data, obtained with hadronic probes as well as with leptonic probes. The authors of these results did not take into account the possibility to associate the discontinuities of their spectra with the topic of narrow baryonic low mass structures. The stability of the observed narrow structure masses, represents a confirmation of their genuine existence.
Aaltonen, T.; /Helsinki Inst. of Phys.; Alvarez Gonzalez, B.; /Oviedo U. /Cantabria Inst. of Phys.; Amerio, S.; /INFN, Padua; Amidei, D.; /Michigan U.; Anastassov, A.; /Northwestern U.; Annovi, A.; /Frascati; Antos, J.; /Comenius U.; Apollinari, G.; /Fermilab; Appel, J.A.; /Fermilab; Apresyan, A.; /Purdue U.; Arisawa, T.; /Waseda U. /Dubna, JINR
2012-01-01T23:59:59.000Z
We report on a search for the standard model Higgs boson decaying into pairs of {tau} leptons in p{bar p} collisions produced by the Tevatron at {radical}s = 1.96 TeV. The analyzed data sample was recorded by the CDFII detector and corresponds to an integrated luminosity of 6.0 fb{sup -1}. The search is performed in the final state with one {tau} decaying leptonically and the second one identified through its semi-hadronic decay. Since no significant excess is observed, a 95% credibility level upper limit on the production cross section times branching ratio to the {tau}{tau} final state is set for hypothetical Higgs boson masses between 100 and 150 GeV/c{sup 2}. For a Higgs boson of 120 GeV/c{sup 2} the observed (expected) limit is 14.6 (15.3) the predicted value.
Lepton flavor violation as a probe of quark-lepton unification
Cheung, Kingman; Kang, Sin Kyu; Kim, C.S.; Lee, Jake [Department of Physics, Tsing Hua Univeristy, Hsinchu, Taiwan (China); School of Physics, Seoul National University, Seoul 151-741 (Korea, Republic of); Department of Physics, Yonsei University, Seoul 120-749 (Korea, Republic of)
2005-08-01T23:59:59.000Z
The recent measurements of the solar neutrino mixing angle {theta}{sub sol} and the Cabibbo mixing angle {theta}{sub C} reveal a surprising relation, {theta}{sub sol}+{theta}{sub C}{approx_equal}({pi}/4), which has been interpreted as an evidence for quark-lepton unification. We show in realizations of quark-lepton unification that the PMNS mixing matrix can be decomposed into a CKM-like matrix and maximal mixing matrices. We explore a possibility to probe such implications by considering the relative sizes of branching ratios for the lepton flavor violating radiative decay processes, l{sub i}{yields}l{sub j}{gamma}, in the context of the supersymmetric standard model with heavy right-handed Majorana neutrinos.
Top Mass Measurements with the D0 Detector
Daniel Boline
2015-01-18T23:59:59.000Z
I present recent results related to the measurement of the top quark mass, using $p\\bar{p}$ collisions recorded with the D{\\O}Detector at the Tevatron. The results are: A direct measurement of the mass difference between top and anti-top quarks, Measurement of the top quark mass in the lepton+jets channel and in the dilepton channel.
An infrared origin of leptonic mixing and its test at DeepCore
F. Terranova
2011-10-10T23:59:59.000Z
Fermion mixing is generally believed to be a low-energy manifestation of an underlying theory whose energy scale is much larger than the electroweak scale. In this paper we investigate the possibility that the parameters describing lepton mixing actually arise from the low-energy behavior of the neutrino interacting fields. In particular, we conjecture that the measured value of the mixing angles for a given process depends on the number of unobservable flavor states at the energy of the process. We provide a covariant implementation of such conjecture, draw its consequences in a two neutrino family approximation and compare these findings with current experimental data. Finally we show that this infrared origin of mixing will be manifest at the Ice Cube DeepCore array, which measures atmospheric oscillations at energies much larger than the tau lepton mass; it will hence be experimentally tested in a short time scale.
Small mixing angle {theta}{sub 13} and the lepton asymmetry
Lee, Song-Haeng; Siyeon, Kim [Department of Physics, Chung-Ang University, Seoul 156-756 (Korea, Republic of)
2005-05-01T23:59:59.000Z
We present the correlation of low-energy CP phases, both Dirac and Majorana, and the lepton asymmetry for the baryon asymmetry in the universe, with a certain class of Yukawa matrices that consist of two right-handed neutrinos whose mass ratio is about 2x10{sup -4} and include one texture zero in themselves. For cases in which the amount of the lepton asymmetry Y{sub L} turns out to be proportional to {theta}{sub 13}{sup 2}, we consider the constraint between two types of CP phases and the relation of Y{sub L} versus the Jarlskog invariant or the amplitude of neutrinoless double beta decay as {theta}{sub 13} varies.
Lepton Universality Test in Upsilon(1S) Decays at BaBar
Guido, Elisa; /Genoa U. /INFN, Genoa
2012-04-10T23:59:59.000Z
Using a sample of 122 million {Upsilon}(3S) decays collected with the BABAR detector at the PEP-II asymmetric energy collider at the SLAC National Accelerator Laboratory, we measure the ratio R{sub {tau}{mu}} = BR({Upsilon}(1S) {yields} {tau}{sup +}{tau}{sup -})/BR({Upsilon}(1S) {yields} {mu}{sup +}{mu}{sup -}); the measurement is intended as a test of lepton universality and as a possible search for a light pseudoscalar Higgs boson in Next to Minimal Supersymmetric Standard Model (NMSSM) scenarios. Such a boson could appear in a deviation of the ratio R{sub {tau}{mu}} from the Standard Model expectation, that is 1, except for small lepton mass corrections. The analysis exploits the decays {Upsilon}(3S) {yields} {Upsilon}(1S){pi}{sup +}{pi}{sup -}, {Upsilon}(1S) {yields} l{sup +}l{sup -}, where l = {mu},{tau}.
Testing solar lepton mixing sum rules in neutrino oscillation experiments
Ballett, Peter; Luhn, Christoph; Pascoli, Silvia; Schmidt, Michael A
2014-01-01T23:59:59.000Z
Small discrete family symmetries such as S4, A4 or A5 may lead to simple leading-order predictions for the neutrino mixing matrix such as the bimaximal, tribimaximal or golden ratio mixing patterns, which may be brought into agreement with experimental data with the help of corrections from the charged-lepton sector. Such scenarios generally lead to relations among the parameters of the physical leptonic mixing matrix known as solar lepton mixing sum rules. In this article, we present a simple derivation of such solar sum rules, valid for arbitrary neutrino and charged lepton mixing angles and phases, assuming only {\\theta}13^{\
Performance of ?q-lepton reconstruction and identification in CMS
Chatrchyan, Serguei; et al.
2012-01-01T23:59:59.000Z
The performance of tau-lepton reconstruction and identification algorithms is studied using a data sample of proton-proton collisions at sqrt(s)=7 TeV, corresponding to an integrated luminosity of 36 inverse picobarns collected with the CMS detector at the LHC. The tau leptons that decay into one or three charged hadrons, zero or more short-lived neutral hadrons, and a neutrino are identified using final-state particles reconstructed in the CMS tracker and electromagnetic calorimeter. The reconstruction efficiency of the algorithms is measured using tau leptons produced in Z-boson decays. The tau-lepton misidentification rates for jets and electrons are determined.
CDF/ANAL/TOP/PUB/7153 Measurement of the Top Quark Mass using the Template Method
Quigg, Chris
CDF/ANAL/TOP/PUB/7153 Measurement of the Top Quark Mass using the Template Method in the Lepton of the top quark mass in the lepton plus jets channel of t #22; t events from p#22;p collisions at p s = 1; t candidates with at least one identi#12;ed b jet. A top quark mass is reconstructed for each event by using
ATLAS Collaboration
2015-03-16T23:59:59.000Z
A low-background inclusive search for new physics in events with same-sign dileptons is presented. The search uses proton-proton collisions corresponding to 20.3 fb$^{-1}$ of integrated luminosity taken in 2012 at a centre-of-mass energy of 8 TeV with the ATLAS detector at the LHC. Pairs of isolated leptons with the same electric charge and large transverse momenta of the type $e^{\\pm}e^{\\pm}, e^{\\pm}\\mu^{\\pm}$, and $\\mu^{\\pm}\\mu^{\\pm}$ are selected and their invariant mass distribution is examined. No excess of events above the expected level of Standard Model background is found. The results are used to set upper limits on the cross-sections for processes beyond the Standard Model. Limits are placed as a function of the dilepton invariant mass within a fiducial region corresponding to the signal event selection criteria. Exclusion limits are also derived for a specific model of doubly charged Higgs boson production.
Limits on flavor changing neutral currents in D-0 meson Decays
Ammar, Raymond G.; Baringer, Philip S.; Bean, Alice; Besson, David Zeke; Coppage, Don; Copty, N.; Davis, Robin E. P.; Hancock, N.; Kotov, S.; Kravchenko, I.; Kwak, Nowhan
1996-04-01T23:59:59.000Z
Using the CLEO II detector at the Cornell Electron Storage Ring, we have searched for flavor changing neutral currents and lepton family number violations in D-0 meson decays. The upper limits on the branching fractions ...
Tevatron New Phenomena; Higgs working group; CDF Collaboration; D0 Collaboration
2008-08-05T23:59:59.000Z
We combine results from CDF and DO searches for a standard model Higgs boson in ppbar collisions at the Fermilab Tevatron, at sqrt{s}=1.96 TeV. With 3.0 fb-1 of data analyzed at CDF, and at DO, the 95% C.L. upper limits on Higgs boson production are a factor of 1.2, 1.0 and 1.3 higher than the SM cross section for a Higgs boson mass of m_{H}=$165, 170 and 175 GeV, respectively. We exclude at 95% C.L. a standard model Higgs boson of m_H=170 GeV. Based on simulation, the ratios of the corresponding median expected upper limit to the Standard Model cross section are 1.2, 1.4 and 1.7. Compared to the previous Higgs Tevatron combination, more data and refined analysis techniques have been used. These results extend significantly the individual limits of each experiment and provide new knowledge on the mass of the standard model Higgs boson beyond the LEP direct searches.
Status and implications of neutrino masses: a brief panorama
Valle, J W F
2015-01-01T23:59:59.000Z
With the historic discovery of the Higgs boson our picture of particle physics would have been complete were it not for the neutrino sector and cosmology. I briefly discuss the role of neutrino masses and mixing upon gauge coupling unification, electroweak breaking and the flavor sector. Time is ripe for new discoveries such as leptonic CP violation, charged lepton flavor violation and neutrinoless double beta decay. Neutrinos could also play a role in elucidating the nature of dark matter and cosmic inflation.
Aaltonen, Timo Antero; et al.,
2014-07-23T23:59:59.000Z
We measure the inclusive forward-backward asymmetry of the charged-lepton pseudorapidities from top-quark pairs produced in proton-antiproton collisions, and decaying to final states that contain two charged leptons (electrons or muons), using data collected with the Collider Detector at Fermilab.
Chatrchyan, Serguei; et al.
2012-03-01T23:59:59.000Z
A search for the standard model Higgs boson decaying to W+W- in pp collisions at sqrt(s) = 7 TeV is reported. The data are collected at the LHC with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. The W+W- candidates are selected in events with two charged leptons and large missing transverse energy. No significant excess of events above the standard model background expectations is observed, and upper limits on the Higgs boson production relative to the standard model Higgs expectation are derived. The standard model Higgs boson is excluded in the mass range 129-270 GeV at 95% confidence level.
Form invariance and symmetry in the neutrino mass matrix
Lashin, E. I. [Department of Physics and Astronomy, College of Science, King Saud University, Riyadh (Saudi Arabia); Ain Shams University, Faculty of Science, Cairo 11566 (Egypt); Nasri, S.; Malkawi, E. [Department of Physics, UAE University, P.O. Box 17551, Al-Ain (United Arab Emirates); Chamoun, N. [Physics Department, HIAST, P.O. Box 31983, Damascus (Syrian Arab Republic)
2011-01-01T23:59:59.000Z
We present the general form of the unitary matrices keeping invariant the Majorana neutrino mass matrix of specific texture suitable for explaining oscillation data. In the case of the tri-bimaximal pattern with two degenerate masses, we give a specific realization of the underlying U(1) symmetry which can be uplifted to a symmetry in a complete theory including charged leptons. For this, we present a model with three light SM-like Higgs doublets and one heavy Higgs triplet and find that one can accommodate the hierarchy of the charged-lepton masses. The lepton mass spectrum can also be achieved in another model extending the SM with three SM-singlet scalars transforming nontrivially under the flavor symmetry. We discuss how such a model has room for generating enough baryon asymmetry through leptogenesis in the framework of type-I and -II seesaw mechanisms.
Higgs boson decay into four leptons at NLOPS electroweak accuracy
Boselli, Stefano; Montagna, Guido; Nicrosini, Oreste; Piccinini, Fulvio
2015-01-01T23:59:59.000Z
In view of precision studies of the Higgs sector at the Run II of the LHC, the improvement of the accuracy of the theoretical prediction is becoming a pressing issue. In this framework, we detail a calculation of the full Next-to-Leading Order (NLO) electroweak corrections to Higgs boson decay into four charged leptons, by considering the gold-plated channel H -> Z(*) Z(*) -> 2l 2l', l,l' = e, mu. We match the NLO corrections with a QED Parton Shower (PS), in order to simulate exclusive multiple photon emission and provide novel results at NLOPS electroweak accuracy. We compare our NLO predictions to those of the program Prophecy4f and present NLOPS phenomenological results relevant for Higgs physics studies, with particular attention to precision measurements of the Higgs boson mass, spin-parity assignment and tests of the Standard Model. Our calculation is implemented in a new code, Hto4l, which can be easily interfaced to any generator describing Higgs boson production. As an example, we provide illustrati...
Scales of Fermion Mass Generation and Electroweak Symmetry Breaking
Duane A. Dicus; Hong-Jian He
2005-06-11T23:59:59.000Z
The scale of mass generation for fermions (including neutrinos) and the scale for electroweak symmetry breaking (EWSB) can be bounded from above by the unitarity of scattering involving longitudinal weak gauge bosons or their corresponding would-be Goldstone bosons. Including the exact n-body phase space we analyze the 2 --> n ($n \\geq 2$) processes for the fermion-(anti)fermion scattering into multiple gauge boson final states. Contrary to naive energy power counting, we demonstrate that as $n$ becomes large, the competition between an increasing energy factor and a phase-space suppression leads to a {\\it strong new upper bound} on the scale of fermion mass generation at a finite value $n=n_s$, which is {\\it independent of the EWSB scale,} $v = (\\sqrt{2}G_F)^{-1/2}$. For quarks, leptons and Majorana neutrinos, the strongest 2 --> n limits range from about 3TeV to 130-170TeV (with $2\\lesssim n_s \\lesssim 24$), depending on the measured fermion masses. Strikingly, given the tiny neutrino masses as constrained by the neutrino oscillations, neutrinoless double-beta decays and astrophysical observations, the unitarity violation of $\
Effect of steriles states on lepton magnetic moments and neutrinoless double beta decay
Abada, A; Teixeira, A M
2014-01-01T23:59:59.000Z
We address the impact of sterile fermion states on the anomalous magnetic moment of charged leptons, as well as their contribution to neutrinoless double beta decays. We illustrate our results in a minimal, effective extension of the Standard Model by one sterile fermion state, and in a well-motivated framework of neutrino mass generation, embedding the Inverse Seesaw into the Standard Model. The simple "3+1" effective case succeeds in alleviating the tension related to the muon anomalous magnetic moment, albeit only at the 3$\\sigma$ level, and for light sterile states (corresponding to a }cosmologically disfavoured regime). Interestingly, our analysis shows that a future $0 \
Taylor, Frank E.
A generic search for anomalous production of events with at least three charged leptons is presented. The search uses a pp-collision data sample at a center-of-mass energy of ?s=7??TeV corresponding to 4.6??fb-1 of integrated ...
Universal neutrino mass hierarchy and cosmological baryon number asymmetry
Xing Zhizhong [CCAST (World Laboratory), P.O. Box 8730, Beijing 100080 (China); Institute of High Energy Physics, Chinese Academy of Sciences, P.O. Box 918 (4), Beijing 100039 (China)
2004-10-01T23:59:59.000Z
We conjecture that three light Majorana neutrinos and their right-handed counterparts may have a universal geometric mass hierarchy. Incorporating this phenomenological conjecture with the Fritzsch texture of lepton mass matrices in a simple seesaw mechanism, we show that it is possible to simultaneously account for current neutrino oscillation data and the cosmological baryon number asymmetry via leptogenesis.
Isolated leptons in events with missing transverse momentum and the search for single top production
Calorimeter Âˇ Optimised for precision measure- ment of the scattered lepton ZEUS Âˇ Depleted Uranium
GeV Gamma-ray Flux Upper Limits from Clusters of Galaxies
al., M Ackermann et
2010-01-01T23:59:59.000Z
The detection of diffuse radio emission associated with clusters of galaxies indicates populations of relativistic leptons infusing the intracluster medium. Those electrons and positrons are either injected into and accelerated directly in the intracluster medium, or produced as secondary pairs by cosmic-ray ions scattering on ambient protons. Radiation mechanisms involving the energetic leptons together with decay of neutral pions produced by hadronic interactions have the potential to produce abundant GeV photons. Here, we report on the search for GeV emission from clusters of galaxies using data collected by the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (Fermi) from August 2008 to February 2010. Thirty-three galaxy clusters have been selected according to their proximity and high mass, X-ray flux and temperature, and indications of non-thermal activity for this study. We report upper limits on the photon flux in the range 0.2-100 GeV towards a sample of observed clusters (typical va...
An explicit SU(12) family and flavor unification model with natural fermion masses and mixings
Albright, Carl H. [Northern Illinois Univ., Dekalb, IL (United States); Feger, Robert P. [Vanderbilt Univ., Nashville, TN (United States); Kephart, Thomas W. [Vanderbilt Univ., Nashville, TN (United States)
2012-07-01T23:59:59.000Z
We present an SU(12) unification model with three light chiral families, avoiding any external flavor symmetries. The hierarchy of quark and lepton masses and mixings is explained by higher dimensional Yukawa interactions involving Higgs bosons that contain SU(5) singlet fields with VEVs about 50 times smaller than the SU(12) unification scale. The presented model has been analyzed in detail and found to be in very good agreement with the observed quark and lepton masses and mixings.
Lepton Number Violation and the Baryon Asymmetry of the Universe
Harz, Julia; Päs, Heinrich
2015-01-01T23:59:59.000Z
Neutrinoless double beta decay, lepton number violating collider processes and the Baryon Asymmetry of the Universe (BAU) are intimately related. In particular lepton number violating processes at low energies in combination with sphaleron transitions will typically erase any pre-existing baryon asymmetry of the Universe. In this contribution we briefly review the tight connection between neutrinoless double beta decay, lepton number violating processes at the LHC and constraints from successful baryogenesis. We argue that far-reaching conclusions can be drawn unless the baryon asymmetry is stabilized via some newly introduced mechanism.
Flavor structure in D-brane models: Majorana neutrino masses
Yuta Hamada; Tatsuo Kobayashi; Shohei Uemura
2014-06-11T23:59:59.000Z
We study the flavor structure in intersecting D-brane models. We study anomalies of the discrete flavor symmetries. We analyze the Majorana neutrino masses, which can be generated by D-brane instanton effects. It is found that a certain pattern of mass matrix is obtained and the cyclic permutation symmetry remains unbroken. As a result, trimaximal mixing matrix can be realized if Dirac neutrino mass and charged lepton mass matrices are diagonal.
Measurements of the tau mass and the mass difference of the tau+ and tau- at BABAR
Fisher, Peter H.
We present the result from a precision measurement of the mass of the tau lepton, M?, based on 423??fb[subscript -1] of data recorded at the ?(4S) resonance with the BABAR detector. Using a pseudomass endpoint method, we ...
Quark-lepton symmetric model at the LHC
Jackson D. Clarke; Robert Foot; Raymond R. Volkas
2012-02-04T23:59:59.000Z
We investigate the quark-lepton symmetric model of Foot and Lew in the context of the Large Hadron Collider (LHC). In this `bottom-up' extension to the Standard Model, quark-lepton symmetry is achieved by introducing a gauged `leptonic colour' symmetry which is spontaneously broken above the electroweak scale. If this breaking occurs at the TeV scale, then we expect new physics to be discovered at the LHC. We examine three areas of interest: the Z$'$ heavy neutral gauge boson, charge $\\pm1/2$ exotic leptons, and a colour triplet scalar diquark. We find that the LHC has already explored and/or will explore new parameter space for these particles over the course of its lifetime.
Lepton flavor violation decays with the fourth generation neutrino
Wu-Jun Huo; Tai-Fu Feng
2002-03-22T23:59:59.000Z
We investigate the lepton flavor violation decays, $\\tau \\to \\mu\\gamma$, $\\tau \\to e\\gamma$ and $\\mu \\to e\\gamma$, in the framwork of a squential fourth generation model with a heavy fourth neutrino, $\
Minimal archi-texture for neutrino mass matrices
Atsushi Watanabe; Koichi Yoshioka
2006-03-15T23:59:59.000Z
The origin of the observed masses and mixing angles of quarks and leptons is one of imperative subjects in and beyond the standard model. Toward a deeper understanding of flavor structure, we investigate in this paper the minimality of fermion mass (Yukawa) matrices in unified theory. That is, the simplest matrix form is explored in light of the current experimental data for quarks and leptons, including the recent measurements of quark CP violation and neutrino oscillations. Two types of neutrino mass schemes are particularly analyzed; (i) Majorana masses of left-handed neutrinos with unspecified mechanism and (ii) Dirac and Majorana masses introducing three right-handed neutrinos. As a result, new classes of neutrino mass matrices are found to be consistent to the low-energy experimental data and high-energy unification hypothesis. For distinctive phenomenological implications of the minimal fermion mass textures, we discuss flavor-violating decay of charged leptons, the baryon asymmetry of the universe via thermal leptogenesis, neutrino-less double beta decay, and low-energy leptonic CP violation.
Buzatu, Adrian; /McGill U.
2011-08-01T23:59:59.000Z
The Higgs boson is the only elementary particle predicted by the Standard Model (SM) that has not yet been observed experimentally. If it exists, it explains the spontaneous electroweak symmetry breaking and the origin of mass for gauge bosons and fermions. We test the validity of the SM by performing a search for the associated production of a Higgs boson and a W boson in the channel where the Higgs boson decays to a bottom-antibottom quark pair and the W boson decays to a charged lepton and a neutrino (the WH channel). We study a dataset of proton-antiproton collisions at a centre-of-mass energy {radical}s = 1.96 TeV provided by the Tevatron accelerator, corresponding to an integrated luminosity of 5.7 fb{sup -1}, and recorded using the Collider Detector at Fermilab (CDF).We select events consistent with the signature of exactly one charged lepton (electron or muon), missing transverse energy due to the undetected neutrino (MET) and two collimated streams of particles (jets), at least one of which is required to be identified as originating from a bottom quark. We improve the discrimination of Higgs signal from backgrounds through the use of an artificial neural network. Using a Bayesian statistical inference approach, we set for each hypothetical Higgs boson mass in the range 100-150 GeV/c{sup 2} with 5 GeV/c{sup 2} increments a 95% credibility level (CL) upper limit on the ratio between the Higgs production cross section times branching fraction and the SM prediction. Our main original contributions are the addition of a novel charged lepton reconstruction algorithm with looser requirements (ISOTRK) with respect the electron or muon tight criteria (TIGHT), as well as the introduction of a novel trigger-combination method that allows to maximize the event yield while avoiding trigger correlations and that is used for the ISOTRK category. The ISOTRK candidate is a high-transverse-momentum good-quality track isolated from other activity in the tracking system and not required to match a calorimeter cluster, as for a tight electron candidate, or an energy deposit in the muon detector, as for a tight muon candidate. The ISOTRK category recovers real charged leptons that otherwise would be lost in the non-instrumented regions of the detector. This allows the reconstruction of more W boson candidates, which in turn increases the number of reconstructed WH signal candidate events, and therefore improves the sensitivity of the WH search. For the TIGHT charged lepton categories, we employ charged-lepton-dedicated triggers to improve the rate of WH signal acceptance during data taking. Since there is no ISOTRK-dedicated trigger at CDF, for the ISOTRK charged lepton category we employ three MET-plus-jets-based triggers. For each trigger we first identify the jet selection where the trigger efficiency is flat with respect to jet information (transverse energy and direction of motion in the transverse plane for the two jets in the event) and then we parametrize the trigger efficiency as a function of trigger MET. On an event-by-event basis, for each trigger we compute a trigger efficiency as a function of trigger parametrization, trigger MET, jet information, trigger prescale and information about whether the trigger is defined or not. For the ISOTRK category we combine the three triggers using a novel method, which allows the combination of any number of triggers in order to maximize the event yield while avoiding trigger correlations. On an event-by-event basis, only the trigger with the largest efficiency is used. By avoiding a logical 'OR' between triggers, the loss in the yield of events accepted by the trigger combination is compensated by a smaller and easier-to-compute corresponding systematic uncertainty. The addition of the ISOTRK charged lepton category to the TIGHT category produces an increase of 33% in the WH signal yield and a decrease of 15.5% to 19.0% in the median expected 95% CL cross-section upper limits across the entire studied Higgs mass interval. The improvement in analysis sensitivity is smaller than the i
CP violation in neutrino mass matrix
Utpal Sarkar; Santosh K. Singh
2006-08-03T23:59:59.000Z
We constructed rephasing invariant measures of CP violation with elements of the neutrino mass matrix, in the basis in which the charged lepton mass matrix is diagonal. We discuss some examples of neutrino mass matrices with texture zeroes, where the present approach is applicable and demonstrate how it simplifies an analysis of CP violation. We applied our approach to study CP violation in all the phenomenologically acceptable 3-generation two-zero texture neutrino mass matrices and shown that in any of these cases there is only one CP phase which contributes to the neutrino oscillation experiment and there are no Majorana phases.
Low and high energy phenomenology of quark-lepton complementarity scenarios
Hochmuth, Kathrin A. [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Foehringer Ring 6, D-80805 Munich (Germany); Rodejohann, Werner [Physik-Department, Technische Universitaet Muenchen, James-Franck-Strasse, D-85748 Garching (Germany)
2007-04-01T23:59:59.000Z
We conduct a detailed analysis of the phenomenology of two predictive seesaw scenarios leading to quark-lepton complementarity. In both cases we discuss the neutrino mixing observables and their correlations, neutrinoless double beta decay and lepton flavor violating decays such as {mu}{yields}e{gamma}. We also comment on leptogenesis. The first scenario is disfavored on the level of one to two standard deviations, in particular, due to its prediction for |U{sub e3}|. There can be resonant leptogenesis with quasidegenerate heavy and light neutrinos, which would imply sizable cancellations in neutrinoless double beta decay. The decays {mu}{yields}e{gamma} and {tau}{yields}{mu}{gamma} are typically observable unless the SUSY masses approach the TeV scale. In the second scenario leptogenesis is impossible. It is, however, in perfect agreement with all oscillation data. The prediction for {mu}{yields}e{gamma} is in general too large, unless the SUSY masses are in the range of several TeV. In this case {tau}{yields}e{gamma} and {tau}{yields}{mu}{gamma} are unobservable.
On the ambiguities in the tri-bimaximal mixing matrix and corresponding charged lepton corrections
Duarah, Chandan
2015-01-01T23:59:59.000Z
Two negative signs naturally appear in the $U_{\\mu 1}$ and $U_{\\tau 2}$ elements of the Tri-bimaximal (TBM) matrix for positive values of the mixing angles $\\theta_{12}$ and $\\theta_{23}$. Apart from this, in other TBM matrices negative signs are shifted to other elements in each case. They account for positive as well as negative values of $\\theta_{12}$ and $\\theta_{23}$. We discuss the sign ambiguity in the TBM matrix and find that the TBM matrices, in fact, can be divided into two groups under certain circumstances. Interestingly, this classification of TBM matrices is accompanied by two different $\\mu-\\tau$ symmetric mass matrices which can separately be related to the groups. To accommodate non-zero value of $\\theta_{13}$ and deviate $\\theta_{23}$ towards first octant, we then perturb the TBM mixing ansatz with the help of charged lepton correction. The diagonalizing matrices for charged lepton mass matrices also possess sign ambiguity and respect the grouping of TBM matrices. They are parametrized in te...
Search for a high mass SM-like Higgs boson in the H to ZZ to llqq decay channel in CMS
De Martino, Eduardo Navarro
2015-01-01T23:59:59.000Z
A search for a high mass standard-model-like Higgs boson decaying into two Z bosons with subsequent decay into two leptons and two quarks performed at CMS is presented. The analysis is based on 19.7 1/fb of proton-proton collisions produced in LHC at center-of-mass energy of 8 TeV. Different categories are exploited in order to isolate hypothetical Higgs boson-like signals in the mass range up to 1 TeV. The data are interpreted in terms of a standard-model-like Higgs boson as well as an electroweak singlet, visible through the interference with the 125 GeV Higgs boson. No evidence of a signal is found and upper limits are set on the production cross section and other model parameters.
Particle physics implications of the WMAP neutrino mass bound
G. Bhattacharyya; H. Päs; L. Song; T. J. Weiler
2003-04-25T23:59:59.000Z
The recently published cosmological bound on the absolute neutrino masses obtained from the Wilkinson Microwave Anisotropy Probe (WMAP) data has important consequences for neutrino experiments and models. Taken at face value, the new bound excludes the determination of the absolute neutrino mass in the KATRIN experiment and disfavors a neutrino oscillation interpretation of the LSND experiment. Combined with the KamLAND and Super-K data, the WMAP bound defines an accessible range for the neutrinoless double beta decay amplitude. The bound also impacts the Z-burst annihilation mechanism for resonant generation of extreme-energy cosmic rays on the cosmic neutrino background in two ways: it constrains the local overdensity of neutrino dark matter which is not helpful, but it also limits the resonant energy to a favorable range. In R-parity violating SUSY models neutrino masses are generated by trilinear and bilinear lepton number violating couplings. The WMAP result improves the constraints on these couplings over their existing values by an order of magnitude.
ATLAS Collaboration
2014-12-22T23:59:59.000Z
This paper describes the trigger and offline reconstruction, identification and energy calibration algorithms for hadronic decays of tau leptons employed for the data collected from $pp$ collisions in 2012 with the ATLAS detector at the LHC center-of-mass energy $\\sqrt{\\mathrm{s}} = 8$ TeV. The performance of these algorithms is measured in most cases with Z decays to tau leptons using the full 2012 dataset, corresponding to an integrated luminosity of 20.3 fb$^{-1}$. An uncertainty on the offline reconstructed tau energy scale of 2% to 4%, depending on transverse energy and pseudorapidity, is achieved using two independent methods. The offline tau identification efficiency is measured with a precision of 2.5% for hadronically decaying tau leptons with one associated track, and of 4% for the case of three associated tracks, inclusive in pseudorapidity and for a visible transverse energy greater than $20$ GeV. For hadronic tau lepton decays selected by offline algorithms, the tau trigger identification efficiency is measured with a precision of 2% to 8%, depending on the transverse energy. The performance of the tau algorithms, both offline and at the trigger level, is found to be stable with respect to the number of concurrent proton--proton interactions and has supported a variety of physics results using hadronically decaying tau leptons at ATLAS.
Fermion Masses and Mixings from a Minimum Principle
Rodrigo Alonso
2014-05-22T23:59:59.000Z
We analyze the structure of quark and lepton mass matrices under the hypothesis that they are determined from a minimum principle applied to a generic potential invariant under the $\\left[U(3)\\right]^5\\otimes {\\mathcal O}(3)$ flavor symmetry, acting on Standard Model fermions and right-handed neutrinos. Unlike the quark case, we show that hierarchical masses for charged leptons are naturally accompanied by degenerate Majorana neutrinos with one mixing angle close to maximal, a second potentially large, a third one necessarily small, and one maximal relative Majorana phase. The scheme presented here could be tested in the near future via neutrino-less double beta decay and cosmological measurements.
Petcov, S.T.; Rodejohann, W. [Scuola Internazionale Superiore di Studi Avanzati, Via Beirut 2-4, I-34014 Trieste, Italy and Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34014 Trieste (Italy)
2005-04-01T23:59:59.000Z
The Pontecorvo-Maki-Nakagawa-Sakata neutrino mixing matrix is given, in general, by the product of two unitary matrices associated with the diagonalization of the charged lepton and neutrino mass matrices. Assuming that the active flavor neutrinos possess a Majorana mass matrix which is diagonalized by a bimaximal mixing matrix, we give the allowed forms of the charged lepton mixing matrix and the corresponding implied forms of the charged lepton mass matrix. We then assume that the origin of bimaximal mixing is a weakly broken flavor symmetry corresponding to the conservation of the nonstandard lepton charge L{sup '}=L{sub e}-L{sub {mu}}-L{sub {tau}}. The latter does not predict, in general, the atmospheric neutrino mixing to be maximal. We study the impact of this fact on the allowed forms of the charged lepton mixing matrix and on the neutrino mixing observables, analyzing the case of CP violation in detail. When compared with the case of exact bimaximal mixing, the deviations from zero U{sub e3} and from maximal atmospheric neutrino mixing are typically more sizable if one assumes just L{sup '} conservation. In fact, |U{sub e3}|{sup 2} can be as small as 0.007 and atmospheric neutrino mixing can take any value inside its currently allowed range. We discuss under which conditions the atmospheric neutrino mixing angle is larger or smaller than {pi}/4. We present also a simple seesaw realization of the implied light neutrino Majorana mass matrix and consider leptogenesis in this scenario.
Top quark mass measurement using the template method at CDF
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aaltonen, T [Helsinki Inst. of Phys.; Alvarez Gonzalez, B [Oviedo U.; Cantabria Inst. of Phys.; Amerio, S [INFN, Padua; Amidei, D [Michigan U.; Anastassov, A [Northwestern U.; Annovi, A [Frascati; Antos, J [Comenius U.; Apollinari, G [Fermilab; Appel, J A [Fermilab; Apresyan, A [Purdue U.; Arisawa, T [Waseda U.; Dubna, JINR
2011-06-03T23:59:59.000Z
We present a measurement of the top quark mass in the lepton+jets and dilepton channels of tt? decays using the template method. The data sample corresponds to an integrated luminosity of 5.6 fb-1 of pp? collisions at Tevatron with ?s = 1.96 TeV, collected with the CDF II detector. The measurement is performed by constructing templates of three kinematic variables in the lepton+jets and two kinematic variables in the dilepton channel. The variables are two reconstructed top quark masses from different jets-to-quarks combinations and the invariant mass of two jets from the W decay in the lepton+jets channel, and a reconstructed top quark mass and mT2, a variable related to the transverse mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the lepton+jets and dilepton channels to the data yields a measured top quark mass of Mtop = 172.1ą1.1 (stat)ą0.9 (syst) GeV/c2.
Top quark mass measurement using the template method at CDF
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aaltonen, T; Alvarez Gonzalez, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Apresyan, A; et al
2011-06-03T23:59:59.000Z
We present a measurement of the top quark mass in the lepton+jets and dilepton channels of tt? decays using the template method. The data sample corresponds to an integrated luminosity of 5.6 fb-1 of pp? collisions at Tevatron with ?s = 1.96 TeV, collected with the CDF II detector. The measurement is performed by constructing templates of three kinematic variables in the lepton+jets and two kinematic variables in the dilepton channel. The variables are two reconstructed top quark masses from different jets-to-quarks combinations and the invariant mass of two jets from the W decay in the lepton+jets channel, and amore ťreconstructed top quark mass and mT2, a variable related to the transverse mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the lepton+jets and dilepton channels to the data yields a measured top quark mass of Mtop = 172.1ą1.1 (stat)ą0.9 (syst) GeV/c2.Ť less
Reaching towards higher masses of supersymmetric particles
Olsen, Agnethe Seim
This thesis presents an optimisation of the search for SUSY in final states with one tau lepton, jets and large missing transverse energy. The search is performed in proton-proton collisions at sqrt(s) = 8TeV corresponding to an integrated luminosity of 20.3 fb^(?1). The SUSY model considered is mSUGRA with parameter values: m0 and m1/2 are treated as grid parameters, A0 = ?2m0, tan beta = 30 and mu>0. The event selection is optimised for maximal sensitivity to mSUGRA in the low m0, high m1/2 region of the mass plane. The result of the optimised analysis is interpreted in the mSUGRA model and a limit in the (m0, m1/2) plane is obtained. Values of m1/2 up to 640 GeV are excluded for low m0 and 300 GeV for high m0 ( 2000 GeV < m0 < 5400 GeV).
Aad, Georges; ATLAS Collaboration; Abdallah, Jalal; Abdinov, Ovsat; Aben, Rosemarie; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Abreu, Ricardo; Abulaiti, Yiming; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Adelman, Jahred; Adomeit, Stefanie; Adye, Tim; Affolder, Tony; Agatonovic-Jovin, Tatjana; Aguilar-Saavedra, Juan Antonio; Ahlen, Steven; Ahmadov, Faig; Aielli, Giulio; Akerstedt, Henrik; Ĺkesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Alberghi, Gian Luigi; Albert, Justin; Albrand, Solveig; Alconada Verzini, Maria Josefina; Aleksa, Martin; Aleksandrov, Igor; Alexa, Calin; Alexander, Gideon; Alexopoulos, Theodoros; Alhroob, Muhammad; Alimonti, Gianluca; Alio, Lion; Alison, John; Alkire, Steven Patrick; Allbrooke, Benedict; Allport, Phillip; Aloisio, Alberto; Alonso, Alejandro; Alonso, Francisco; Alpigiani, Cristiano; Altheimer, Andrew David; Alvarez Gonzalez, Barbara; ?lvarez Piqueras, Damián; Alviggi, Mariagrazia; Amadio, Brian Thomas; Amako, Katsuya; Amaral Coutinho, Yara; Amelung, Christoph; Amidei, Dante; Amor Dos Santos, Susana Patricia; Amorim, Antonio; Amoroso, Simone; Amram, Nir; Amundsen, Glenn; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anders, John Kenneth; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Angelidakis, Stylianos; Angelozzi, Ivan; Anger, Philipp; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antonelli, Mario; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoki, Masato; Aperio Bella, Ludovica; Arabidze, Giorgi; Arai, Yasuo; Araque, Juan Pedro; Arce, Ayana; Arduh, Francisco Anuar; Arguin, Jean-Francois; Argyropoulos, Spyridon; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnal, Vanessa; Arnold, Hannah; Arratia, Miguel; Arslan, Ozan; Artamonov, Andrei; Artoni, Giacomo; Asai, Shoji; Asbah, Nedaa; Ashkenazi, Adi; Ĺsman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astalos, Robert; Atkinson, Markus; Atlay, Naim Bora; Auerbach, Benjamin; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Axen, Bradley; Ayoub, Mohamad Kassem; Azuelos, Georges; Baak, Max; Baas, Alessandra; Bacci, Cesare; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Bagiacchi, Paolo; Bagnaia, Paolo; Bai, Yu; Bain, Travis; Baines, John; Baker, Oliver Keith; Balek, Petr; Balestri, Thomas; Balli, Fabrice; Banas, Elzbieta; Banerjee, Swagato; Bannoura, Arwa A E; Bansil, Hardeep Singh; Barak, Liron; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnes, Sarah Louise; Barnett, Bruce; Barnett, Michael; Barnovska, Zuzana; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimarăes da Costa, Joăo; Bartoldus, Rainer; Barton, Adam Edward; Bartos, Pavol; Basalaev, Artem; Bassalat, Ahmed; Basye, Austin; Bates, Richard; Batista, Santiago Juan; Batley, Richard; Battaglia, Marco; Bauce, Matteo; Bauer, Florian; Bawa, Harinder Singh; Beacham, James Baker; Beattie, Michael David; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Becker, Anne Kathrin; Becker, Maurice; Becker, Sebastian; Beckingham, Matthew; Becot, Cyril; Beddall, Andrew; Beddall, Ayda; Bednyakov, Vadim; Bee, Christopher; Beemster, Lars; Beermann, Thomas; Begel, Michael; Behr, Janna Katharina; Belanger-Champagne, Camille; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellerive, Alain; Bellomo, Massimiliano; Belotskiy, Konstantin; Beltramello, Olga; Benary, Odette; Benchekroun, Driss; Bender, Michael; Bendtz, Katarina; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez Garcia, Jorge-Armando; Benjamin, Douglas; Bensinger, James; Bentvelsen, Stan; Beresford, Lydia; Beretta, Matteo; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Beringer, Jürg; Bernard, Clare; Bernard, Nathan Rogers; Bernius, Catrin; Bernlochner, Florian Urs; Berry, Tracey; Berta, Peter; Bertella, Claudia; Bertoli, Gabriele; Bertolucci, Federico; Bertsche, Carolyn; Bertsche, David; Besana, Maria Ilaria; Besjes, Geert-Jan; Bessidskaia Bylund, Olga; Bessner, Martin Florian; Besson, Nathalie; Betancourt, Christopher; Bethke, Siegfried; Bevan, Adrian John; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianchini, Louis; Bianco, Michele; Biebel, Otmar; Bieniek, Stephen Paul; Biglietti, Michela; Bilbao De Mendizabal, Javier; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien; Bingul, Ahmet
2015-01-01T23:59:59.000Z
This paper presents a search for Higgs bosons decaying to four leptons, either electrons or muons, via one or two light exotic gauge bosons $Z_d$, $H\\to Z Z_d \\to 4\\ell$ or $H\\to Z_d Z_d \\to 4\\ell$. The search was performed using $pp$ collision data corresponding to an integrated luminosity of about 20 fb$^{-1}$ at the center-of-mass energy of $\\sqrt{s}=8 $TeV recorded with the ATLAS detector at the Large Hadron Collider. The observed data are well described by the Standard Model prediction. Upper bounds on the branching ratio of $H\\to Z Z_d \\to 4\\ell$ and on the kinetic mixing parameter between the $Z_d$ and the Standard Model hypercharge gauge boson are set in the range $(1$--$9)\\times10^{-5}$ and $(4$--$17)\\times10^{-2}$ respectively, at 95% confidence level assuming the Standard Model branching ratio of $H\\to Z Z^* \\to 4\\ell$, for $Z_d$ masses between 15 and 55 GeV. Upper bounds on the effective mass mixing parameter between the $Z$ and the $Z_d$ are also set using the branching ratio limits in the $H \\to...
Phenomenological relations for neutrino masses and mixing parameters
Khruschov, V. V., E-mail: khru@imp.kiae.ru [National Research Center Kurchatov Institute (Russian Federation)
2013-11-15T23:59:59.000Z
Phenomenological relations for masses, angles, and CP phases in the neutrino mixing matrix are proposed with allowance for available experimental data. For the case of CP violation in the lepton sector, an analysis of the possible structure of the neutrino mass matrix and a calculation of the neutrino mass features and the Dirac CP phase for the bimodal-neutrino model are performed. The values obtained in this way can be used to interpret and predict the results of various neutrino experiments.
An SO(10) GUT Model With Lopsided Mass Matrix and Neutrino Mixing Angle theta_13
Xiangdong Ji; Yingchuan Li; R. N. Mohapatra
2005-10-27T23:59:59.000Z
An alternative supersymmetric SO(10) grand unification model with lopsided fermion mass matrices is introduced. It generates a large solar-neutrino-mixing angle through the neutrinos' Dirac mass matrix constrained by the SO(10) group structure, avoiding the fine-tuning required in the Majorana mass matrix of right-handed neutrinos. The model fits well the known data on masses and mixings of quarks and leptons, and predicts a sizable lepton mixing $\\sin^22\\theta_{13}\\simeq 0.074$, which is significantly larger than that of the original lopsided model.
Neutrino masses from U(1) symmetries and the Super-Kamiokande data
Smaragda Lola; Graham G. Ross
1999-02-09T23:59:59.000Z
Motivated by the Super-Kamiokande data, we revisit models with U(1) symmetries and discuss the origin of neutrino masses and mixings in such theories. We show that, in models with just three light neutrinos and a hierarchy of neutrino masses, large (2-3) mixing fixes the lepton doublet U(1) charges and is thus related to the structure of the charged lepton mass matrix. We discuss the fermion mass structure that follows from the Abelian family symmetry with an extended gauge group. Requiring that the quark and lepton masses be ordered by the family symmetry, we identify the most promising scheme. This requires large, but not necessarily maximal, mixing in the mu-tau sector and gives small e-mu mixing in the range that is required for the small angle solution of the solar neutrino deficit.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Khachatryan, Vardan; et al.,
2015-04-01T23:59:59.000Z
The results of a search for new physics in final states with jets, either photons or leptons, and low missing transverse momentum are reported. The study is based on a sample of proton-proton collisions collected at center-of-mass energy $\\sqrt{s}$ = 8 TeV with the CMS detector in 2012. The integrated luminosity of the sample is 19.7 inverse femtobarns. Many models of new physics predict the production of events with jets, electroweak gauge bosons, and little or no missing transverse momentum. Examples include stealth models of supersymmetry (SUSY), which predict a hidden sector at the electroweak energy scale in which SUSYmore ťis approximately conserved. The data are used to search for stealth SUSY signatures in final states with either two photons or an oppositely charged electron and muon. No excess is observed with respect to the standard model expectation, and the results are used to set limits on squark pair production in the stealth SUSY framework.Ť less
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Khachatryan, Vardan [Yerevan Physics Institute (Armenia); et al.,
2015-04-01T23:59:59.000Z
The results of a search for new physics in final states with jets, either photons or leptons, and low missing transverse momentum are reported. The study is based on a sample of proton-proton collisions collected at center-of-mass energy $\\sqrt{s}$ = 8 TeV with the CMS detector in 2012. The integrated luminosity of the sample is 19.7 inverse femtobarns. Many models of new physics predict the production of events with jets, electroweak gauge bosons, and little or no missing transverse momentum. Examples include stealth models of supersymmetry (SUSY), which predict a hidden sector at the electroweak energy scale in which SUSY is approximately conserved. The data are used to search for stealth SUSY signatures in final states with either two photons or an oppositely charged electron and muon. No excess is observed with respect to the standard model expectation, and the results are used to set limits on squark pair production in the stealth SUSY framework.
Possible textures of the fermion mass matrices
Gupta, Manmohan
2012-01-01T23:59:59.000Z
Texture specific fermion mass matrices have played an important role in understanding several features of fermion masses and mixings. In the present work, we have given an overview of all possible cases of Fritzsch-like as well as non Fritzsch-like texture 6 and 5 zero fermion mass matrices. Further, for the case of texture 4 zero Fritzsch-like quark mass matrices, the issue of the hierarchy of the elements of the mass matrices and the role of their phases have been discussed. Furthermore, the case of texture 4 zero Fritzsch-like lepton mass matrices has also been discussed with an emphasis on the hierarchy of neutrino masses for both Majorana and Dirac neutrinos.
Possible textures of the fermion mass matrices
Manmohan Gupta; Gulsheen Ahuja
2012-06-18T23:59:59.000Z
Texture specific fermion mass matrices have played an important role in understanding several features of fermion masses and mixings. In the present work, we have given an overview of all possible cases of Fritzsch-like as well as non Fritzsch-like texture 6 and 5 zero fermion mass matrices. Further, for the case of texture 4 zero Fritzsch-like quark mass matrices, the issue of the hierarchy of the elements of the mass matrices and the role of their phases have been discussed. Furthermore, the case of texture 4 zero Fritzsch-like lepton mass matrices has also been discussed with an emphasis on the hierarchy of neutrino masses for both Majorana and Dirac neutrinos.
Nuclear PDF for neutrino and charged lepton data
K. Kovarik
2010-12-13T23:59:59.000Z
Neutrino Deep Inelastic Scattering on nuclei is an essential process to constrain the strange quark parton distribution functions in the proton. The critical component on the way to using the neutrino DIS data in a proton PDF analysis is understanding the nuclear effects in parton distribution functions. We parametrize these effects by nuclear parton distribution functions. Here we compare results from two analysis of NPDF both done at next-to-leading order in QCD. The first uses neutral current charged-lepton lA Deeply Inelastic Scattering and Drell-Yan data for several nuclear targets and the second uses neutrino-nucleon DIS data. We compare the nuclear corrections factors F_2^Fe/F_2^D for the charged-lepton data with other results from the literature. In particular, we compare and contrast fits based upon the charged-lepton DIS data with those using neutrino-nucleon DIS data.
Preon Trinity - a new model of leptons and quarks
Jean-Jacques Dugne; Sverker Fredriksson; Johan Hansson; Enrico Predazzi
1999-10-12T23:59:59.000Z
A new model for the substructure of quarks, leptons and weak gauge bosons is discussed. It is based on three fundamental and absolutely stable spin-1/2 preons. Its preon flavour SU(3) symmetry leads to a prediction of nine quarks, nine leptons and nine heavy vector bosons. One of the quarks has charge $-4e/3$, and is speculated to be the top quark (whose charge has not been measured). The flavour symmetry leads to three conserved lepton numbers in all known weak processes, except for some neutrinos, which might either oscillate or decay. There is also a (Cabibbo) mixing of the $d$ and $s$ quarks due to an internal preon-antipreon annihilation channel. An identical channel exists inside the composite $Z^0$, leading to a relation between the Cabibbo and Weinberg mixing angles.
NLO QCD and electroweak corrections to W+? production with leptonic W-boson decays
Ansgar Denner; Stefan Dittmaier; Markus Hecht; Christian Pasold
2014-12-23T23:59:59.000Z
We present a calculation of the next-to-leading-order electroweak corrections to W+\\gamma\\ production, including the leptonic decay of the W boson and taking into account all off-shell effects of the W boson, where the finite width of the W boson is implemented using the complex-mass scheme. Corrections induced by incoming photons are fully included and find particular emphasis in the discussion of phenomenological predictions for the LHC. The corresponding next-to-leading-order QCD corrections are reproduced as well. In order to separate hard photons from jets, a quark-to-photon fragmentation function a la Glover and Morgan is employed. Our results are implemented into Monte Carlo programs allowing for the evaluation of arbitrary differential cross sections. We present integrated cross sections for the LHC at 7TeV, 8TeV, and 14TeV as well as differential distributions at 14TeV for bare muons and dressed leptons. Finally, we discuss the impact of anomalous WW\\gamma\\ couplings.
Particle Production Reactions in Laser-Boosted Lepton Collisions
Sarah J. Müller; Christoph H. Keitel; Carsten Müller
2014-12-28T23:59:59.000Z
The need for ever higher energies in lepton colliders gives rise to the investigation of new accelerator schemes for elementary particle physics experiments. One perceivable way to increase the collision energy would be to combine conventional lepton acceleration with strong laser fields, making use of the momentum boost a charged particle experiences inside a plane electromagnetic wave. As an example for a process taking place in such a laser-boosted collision, Higgs boson creation is studied in detail. We further discuss other possible particle production processes that could be implemented in such a collider scheme and specify the required technical demands.
Lepton number violation and W ? chiral couplings at the LHC
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Han, Tao; Lewis, Ian; Ruiz, Richard; Si, Zong-guo
2013-02-01T23:59:59.000Z
We study the observability for a heavy Majorana neutrino N along with a new charged gauge boson W' at the LHC. We emphasize the complementarity of these two particles in their production and decay to unambiguously determine their properties. We show that the Majorana nature of N can be verified by the lepton number violating like-sign dilepton process, and by polar and azimuthal angular distributions. The chirality of the W' coupling to leptons and to quarks can be determined by a polar angle distribution in the reconstructed frame and an azimuthal angle distribution.
Particle Production Reactions in Laser-Boosted Lepton Collisions
Müller, Sarah J; Müller, Carsten
2014-01-01T23:59:59.000Z
The need for ever higher energies in lepton colliders gives rise to the investigation of new accelerator schemes for elementary particle physics experiments. One perceivable way to increase the collision energy would be to combine conventional lepton acceleration with strong laser fields, making use of the momentum boost a charged particle experiences inside a plane electromagnetic wave. As an example for a process taking place in such a laser-boosted collision, Higgs boson creation is studied in detail. We further discuss other possible particle production processes that could be implemented in such a collider scheme and specify the required technical demands.
Gauge Trimming of Neutrino Masses
Chen, Mu-Chun; /Fermilab /UC, Irvine; de Gouvea, Andre; /Northwestern U. /Fermilab; Dobrescu, Bogdan A.; /Fermilab
2006-12-01T23:59:59.000Z
We show that under a new U(1) gauge symmetry, which is non-anomalous in the presence of one ''right-handed neutrino'' per generation and consistent with the standard model Yukawa couplings, the most general fermion charges are determined in terms of four rational parameters. This generalization of the B-L symmetry with generation-dependent lepton charges leads to neutrino masses induced by operators of high dimensionality. Neutrino masses are thus naturally small without invoking physics at energies above the TeV scale, whether neutrinos are Majorana or Dirac fermions. This ''Leptocratic'' Model predicts the existence of light quasi-sterile neutrinos with consequences for cosmology, and implies that collider experiments may reveal the origin of neutrino masses.
Bounds on R-parity violating supersymmetric couplings from leptonic and semileptonic meson decays
Dreiner, H. K.; Kraemer, M.; O'Leary, Ben [Physikalisches Institut der Universitaet Bonn, Nussallee 12, 53115 Bonn (Germany); Institut fuer Theoretische Physik E, RWTH Aachen, 52056 Aachen (Germany); S.U.P.A., School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, Scotland (United Kingdom) and Institut fuer Theoretische Physik E, RWTH Aachen, 52056 Aachen (Germany)
2007-06-01T23:59:59.000Z
We present a comprehensive update of the bounds on R-parity violating supersymmetric couplings from lepton-flavor- and lepton-number-violating decay processes. We consider {tau} and {mu} decays as well as leptonic and semileptonic decays of mesons. We present several new bounds resulting from {tau}, {eta}, and kaon decays and correct some results in the literature concerning B meson decays.
Vector Boson Fusion Higgs Production at the LHC - Mass Variables
Dan Green
2005-01-12T23:59:59.000Z
There exist substantial backgrounds to the vector boson fusion production of Higgs at the LHC. Mass variables are studied which may alleviate the need to assume a spin zero WW resonance in order to achieve a sufficient signal to noise ratio in the two jet plus two lepton and missing energy final state.
Hadronic mass moments in inclusive semileptonic B meson decays
Ammar, Raymond G.; Bean, Alice; Besson, David Zeke; Zhao, X.
2001-12-01T23:59:59.000Z
We have measured the first and second moments of the hadronic mass-squared distribution in B --> X(c)l nu, for P-lepton > 1.5 GeV/c. We find (M-x(2) - (M) over bar (2)(D)) = 0.251 +/- 0.066 GeV2, ((M-X(2) - (M-X(2))(2)) = ...
Stoica, Sabin [Horia Hulubei Foundation, P.O. Box MG-12, 077125 Magurele-Bucharest (Romania) and Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O. Box MG-6, Magurele-Bucharest 077125 (Romania)
2012-11-20T23:59:59.000Z
There is nowadays a significant progress in understanding the neutrino properties. The results of the neutrino oscillation experiments have convincingly showed that neutrinos have mass and oscillate, in contradiction with the Standard Model (SM) assumptions, and these are the first evidences of beyond SM physics. However, fundamental properties of the neutrinos like their absolute mass, their character (are they Dirac or Majorana particles?), their mass hierarchy, the number of neutrino flavors, etc., still remain unknown. In this context there is an increased interest in the study of the lepton number violating (LNV) processes, since they could complete our understanding on the neutrino properties. Since recently, the neutrinoless double beta decay was considered the only process able to distinguish between Dirac or Majorana neutrinos and to give a hint on the absolute mass of the electron neutrino. At present, the increased luminosity of the LHC experiments makes feasible the search of LNV processes at high energy as well. In this lecture I will make a brief review on our present knowledge of the neutrino properties, on the present status of the double-beta decay studies and on the first attempts to search LNV processes at LHC.
Tau decays into three charged leptons and two neutrinos
Ammar, Raymond G.; Baringer, Philip S.; Bean, Alice; Besson, David Zeke; Coppage, Don; Copty, N.; Davis, Robin E. P.; Hancock, N.; Kotov, S.; Kravchenko, I.; Kwak, Nowhan
1996-04-01T23:59:59.000Z
We search for the radiative leptonic tau decays tau --> ee(+) e(-)nu(tau)nu(e) and tau --> mu e(+)e(-)nu(tau)nu(mu) using 3.60 fb(-1) of data collected by the CLEO-II experiment at the Cornell Electron Storage Ring. We present a first observation...
Weak interactions of quarks and leptons: experimental status
Wojcicki, S.
1984-09-01T23:59:59.000Z
The present experimental status of weak interactions is discussed with emphasis on the problems and questions and on the possible lines of future investigations. Major topics include; (1) the quark mixing matrix, (2) CP violation, (3) rare decays, (4) the lepton sector, and (5) right handed currents. 118 references. (WHK)
Azimuthal asymmetry in lepton-proton scattering at high energies
Chay, J.; Ellis, S.D.; Stirling, W.J. (Department of Physics, FM-15, University of Washington, Seattle, Washington 98195 (United States))
1992-01-01T23:59:59.000Z
We consider the azimuthal angular dependence of the distribution of final-state hadrons in high-energy lepton-proton scattering. The distribution displays an azimuthal asymmetry due to both perturbative and nonperturbative effects. At the large momentum transfers attainable, for example, at the DESY {ital ep} collider HERA we expect the perturbative effects to dominate and constitute a clear test of QCD.
Implications of precision measurements on texture specific fermion mass matrices
Manmohan Gupta; Gulsheen Ahuja; Rohit Verma
2009-11-04T23:59:59.000Z
Implications of texture specific mass matrices have been investigated for both quarks and neutrinos. Interestingly, for the case of quarks Fritzsch-like texture 4 zero mass matrices have been found to be compatible with the present precisely known sin2\\beta as well as other precise CKM matrix elements. In the case of leptonic mass matrices, for both Majorana and Dirac neutrinos we find that for texture 4, 5, 6 zero mass matrices the inverted hierarchy and degenerate scenarios of neutrino masses are ruled out by the present data.
Implications of precision measurements on texture specific fermion mass matrices
Gupta, Manmohan; Verma, Rohit
2009-01-01T23:59:59.000Z
Implications of texture specific mass matrices have been investigated for both quarks and neutrinos. Interestingly, for the case of quarks Fritzsch-like texture 4 zero mass matrices have been found to be compatible with the present precisely known sin2\\beta as well as other precise CKM matrix elements. In the case of leptonic mass matrices, for both Majorana and Dirac neutrinos we find that for texture 4, 5, 6 zero mass matrices the inverted hierarchy and degenerate scenarios of neutrino masses are ruled out by the present data.
Leptonic dark matter annihilation in the evolving universe: constraints and implications
Yuan, Qiang; Bi, Xiaojun; Chen, Xuelei; Zhang, Xinmin
2009-01-01T23:59:59.000Z
The cosmic electron and positron excesses have been explained as possible dark matter (DM) annihilation products. In this work we investigate the possible effects of such kind of DM annihilation scenario during the evolution history of the Universe. We first calculate the extragalactic $\\gamma$-ray background (EGRB) produced through electrons/positrons inverse Compton scattering with the cosmic microwave background and the final state radiation. %by adopting a generic structure formation scenario. The DM halo profile and the minimal halo mass, which are not yet well determined from the current N-body simulations, are constrained by the EGRET data of EGRB. The preliminary EGRB data from the Fermi satellite are expected to set much stronger constraints. Then we discuss the impact of such leptonic DM model on cosmic evolution, such as the reionization and heating of intergalactic medium, neutral hydrogen 21 cm signal and suppression on structure formation. In some cases the 21 cm signal could be altered signific...
High energy neutrino telescopes as a probe of the neutrino mass mechanism
Kfir Blum; Anson Hook; Kohta Murase
2014-08-17T23:59:59.000Z
We show that measurements of the spectral shape and flavor ratios of high energy astrophysical neutrinos at neutrino telescopes can be sensitive to the details of the neutrino mass mechanism. We propose a simple model for Majorana neutrino mass generation that realizes the relevant parameter space, in which small explicit lepton number violation is mediated to the Standard Model through the interactions of a light scalar. IceCube, with about ten years of exposure time, could reveal the presence of anomalous neutrino self-interactions. Precision electroweak and lepton flavor laboratory experiments and a determination of the total neutrino mass from cosmology would provide consistency checks on the interpretation of a signal.
Chaden Djalali
2011-12-01T23:59:59.000Z
Recent studies of light vector meson production in heavy nuclear targets has generated interest in {rho}-{omega} interference in the leptonic e{sup +}e{sup -} decay channel. An experimental study of the elementary process provides valuable input for theoretical models and calculations. In experiment E04-005 (g12), high statistics photoproduction data has been taken in Jefferson Lab's Hall B with the Cebaf Large Acceptance Spectrometer (CLAS). The invariant mass spectrum is fitted with two interfering relativistic Breit-Wigner functions to determine the interference phase. Preliminary analysis indicate a measurable {rho}-{omega} interference.
DELAYED ONSET OF HIGH-ENERGY EMISSIONS IN LEPTONIC AND HADRONIC MODELS OF GAMMA-RAY BURSTS
Asano, Katsuaki [Interactive Research Center of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Meszaros, Peter, E-mail: asano@phys.titech.ac.jp, E-mail: nnp@astro.psu.edu [Department of Astronomy and Astrophysics, Department of Physics, Center for Particle and Gravitational Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)
2012-10-01T23:59:59.000Z
The temporal-spectral evolution of the prompt emission of gamma-ray bursts is simulated numerically for both leptonic and hadronic models. For weak enough magnetic fields, leptonic models can reproduce the few seconds delay of the onset of GeV photon emission observed by Fermi-LAT, due to the slow growth of the target photon field for inverse Compton scattering. For stronger magnetic fields, the GeV delay can be explained with hadronic models, due to the long acceleration timescale of protons and the continuous photopion production after the end of the particle injection. While the FWHMs of the MeV and GeV light curves are almost the same in one-zone leptonic models, the FWHMs of the 1-30 GeV light curves in hadronic models are significantly wider than those of the 0.1-1 MeV light curves. The amount of the GeV delay depends on the importance of the Klein-Nishina effect in both the leptonic and hadronic models. In our examples of hadronic models the energies of the escaped neutrons are comparable to the gamma-ray energy, although their contribution to the ultra high-energy cosmic rays is still subdominant. The resulting neutrino spectra are hard enough to avoid the flux limit constraint from IceCube. The delay of the neutrino emission onset is up to several times longer than the corresponding delay of the GeV photon emission onset. The quantitative differences in the light curves for various models may be further tested with future atmospheric Cerenkov telescopes whose effective area is larger than that of Fermi-LAT, such as CTA.
Neutrinoless Double Beta Decay and Neutrino Masses
Michael Duerr
2012-06-04T23:59:59.000Z
Neutrinoless double beta decay is a promising test for lepton number violating physics beyond the standard model of particle physics. There is a deep connection between this decay and the phenomenon of neutrino masses. In particular, we will discuss the relation between neutrinoless double beta decay and Majorana neutrino masses provided by the so-called Schechter--Valle theorem in a quantitative way. Furthermore, we will present an experimental cross check to discriminate neutrinoless double beta decay from unknown nuclear background using only one isotope, i.e., within one experiment.
Neutrinoless double beta decay and neutrino masses
Duerr, Michael [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany)
2012-07-27T23:59:59.000Z
Neutrinoless double beta decay (0{nu}{beta}{beta}) is a promising test for lepton number violating physics beyond the standard model (SM) of particle physics. There is a deep connection between this decay and the phenomenon of neutrino masses. In particular, we will discuss the relation between 0{nu}{beta}{beta} and Majorana neutrino masses provided by the so-called Schechter-Valle theorem in a quantitative way. Furthermore, we will present an experimental cross check to discriminate 0{nu}{beta}{beta} from unknown nuclear background using only one isotope, i.e., within one experiment.
Chuang, Shan-Huei S.; /Wisconsin U., Madison
2006-12-01T23:59:59.000Z
By way of retaining the gauge invariance of the Standard Model (SM) and giving masses to the W{sup {+-}} and Z{sup 0} bosons and the fermions, the Higgs mechanism predicts the existence of a neutral scalar bosonic particle, whose mass is not exactly known. The Higgs boson is the only experimentally unconfirmed SM particle to date. This thesis documents a search for the Higgs boson in p{bar p} collisions at {radical}s = 1.96 TeV at the Tevatron, using 360 {+-} pb {sup -1} data collected by the Run II Collider Detector at Fermilab (CDF II), as part of the most important quest for contemporary particle physicists. The search was for a Higgs boson decaying to a pair of W{sup {+-}} bosons, where each W boson decays to an electron, a muon or a tau that further decays to an electron or a muon with associated neutrinos. Events with two charged leptons plus large missing energy were selected in data triggered on a high p{sub t} lepton and compared to the signal and backgrounds modeled using Monte Carlo and jet data. No signal-like excess was observed in data. Therefore, upper limits on the HWW production cross-section in the analyzed mass range were extracted using the binned likelihood maximum from distributions of dilepton azimuthal angle at 95% Bayesian credibility level (CL), as shown in the table below.
Running Effects on Lepton Mixing Angles in Flavour Models with Type I Seesaw
Yin Lin; Luca Merlo; Alessio Paris
2009-11-27T23:59:59.000Z
We study renormalization group running effects on neutrino mixing patterns when a (type I) seesaw model is implemented by suitable flavour symmetries. We are particularly interested in mass-independent mixing patterns to which the widely studied tribimaximal mixing pattern belongs. In this class of flavour models, the running contribution from neutrino Yukawa coupling, which is generally dominant at energies above the seesaw threshold, can be absorbed by a small shift on neutrino mass eigenvalues leaving mixing angles unchanged. Consequently, in the whole running energy range, the change in mixing angles is due to the contribution coming from charged lepton sector. Subsequently, we analyze in detail these effects in an explicit flavour model for tribimaximal neutrino mixing based on an A4 discrete symmetry group. We find that for normally ordered light neutrinos, the tribimaximal prediction is essentially stable under renormalization group evolution. On the other hand, in the case of inverted hierarchy, the deviation of the solar angle from its TB value can be large depending on mass degeneracy.
L. Cerrito
2004-07-16T23:59:59.000Z
Preliminary results on the measurement of the top quark mass at the Tevatron Collider are presented. In the dilepton decay channel, the CDF Collaboration measures m{sub t} = 175.0{sub -16.9}{sup +17.4}(stat.){+-}8.4(syst.) GeV/c{sup 2}, using a sample of {approx} 126 pb{sup -1} of proton-antiproton collision data at {radical}s = 1.96 TeV (Run II). In the lepton plus jets channel, the CDF Collaboration measures 177.5{sub -9.4}{sup +12.7}(stat.) {+-} 7.1(syst.) GeV/c{sup 2}, using a sample of {approx} 102 pb{sup -1} at {radical}s = 1.96 TeV. The D0 Collaboration has newly applied a likelihood technique to improve the analysis of {approx} 125 pb{sup -1} of proton-antiproton collisions at {radical}s = 1.8 TeV (Run I), with the result: m{sub t} = 180.1 {+-} 3.6(stat.) {+-}3.9(syst.) GeV/c{sup 2}. The latter is combined with all the measurements based on the data collected in Run I to yield the most recent and comprehensive experimental determination of the top quark mass: m{sub t} = 178.0 {+-} 2.7(stat.) {+-} 3.3(syst.) GeV/c{sup 2}.
U(2)? flavor symmetry and lepton universality violation in W?????
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Filipuzzi, Alberto; Portolés, Jorge; González-Alonso, Martín
2012-06-01T23:59:59.000Z
The seeming violation of universality in the ? lepton coupling to the W boson suggested by LEP-II data is studied using an effective field theory (EFT) approach. Within this framework we explore how this feature fits into the current constraints from electroweak precision observables using different assumptions about the flavor structure of New Physics, namely [U(2)×U(1)]? and U(2)?. We show the importance of leptonic and semileptonic tau decay measurements, giving 34 TeV bounds on the New Physics effective scale at 90% C.L. We conclude under very general assumptions that it is not possible to accommodate this deviation from universality inmore ťthe EFT framework, and thus such a signal could only be explained by the introduction of light degrees of freedom or New Physics strongly coupled at the electroweak scale.Ť less
U(2)? flavor symmetry and lepton universality violation in W?????
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Filipuzzi, Alberto; Portolés, Jorge; González-Alonso, Martín
2012-06-01T23:59:59.000Z
The seeming violation of universality in the ? lepton coupling to the W boson suggested by LEP-II data is studied using an effective field theory (EFT) approach. Within this framework we explore how this feature fits into the current constraints from electroweak precision observables using different assumptions about the flavor structure of New Physics, namely [U(2)×U(1)]? and U(2)?. We show the importance of leptonic and semileptonic tau decay measurements, giving 34 TeV bounds on the New Physics effective scale at 90% C.L. We conclude under very general assumptions that it is not possible to accommodate this deviation from universality in the EFT framework, and thus such a signal could only be explained by the introduction of light degrees of freedom or New Physics strongly coupled at the electroweak scale.
Lepton Mixing Predictions from (Generalised) CP and Discrete Flavour Symmetry
Thomas Neder
2015-03-31T23:59:59.000Z
An important class of flavour groups, that are subgroups of $U(3)$ and that predict experimentally viable lepton mixing parameters including Majorana phases, is the $\\Delta(6n^2)$ series. The most well-known member is $\\Delta(24)=S_4$. I present results of several extensive studies of lepton mixing predictions obtained in models with a $\\Delta(6n^2)$ flavour group that preserve either the full residual $Z_2\\times Z_2$ or a $Z_2$ subgroup for neutrinos and can include a generalised CP symmetry. Predictions include mixing angles and Dirac CP phase generally; and if invariance under a generalised CP symmetry is included, also Majorana phases. For this, the interplay of flavour group and generalised CP symmetry has to be studied carefully.
Abazov, V M; Abolins, M; Acharya, B S; Adams, M; Adams, T; Aguiló, E; Ahn, S H; Ahsan, M; Alexeev, G D; Alkhazov, G; Alton, A; Alverson, G; Alves, G A; Anastasoaie, M; Ancu, L S; Andeen, T; Anderson, S; Andrieu, B; Anzelc, M S; Arnoud, Y; Arov, M; Arthaud, M; Askew, A; Ĺsman, B; Assis-Jesus, A C S; Atramentov, O; Autermann, C; Avila, C; Ay, C; Badaud, F; Baden, A; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, P; Banerjee, S; Barberis, E; Barfuss, A F; Bargassa, P; Baringer, P; Barreto, J; Bartlett, J F; Bassler, U; Bauer, D; Beale, S; Bean, A; Begalli, M; Begel, M; Belanger-Champagne, C; Bellantoni, L; Bellavance, A; Benítez, J A; Beri, S B; Bernardi, G; Bernhard, R; Berntzon, L; Bertram, I; Besançon, M; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Biscarat, C; Blazey, G; Blekman, F; Blessing, S; Bloch, D; Bloom, K; Böhnlein, A; Boline, D; Bolton, T A; Borissov, G; Bos, K; Bose, T; Brandt, A; Brock, R; Brooijmans, G; Bross, A; Brown, D; Buchanan, N J; Buchholz, D; Bühler, M; Büscher, V; Burdin, S; Burke, S; Burnett, T H; Buszello, C P; Butler, J M; Calfayan, P; Calvet, S; Cammin, J; Caron, S; Carvalho, W; Casey, B C K; Cason, N M; Castilla-Valdez, H; Chakrabarti, S; Chakraborty, D; Chan, K; Chan, K M; Chandra, A; Charles, F; Cheu, E; Chevallier, F; Cho, D K; Choi, S; Choudhary, B; Christofek, L; Christoudias, T; Cihangir, S; Claes, D; Clement, B; Clément, C; Coadou, Y; Cooke, M; Cooper, W E; Corcoran, M; Couderc, F; Cousinou, M C; Crepe-Renaudin, S; Cutts, D; Cwiok, M; Da Motta, H; Das, A; Davies, G; De, K; de Jong, P; De Jong, S J; De La Cruz-Burelo, E; De Oliveira Martins, C; Degenhardt, J D; Déliot, F; Demarteau, M; Demina, R; Denisov, D; Denisov, S P; Desai, S; Diehl, H T; Diesburg, M; Dominguez, A; Dong, H; Dudko, L V; Duflot, L; Dugad, S R; Duggan, D; Duperrin, A; Dyer, J; Dyshkant, A; Eads, M; Edmunds, D; Ellison, J; Elvira, V D; Enari, Y; Eno, S; Ermolov, P; Evans, H; Evdokimov, A; Evdokimov, V N; Ferapontov, A V; Ferbel, T; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Ford, M; Fortner, M; Fox, H; Fu, S; Fuess, S; Gadfort, T; Galea, C F; Gallas, E; Galyaev, E; García, C; García-Bellido, A; Gavrilov, V; Gay, P; Geist, W; Gelé, D; Gerber, C E; Gershtein, Yu; Gillberg, D; Ginther, G; Gollub, N; Gómez, B; Goussiou, A; Grannis, P D; Greenlee, H; Greenwood, Z D; Gregores, E M; Grenier, G; Gris, P; Grivaz, J F; Grohsjean, A; Grünendahl, S; Grünewald, M W; Guo, F; Guo, J; Gutíerrez, G; Gutíerrez, P; Haas, A; Hadley, N J; Haefner, P; Hagopian, S; Haley, J; Hall, I; Hall, R E; Han, L; Hanagaki, K; Hansson, P; Harder, K; Harel, A; Harrington, R; Hauptman, J M; Hauser, R; Hays, J; Hebbeker, T; Hedin, D; Hegeman, J G; Heinmiller, J M; Heinson, A P; Heintz, U; Hensel, C; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hobbs, J D; Hoeneisen, B; Hoeth, H; Hohlfeld, M; Hong, S J; Hooper, R; Hossain, S; Houben, P; Hu, Y; Hubacek, Z; Hynek, V; Iashvili, I; Illingworth, R; Ito, A S; Jabeen, S; Jaffré, M; Jain, S; Jakobs, K; Jarvis, C; Jesik, R; Johns, K; Johnson, C; Johnson, M; Jonckheere, A; Jonsson, P; Juste, A; Käfer, D; Kahn, S; Kajfasz, E; Kalinin, A M; Kalk, J M; Kalk, J R; Kappler, S; Karmanov, D; Kasper, J; Kasper, P; Katsanos, I; Kau, D; Kaur, R; Kaushik, V; Kehoe, R; Kermiche, S; Khalatyan, N; Khanov, A; Kharchilava, A I; Kharzheev, Yu M; Khatidze, D; Kim, H; Kim, T J; Kirby, M H; Kirsch, M; Klima, B; Kohli, J M; Konrath, J P; Kopal, M; Korablev, V M; Kothari, B; Kozelov, A V; Krop, D; Kryemadhi, A; Kühl, T; Kumar, A; Kunori, S; Kupco, A; Kurca, T; Kvita, J; Lam, D; Lammers, S; Landsberg, G L; Lazoflores, J; Lebrun, P; Lee, W M; Leflat, A; Lehner, F; Lellouch, J; Lesne, V; Lévęque, J; Lewis, P; Li, J; Li, L; Li, Q Z; Lietti, S M; Lima, J G R; Lincoln, D; Linnemann, J; Lipaev, V V; Lipton, R; Liu, Y; Liu, Z; Lobo, L; Lobodenko, A; Lokajícek, M; Lounis, A; Love, P; Lubatti, H J; Lyon, A L; Maciel, A K A; Mackin, D; Madaras, R J; Mättig, P; Magass, C; Magerkurth, A; Makovec, N; Mal, P K; Malbouisson, H B; Malik, S; Malyshev, V L; Mao, H S; Maravin, Y; Martin, B; McCarthy, R; Melnitchouk, A; Mendes, A; Mendoza, L; Mercadante, P G; Merkin, M; Merritt, K W; Meyer, A; Meyer, J; Michaut, M; Millet, T; Mitrevski, J; Molina, J; Mommsen, R K; Mondal, N K; Moore, R W; Moulik, T; Muanza, G S; Mulders, M; Mulhearn, M; Mundal, O; Mundim, L; Nagy, E; Naimuddin, M; Narain, M; Naumann, N A; Neal, H A; Negret, J P; Neustroev, P; Nilsen, H; Nöding, C; Nomerotski, A; Novaes, S F; Nunnemann, T; O'Dell, V; O'Neil, D C; Obrant, G; Ochando, C; Onoprienko, D; Oshima, N; Osta, J; Otec, R; Oteroy-Garzon, G J; Owen, M; Padley, P; Pangilinan, M; Parashar, N; Park, S J; Park, S K; Parsons, J; Partridge, R; Parua, N; Patwa, A; Pawloski, G; Perea, P M; Peters, K; Peters, Y; Petroff, P; Petteni, M; Piegaia, R; Piper, J; Pleier, M A; Podesta-Lerma, P L M; Podstavkov, V M; Pogorelov, Y; Pol, M E; Pompos, A
2007-01-01T23:59:59.000Z
We present a study of eegamma and mumugamma events using over 1 fb-1 of data collected with the D0 detector at the Fermilab Tevatron ppbar Collider at $\\sqrt{s}$ = 1.96 TeV. Having observed 453 (515) candidates in the eegamma (mumugamma) final state, we measure the Zgamma production cross section for a photon with transverse energy ET > 7 GeV, separation between the photon and leptons Delta R(lgamma} > 0.7, and invariant mass of the di-lepton pair M(ll) > 30 GeV, to be 4.96 +/- 0.30(stat. + syst.) +/- 0.30(lumi.) pb, in agreement with the standard model prediction of 4.74 +/- 0.22 pb. This is the most precise Zgamma cross section measurement at a hadron collider. We set limits on anomalous trilinear Zgammagamma and ZZgamma gauge boson couplings of -0.085 < h(30)^(gamma) < 0.084, -0.0053 < h(40)^(gamma) < 0.0054 and -0.083 < h(30)^(Z) < 0.082, -0.0053 < h(40)^(Z) < 0.0054 at the 95% C.L. for the form-factor scale Lambda = 1.2 TeV.
The vertex detector for the Lepton/Photon collaboration
Sullivan, J.P.; Boissevain, J.G.; Fox, D.; Hecke, H. van; Jacak, B.V.; Kapustinsky, J.S.; Leitch, M.J.; McGaughey, P.L.; Moss, J.M.; Sondheim, W.E. [Los Alamos National Lab., NM (United States)
1991-12-31T23:59:59.000Z
The conceptual design of the vertex detector for the Lepton/Photon Collaboration at RHIC is described, including simulations of its expected performance. The design consists of two con- centric layers of single-sided Si strips. The expected performance as a multiplicity detector and in measuring the pseudo-rapidity ({nu}) distribution is discussed as well as the expected vertex finding efficiency and accuracy. Various options which could be used to reduce the cost of the detector are also discussed.
Lepton flavor violation two-body decays of quarkoniums
W. J. Huo; T. F. Feng; Y. C. Xing
2002-12-15T23:59:59.000Z
In this paper we firstly study various model-independent bounds on lepton flavor violation (LFV) in processes of $J/\\Psi$, $\\Psi'$ and $\\Upsilon$ two-body decays, then calculate their branch ratios % By using the constraints from other ways, we obtain %the indirect bounds of ${\\rm Br} (J/\\Psi,\\Psi',\\Upsilon \\to ll')$ in models of the leptoquark, $R$ violating MSSM and topcolor assisted technicolor(TC2) models.
Prospects of Heavy Neutrino Searches at Future Lepton Colliders
Banerjee, Shankha; Ibarra, Alejandro; Mandal, Tanumoy; Mitra, Manimala
2015-01-01T23:59:59.000Z
We discuss the future prospects of heavy neutrino searches at next generation lepton colliders. In particular, we focus on the planned electron-positron colliders, operating in two different beam modes, namely, $e^+e^-$ and $e^-e^-$. In the $e^+e^-$ beam mode, we consider various production and decay modes of the heavy neutrino ($N$), and find that the final state with $e+2j+\\slashed{E}$, arising from the $e^+e^-\\to N\
Textures with two traceless submatrices of the neutrino mass matrix
H. A. Alhendi; E. I. Lashin; A. A. Mudlej
2008-02-27T23:59:59.000Z
We propose a new texture for the light neutrino mass matrix. The proposal is based upon imposing zero-trace condition on the two by two sub-matrices of the complex symmetric Majorana mass matrix in the flavor basis where the charged lepton mass matrix is diagonal. Restricting the mass matrix to have two traceless sub-matrices may be found sufficient to describe the current data. Eight out of fifteen independent possible cases are found to be compatible with current data. Numerical and some approximate analytical results are presented.
Neutrino Mixing and Masses from a Minimum Principle
Alonso, R; Isidori, G; Maiani, L
2013-01-01T23:59:59.000Z
We analyze the structure of quark and lepton mass matrices under the hypothesis that they are determined from a minimum principle applied to a generic potential invariant under the $[SU(3)]^5\\otimes {\\mathcal O}(3)$ flavor symmetry, acting on Standard Model fermions and right-handed neutrinos. Unlike the quark case, we show that hierarchical masses for charged leptons are naturally accompanied by degenerate Majorana neutrinos with one angle close to maximal, a second potentially large, a third one necessarily small, and precise values for the two Majorana phases. Adding small perturbations the predicted structure for the neutrino mass matrix is in excellent agreement with present observations and could be tested in the near future via neutrino-less double beta decay. The generalization of these results to arbitrary sew-saw models is also discussed.
S3 x Z2 model for neutrino mass matrices
W. Grimus; L. Lavoura
2005-08-02T23:59:59.000Z
We propose a model for lepton mass matrices based on the seesaw mechanism, a complex scalar gauge singlet and a horizontal symmetry $S_3 \\times \\mathbbm{Z}_2$. In a suitable weak basis, the charged-lepton mass matrix and the neutrino Dirac mass matrix are diagonal, but the vacuum expectation value of the scalar gauge singlet renders the Majorana mass matrix of the right-handed neutrinos non-diagonal, thereby generating lepton mixing. When the symmetry $S_3$ is not broken in the scalar potential, the effective light-neutrino Majorana mass matrix enjoys $\\mu$--$\\tau$ interchange symmetry, thus predicting maximal atmospheric neutrino mixing together with $U_{e3} = 0$. A partial and less predictive form of $\\mu$--$\\tau$ interchange symmetry is obtained when the symmetry $S_3$ is softly broken in the scalar potential. Enlarging the symmetry group $S_3 \\times \\mathbbm{Z}_2$ by an additional discrete electron-number symmetry $\\mathbbm{Z}_2^{(e)}$, a more predicitive model is obtained, which is in practice indistinguishable from a previous one based on the group $D_4$.
Baryogenesis via leptogenesis from quark-lepton symmetry and a compact heavy N{sub R} spectrum
Buccella, F.; Falcone, D.; Oliver, L. [Dipartimento di Scienze Fisiche, Universita di Napoli, Via Cintia, Napoli (Italy); INFN, Sezione di Napoli (Italy); Dipartimento di Scienze Fisiche, Universita di Napoli, Via Cintia, Napoli (Italy); Laboratoire de Physique Theorique Universite de Paris XI, Batiment 210, 91405 Orsay Cedex (France)
2011-05-01T23:59:59.000Z
By demanding a compact spectrum for the right-handed neutrinos and an approximate quark-lepton symmetry inspired from SO(10) gauge unification (assuming a Dirac neutrino mass matrix close to the up quark mass matrix), we construct a fine-tuning scenario for baryogenesis via leptogenesis. We find two solutions with a normal hierarchy, with the lightest neutrino mass m{sub 1} different from zero, providing an absolute scale for the spectrum. In the approximations of the model, there are three independent CP phases: {delta}{sub L} (that we take of the order of the quark Kobayashi-Maskawa phase) and the two light neutrino Majorana phases {alpha} and {beta}. A main conclusion is that, although this general scheme is rather flexible, in some regions of parameter space we find that the necessary baryogenesis with its sign is given in terms of the {delta}{sub L} phase alone. The light Majorana phases can also be computed, and they turn out to be close to {pi}/2 or very small. Moreover, SO(10) breaks down to the Pati-Salam group SU(4)xSU(2)xSU(2) at the expected natural intermediate scale of about 10{sup 10}-10{sup 11} GeV. A prediction is made for the effective mass in ({beta}{beta}){sub 0{nu}} decay, the {nu}{sub e} mass, and the sum of all light neutrino masses.
Double beta decay and neutrino mass models
Helo, J C; Ota, T; Santos, F A Pereira dos
2015-01-01T23:59:59.000Z
Neutrinoless double beta decay allows to constrain lepton number violating extensions of the standard model. If neutrinos are Majorana particles, the mass mechanism will always contribute to the decay rate, however, it is not a priori guaranteed to be the dominant contribution in all models. Here, we discuss whether the mass mechanism dominates or not from the theory point of view. We classify all possible (scalar-mediated) short-range contributions to the decay rate according to the loop level, at which the corresponding models will generate Majorana neutrino masses, and discuss the expected relative size of the different contributions to the decay rate in each class. We also work out the phenomenology of one concrete 2-loop model in which both, mass mechanism and short-range diagram, might lead to competitive contributions, in some detail.
Probing long-range leptonic forces with solar and reactor neutrinos
González-Garciá, M C; Massó, E; Zukanovich-Funchal, R
2007-01-01T23:59:59.000Z
In this work we study the phenomenological consequences of the existence of long-range forces coupled to lepton flavour numbers in solar neutrino oscillations. We study electronic forces mediated by scalar, vector or tensor neutral bosons and analyze their effect on the propagation of solar neutrinos as a function of the force strength and range. Under the assumption of one mass scale dominance, we perform a global analysis of solar and KamLAND neutrino data which depends on the two standard oscillation parameters, \\Delta m^2_{21} and \\tan^2\\theta_{12}, the force coupling constant, its range and, for the case of scalar-mediated interactions, on the neutrino mass scale as well. We find that, generically, the inclusion of the new interaction does not lead to a very statistically significant improvement on the description of the data in the most favored MSW LMA (or LMA-I) region. It does, however, substantially improve the fit in the high-\\Delta m^2 LMA (or LMA-II) region which can be allowed for vector and scal...
Family number non-conservation induced by the supersymmetric mixing of scalar leptons
Levine, M.J.S.
1987-08-01T23:59:59.000Z
The most egregious aspect of (N = 1) supersymmetric theories is that each particle state is accompanied by a 'super-partner', a state with identical quantum numbers save that it differs in spin by one half unit. For the leptons these are scalars and are called ''sleptons'', or scalar leptons. These consist of the charged sleptons (selectron, smuon, stau) and the scalar neutrinos ('sneutrinos'). We examine a model of supersymmetry with soft breaking terms in the electroweak sector. Explicit mixing among the scalar leptons results in a number of effects, principally non-conservation of lepton family number. Comparison with experiment permits us to place constraints upon the model. 49 refs., 12 figs.
Generalised CP and $\\Delta (6n^2)$ Family Symmetry in Semi-Direct Models of Leptons
Ding, Gui-Jun; Neder, Thomas
2014-01-01T23:59:59.000Z
We perform a detailed analysis of $\\Delta (6n^2)$ family symmetry combined with a generalised CP symmetry in the lepton sector, breaking to different remnant symmetries $G_{\
G. G. Nyambuya
2010-01-22T23:59:59.000Z
This reading is a continuation of the earlier reading Nyambuya (2008); where three new Curved Spacetime Dirac Equations have been derived mainly to try and account in a natural way for the observed anomalous gyromagnetic ratio of fermions and the suggestions is that particles including the Electron, which is thought to be a point particle, do have a finite spatial size and this is one of the reasons for the observed anomalous gyromagnetic ratio. Combining the idea in Nyambuya (2008) which lead to the derivation of the three new Curved Spacetime Dirac Equations, and the proposed Unified Field Theory (Nyambuya 2007), a total of 12 equations each with 16 sub-components are generated thus leading to a total of 192 equations for the Curved Spacetime Dirac Equation. Some symmetries of these equations are investigated, i.e., the Lorentz symmetry, charge conjugation symmetry (C), time reversal symmetry (T), Space reversal (P) and a combination of the C, P and T - symmetries. It is shown that these equations are Lorentz invariant, obey C-symmetry and that some violate T and P-symmetry while others do not and that they all obey PT-symmetry. These symmetries show (or modestly said -- seem to suggest) that anti-particles have positive mass and energy but a negative rest-mass and the opposite sign in electronic charge. Through the inspection of these symmetries, a suggestion is (here) made to the effect that the rest-mass of a particle must be related to the electronic charge of that particle thus leading us to a possible resolution of whether or not Neutrinos do have a none-zero rest-mass. Additionally, we demonstrate that these equations have the potency to explain naturally the observed lepton generation phenomena.
mixing and will provide important input for interpretation of next-generation neutrinoless double beta decay experiments. Measurement of the mass hierarchy is important input to the search for leptonic CP
Mills, Corrinne Elaine; /UC, Santa Barbara
2007-06-01T23:59:59.000Z
Using 1.1 fb{sup -1} of data collected by the Collider Detector at Fermilab (CDF) from Run II of the Fermilab Tevatron, they measure the t{bar t} production cross section in events with two leptons, significant missing transverse energy, and {ge} 2 jets. As the Run II dataset grows, more stringent tests of Standard Model predictions for the top quark sector are becoming possible. The dilepton channel, where both top quarks decay t {yields} Wb {yields} {ell}{nu}b, is of particular interest due to its high purity even in the absence of a b jet 'tagging' requirement. Use of an isolated track as the second lepton significant increases the dilepton acceptance, at the price of some increase in background, particular from W + jets events where one of the jets is identified as a lepton. With the amount of data available, it has been possible to improve the estimate of the contribution from that background, reflected in a reduced systematic uncertainty. Assuming a branching ratio of BR(W {yields} {ell}{nu}) = 10.8% and a top mass of m{sub t} = 175 GeV/c{sup 2}, the measured cross-section is {sigma}(p{bar p} {yields} t{bar t}) = 8.3 {+-} 1.3(stat.) {+-} 0.7(syst.) {+-} 0.5(lumi.) pb. The result is consistent with the Standard Model prediction of 6.7{sub -0.9}{sup +0.7} pb and represents a significant improvement in precision over previous results using this selection.
Neutrino Mass Matrix in Triplet Higgs Models with A-bar 4 Symmetry
Baek, Seungwon [Institute of Basic Science and Department of Physics, Korea University, Seoul (Korea, Republic of); Chu Oh, Myoung [Department of Physics, University of Seoul, Seoul (Korea, Republic of)
2009-04-19T23:59:59.000Z
The tribimaximal form of the neutrino mixing matrix can be naturally obtained with A-bar 4 flavor symmetry. We consider triplet Higgs model with A-bar 4 symmetry to generate the neutrino masses. With neutrino oscillation data we show that the mass matrix can be (almost) reconstructed, which allows us to predict the absolute neutrino mass scale including the neutrinoless double beta decay, the decay rates of the doubly charged Higgs boson to lepton pairs.
Search for Nucleon Decay into Charged Anti-lepton plus Meson in Super-Kamiokande I and II
Nishino, H; Hayato, Y; Iida, T; Ikeda, M; Kameda, J; Koshio, Y; Miura, M; Moriyama, S; Nakahata, M; Nakayama, S; Obayashi, Y; Sekiya, H; Shiozawa, M; Suzuki, Y; Takeda, A; Takenaga, Y; Takeuchi, Y; Ueno, K; Ueshima, K; Watanabe, H; Yamada, S; Hazama, S; Higuchi, I; Ishihara, C; Kaji, H; Kajita, T; Kaneyuki, K; Mitsuka, G; Okumura, K; Tanimoto, N; Dufour, F; Kearns, E; Litos, M; Raaf, J L; Stone, J L; Sulak, L R; Goldhaber, M; Bays, K; Cravens, J P; Kropp, W R; Mine, S; Regis, C; Smy, M B; Sobel, H W; Ganezer, K S; Hill, J; Keig, W E; Jang, J S; Kim, J Y; Lim, I T; Albert, J B; Scholberg, K; Walter, C W; Wendell, R; Ishizuka, T; Tasaka, S; Learned, J G; Matsuno, S; Watanabe, Y; Hasegawa, T; Ishida, T; Ishii, T; Kobayashi, T; Nakadaira, T; Nakamura, K; Nishikawa, K; Oyama, Y; Sakashita, K; Sekiguchi, T; Tsukamoto, T; Suzuki, A T; Minamino, A; Nakaya, T; Yokoyama, M; Fukuda, Y; Itow, Y; Tanaka, T; Jung, C K; Lopez, G; McGrew, C; Yanagisawa, C; Tamura, N; Idehara, Y; Sakuda, M; Kuno, Y; Yoshida, M; Kim, S B; Yang, B S; Okazawa, H; Choi, Y; Seo, H K; Furuse, Y; Nishijima, K; Yokosawa, Y; Koshiba, M; Totsuka, Y; Vagins, M R; Chen, S; Heng, Y; Liu, J; Yang, Z; Zhang, H; Kielczewska, D; Connolly, K; Thrane, E; Wilkes, R J
2012-01-01T23:59:59.000Z
Searches for a nucleon decay into a charged anti-lepton (e^+ or {\\mu}^+) plus a light meson ({\\pi}^0, {\\pi}^-, {\\eta}, {\\rho}^0, {\\rho}^-, {\\omega}) were performed using the Super-Kamiokande I and II data. Twelve nucleon decay modes were searched for. The total exposure is 140.9 kiloton \\cdot years, which includes a 91.7 kiloton \\cdot year exposure (1489.2 live days) of Super-Kamiokande-I and a 49.2 kiloton \\cdot year exposure (798.6 live days) of Super-Kamiokande-II. The number of candidate events in the data was consistent with the atmospheric neutrino background expectation. No significant evidence for a nucleon decay was observed in the data. Thus, lower limits on the nucleon partial lifetime at 90% confidence level were obtained. The limits range from 3.6 \\times 10^31 to 8.2 \\times 10^33 years, depending on the decay modes.
Search for Nucleon Decay into Charged Anti-lepton plus Meson in Super-Kamiokande I and II
Super-Kamiokande Collaboration; :; H. Nishino; K. Abe; Y. Hayato; T. Iida; M. Ikeda; J. Kameda; Y. Koshio; M. Miura; S. Moriyama; M. Nakahata; S. Nakayama; Y. Obayashi; H. Sekiya; M. Shiozawa; Y. Suzuki; A. Takeda; Y. Takenaga; Y. Takeuchi; K. Ueno; K. Ueshima; H. Watanabe; S. Yamada; S. Hazama; I. Higuchi; C. Ishihara; H. Kaji; T. Kajita; K. Kaneyuki; G. Mitsuka; K. Okumura; N. Tanimoto; F. Dufour; E. Kearns; M. Litos; J. L. Raaf; J. L. Stone; L. R. Sulak; M. Goldhaber; K. Bays; J. P. Cravens; W. R. Kropp; S. Mine; C. Regis; M. B. Smy; H. W. Sobel; K. S. Ganezer; J. Hill; W. E. Keig; J. S. Jang; J. Y. Kim; I. T. Lim; J. B. Albert; K. Scholberg; C. W. Walter; R. Wendell; T. Ishizuka; S. Tasaka; J. G. Learned; S. Matsuno; Y. Watanabe; T. Hasegawa; T. Ishida; T. Ishii; T. Kobayashi; T. Nakadaira; K. Nakamura; K. Nishikawa; Y. Oyama; K. Sakashita; T. Sekiguchi; T. Tsukamoto; A. T. Suzuki; A. Minamino; T. Nakaya; M. Yokoyama; Y. Fukuda; Y. Itow; T. Tanaka; C. K. Jung; G. Lopez; C. McGrew; C. Yanagisawa; N. Tamura; Y. Idehara; M. Sakuda; Y. Kuno; M. Yoshida; S. B. Kim; B. S. Yang; H. Okazawa; Y. Choi; H. K. Seo; Y. Furuse; K. Nishijima; Y. Yokosawa; M. Koshiba; Y. Totsuka; M. R. Vagins; S. Chen; Y. Heng; J. Liu; Z. Yang; H. Zhang; D. Kielczewska; K. Connolly; E. Thrane; R. J. Wilkes
2012-06-22T23:59:59.000Z
Searches for a nucleon decay into a charged anti-lepton (e^+ or {\\mu}^+) plus a light meson ({\\pi}^0, {\\pi}^-, {\\eta}, {\\rho}^0, {\\rho}^-, {\\omega}) were performed using the Super-Kamiokande I and II data. Twelve nucleon decay modes were searched for. The total exposure is 140.9 kiloton \\cdot years, which includes a 91.7 kiloton \\cdot year exposure (1489.2 live days) of Super-Kamiokande-I and a 49.2 kiloton \\cdot year exposure (798.6 live days) of Super-Kamiokande-II. The number of candidate events in the data was consistent with the atmospheric neutrino background expectation. No significant evidence for a nucleon decay was observed in the data. Thus, lower limits on the nucleon partial lifetime at 90% confidence level were obtained. The limits range from 3.6 \\times 10^31 to 8.2 \\times 10^33 years, depending on the decay modes.
Muon g-2 Anomaly and Dark Leptonic Gauge Boson
Lee, Hye-Sung [W& M
2014-11-01T23:59:59.000Z
One of the major motivations to search for a dark gauge boson of MeV-GeV scale is the long-standing muon g-2 anomaly. Because of active searches such as fixed target experiments and rare meson decays, the muon g-2 favored parameter region has been rapidly reduced. With the most recent data, it is practically excluded now in the popular dark photon model. We overview the issue and investigate a potentially alternative model based on the gauged lepton number or U(1)_L, which is under different experimental constraints.
Exploring the Role of Lepton Mass in the Hydrogen Atom Frank Rioux
Rioux, Frank
kinetic energy. Substitution of the deBroglie relation ( = h/mv) into the classical expression for kinetic energy yields a quantum mechanical expression for kinetic energy. It is of utmost importance general and versatile quantum mechanical expression for kinetic energy is the differential operator shown
Electron generation of leptons and hadrons with reciprocal -quantized lifetimes and masses
generation occurs via an initial "-leap" from an electron pair to a "platform state" M, and then subsequent in modern physics has been the theory of quantum electrodynamics (QED). This is the theory for the much stronger had- ron interactions is quantum chromodynamics (QCD), which was patterned after QED
Top Quark Mass Measurement in the 2 fb -1 Tight Lepton and Isolated Track Sample using
Quigg, Chris
have been specified (see below). y Part of this work was supported by DARA grant WE2 50 OR 9411. 1 #12
LSP Squark Decays at the LHC and the Neutrino Mass Hierarchy
Zachary Marshall; Burt A. Ovrut; Austin Purves; Sogee Spinner
2014-08-05T23:59:59.000Z
The existence of R-parity in supersymmetric models can be naturally explained as being a discrete subgroup of gauged baryon minus lepton number (B-L). The most minimal supersymmetric B-L model triggers spontaneous R-parity violation, while remaining consistent with proton stability. This model is well-motivated by string theory and makes several interesting, testable predictions. Furthermore, R-parity violation contributes to neutrino masses, thereby connecting the neutrino sector to the decay of the lightest supersymmetric particle (LSP). This paper analyzes the decays of third generation squark LSPs into a quark and a lepton. In certain cases, the branching ratios into charged leptons reveal information about the neutrino mass hierarchy, a current goal of experimental neutrino physics, as well as the $\\theta_{23}$ neutrino mixing angle. Furthermore, optimization of leptoquark searches for this scenario is discussed. Using currently available data, the lower bounds on the third generation squarks are computed.
Disentangling the various Mechanisms of neutrinoless double beta decay to extract the neutrino mass
Vergados, J. D. [Physics Department, University of Ioannina, Ioannina, GR 451 10, Greece and Theory Division, CERN 1211, Geneva 23 (Greece)
2011-12-16T23:59:59.000Z
It is well known that there exist many mechanisms that may contribute to neutrinoless double beta decay. By exploiting the fact that the associated nuclear matrix elements are target dependent we show that, given definite experimental results on a sufficient number of targets, one can determine or sufficiently constrain all lepton violating parameters including the mass term. As a specific example we show that, given the observation of the 0{nu}{beta}{beta}-decay in three different nuclei, e.g. {sup 76}Ge, {sup 100}Mo and {sup 130}Te, and assuming just three active lepton number violating parameters, e.g. light and heavy neutrino mass mechanisms in left handed currents as well as R-parity breaking SUSY mechanism, one may determine all lepton violating parameters, provided that they are relatively real.
Hasinoff, M D; Azuelos, Georges; Bertl, W; Blecher, M; Chen, C Q; Depommier, P; Doyle, B; Von Egidy, T; Gorringe, T P; Gumplinger, P; Henderson, R; Jonkmans, G; Larabee, A J; MacDonald, J A; McDonald, S C; Munro, M H; Poutissou, J M; Poutissou, R; Robertson, B C; Sample, D G; Schott, W; Taylor, G N; Veillette, S; Wright, D H
1992-01-01T23:59:59.000Z
Determination of the semi-leptonic weak interaction pseudoscalar coupling constant , g$_{P}$, using the reaction $\\mu^{-}$p --> $\
Neutrino Majorana Mass from Black Hole
Yosuke Uehara
2002-05-25T23:59:59.000Z
We propose a new mechanism to generate the neutrino Majorana mass in TeV-scale gravity models. The black hole violates all non-gauged symmetries and can become the origin of lepton number violating processes. The fluctuation of higher-dimensional spacetime can result in the production of a black hole, which emits 2 neutrinos. If neutrinos are Majorana particles, this process is equivalent to the free propagation of a neutrino with the insertion of the black hole. From this fact, we derive the neutrino Majorana mass. The result is completely consistent with the recently observed evidence of neutrinoless double beta decay. And the obtained neutrino Majorana mass satisfies the constraint from the density of the neutrino dark matter, which affects the cosmic structure formation. Furthermore, we can explain the ultrahigh energy cosmic rays by the Z-burst scenario with it.
White, Stephen
of 10 mJy. Although compatible with the tentative detection of YZ CMi at 1.1 mm reported by Mullan.5 mm of the dMe flare stars YZ CMi and AD Leo, during which neither star was detected at an upper limit also are unlikely to explain the reported millimeter emission from dMe flare stars, and that the time
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Process Limits Process Limits Limit Hard Soft core file size (blocks) 0 unlimited data seg size (kbytes) unlimited unlimited scheduling priority 0 0 file size (blocks) unlimited...
William D. Heacox
2005-10-10T23:59:59.000Z
A non-parametric statistical model is constructed to directly relate The distribution of observed microlens timescales to that of the mass Function of the population from which the lenses are drawn, corrected For observational selection based on timescales and event amplifications. Explicit distributions are derived for microlensing impact parameters and maximum amplifications; both are shown to be statistically independent of all other parameters in the problem, including lens mass. The model is used to demonstrate that the narrow range of microlens timescales observed toward the Large Magellanic Cloud (LMC) is probably not consistent with lensing by a widely distributed spheroidal population of large velocity dispersion, as expected of a dark halo; but is consistent with lensing within a rotating thick disk. Poor numerical conditioning on the statistical connection between lens masses and event timescales, and small number statistics, severely limit the mass function information obtainable from current microlensing surveys toward the LMC.
Measurement of the Mass Difference between t and t[over-bar] Quarks
Bauer, Gerry P.
We present a direct measurement of the mass difference between t and t[over-bar] quarks using tt[over-bar] candidate events in the lepton+jets channel, collected with the CDF II detector at Fermilabs 1.96 TeV Tevatron ...
Airapetian, A; Amarian, M; Arrington, J; Aschenauer, E C; Avakian, H; Avakian, R; Avetisian, A; Avetissian, E; Bailey, P; Bains, B; Baumgarten, C; Beckmann, M; Belostotskii, S; Bernreuther, S; Bianchi, N; Böttcher, Helmut B; Borisov, A; Bouwhuis, M; Brack, J; Brauksiepe, S; Braun, B; Brückner, W; Brüll, A; Budz, P; Bulten, H J; Capitani, G P; Carter, P; Chumney, P; Cisbani, E; Court, G R; Dalpiaz, P F; De Leo, R; De Nardo, L; De Sanctis, E; De Schepper, D; Devitsin, E G; De Witt-Huberts, P K A; Di Nezza, P; Dzhordzhadze, V; Düren, M; Dvoredsky, A P; Elbakian, G M; Ely, J; Fantoni, A; Feshchenko, A; Felawka, L; Ferro-Luzzi, M; Fiedler, K; Filippone, B W; Fischer, H; Fox, B; Franz, J; Frullani, S; Gärber, Y; Garibaldi, F; Garutti, E; Gavrilov, G E; Karibian, V; Golendukhin, A; Graw, G; Grebenyuk, O; Green, P W; Greeniaus, L G; Gute, A; Haeberli, W; Hartig, M; Hasch, D; Heesbeen, D; Heinsius, F H; Henoch, M; Hertenberger, R; Hesselink, W H A; Hofman, G J; Holler, Y; Holt, R J; Hommez, B; Iarygin, G; Iodice, M; Izotov, A A; Jackson, H E; Jgoun, A; Jung, P; Kaiser, R; Kanesaka, J; Kinney, E R; Kiselev, A; Kitching, P; Kobayashi, H; Koch, N; Königsmann, K C; Kolster, H; Korotkov, V A; Kotik, E; Kozlov, V; Krivokhizhin, V G; Kyle, G S; Lagamba, L; Laziev, A; Lenisa, P; Lindemann, T; Lorenzon, W; Makins, N C R; Martin, J W; Marukyan, H O; Masoli, F; McAndrew, M; McIlhany, K; McKeown, R D; Meissner, F; Menden, F; Metz, A; Meyners, N; Miklukho, O; Miller, C A; Milner, R; Muccifora, V; Mussa, R; Nagaitsev, A P; Nappi, E; Naryshkin, Yu; Nass, A; Negodaeva, K; Nowak, Wolf-Dieter; Oganesyan, K A; O'Neill, T G; Openshaw, R; Ouyang, J; Owen, B R; Pate, S F; Potashov, S Yu; Potterveld, D H; Rakness, G; Rappoport, V; Redwine, R P; Reggiani, D; Reolon, A R; Ristinen, R; Rith, K; Robinson, D; Rostomyan, A; Ruh, M; Ryckbosch, D; Sakemi, Y; Sato, F; Savin, I A; Scarlett, C; Schäfer, A; Schill, C; Schmidt, F; Schnell, G; Schüler, K P; Schwind, A; Seibert, J; Seitz, B; Shibata, T A; Shin, T; Shutov, V B; Simani, C; Simon, A; Sinram, K; Steffens, E; Steijger, J J M; Stewart, J; Stösslein, U; Suetsugu, K; Sutter, M F; Szymanowski, L; Taroian, S P; Terkulov, A R; Teryaev, O V; Tessarin, S; Thomas, E; Tipton, B; Tytgat, M; Urciuoli, G M; Van den Brand, J F J; van der Steenhoven, G; Van de Vyver, R; Van Hunen, J J; Vetterli, Martin C; Vikhrov, V V; Vincter, M G; Visser, J; Volk, E; Weiskopf, C; Wendland, J; Wilbert, J; Wise, T; Yen, S; Yoneyama, S; Zohrabyan, H G
2001-01-01T23:59:59.000Z
Evidence for a positive longitudinal double-spin asymmetry = 0.24 +-0.11 (stat) +-0.02 (syst) in the cross section for exclusive diffractive rho^0(770) vector meson production in polarised lepton-proton scattering was observed by the HERMES experiment. The longitudinally polarised 27.56 GeV HERA positron beam was scattered off a longitudinally polarised pure hydrogen gas target. The average invariant mass of the photon-proton system has a value of = 4.9 GeV, while the average negative squared four-momentum of the virtual photon is = 1.7 GeV^2. The ratio of the present result to the corresponding spin asymmetry in inclusive deep-inelastic scattering is in agreement with an early theoretical prediction based on the generalised vector meson dominance model.
Absolute neutrino mass measurements
Wolf, Joachim [Karlsruhe Institute of Technology (KIT), IEKP, Postfach 3640, 76021 Karlsruhe (Germany)
2011-10-06T23:59:59.000Z
The neutrino mass plays an important role in particle physics, astrophysics and cosmology. In recent years the detection of neutrino flavour oscillations proved that neutrinos carry mass. However, oscillation experiments are only sensitive to the mass-squared difference of the mass eigenvalues. In contrast to cosmological observations and neutrino-less double beta decay (0v2{beta}) searches, single {beta}-decay experiments provide a direct, model-independent way to determine the absolute neutrino mass by measuring the energy spectrum of decay electrons at the endpoint region with high accuracy.Currently the best kinematic upper limits on the neutrino mass of 2.2eV have been set by two experiments in Mainz and Troitsk, using tritium as beta emitter. The next generation tritium {beta}-experiment KATRIN is currently under construction in Karlsruhe/Germany by an international collaboration. KATRIN intends to improve the sensitivity by one order of magnitude to 0.2eV. The investigation of a second isotope ({sup 137}Rh) is being pursued by the international MARE collaboration using micro-calorimeters to measure the beta spectrum. The technology needed to reach 0.2eV sensitivity is still in the R and D phase. This paper reviews the present status of neutrino-mass measurements with cosmological data, 0v2{beta} decay and single {beta}-decay.
Yue, Chong-Xing; Guo, Yu-Chen
2015-01-01T23:59:59.000Z
Taking into account of the constraints on the lepton flavor violation (LFV) couplings of the standard model (SM) Higgs boson H with leptons from low energy experiments and the recent CMS results, we investigate production of the SM Higgs boson associated with a lepton $\\tau$ via $e\\gamma$ collision at the ILC and LHeC experiments. The production cross sections are calculated, the LFV signals and the relevant SM backgrounds are examined. The LFV signals of the SM Higgs boson might be observed via $e\\gamma$ collision in future ILC experiments.
Lepton flavor violating Higgs couplings and single production of the Higgs boson via e ?collision
Chong-Xing Yue; Cong Pang; Yu-Chen Guo
2015-05-08T23:59:59.000Z
Taking into account of the constraints on the lepton flavor violation (LFV) couplings of the standard model (SM) Higgs boson H with leptons from low energy experiments and the recent CMS results, we investigate production of the SM Higgs boson associated with a lepton $\\tau$ via $e\\gamma$ collision at the ILC and LHeC experiments. The production cross sections are calculated, the LFV signals and the relevant SM backgrounds are examined. The LFV signals of the SM Higgs boson might be observed via $e\\gamma$ collision in future ILC experiments.
Falsifying High-Scale Baryogenesis with Neutrinoless Double Beta Decay and Lepton Flavor Violation
Deppisch, Frank F; Hirsch, Martin; Huang, Wei-Chih; Päs, Heinrich
2015-01-01T23:59:59.000Z
Interactions that manifest themselves as lepton number violating processes at low energies in combination with sphaleron transitions typically erase any pre-existing baryon asymmetry of the universe. In this letter, we discuss the constraints obtained from an observation of neutrinoless double beta decay in this context. If a new physics mechanism of neutrinoless double beta decay is observed, typical scenarios of high-scale baryogenesis will be excluded unless the baryon asymmetry is stabilized via some new mechanism. We also sketch how this conclusion can be extended beyond the first lepton generation by incorporating lepton flavor violating processes.
Falsifying High-Scale Baryogenesis with Neutrinoless Double Beta Decay and Lepton Flavor Violation
Frank F. Deppisch; Julia Harz; Martin Hirsch; Wei-Chih Huang; Heinrich Päs
2015-03-16T23:59:59.000Z
Interactions that manifest themselves as lepton number violating processes at low energies in combination with sphaleron transitions typically erase any pre-existing baryon asymmetry of the universe. In this letter, we discuss the constraints obtained from an observation of neutrinoless double beta decay in this context. If a new physics mechanism of neutrinoless double beta decay is observed, typical scenarios of high-scale baryogenesis will be excluded unless the baryon asymmetry is stabilized via some new mechanism. We also sketch how this conclusion can be extended beyond the first lepton generation by incorporating lepton flavor violating processes.
Origin of families of fermions and their mass matrices
Bracic, A. Borstnik; Borstnik, N. S. Mankoc [Educational Faculty, University of Ljubljana, Kardeljeva ploscad 17, 1000 Ljubljana (Slovenia); Department of Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia)
2006-10-01T23:59:59.000Z
We are proposing a new way of describing families of quarks and leptons, using the approach unifying all the internal degrees of freedom, proposed by one of us [N. Mankoc Borstnik, Phys. Lett. B 292, 25 (1992).][N. Mankoc-Borstnik, J. Math. Phys. (N.Y.) 34, 3731 (1993).][N. Mankoc Borstnik, J. Math. Phys. (N.Y.) 36, 1593 (1995).][N. S. Mankoc Borstnik, Mod. Phys. Lett. A 10, 587 (1995).][N. S. Mankoc Borstnik and S. Fajfer, Nuovo Cimento Soc. Ital. Fis. B 112, 1637 (1997).][A. Borstnik and N. S. Mankoc Borstnik, in Proceedings to the International Workshop on ''What Comes Beyond the Standard Model, Bled, Slovenia, 1998, edited by N. Mankoc Borstnik, H. B. Nielsen, and C. Froggatt (DMFA, Zaloznistvo, 1999), p. 52.][N. S. Mankoc Borstnik and H. B. Nielsen, Phys. Rev. 62, 04010 (2000).][N. S. Mankoc Borstnik, Int. J. Theor. Phys. 40, 315 (2001), and references therein.][A. Borstnik and N. S. Mankoc Borstnik, in Proceedings to the International Workshop on ''What Comes Beyond the Standard Model'', Bled 2000, 2001, 2002 Volume 2, edited by N. Mankoc Borstnik, H. B. Nielsen, C. Froggatt, and D. Lukman (DMFA, Zaloznistvo, 2002), p. 27 and the paper (unpublished).][A. Borstnik and N. S. Mankoc Borstnik, in Proceedings to the Euroconference on Symmetries Beyond the Standard Model, Portoroz, 2003 edited by N. Mankoc Borstnik, H. B. Nielsen, C. Froggatt, and D. Lukman (DMFA, Zaloznistvo, 2003), pp. 27-51.]. Spinors, living in d(=1+13)-dimensional space, carry in this approach only the spin and interact with only the gravity through vielbeins and two kinds of the spin connection fields--the gauge fields of the Poincare group (p{sup a},S{sup ab}) and the second kind of the Clifford algebra objects (S-tilde{sup ab}). All the quarks and the leptons of one family appear in one Weyl representation of a chosen handedness of the Lorentz group, if analyzed with respect to the standard model gauge groups, which are subgroups of the group SO(1,13): the right handed (with respect to SO(1,3)) weak chargeless quarks and leptons and the left handed weak charged quarks and leptons (with the right handed neutrino included). A part of the starting Lagrange density of a Weyl spinor in d=1+13 transforms right handed quarks and leptons into left handed quarks and leptons manifesting as the Yukawa couplings of the standard model. A kind of the Clifford algebra objects generates families of quarks and leptons and contributes to diagonal and off-diagonal Yukawa couplings. The approach predicts an even number of families, treating leptons and quarks equivalently (we do not study a possible appearance of Majorana fermions yet). In this paper we investigate within this approach the appearance of the Yukawa couplings within one family of quarks and leptons as well as among the families (without assuming any Higgs fields like in the standard model). We present the mass matrices for four families and investigate whether our way of generating families might explain the origin of families of quarks and leptons as well as their observed properties--the masses and the mixing matrices. Numerical results are presented in Ref. [M. Breskvar, D. Lukman, and N. S. Mankoc Borstnik, hep-ph/0606159.].
Neutrino Masses in Astroparticle Physics
G. G. Raffelt
2002-08-08T23:59:59.000Z
The case for small neutrino mass differences from atmospheric and solar neutrino oscillation experiments has become compelling, but leaves the overall neutrino mass scale m_nu undetermined. The most restrictive limit of m_nu neutrinos. If solar neutrino oscillations indeed correspond to the favored large mixing angle MSW solution, then big-bang nucleosynthesis gives us a restrictive limit on all neutrino chemical potentials, removing the previous uncertainty of n_nu. Therefore, a possible future measurement of m_nu will directly establish the cosmic neutrino mass fraction Omega_nu. Cosmological neutrinos with sub-eV masses can play an interesting role for producing the highest-energy cosmic rays (Z-burst scenario). Sub-eV masses also relate naturally to leptogenesis scenarios of the cosmic baryon asymmetry. Unfortunately, the time-of-flight dispersion of a galactic or local-group supernova neutrino burst is not sensitive in the sub-eV range.
Search for the Higgs boson in lepton, tau and jets final states...
Office of Scientific and Technical Information (OSTI)
Search for the Higgs boson in lepton, tau and jets final states Re-direct Destination: Abstract Not Provided U.S. Department of Energy U.S. Department of Energy Office of Science...
Dieperink, A.E.L.; Miller, G.A. (Department of Physics, FM-15, University of Washington, Seattle, Washington (USA))
1991-08-01T23:59:59.000Z
Nuclear spectral functions computed with realistic nuclear forces are used to compute mean separation energies and to estimate the binding corrections to lepton-nucleus deep inelastic scattering. The separation energies are large and significant binding effects are obtained.
Search for neutrinoless decays of the tau lepton
Ammar, Raymond G.; Ball, S.; Baringer, Philip S.; Bean, Alice; Besson, David Zeke; Coppage, Don; Copty, N.; Davis, Robin E. P.; Hancock, N.; Kelly, M.; Kotov, S.; Kravchenko, I.; Kwak, Nowhan; Lam, H.
1994-10-01T23:59:59.000Z
. The upper limits obtained for 22 decay branching fractions are several times more stringent than those set previously....
Calculation of conventional and prompt lepton fluxes at very high energy
Fedynitch, Anatoli; Gaisser, Thomas K; Riehn, Felix; Stanev, Todor
2015-01-01T23:59:59.000Z
An efficient method for calculating inclusive conventional and prompt atmospheric leptons fluxes is presented. The coupled cascade equations are solved numerically by formulating them as matrix equation. The presented approach is very flexible and allows the use of different hadronic interaction models, realistic parametrizations of the primary cosmic-ray flux and the Earth's atmosphere, and a detailed treatment of particle interactions and decays. The power of the developed method is illustrated by calculating lepton flux predictions for a number of different scenarios.
Test of Lepton Flavour Universality in K+ --> l+nu Decays
C. Lazzeroni et al.
2011-03-01T23:59:59.000Z
A precision test of lepton flavour universality has been performed by measuring the ratio RK of kaon leptonic decay rates K+ --> e+nu and K+ --> mu+nu in a sample of 59813 reconstructed K+ --> e+nu candidates with (8.71 +- 0.24)% background contamination. The result RK = (2.487 +- 0.013) * 10^{-5} is in agreement with the Standard Model expectation.
Thermal and non-thermal leptogenesis in different neutrino mass models with tribimaximal mixings
N. Nimai Singh; H. Zeen Devi; Amal Kr Sarma
2008-07-15T23:59:59.000Z
In the present work we study both thermal and non-thermal leptogenesis in all neutrino mass models describing the presently available neutrino mass patterns. We consider the Majorana CP violating phases coming from right-handed Majorana mass matrices to estimate the baryon asymmetry of the universe, for different neutrino mass models namely degenerate, inverted hierarchical and normal hierarchical models, with tribimaximal mixings. Considering two possible diagonal forms of Dirac neutrino mass matrix as either charged lepton or up-quark mass matrix, the right-handed Majorana mass matrices are constructed from the light neutrino mass matrix through the inverse seesaw formula. Only the normal hierarchical model leads to the best predictions for baryon asymmetry of the universe, consistent with observations in both thermal and non-thermal leptogenesis scenario. The analysis though phenomenological may serve as an additional information in the discrimination among the presently available neutrino mass models.
W boson production and mass at the Tevatron
Stelzer-Chilton, Oliver; /Toronto U.
2005-06-01T23:59:59.000Z
The CDF and D0 collaborations have analyzed up to {approx} 200 pb{sup -1} of Run 2 physics data to measure W production properties such as the W cross section, the W width, lepton universality and the W charge asymmetry. From the cross section measurements, CDF obtains a lepton universality of g{sub {mu}}/g{sub e} = 0.998 {+-} 0.012 and g{sub {tau}}/g{sub e} = 0.99 {+-} 0.04 and an indirect W width of {Lambda}{sub W} = 2079 {+-} 41 MeV. D0 measured the W width directly and finds {Lambda}{sub W} = 2011 {+-} 142 MeV. CDF has estimated the uncertainties on the W boson mass measurements in the electron and muon decay channels and obtains an overall uncertainty of 76 MeV.
Frank F. Deppisch; Tomas E. Gonzalo; Sudhanwa Patra; Narendra Sahu; Utpal Sarkar
2014-10-23T23:59:59.000Z
We propose a class of left-right symmetric models (LRSMs) with spontaneous D parity breaking, where SU(2)_R breaks at the TeV scale while discrete left-right symmetry breaks around 10^9 GeV. By embedding this framework in a non-supersymmetric SO(10) Grand Unified Theory (GUT) with Pati-Salam symmetry as the highest intermediate breaking step, we obtain g_R / g_L ~ 0.6 between the right- and left-handed gauge couplings at the TeV scale. This leads to a suppression of beyond the Standard Model phenomena induced by the right-handed gauge coupling. Here we focus specifically on the consequences for neutrinoless double beta decay, low energy lepton flavour violation and LHC signatures due to the suppressed right handed currents. Interestingly, the reduced g_R allows us to interpret an excess of events observed recently in the range of 1.9 TeV to 2.4 TeV by the CMS group at the LHC as the signature of a right handed gauge boson in LRSMs with spontaneous D parity breaking. Moreover, the reduced right-handed gauge coupling also strongly suppresses the non-standard contribution of heavy states to the neutrinoless double beta decay rate as well as the amplitude of low energy lepton flavour violating processes. In a dominant type-II Seesaw mechanism of neutrino mass generation, we find that both sets of observables provide stringent and complimentary bounds which make it challenging to observe the scenario at the LHC.
M. K. Parida; Sudhanwa Patra
2013-01-14T23:59:59.000Z
In TeV scale left-right symmetric models, new dominant predictions to neutrinoless double beta decay and light neutrino masses are in mutual contradiction because of large contribution to the latter through popular seesaw mechanisms. We show that in a class of left-right models with high-scale parity restoration, these results coexist without any contravention with neutrino oscillation data and the relevant formula for light neutrino masses is obtained via gauged inverse seesaw mechanism. The most dominant contribution to the double beta decay is shown to be via $W^-_L- W^-_R$ mediation involving both light and heavy neutrino exchanges, and the model predictions are found to discriminate whether the Dirac neutrino mass is of quark-lepton symmetric origin or without it. We also discuss associated lepton flavor violating decays.
Ram Lal Awasthi; M. K. Parida; Sudhanwa Patra
2013-01-21T23:59:59.000Z
In the inverse seesaw extension of the standard model, supersymmetric or non-supersymmetric, while the light left-handed neutrinos are Majorana, the heavy right-handed neutrinos are pseudo-Dirac fermions. We show how one of these latter category of particles can contribute quite significantly to neutrinoless double beta decay. The neutrino virtuality momentum is found to play a crucial role in the non-standard contributions leading to the prediction of the pseudo-Dirac fermion mass in the range of $120\\, {MeV}-500\\, {MeV}$. When the Dirac neutrino mass matrix in the inverse seesaw formula is similar to the up-quark mass matrix, characteristic of high scale quark-lepton symmetric origin, the predicted branching ratios for lepton flavor violating decays are also found to be closer to the accessible range of ongoing experiments.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Khachatryan, Vardan; et al.,
2014-09-01T23:59:59.000Z
Searches for the direct electroweak production of supersymmetric charginos, neutralinos, and sleptons in a variety of signatures with leptons and $\\mathrm{W}$ , $\\mathrm{Z}$ , and Higgs bosons are presented. Results are based on a sample of proton-proton collision data collected at center-of-mass energy $\\sqrt{s}=8\\,\\mathrm{TeV}$ with the CMS detector in 2012, corresponding to an integrated luminosity of 19.5 $\\,\\text {fb}^\\text {-1}$ . The observed event rates are in agreement with expectations from the standard model. These results probe charginos and neutralinos with masses up to 720 $\\,\\text {GeV}$ , and sleptons up to 260 $\\,\\text {GeV}$ , depending on the modelmore ťdetails.Ť less
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Khachatryan, Vardan [Yerevan Physics Institute (Armenia); et al.,
2014-09-01T23:59:59.000Z
Searches for the direct electroweak production of supersymmetric charginos, neutralinos, and sleptons in a variety of signatures with leptons and $\\mathrm{W}$ , $\\mathrm{Z}$ , and Higgs bosons are presented. Results are based on a sample of proton-proton collision data collected at center-of-mass energy $\\sqrt{s}=8\\,\\mathrm{TeV}$ with the CMS detector in 2012, corresponding to an integrated luminosity of 19.5 $\\,\\text {fb}^\\text {-1}$ . The observed event rates are in agreement with expectations from the standard model. These results probe charginos and neutralinos with masses up to 720 $\\,\\text {GeV}$ , and sleptons up to 260 $\\,\\text {GeV}$ , depending on the model details.
Neutrino masses and mixings in a Minimal S3-invariant Extension of the Standard Model
Felix, O.; Mondragon, A.; Mondragon, M.; Peinado, E. [Departamento de Fisica Teorica, Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apdo. Postal 20-364, 01000 Mexico D.F. (Mexico)
2007-06-19T23:59:59.000Z
The mass matrices of the charged leptons and neutrinos, that had been derived in the framework of a Minimal S3-invariant Extension of the Standard Model, are here reparametrized in terms of their eigenvalues. The neutrino mixing matrix, VPMNS, is then computed and exact, explicit analytical expressions for the neutrino mixing angles as functions of the masses of the neutrinos and charged leptons are obtained. The reactor, {theta}13, and the atmosferic, {theta}23, mixing angles are found to be functions only of the masses of the charged leptons. The numerical values of {theta}{sub 13}{sup th} and {theta}{sub 23}{sup th} computed from our theoretical expressions are found to be in excellent agreement with the latest experimental determinations. The solar mixing angle, {theta}{sub 12}{sup th}, is found to be a function of both, the charged lepton and neutrino masses, as well as of a Majorana phase {phi}{nu}. A comparison of our theoretical expression for the solar angle {theta}{sub 12}{sup th} with the latest experimental value {theta}{sub 13}{sup exp} {approx_equal} 34 deg. allowed us to fix the scale and origin of the neutrino mass spectrum and obtain the mass values |m{nu}2| = 0.0507eV, |m{nu}1| = 0.0499eV and |m{nu}3| = 0.0193eV, in very good agreement with the observations of neutrino oscillations, the bounds extracted from neutrinoless double beta decay and the precision cosmological measurements of the CMB.
Tribimaximal mixing in neutrino mass matrices with texture zeros or vanishing minors
Dev, S; Gautam, Radha Raman
2010-01-01T23:59:59.000Z
We study the existence of one/two texture zeros or one/two vanishing minors in the neutrino mass matrix with $\\mu\\tau$ symmetry. In the basis where the charged lepton mass matrix and the Dirac neutrino mass matrix are diagonal, the one/two zeros or one/two vanishing minors in the right-handed Majorana mass matrix having $\\mu\\tau$ symmetry will propagate via seesaw mechanism as one/two vanishing minors or one/two texture zeros in the neutrino mass matrix with $\\mu\\tau$ symmetry respectively. It is found that only five such texture structures of the neutrino mass matrix are phenomenologically viable. For tribimaximal mixing, these texture structures reduce the number of free parameters to one. Interesting predictions are obtained for the effective Majorana mass $M_{ee}$, the absolute mass scale and the Majorana-type CP violating phases.
Tribimaximal mixing in neutrino mass matrices with texture zeros or vanishing minors
S. Dev; Shivani Gupta; Radha Raman Gautam
2010-11-25T23:59:59.000Z
We study the existence of one/two texture zeros or one/two vanishing minors in the neutrino mass matrix with $\\mu\\tau$ symmetry. In the basis where the charged lepton mass matrix and the Dirac neutrino mass matrix are diagonal, the one/two zeros or one/two vanishing minors in the right-handed Majorana mass matrix having $\\mu\\tau$ symmetry will propagate via seesaw mechanism as one/two vanishing minors or one/two texture zeros in the neutrino mass matrix with $\\mu\\tau$ symmetry respectively. It is found that only five such texture structures of the neutrino mass matrix are phenomenologically viable. For tribimaximal mixing, these texture structures reduce the number of free parameters to one. Interesting predictions are obtained for the effective Majorana mass $M_{ee}$, the absolute mass scale and the Majorana-type CP violating phases.
Top-quark mass measurements: Alternative techniques (LHC + Tevatron)
Stefanie Adomeit
2014-11-28T23:59:59.000Z
Measurements of the top-quark mass employing alternative techniques are presented, performed by the D0 and CDF collaborations at the Tevatron as well as the ATLAS and CMS experiments at the LHC. The alternative methods presented include measurements using the lifetime of $B$-hadrons, the transverse momentum of charged leptons and the endpoints of kinematic distributions in top quark anti-quark pair ($t\\bar{t}$) final states. The extraction of the top-quark pole mass from the $t\\bar{t}$ production cross-section and the normalized differential $t\\bar{t}$ + 1-jet cross-section are discussed as well as the top-quark mass extraction using fixed-order QCD predictions at detector level. Finally, a measurement of the top-quark mass using events enhanced in single top t-channel production is presented.
Loop-induced Neutrino Masses: A Case Study
Geng, Chao-Qiang; Tsai, Lu-Hsing
2014-01-01T23:59:59.000Z
We study the cocktail model in which the Majorana neutrino masses are generated by the so-called "cocktail" three-loop diagrams with the dark matter particle running in the loops. In particular, we give the correct analytic expressions of the neutrino masses in the model by the detailed calculation of the cocktail diagrams. Based on the reliable numerical calculation of the loop integrals, we explore the parameter space which can give the correct orders of neutrino masses while satisfying other experimental constraints, such as those from the neutrinoless double beta decay, low-energy lepton flavor violation processes, electroweak precision tests, and collider searches. As a result, the large couplings and the large mass difference between the two singly-charged (neutral) scalars are required.
Hernandez-Galeana, Albino [Departamento de Fisica de la Escuela Superior de Fisica y Matematicas, Instituto Politecnico Nacional, U.P. Adolfo Lopez Mateos, C.P. 07738. Mexico D.F. (Mexico)
2007-11-01T23:59:59.000Z
I report the analysis performed on fermion masses and mixing, including neutrino mixing, within the context of a model with hierarchical radiative mass generation mechanism for light charged fermions, mediated by exotic scalar particles at one and two loops, respectively, meanwhile the neutrinos get Majorana mass terms at tree level through the Yukawa couplings with two SU(2){sub L} Higgs triplets. All the resulting mass matrices in the model, for the u, d, and e fermion charged sectors, the neutrinos and the exotic scalar particles, are diagonalized in exact analytical form. Quantitative analysis shows that this model is successful to accommodate the hierarchical spectrum of masses and mixing in the quark sector as well as the charged lepton masses. The lepton mixing matrix, V{sub PMNS}, is written completely in terms of the neutrino masses m{sub 1}, m{sub 2}, and m{sub 3}. Large lepton mixing for {theta}{sub 12} and {theta}{sub 23} is predicted in the range of values 0.7 < or approx. sin{sup 2}2{theta}{sub 12} < or approx. 0.7772 and 0.87 < or approx. sin{sup 2}2{theta}{sub 23} < or approx. 0.9023 by using 0.033 < or approx. s{sub 13}{sup 2} < or approx. 0.04. These values for lepton mixing are consistent with 3{sigma} allowed ranges provided by recent global analysis of neutrino data oscillation. From {delta}m{sub sol}{sup 2} bounds, neutrino masses are predicted in the range of values m{sub 1}{approx_equal}(1.706-2.494)x10{sup -3} eV, m{sub 2}{approx_equal}(6.675-12.56)x10{sup -3} eV, and m{sub 3}{approx_equal}(1.215-2.188)x10{sup -2} eV, respectively. The above allowed lepton mixing leads to the quark-lepton complementary relations {theta}{sub 12}{sup CKM}+{theta}{sub 12}{sup PMNS}{approx_equal}41.543 deg. -44.066 deg. and {theta}{sub 23}{sup CKM}+{theta}{sub 23}{sup PMNS}{approx_equal}36.835 deg. -38.295 deg. The new exotic scalar particles induce flavor changing neutral currents and contribute to lepton flavor violating processes such as E{yields}e{sub 1}e{sub 2}e{sub 3}, to radiative rare decays, {tau}{yields}{mu}{gamma}, {tau}{yields}e{gamma}, {mu}{yields}e{gamma}, as well as to the anomalous magnetic moments of fermions. I give general analytical expressions for the branching ratios of these rare decays and for the anomalous magnetic moments for charged leptons.
Improved limits on scalar weak couplings
Adelberger, E.G. (PPE Division, CERN, CH-1211 Geneve 23 (Switzerland) Department of Physics, FM-15, University of Washington, Seattle, Washington 98195 (United States))
1993-05-10T23:59:59.000Z
I point out that [beta]-delayed proton spectroscopy is a powerful probe of possible scalar contributions to nuclear [beta] decay, and use Schardt and Riisager's data on the shape of the beta-delayed proton peaks from the superallowed decays of [sup 32]Ar and [sup 33]Ar to set improved upper limits on such couplings. Implications of these limits for leptoquark masses are mentioned.
Mass Distributions of Clusters Using Gravitational Magnification
Tom Broadhurst
1995-05-03T23:59:59.000Z
Lensing in the context of rich clusters is normally quantified from small image distortions, yielding a relative mass distribution in the limit of weak lensing. Here we show the magnification effect of lensing can also be mapped over a cluster, resulting in absolute mass determinations for the weak limit. Furthermore, given both magnification and distortion measurements, the mass distribution may be constrained in the strong regime. Methods for obtaining the magnification using spectroscopic and/or photometric information are discussed, for object detection within a fixed isophote or to a given flux limit. A map of the magnification around A1689 is constructed from the observed depletion of background red galaxy counts.
Williams, M.
Limits on the cross-section times branching fraction for neutral Higgs bosons, produced in pp collisions at ?[overbar]s=7 TeV, and decaying to two tau leptons with pseudorapidities between 2.0 and 4.5, are presented. The ...
Preon Trinity - A Schematic Model of Leptons, Quarks and Heavy Vector Bosons
Jean-Jacques Dugne; Sverker Fredriksson; Johan Hansson
2002-08-14T23:59:59.000Z
Quarks, leptons and heavy vector bosons are suggested to be composed of stable spin-1/2 preons, existing in three flavours, combined according to simple rules. Straightforward consequences of an SU(3) preon-flavour symmetry are the conservation of three lepton numbers, oscillations and decays between some neutrinos, and the mixing of the d and s quarks, as well as of the vector fields W^0 and B^0. We find a relation between the Cabibbo and Weinberg mixing angles, and predict new (heavy) leptons, quarks and vector bosons, some of which might be observable at the Fermilab Tevatron and the future CERN LHC. A heavy neutrino might even be visible in existing data from the CERN LEP facility.
The neutron star mass distribution
Kiziltan, Bülent [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Kottas, Athanasios; De Yoreo, Maria [Department of Applied Mathematics and Statistics, University of California, Santa Cruz, CA 95064 (United States); Thorsett, Stephen E., E-mail: bkiziltan@cfa.harvard.edu [Department of Astronomy and Astrophysics, University of California and UCO/Lick Observatory, Santa Cruz, CA 95064 (United States)
2013-11-20T23:59:59.000Z
In recent years, the number of pulsars with secure mass measurements has increased to a level that allows us to probe the underlying neutron star (NS) mass distribution in detail. We critically review the radio pulsar mass measurements. For the first time, we are able to analyze a sizable population of NSs with a flexible modeling approach that can effectively accommodate a skewed underlying distribution and asymmetric measurement errors. We find that NSs that have evolved through different evolutionary paths reflect distinctive signatures through dissimilar distribution peak and mass cutoff values. NSs in double NS and NS-white dwarf (WD) systems show consistent respective peaks at 1.33 M {sub ?} and 1.55 M {sub ?}, suggesting significant mass accretion (?m ? 0.22 M {sub ?}) has occurred during the spin-up phase. The width of the mass distribution implied by double NS systems is indicative of a tight initial mass function while the inferred mass range is significantly wider for NSs that have gone through recycling. We find a mass cutoff at ?2.1 M {sub ?} for NSs with WD companions, which establishes a firm lower bound for the maximum NS mass. This rules out the majority of strange quark and soft equation of state models as viable configurations for NS matter. The lack of truncation close to the maximum mass cutoff along with the skewed nature of the inferred mass distribution both enforce the suggestion that the 2.1 M {sub ?} limit is set by evolutionary constraints rather than nuclear physics or general relativity, and the existence of rare supermassive NSs is possible.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Khachatryan, Vardan
2015-04-01T23:59:59.000Z
Dimuon and dielectron mass spectra, obtained from data resulting from proton-proton collisions at 8 TeV and recorded by the CMS experiment, are used to search for both narrow resonances and broad deviations from standard model predictions. The data correspond to an integrated luminosity of 20.6 (19.7) fb?š for the dimuon (dielectron) channel. No evidence for non-standard-model physics is observed and 95% confidence level limits are set on parameters from a number of new physics models. The narrow resonance analyses exclude a Sequential Standard Model Z'SSM resonance lighter than 2.90 TeV, a superstring-inspired Z'? lighter than 2.57 TeV and Randall-Sundrummore ťKaluza-Klein gravitons with masses below 2.73, 2.35, and 1.27 TeV for couplings of 0.10, 0.05, and 0.01, respectively. A notable feature is that the limits have been calculated in a model-independent way to enable straightforward reinterpretation in any model predicting a resonance structure. The observed events are also interpreted within the framework of two non-resonant analyses: one based on a large extra dimensions model and one based on a quark and lepton compositeness model with a left-left isoscalar contact interaction. Lower limits are established on MS, the scale characterizing the onset of quantum gravity, which range from 4.9 to 3.3 TeV, where the number of additional spatial dimensions varies from 3 to 7. Similarly, lower limits on ?, the energy scale parameter for the contact interaction, are found to be 12.0 (15.2) TeV for destructive (constructive) interference in the dimuon channel and 13.5 (18.3) TeV in the dielectron channel.Ť less
STAR Collaboration; L. Adamczyk; J. K. Adkins; G. Agakishiev; M. M. Aggarwal; Z. Ahammed; I. Alekseev; J. Alford; A. Aparin; D. Arkhipkin; E. C. Aschenauer; G. S. Averichev; A. Banerjee; R. Bellwied; A. Bhasin; A. K. Bhati; P. Bhattarai; J. Bielcik; J. Bielcikova; L. C. Bland; I. G. Bordyuzhin; J. Bouchet; A. V. Brandin; I. Bunzarov; T. P. Burton; J. Butterworth; H. Caines; M. Calder'on de la Barca S'anchez; J. M. Campbell; D. Cebra; M. C. Cervantes; I. Chakaberia; P. Chaloupka; Z. Chang; S. Chattopadhyay; J. H. Chen; X. Chen; J. Cheng; M. Cherney; W. Christie; M. J. M. Codrington; G. Contin; H. J. Crawford; S. Das; L. C. De Silva; R. R. Debbe; T. G. Dedovich; J. Deng; A. A. Derevschikov; B. di Ruzza; L. Didenko; C. Dilks; X. Dong; J. L. Drachenberg; J. E. Draper; C. M. Du; L. E. Dunkelberger; J. C. Dunlop; L. G. Efimov; J. Engelage; G. Eppley; R. Esha; O. Evdokimov; O. Eyser; R. Fatemi; S. Fazio; P. Federic; J. Fedorisin; Feng; P. Filip; Y. Fisyak; C. E. Flores; L. Fulek; C. A. Gagliardi; D. Garand; F. Geurts; A. Gibson; M. Girard; L. Greiner; D. Grosnick; D. S. Gunarathne; Y. Guo; A. Gupta; S. Gupta; W. Guryn; A. Hamad; A. Hamed; R. Haque; J. W. Harris; L. He; S. Heppelmann; S. Heppelmann; A. Hirsch; G. W. Hoffmann; D. J. Hofman; S. Horvat; B. Huang; X. Huang; H. Z. Huang; P. Huck; T. J. Humanic; G. Igo; W. W. Jacobs; H. Jang; K. Jiang; E. G. Judd; S. Kabana; D. Kalinkin; K. Kang; K. Kauder; H. W. Ke; D. Keane; A. Kechechyan; Z. H. Khan; D. P. Kikola; I. Kisel; A. Kisiel; D. D. Koetke; T. Kollegger; L. K. Kosarzewski; L. Kotchenda; A. F. Kraishan; P. Kravtsov; K. Krueger; I. Kulakov; L. Kumar; R. A. Kycia; M. A. C. Lamont; J. M. Landgraf; K. D. Landry; J. Lauret; A. Lebedev; R. Lednicky; J. H. Lee; Z. M. Li; Y. Li; X. Li; C. Li; W. Li; X. Li; M. A. Lisa; F. Liu; T. Ljubicic; W. J. Llope; M. Lomnitz; R. S. Longacre; X. Luo; Y. G. Ma; R. Ma; G. L. Ma; L. Ma; N. Magdy; R. Majka; A. Manion; S. Margetis; C. Markert; H. Masui; H. S. Matis; D. McDonald; K. Meehan; N. G. Minaev; S. Mioduszewski; B. Mohanty; M. M. Mondal; D. A. Morozov; M. K. Mustafa; B. K. Nandi; Md. Nasim; T. K. Nayak; G. Nigmatkulov; L. V. Nogach; S. Y. Noh; J. Novak; S. B. Nurushev; G. Odyniec; A. Ogawa; K. Oh; V. Okorokov; D. L. Olvitt Jr.; B. S. Page; R. Pak; Y. X. Pan; Y. Pandit; Y. Panebratsev; T. Pawlak; B. Pawlik; H. Pei; C. Perkins; A. Peterson; P. Pile; M. Planinic; J. Pluta; N. Poljak; K. Poniatowska; J. Porter; M. Posik; A. M. Poskanzer; N. K. Pruthi; J. Putschke; H. Qiu; A. Quintero; S. Ramachandran; S. Raniwala; R. Raniwala; R. L. Ray; H. G. Ritter; J. B. Roberts; O. V. Rogachevskiy; J. L. Romero; A. Roy; L. Ruan; J. Rusnak; O. Rusnakova; N. R. Sahoo; P. K. Sahu; I. Sakrejda; S. Salur; A. Sandacz; J. Sandweiss; A. Sarkar; J. Schambach; R. P. Scharenberg; A. M. Schmah; W. B. Schmidke; N. Schmitz; J. Seger; P. Seyboth; N. Shah; E. Shahaliev; P. V. Shanmuganathan; M. Shao; B. Sharma; M. K. Sharma; W. Q. Shen; S. S. Shi; Q. Y. Shou; E. P. Sichtermann; R. Sikora; M. Simko; M. J. Skoby; N. Smirnov; D. Smirnov; D. Solanki; L. Song; P. Sorensen; H. M. Spinka; B. Srivastava; T. D. S. Stanislaus; M. Stepanov; R. Stock; M. Strikhanov; B. Stringfellow; M. Sumbera; B. J. Summa; Y. Sun; X. M. Sun; X. Sun; Z. Sun; B. Surrow; D. N. Svirida; M. A. Szelezniak; A. H. Tang; Z. Tang; T. Tarnowsky; A. N. Tawfik; J. H. Thomas; A. R. Timmins; D. Tlusty; M. Tokarev; S. Trentalange; R. E. Tribble; P. Tribedy; S. K. Tripathy; B. A. Trzeciak; O. D. Tsai; T. Ullrich; D. G. Underwood; I. Upsal; G. Van Buren; G. van Nieuwenhuizen; M. Vandenbroucke; R. Varma; A. N. Vasiliev; R. Vertesi; F. Videbaek; Y. P. Viyogi; S. Vokal; S. A. Voloshin; A. Vossen; J. S. Wang; G. Wang; F. Wang; Y. Wang; Y. Wang; H. Wang; G. Webb; J. C. Webb; L. Wen; G. D. Westfall; H. Wieman; S. W. Wissink; R. Witt; Y. F. Wu; Z. Xiao; W. Xie; K. Xin; Q. H. Xu; Z. Xu; Y. F. Xu; N. Xu; H. Xu; Y. Yang; S. Yang; Q. Yang; Y. Yang; C. Yang; Z. Ye; P. Yepes; L. Yi; K. Yip; I. -K. Yoo; N. Yu; H. Zbroszczyk; W. Zha; X. P. Zhang; J. B. Zhang; Y. Zhang; J. Zhang; Z. Zhang; J. L. Zhang; S. Zhang; J. Zhao; F. Zhao; C. Zhong; L. Zhou; X. Zhu; Y. Zoulkarneeva; M. Zyzak
2015-03-13T23:59:59.000Z
We report the measurement of the phi(1020) meson production via the leptonic decay channel in Au+Au collisions at $\\sqrt{s_{\\rm NN}}$ = 200 GeV from the STAR (Solenoidal Tracker at RHIC) experiment. The transverse momentum ($p_{\\rm T}$) spectrum is measured for 0.1 $\\le p_{\\rm T} \\le 2.5$ GeV/$c$ at mid-rapidity ($|y|\\le1$) with a similar detector setup of corresponding measurements via the hadronic decay channel. We obtain the $p_{\\rm T}$-integrated phi(1020) mass $M_{\\phi}=1017.7\\pm0.8 (\\rm {stat.}) \\pm0.9 (\\rm {sys.})$ MeV/$c^{2}$ and width $\\Gamma_{\\phi} = 8.0\\pm 2.5(\\rm {stat.}) \\pm 2.3(\\rm {sys.}) \\textrm{MeV/}c^{2}$, which are within 1.5 $\\sigma$ and 1.1 $\\sigma$ of the vacuum values, respectively. No significant difference is observed in the reconstructed phi(1020) $p_{\\rm T}$ spectrum, $dN/dy$, or $\\left$ between the leptonic and hadronic decay channels. The experimental results are compared to a theoretical model including the medium-modified phi(1020).
Measuring the Higgs boson mass in dileptonic W-boson decays at hadron colliders
Barr, Alan; Gripaios, Ben; Lester, Christopher G
2009-01-01T23:59:59.000Z
ar X iv :0 90 2. 48 64 v2 [ he p- ph ] 22 Ju l 2 00 9 Cavendish-HEP-09/04 Measuring the Higgs boson mass in dileptonic W -boson decays at hadron colliders Alan J. Barr,1, ? Ben Gripaios,2, and Christopher G. Lester3, 1Denys Wilkinson... measurements of the Higgs boson mass using the decay h ? W+W?, followed by the leptonic decay of each W -boson, will be performed by fitting the shape of a distribution that is sensitive to the Higgs mass. We demonstrate that the variable most commonly used...
Minimal Textures in Seesaw Mass Matrices and their low and high Energy Phenomenology
Srubabati Goswami; Subrata Khan; Werner Rodejohann
2009-07-09T23:59:59.000Z
In an attempt to find minimal scenarios we study the implications of Dirac and Majorana mass matrices with texture zeros within the type I seesaw mechanism. For the Dirac mass matrices we consider 5 zero textures which we show to be the most minimal form that can successfully account for low energy phenomenology if the Majorana mass matrices are chosen minimal as well. For those, we consider both diagonal and even more minimal non-diagonal forms. The latter can be motivated e.g. by simple U(1) flavour symmetries and have two degenerate eigenvalues. We classify the allowed textures and discuss the ramifications for leptogenesis and lepton flavour violation.
Minimal Textures in Seesaw Mass Matrices and their low and high Energy Phenomenology
Goswami, Srubabati; Rodejohann, Werner
2009-01-01T23:59:59.000Z
In an attempt to find minimal scenarios we study the implications of Dirac and Majorana mass matrices with texture zeros within the type I seesaw mechanism. For the Dirac mass matrices we consider 5 zero textures which we show to be the most minimal form that can successfully account for low energy phenomenology if the Majorana mass matrices are chosen minimal as well. For those, we consider both diagonal and even more minimal non-diagonal forms. The latter can be motivated e.g. by simple U(1) flavour symmetries and have two degenerate eigenvalues. We classify the allowed textures and discuss the ramifications for leptogenesis and lepton flavour violation.
Leptogenesis from right-handed neutrino decays to right-handed leptons
Thomas Hambye
2006-06-16T23:59:59.000Z
We investigate what would be the consequences for leptogenesis of the existence of a charged SU(2)_L singlet scalar delta^+. If such a scalar particle exists, it allows the right-handed neutrinos to couple not only to left-handed lepton and Higgs doublets as in ordinary leptogenesis, but also to a right-handed charged lepton and a delta^+. This provides a new source of leptogenesis which can be successful in a non-resonant way at scales as low as TeV. The incorporation of this scenario in left-right symmetric and unified models is discussed.
Continuum limit physics from 2+1 flavor domain wall QCD
Aoki, Y.; Izubuchi, T.; Arthur, R.; Blum, T.; Boyle, P.A.; Brommel, D.; Christ, N.H.; Dawson, C.; Flynn, J.M.; Jin, X.Y.; Jung, C.; Kelly, C.; Li, M.; Lichtl, A.; Lightman, M.; Lin, M.F.; Mawhinney, R.D.; Maynard,C.M.; Ohta, S.; Pendleton, B.J.; Sachrajda, C.T.; Scholz, E.E.; Soni, A.; Wennekers, J.; Zanotti, J.M.; Zhou, R.
2011-04-22T23:59:59.000Z
We present physical results obtained from simulations using 2+1 flavors of domain wall quarks and the Iwasaki gauge action at two values of the lattice spacing a, [a{sup -1} = 1.73(3) GeV and a{sup -1} = 2.28(3) GeV]. On the coarser lattice, with 24{sup 3} x 64 x 16 points (where the 16 corresponds to L{sub s}, the extent of the 5th dimension inherent in the domain wall fermion formulation of QCD), the analysis of C. Allton et al. Phys. Rev. D 78 is extended to approximately twice the number of configurations. The ensembles on the finer 32{sup 3} x 64 x 16 lattice are new. We explain in detail how we use lattice data obtained at several values of the lattice spacing and for a range of quark masses in combined continuum-chiral fits in order to obtain results in the continuum limit and at physical quark masses. We implement this procedure for our data at two lattice spacings and with unitary pion masses in the approximate range 290-420 MeV (225-420 MeV for partially quenched pions). We use the masses of the {pi} and K mesons and the {Omega} baryon to determine the physical quark masses and the values of the lattice spacing. While our data in the mass ranges above are consistent with the predictions of next-to-leading order SU(2) chiral perturbation theory, they are also consistent with a simple analytic ansatz leading to an inherent uncertainty in how best to perform the chiral extrapolation that we are reluctant to reduce with model-dependent assumptions about higher order corrections. In some cases, particularly for f{sub {pi}}, the pion leptonic decay constant, the uncertainty in the chiral extrapolation dominates the systematic error. Our main results include f{sub {pi}} = 124(2){sub stat}(5){sub syst} MeV, f{sub K}/f{sub {pi}} = 1.204(7)(25) where f{sub K} is the kaon decay constant, m{sub s}{sup MS} (2 GeV) = (96.2 {+-} 2.7) MeV and m{sub ud}{sup MS} (2 GeV) = (3.59 {+-} 0.21) MeV (m{sub s}/m{sub ud} = 26.8 {+-} 1.4) where m{sub s} and m{sub ud} are the mass of the strange quark and the average of the up and down quark masses, respectively, [{Sigma}{sup MS} (2 GeV)]{sup 1/3} = 256(6) MeV, where {Sigma} is the chiral condensate, the Sommer scale r{sub 0} = 0.487(9) fm and r{sub 1} = 0.333(9) fm.
Study of Two-Loop Neutrino Mass Generation Models
Geng, Chao-Qiang
2015-01-01T23:59:59.000Z
We study the models with the Majorana neutrino masses generated radiatively by two-loop diagrams due to the Yukawa $\\rho \\bar \\ell_R^c \\ell_R$ and effective $\\rho^{\\pm\\pm} W^\\mp W^\\mp$ couplings along with a scalar triplet $\\Delta$, where $\\rho$ is a doubly charged singlet scalar, $\\ell_R$ the charged lepton and $W$ the charged gauge boson. A generic feature in these types of models is that the neutrino mass spectrum has to be a normal hierarchy. Furthermore, by using the neutrino oscillation data and comparing with the global fitting result in the literature, we find a unique neutrino mass matrix and predict the Dirac and two Majorana CP phases to be $1.40\\pi$, $1.11\\pi$ and $1.47\\pi$, respectively. We also discuss the model parameters constrained by the lepton flavor violating processes and electroweak oblique parameters. In addition, we show that the rate of the neutrinoless double beta decay $(0\
Khotilovich, Vadim Gennadyevich
2009-05-15T23:59:59.000Z
~t1 decays into a tau lepton and a b quark, with branching ratio B, and search for final states containing either an electron or a muon from a leptonic tau decay, a hadronically decaying tau lepton, and two or more jets. Two candidate events pass my...
The Neutrino Mass Hierarchy from Nuclear Reactor Experiments
Emilio Ciuffoli; Jarah Evslin; Xinmin Zhang
2013-08-14T23:59:59.000Z
10 years from now reactor neutrino experiments will attempt to determine which neutrino mass eigenstate is the most massive. In this letter we present the results of more than seven million detailed simulations of such experiments, studying the dependence of the probability of successfully determining the mass hierarchy upon the analysis method, the neutrino mass matrix parameters, reactor flux models, geoneutrinos and, in particular, combinations of baselines. We show that a recently reported spurious dependence of the data analysis upon the high energy tail of the reactor spectrum can be removed by using a weighted Fourier transform. We determine the optimal baselines and corresponding detector locations. For most values of the CP-violating, leptonic Dirac phase delta, a degeneracy prevents NOvA and T2K from determining either delta or the hierarchy. We determine the confidence with which a reactor experiment can determine the hierarchy, breaking the degeneracy.
Apply early! Limited enrollment.
volcano. Experience the culture and history of Hawaii, and the impact of human activitiesApply early! Limited enrollment. Environmental Science in the Hawaiian Islands Observe, research
Apresyan, Artur; /Purdue U.
2009-05-01T23:59:59.000Z
We report on the results of a search for the standard model Higgs boson produced in association with a W or Z boson in p{bar p} collisions at {radical}s = 1.96 TeV recorded by the CDF II experiment at the Tevatron in a data sample corresponding to an integrated luminosity of 2.1 fb{sup -1}. We consider events having no identified charged leptons, a large imbalance in transverse momentum, and two or three jets where at least one jet contains a secondary vertex consistent with the decay of a b hadron. The main backgrounds are modeled with innovative techniques using data. The sensitivity of the search is optimized using multivariate discriminant techniques. We find good agreement between data and the standard model predictions. We place 95% confidence level upper limits on production cross section times branching ratio for several Higgs boson masses ranging from 110 GeV=c{sup 2} to 150 GeV=c{sup 2}. For a mass of 115 GeV=c{sup 2} the observed (expected) limit is 6.9 (5.6) times the standard model prediction.
Baryon Asymmetry in Neutrino Mass Models with and without ?_13
Ng. K. Francis
2014-03-26T23:59:59.000Z
We investigate the comparative studies of cosmological baryon asymmetry in different neutrino mass models with and without {\\theta}_13 by considering the three diagonal form of Dirac neutrino mass matrices, down-quark (4,2), up-quark (8,4) and charged lepton (6,2). The predictions of any models with {\\theta}_13 are consistent in all the three stages of leptogenesis calculations and the results are better than the predictions of any models without {\\theta}_13 which are consistent in a piecemeal manner with the observational data. For the best model, the normal hierarchy Type-IA for charged lepton (6,2) without {\\theta}_13, the predicted inflaton mass required to produce the observed baryon asymmetry is found to be 3.6x10 to the power 10 GeV corresponding to reheating temperature TR 4.5x10 to the power 6 GeV, while for the same model with {\\theta}_13, the inflaton mass is 2.24x10 to the power 11 GeV, TR 4.865x10 to the power 6 GeV and weak scale gravitino mass m(2 divided by 3) 100 GeV without causing the gravitino problem. These values apply to the recent discovery of Higgs boson of mass 125 GeV. The relic abundance of gravitino is proportional to the reheating temperature of the thermal bath. One can have the right order of relic dark matter abundance only if the reheating temperature is bounded to below 10 to the power 7 GeV.
Drell-Yan Lepton pair production at NNLO QCD with parton showers
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Hoeche, Stefan [SLAC National Accelerator Lab., Menlo Park, CA (United States); Li, Ye [SLAC National Accelerator Lab., Menlo Park, CA (United States); Prestel, Stefan [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2015-04-01T23:59:59.000Z
We present a simple approach to combine NNLO QCD calculations and parton showers, based on the UNLOPS technique. We apply the method to the computation of Drell-Yan lepton-pair production at the Large Hadron Collider. We comment on possible improvements and intrinsic uncertainties.
Forschung an Lepton Collidern Abbildung 49: Perspektivische Ansicht des TESLA-Detektors.
Forschung an Lepton Collidern Abbildung 49: Perspektivische Ansicht des TESLA-Detektors. 86 #12An- strengung vieler Gruppen und Institute der ,,Tech- nical Design Report" fĂźr TESLA verĂśffentlicht wer- den von TESLA, besonders in Bereichen, die im TDR nicht ausreichend behandelt werden konnten, und die
Non-perturbative Heavy Quark Effective Theory: An application to semi-leptonic B-decays
Michele Della Morte; Jochen Heitger; Hubert Simma; Rainer Sommer
2015-01-14T23:59:59.000Z
We review a lattice strategy how to non-perturbatively determine the coefficients in the HQET expansion of all components of the heavy-light axial and vector currents, including 1/m_h-corrections. We also discuss recent preliminary results on the form factors parameterizing semi-leptonic B-decays at the leading order in 1/m_h.
Higher twist contributions to lepton-pair production and other QCD processes
Brodsky, S.J.; Berger, E.L.; Lepage, G.P.
1982-12-01T23:59:59.000Z
A general discussion of the calculations and phenomenological consequences of power-law suppressed QCD processes is given with emphasis on tests in massive lepton pair production. Absolutely normalized predictions are given for the leading twist (transverse current) and higher twist (longitudinal current) contributions to the meson structure function in the region of large x.
Search for WW and WZ production in lepton plus jets final state at CDF
Xie, Si
We present a search for WW and WZ production in final states that contain a charged lepton (electron or muon) and at least two jets, produced in ?s=1.96??TeV pp? collisions at the Fermilab Tevatron, using data corresponding ...
Search for Associated Production of a Single Top Quark and a Higgs Boson in Leptonic Channels
CMS Collaboration
2015-01-01T23:59:59.000Z
A search for the production of a Higgs boson in association with a single top quark is presented, focusing on leptonic signatures provided by the $\\mathrm{H}\\rightarrow\\mathrm{W}\\mathrm{W}$ and $\\mathrm{H}\\rightarrow\\tau\\tau$ decay modes.
A measurement of the Michel parameters in leptonic decays of the tau
Ammar, Raymond G.; Baringer, Philip S.; Bean, Alice; Besson, David Zeke; Coppage, Don; Darling, C.; Davis, Robin E. P.; Hancock, N.; Kotov, S.; Kravchenko, I.; Kwak, Nowhan
1997-06-01T23:59:59.000Z
We have measured the spectral shape Michel parameters rho and eta using leptonic decays of the tau, recorded by the CLEO II detector. Assuming e-mu universality in the vectorlike couplings, we find rho(e mu) = 0.735 +/- 0.013 +/- 0.008 and eta(e mu...
The anomalous lepton magnetic moment, LFV decays and the fourth generation
W. J. Huo; T. F. Feng
2003-01-20T23:59:59.000Z
We investigate the lepton flavor violation (LFV) decays, $\\tau\\to l\\gamma$ ($l=\\mu, e$) and $\\mu\\to e\\gamma$, and the newly observed muon $g-2$ anomaly in the framwork of a squential fourth generation model with a heavy fourth neutrino, $\
Novel inclusive search for the Higgs boson in the four-lepton final state at CDF
Gomez-Ceballos, Guillelmo
An inclusive search for the standard model Higgs boson using the four-lepton final state in proton-antiproton collisions produced by the Tevatron at ?s=1.96??TeV is conducted. The data are recorded by the CDF II detector ...
Evidence for the 125 GeV Higgs boson decaying to a pair of ? leptons
Apyan, Aram
A search for a standard model Higgs boson decaying into a pair of ? leptons is performed using events recorded by the CMS experiment at the LHC in 2011 and 2012. The dataset corresponds to an integrated luminosity of 4.9 ...
Pentland, Alex Paul
The Internet and social media have enabled the mobilization of large crowds to achieve time-critical feats, ranging from mapping crises in real time, to organizing mass rallies, to conducting search-and-rescue operations ...
Top-quark mass measurement using events with missing transverse energy and jets at CDF
Aaltonen, T; Alvarez Gonzalez, B; Amerio, S; Anastassov, A; Amidei, D; Antos, J; Annovi, A
2013-07-01T23:59:59.000Z
We present a measurement of the top-quark mass with tt? events using a data sample corresponding to an integrated luminosity of 5.7 fb^{ -1} of pp? collisions at the Fermilab Tevatron with ?s = 1.96 TeV and collected by the CDF II Detector. We select events having no identified charged leptons, large missing transverse energy, and four, five, or six jets with at least one jet containing a secondary vertex consistent with the decay of a b quark. This analysis considers events from the semileptonic tt? decay channel, including events that contain tau leptons, which are usually not included in the top-quark mass measurements. The measurement uses as kinematic variables the invariant mass of two jets consistent with the mass of the W boson, and the invariant masses of two different three-jet combinations. We fit the data to signal templates of varying top-quark masses and background templates, and measure a top-quark mass of M_{top} = 172.3 ą 2.4 (stat) ą 1.0 (syst) GeV/c^{2}.
Top-quark mass measurement using events with missing transverse energy and jets at CDF
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aaltonen, T; Alvarez Gonzalez, B; Amerio, S; Anastassov, A; Amidei, D; Antos, J; Annovi, A
2013-07-01T23:59:59.000Z
We present a measurement of the top-quark mass with tt? events using a data sample corresponding to an integrated luminosity of 5.7 fb -1 of pp? collisions at the Fermilab Tevatron with ?s = 1.96 TeV and collected by the CDF II Detector. We select events having no identified charged leptons, large missing transverse energy, and four, five, or six jets with at least one jet containing a secondary vertex consistent with the decay of a b quark. This analysis considers events from the semileptonic tt? decay channel, including events that contain tau leptons, which are usually not included inmore ťthe top-quark mass measurements. The measurement uses as kinematic variables the invariant mass of two jets consistent with the mass of the W boson, and the invariant masses of two different three-jet combinations. We fit the data to signal templates of varying top-quark masses and background templates, and measure a top-quark mass of Mtop = 172.3 ą 2.4 (stat) ą 1.0 (syst) GeV/c2.Ť less
Top-quark mass measurement using events with missing transverse energy and jets at CDF
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aaltonen, T; Alvarez Gonzalez, B; Amerio, S; Anastassov, A; Amidei, D; Antos, J; Annovi, A
2013-07-01T23:59:59.000Z
We present a measurement of the top-quark mass with tt? events using a data sample corresponding to an integrated luminosity of 5.7 fb -1 of pp? collisions at the Fermilab Tevatron with ?s = 1.96 TeV and collected by the CDF II Detector. We select events having no identified charged leptons, large missing transverse energy, and four, five, or six jets with at least one jet containing a secondary vertex consistent with the decay of a b quark. This analysis considers events from the semileptonic tt? decay channel, including events that contain tau leptons, which are usually not included in the top-quark mass measurements. The measurement uses as kinematic variables the invariant mass of two jets consistent with the mass of the W boson, and the invariant masses of two different three-jet combinations. We fit the data to signal templates of varying top-quark masses and background templates, and measure a top-quark mass of Mtop = 172.3 ą 2.4 (stat) ą 1.0 (syst) GeV/c2.
Paredes Hernandez, Daniela; The ATLAS collaboration
2015-01-01T23:59:59.000Z
This study presents a search for Higgs bosons decaying to four leptons via one or two light exotic gauge bosons $Z_d$, $H\\rightarrow ZZ_d\\rightarrow4\\ell$ and $H\\rightarrow Z_dZ_d\\rightarrow4\\ell$. The search uses the data taken in $pp$ collisions with the ATLAS detector at the LHC at $\\sqrt{s}=8$~TeV. The observed data are well described by the Standard Model prediction. Upper bounds on the branching ratios of $H\\rightarrow ZZ_d\\rightarrow4\\ell$ and $H\\rightarrow Z_dZ_d\\rightarrow4\\ell$, relative to the branching ratio of $H\\rightarrow 4\\ell$ and to the Standard Model branching ratio of $H\\rightarrow ZZ^*\\rightarrow4\\ell$ respectively, are set as a function of the mass of the exotic vector boson at 95\\% confidence level.
Spontaneous R-Parity Breaking, Stop LSP Decays and the Neutrino Mass Hierarchy
Zachary Marshall; Burt A. Ovrut; Austin Purves; Sogee Spinner
2014-06-03T23:59:59.000Z
The MSSM with right-handed neutrino supermultiplets, gauged B-L symmetry and a non-vanishing sneutrino expectation value is the minimal theory that spontaneously breaks R-parity and is consistent with the bounds on proton stability and lepton number violation. This minimal B-L MSSM can have a colored/charged LSP, of which a stop LSP is the most amenable to observation at the LHC. We study the R-parity violating decays of a stop LSP into a bottom quark and charged leptons--the dominant modes for a generic "admixture" stop. A numerical analysis of the relative branching ratios of these decay channels is given using a wide scan over the parameter space. The fact that R-parity is violated in this theory by a vacuum expectation value of a sneutrino links these branching ratios directly to the neutrino mass hierarchy. It is shown how a discovery of bottom-charged lepton events at the LHC can potentially determine whether the neutrino masses are in a normal or inverted hierarchy, as well as determining the theta_23 neutrino mixing angle. Finally, present LHC bounds on these leptoquark signatures are used to put lower bounds on the stop mass.
Upper limit on branching ratio the decay B. Bassalleck,
National Laboratory (BNL). The decay forbidden angular momentum conservation neutrinos purely massless left## # cosmological constraints neutrino masses imply more stringent limits. branching 0 ## case massive Majorana Brookhaven National Laboratory, Upton, New 11973, USA TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia
McBranch, Duncan W. (Santa Fe, NM); Mattes, Benjamin R. (Santa Fe, NM); Koskelo, Aaron C. (Los Alamos, NM); Heeger, Alan J. (Santa Barbara, CA); Robinson, Jeanne M. (Los Alamos, NM); Smilowitz, Laura B. (Los Alamos, NM); Klimov, Victor I. (Los Alamos, NM); Cha, Myoungsik (Goleta, CA); Sariciftci, N. Serdar (Santa Barbara, CA); Hummelen, Jan C. (Groningen, NL)
1998-01-01T23:59:59.000Z
Optical limiting materials. Methanofullerenes, fulleroids and/or other fullerenes chemically altered for enhanced solubility, in liquid solution, and in solid blends with transparent glass (SiO.sub.2) gels or polymers, or semiconducting (conjugated) polymers, are shown to be useful as optical limiters (optical surge protectors). The nonlinear absorption is tunable such that the energy transmitted through such blends saturates at high input energy per pulse over a wide range of wavelengths from 400-1100 nm by selecting the host material for its absorption wavelength and ability to transfer the absorbed energy into the optical limiting composition dissolved therein. This phenomenon should be generalizable to other compositions than substituted fullerenes.
TeV Scale Lepton Number Violation and Baryogenesis
Dev, P S Bhupal; Mohapatra, R N
2015-01-01T23:59:59.000Z
Contrary to the common lore based on naive dimensional analysis, the seesaw scale for neutrino masses can be naturally in the TeV range, with small parameters coming from radiative corrections. We present one such class of type-I seesaw models, based on the left-right gauge group $SU(2)_L\\times SU(2)_R\\times U(1)_{B-L}$ realized at the TeV scale, which fits the observed neutrino oscillation parameters as well as other low energy constraints. We discuss how the small parameters of this scenario can arise naturally from one loop effects. The neutrino fits in this model use quasi-degenerate heavy Majorana neutrinos, as also required to explain the matter-antimatter asymmetry in our Universe via resonant leptogenesis mechanism. We discuss the constraints implied by the dynamics of this mechanism on the mass of the right-handed gauge boson in this class of models with enhanced neutrino Yukawa couplings compared to the canonical seesaw model and find a lower bound of $m_{W_R}\\geq 9.9$ TeV for successful leptogenesi...
Changpin Li; Weihua Deng
2005-10-10T23:59:59.000Z
In this Letter, we derive a sufficient condition of synchronizing limit sets (attractors and repellers) by using the linear feedback control technique proposed here. There examples are included. The numerical simulations and computer graphics show that our method work well.
Thomas M. Stace
2010-06-08T23:59:59.000Z
The precision of typical thermometers consisting of $N$ particles is shot noise limited, improving as $\\sim1/\\sqrt{N}$. For high precision thermometry and thermometric standards this presents an important theoretical noise floor. Here it is demonstrated that thermometry may be mapped onto the problem of phase estimation, and using techniques from optimal phase estimation, it follows that the scaling of the precision of a thermometer may in principle be improved to $\\sim1/N$, representing a Heisenberg limit to thermometry.
Hannestad, S
2003-01-01T23:59:59.000Z
We have performed a thorough analysis of the constraints which can be put on neutrino parameters from cosmological observations, most notably those from the WMAP satellite and the 2dF galaxy survey. In terms of the relativistic energy density in neutrinos or other weakly interacting species we find, in units of equivalent number of neutrino species, N_nu, that N_nu = 2.1+1.6-1.8 (95% conf.). This limit on relativistic energy density can be translated into a bound on the neutrino lepton asymmetry of |eta| 5% conf), assuming that the asymmetry is entirely in one flavour. When BBN constraints are added, the bound on N_nu is 2.5 +- 0.5 (95% conf), suggesting that N_nu could possibly be lower than the standard model value of 3. this can for instance be the case in models with very low reheating temperature and incomplete neutrino thermalization.
The Maximum Mass of a Neutron Star
Vassiliki Kalogera; Gordon Baym
1996-08-11T23:59:59.000Z
Observational identification of black holes as members of binary systems requires the knowledge of the upper limit on the gravitational mass of a neutron star. We use modern equations of state for neutron star matter, fitted to experimental nucleon-nucleon scattering data and the properties of light nuclei, to calculate, within the framework of Rhoades & Ruffini (1974), the minimum upper limit on a neutron star mass. Regarding the equation of state as valid up to twice nuclear matter saturation density, rho_{nm}, we obtain a secure upper bound on the neutron star mass equal to 2.9 solar masses. We also find that in order to reach the lowest possible upper bound of 2.2 solar masses, we need understand the physical properties of neutron matter up to a density of about 4 times rho_{nm}.
Apyan, Aram
This Letter describes the search for an enhanced production rate of events with a charged lepton and a neutrino in high-energy pp collisions at the LHC. The analysis uses data collected with the CMS detector, with an ...
Baringer, Philip S.; Bean, Alice; Benelli, Gabriele; Kenny, R. P. III; Murray, Michael J.; Noonan, Danny; Sanders, Stephen J.; Stringer, Robert W.; Tinti, Gemma; Wood, Jeffrey Scott; Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Aguilo, E.; Bergauer, T.; Dragicevic, M.
2013-04-08T23:59:59.000Z
This Letter describes the search for an enhanced production rate of events with a charged lepton and a neutrino in high-energy pp collisions at the LHC. The analysis uses data collected with the CMS detector, with an ...
A Search for Prompt Lepton-Jets in pp Collisions at ?s = 7 TeV with the ATLAS Detector
Taylor, Frank E.
We present a search for a light (<2 GeV) boson predicted by Hidden Valley supersymmetric models that decays into a final state consisting of collimated muons or electrons, denoted lepton-jets. The analysis uses 5 ...
Three body kinematic endpoints in SUSY models with non-universal Higgs masses.
Lester, Christopher G; Parker, Michael A; White, Martin J
002. [9] G. Comune, SUSY with ATLAS: Leptonic signatures, coannihilation region, ATLAS Physics note (2004) ATLPHYSCONF2005003. [10] A. De Roeck et al., Supersymmetric benchmarks with non-universal scalar masses or gravitino dark matter, hep-ph/0508198... . [11] H. Baer, A. Mustafayev, S. Profumo, A. Belyaev, and X. Tata, Direct, indirect and collider detection of neutralino dark matter in SUSY models with non-universal higgs masses, JHEP 07 (2005) 065, [hep-ph/0504001]. [12] F. E. Paige and S. D...
0+ -> 2+ neutrinoless double beta decay triggered directly by the Majorana neutrino mass
T. Tomoda
1999-09-12T23:59:59.000Z
We treat 0+ -> 2+ neutrinoless double beta decays taking into account recoil corrections to the nuclear currents. The decay probability can be written as a quadratic form of the effective coupling constants of the right-handed leptonic currents and the effective neutrino mass. We calculate the nuclear matrix elements for the 0+ -> 2+ neutrinoless double beta decays of 76Ge and 100Mo, and demonstrate that the relative sensitivities of 0+ -> 2+ decays to the neutrino mass and the right-handed currents are comparable to those of 0+ -> 0+ decays.
New method for precise determination of top quark mass at LHC
Kawabata, Sayaka
2015-01-01T23:59:59.000Z
Current measurements of the top quark mass which have achieved a precision of less than 1 GeV involve a theoretical problem that the definition of the measured mass is ambiguous in perturbation theory. As a possible solution to the problem, we present a new method to measure the top quark mass at the LHC. This method uses lepton energy distribution and has a boost-invariant nature. We discuss strategies towards a precise determination of theoretically well-defined top quark masses such as the MSbar mass with the method. As a first step in this direction, a simulation analysis at the leading order is performed considering actual experimental circumstances. The result indicates that this method with further improvements is capable of realizing a precision of less than 1 GeV at the LHC.
Bounds on neutrino masses from leptogenesis in type-II seesaw models
Sahu, Narendra; Sankar, S. Uma [Department of Physics, Indian Institute of Technology, Bombay, Mumbai 400076 (India)
2005-01-01T23:59:59.000Z
The presence of the triplet {delta}{sub L} in left-right symmetric theories leads to type-II seesaw mechanism for the neutrino masses. In these models, assuming a normal mass hierarchy for the heavy Majorana neutrinos, we derive a lower bound on the mass of the lightest of heavy Majorana neutrinos from the leptogenesis constraint. From this bound we establish a consistent picture for the hierarchy of heavy Majorana neutrinos in a class of left-right symmetric models in which we identify the neutrino Dirac mass matrix with that of Fritzsch type charged lepton mass matrix. It is shown that these values are compatible with the current neutrino oscillation data.
McBranch, D.W.; Mattes, B.R.; Koskelo, A.C.; Heeger, A.J.; Robinson, J.M.; Smilowitz, L.B.; Klimov, V.I.; Cha, M.; Sariciftci, N.S.; Hummelen, J.C.
1998-04-21T23:59:59.000Z
Methanofullerenes, fulleroids and/or other fullerenes chemically altered for enhanced solubility, in liquid solution, and in solid blends with transparent glass (SiO{sub 2}) gels or polymers, or semiconducting (conjugated) polymers, are shown to be useful as optical limiters (optical surge protectors). The nonlinear absorption is tunable such that the energy transmitted through such blends saturates at high input energy per pulse over a wide range of wavelengths from 400--1,100 nm by selecting the host material for its absorption wavelength and ability to transfer the absorbed energy into the optical limiting composition dissolved therein. This phenomenon should be generalizable to other compositions than substituted fullerenes. 5 figs.
A model of leptons, quarks and bosons as composites of spinons
Eckart Marsch
2010-04-20T23:59:59.000Z
A model is presented of the leptons, quarks and bosons as non-elementary particles being composed of spinons. They are defined as massless fermions obeying the Weyl equations, but in addition are charged and assumed to have two internal degrees of freedom (weak colour charges). The corresponding total Lagrangian density of the quantized fields has a fermionic part and a gauge-field part, which leads to the interaction of the charged spinons. They are bound together by the gauge fields of the non-Abelian SU(2) symmetry group, and three of them can combine to a triple state forming the well known first generation of left- and right-handed leptons and quarks, including their proper electric charges (fractional for the quarks). The neutral and charged vector bosons of the weak interactions or the Higgs bosons can be constructed as binaries of two spinons.
Measurement of J/psi leptonic width with the KEDR detector
Anashin, V V; Baldin, E M; Barladyan, A K; Barnyakov, A Yu; Barnyakov, M Yu; Baru, S E; Basok, I Yu; Beloborodova, O L; Blinov, A E; Blinov, V E; Bobrov, A V; Bobrovnikov, V S; Bogomyagkov, A V; Bondar, A E; Buzykaev, A R; Eidelman, S I; Grigoriev, D N; Glukhovchenko, Yu M; Gulevich, V V; Gusev, D V; Karnaev, S E; Karpov, G V; Karpov, S V; Kharlamova, T A; Kiselev, V A; Kolmogorov, V V; Kononov, S A; Kotov, K Yu; Kravchenko, E A; Kudryavtsev, V N; Kulikov, V F; Kurkin, G Ya; Kuper, E A; Levichev, E B; Maksimov, D A; Malyshev, V M; Maslennikov, A L; Medvedko, A S; Meshkov, O I; Mishnev, S I; Morozov, I I; Muchnoi, N Yu; Neufeld, V V; Nikitin, S A; Nikolaev, I B; Okunev, I N; Onuchin, A P; Oreshkin, S B; Orlov, I O; Osipov, A A; Peleganchuk, S V; Pivovarov, S G; Piminov, P A; Petrov, V V; Poluektov, A O; Prisekin, V G; Ruban, A A; Sandyrev, V K; Savinov, G A; Shamov, A G; Shatilov, D N; Shwartz, B A; Simonov, E A; Sinyatkin, S V; Skrinsky, A N; Smaluk, V V; Sokolov, A V; Sukharev, A M; Starostina, E V; Talyshev, A A; Tayursky, V A; Telnov, V I; Tikhonov, Yu A; Todyshev, K Yu; Tumaikin, G M; Usov, Yu V; Vorobiov, A I; Yushkov, A N; Zhilich, V N; Zhulanov, V V; Zhuravlev, A N
2011-01-01T23:59:59.000Z
We report a new precise determination of the leptonic widths of the J/psi meson performed with the KEDR detector at the VEPP-4M $e^{+}e^{-}$ collider. The measured values of the J/psi parameters are: \\Gamma_{ee}\\times\\Gamma_{ee}/\\Gamma = 0.3323 \\pm 0.0064 (stat.) \\pm 0.0048 (syst.) keV \\Gamma_{ee}\\times\\Gamma_{\\mu\\mu}/\\Gamma=0.3318 \\pm 0.0052 (stat.) \\pm 0.0063 (syst.) keV. Assuming $e\\mu$ universality and using the table value of the branching ratios the leptonic \\Gamma_{ll}= 5.59 \\pm 0.12 keV width and the total \\Gamma=94.1 \\pm 2.7 keV widths were obtained. We also discuss in detail a method to calculate radiative corrections at a narrow resonance.
Transverse self-modulation of ultra-relativistic lepton beams in the plasma wakefield accelerator
Vieira, J; Mori, W B; Silva, L O; Muggli, P
2015-01-01T23:59:59.000Z
The transverse self-modulation of ultra-relativistic, long lepton bunches in high-density plasmas is explored through full-scale particle-in-cell simulations. We demonstrate that long SLAC-type electron and positron bunches can become strongly self-modulated over centimeter distances, leading to wake excitation in the blowout regime with accelerating fields in excess of 20 GV/m. We show that particles energy variations exceeding 10 GeV can occur in meter-long plasmas. We find that the self-modulation of positively and negatively charged bunches differ when the blowout is reached. Seeding the self-modulation instability suppresses the competing hosing instability. This work reveals that a proof-of-principle experiment to test the physics of bunch self-modulation can be performed with available lepton bunches and with existing experimental apparatus and diagnostics.
Lepton-flavor-violating decay {tau}{yields}{mu}{mu}{mu} at the CERN LHC
Giffels, M.; Stahl, A. [III. Physikalisches Institut, RWTH Aachen, 52056 Aachen (Germany); Kallarackal, J. [Institut fuer Theoretische Physik, RWTH Aachen, 52074 Aachen (Germany); Institut fuer Physik, Humboldt-Universitaet zu Berlin, 12489 Berlin (Germany); Kraemer, M.; O'Leary, B. [Institut fuer Theoretische Physik, RWTH Aachen, 52074 Aachen (Germany)
2008-04-01T23:59:59.000Z
Lepton-flavor-violating {tau} decays are predicted in many extensions of the standard model at a rate observable at future collider experiments. In this article we focus on the decay {tau}{yields}{mu}{mu}{mu}, which is a promising channel to observe lepton-flavor violation at the CERN Large Hadron Collider (LHC). We present analytic expressions for the differential decay width derived from a model-independent effective Lagrangian with general four-fermion operators, and estimate the experimental acceptance for detecting the decay {tau}{yields}{mu}{mu}{mu} at the LHC. Specific emphasis is given to decay angular distributions and how they can be used to discriminate new physics models. We provide specific predictions for various extensions of the standard model, including supersymmetric, little Higgs, and technicolor models.
Mass-loading of bow shock pulsar wind nebulae
Morlino, G; Vorster, M J
2015-01-01T23:59:59.000Z
We investigate the dynamics of bow shock nebulae created by pulsars moving supersonically through a partially ionized interstellar. A fraction of interstellar neutrals penetrating into the tail region of a pulsar wind will undergo photo-ionization due to the UV light emitted by the nebula, with the resulting mass loading dramatically changing the flow dynamics of the light leptonic pulsar wind. Using a quasi 1-D hydrodynamic model of both non-relativistic and relativistic flow, and focusing on scales much larger than the stand-off distance, we find that a relatively small density of neutrals, as low as $n_{\\rm ISM}=10^{-4}\\,\\text{cm}^{-3}$, is sufficient to strongly affect the tail flow. Mass loading leads to the fast expansion of the pulsar wind tail, making the tail flow intrinsically non-stationary. The shapes predicted for the bow shock nebulae compare well with observations, both in H$\\alpha$ and X-rays.
Supersymmetric Froggatt-Nielsen Models with Baryon- and Lepton-Number Violation
Dreiner, Herbi K.
2009-01-01T23:59:59.000Z
handed neutrino Majorana mass matrix. The latter depends onthe Dirac and Majorana neutrino mass matrices to be without
A 233 km tunnel for lepton and hadron colliders
Summers, D. J.; Cremaldi, L. M.; Datta, A.; Duraisamy, M.; Luo, T.; Lyons, G. T. [Dept. of Physics and Astronomy, University of Mississippi-Oxford, University, MS 38677 (United States)
2012-12-21T23:59:59.000Z
A decade ago, a cost analysis was conducted to bore a 233 km circumference Very Large Hadron Collider (VLHC) tunnel passing through Fermilab. Here we outline implementations of e{sup +}e{sup -}, pp-bar , and {mu}{sup +}{mu}{sup -} collider rings in this tunnel using recent technological innovations. The 240 and 500 GeV e{sup +}e{sup -} colliders employ Crab Waist Crossings, ultra low emittance damped bunches, short vertical IP focal lengths, superconducting RF, and low coercivity, grain oriented silicon steel/concrete dipoles. Some details are also provided for a high luminosity 240 GeV e{sup +}e{sup -} collider and 1.75 TeV muon accelerator in a Fermilab site filler tunnel. The 40 TeV pp-bar collider uses the high intensity Fermilab p-bar source, exploits high cross sections for pp-bar production of high mass states, and uses 2 Tesla ultra low carbon steel/YBCO superconducting magnets run with liquid neon. The 35 TeV muon ring ramps the 2 Tesla superconducting magnets at 9 Hz every 0.4 seconds, uses 250 GV of superconducting RF to accelerate muons from 1.75 to 17.5 TeV in 63 orbits with 71% survival, and mitigates neutrino radiation with phase shifting, roller coaster motion in a FODO lattice.
Phenomenology of Maximal and Near-Maximal Lepton Mixing
M. C. Gonzalez-Garcia; C. Peńa-Garay; Y. Nir; A. Yu. Smirnov
2000-09-18T23:59:59.000Z
We study the phenomenological consequences of maximal and near-maximal mixing of the electron neutrino with other ($x$=tau and/or muon) neutrinos. We describe the deviations from maximal mixing in terms of a parameter $\\epsilon\\equiv1-2\\sin^2\\theta_{ex}$ and quantify the present experimental status for $|\\epsilon|<0.3$. We find that the global analysis of solar neutrino data allows maximal mixing with confidence level better than 99% for $10^{-8}$ eV$^2\\lsim\\Delta m^2\\lsim2\\times10^{-7}$ eV$^2$. In the mass ranges $\\Delta m^2\\gsim 1.5\\times10^{-5}$ eV$^2$ and $4\\times10^{-10}$ eV$^2\\lsim\\Delta m^2\\lsim2\\times10^{-7}$ eV$^2$ the full interval $|\\epsilon|<0.3$ is allowed within 4$\\sigma$(99.995 % CL). We suggest ways to measure $\\epsilon$ in future experiments. The observable that is most sensitive to $\\epsilon$ is the rate [NC]/[CC] in combination with the Day-Night asymmetry in the SNO detector. With theoretical and statistical uncertainties, the expected accuracy after 5 years is $\\Delta \\epsilon\\sim 0.07$. We also discuss the effects of maximal and near-maximal $\
Precision Measurement of the Ratio of the Charged Kaon Leptonic Decay Rates
The NA62 collaboration
2013-01-29T23:59:59.000Z
A precision measurement of the ratio RK of the rates of kaon leptonic decays K+- --> e nu and K+- --> mu nu with the full data sample collected by the NA62 experiment at CERN in 2007-2008 is reported. The result, obtained by analysing ~150000 reconstructed K+- --> e nu candidates with 11% background contamination, is RK = (2.488+-0.010)*10^{-5}, in agreement with the Standard Model expectation.
On leptonic decay of a heavy quarkonium with a Higgs-boson emission
G. A. Kozlov
2005-06-27T23:59:59.000Z
A leptonic $(\\bar l l)$ decay of a heavy quark-antiquark bound state $T(\\bar QQ)$ with a Higgs-boson $H$ emission is investigated. The applying of the well-known low-energy theorem to meson-Higgs coupling allows one to estimate the probability of the decay $T(\\bar QQ)\\to \\bar ll H$. The only a simple version of the Standard Model extension containing two-Higgs doublet is considered.
Canepa, Anadi; /Purdue U.
2006-02-01T23:59:59.000Z
Supersymmetry, if realized in nature, predicts the existence of new particles, as chargino and neutralino, which might manifest themselves with peculiar signatures. Three leptons and large missing transverse energy in the event could signal their associated production. They report the latest results of the search performed by the CDF Collaboration in {radical}s = 1.96 TeV proton-antiproton collisions at Tevatron Run II.
Semi-leptonic Decay of Lambda-b in the Standard Model and with New Physics
Wanwei Wu
2015-05-13T23:59:59.000Z
Heavy quark decays provide a very advantageous investigation to test the Standard Model (SM). Recently, promising experiments with \\textit{b} quark, as well as the analysis of the huge data sets produced at the B factories, have led to an increasing study and sensitive measurements of relative \\textit{b} quark decays. In this thesis, I calculate various observables in the semi-leptonic decay process $\\Lambda_{b}\\to \\Lambda_{c}\\tau\\bar{\
Neutrino masses and Neutrinoless Double Beta Decay: Status and expectations
Oliviero Cremonesi
2010-02-07T23:59:59.000Z
Two most outstanding questions are puzzling the world of neutrino Physics: the possible Majorana nature of neutrinos and their absolute mass scale. Direct neutrino mass measurements and neutrinoless double beta decay (0nuDBD) are the present strategy to solve the puzzle. Neutrinoless double beta decay violates lepton number by two units and can occurr only if neutrinos are massive Majorana particles. A positive observation would therefore necessarily imply a new regime of physics beyond the standard model, providing fundamental information on the nature of the neutrinos and on their absolute mass scale. After the observation of neutrino oscillations and given the present knowledge of neutrino masses and mixing parameters, a possibility to observe 0nuDBDD at a neutrino mass scale in the range 10-50 meV could actually exist. This is a real challenge faced by a number of new proposed projects. Present status and future perpectives of neutrinoless double-beta decay experimental searches is reviewed. The most important parameters contributing to the experimental sensitivity are outlined. A short discussion on nuclear matrix element calculations is also given. Complementary measurements to assess the absolute neutrino mass scale (cosmology and single beta decays) are also discussed.
RSMASS: A simple model for estimating reactor and shield masses
Marshall, A.C.; Aragon, J.; Gallup, D.
1987-01-01T23:59:59.000Z
A simple mathematical model (RSMASS) has been developed to provide rapid estimates of reactor and shield masses for space-based reactor power systems. Approximations are used rather than correlations or detailed calculations to estimate the reactor fuel mass and the masses of the moderator, structure, reflector, pressure vessel, miscellaneous components, and the reactor shield. The fuel mass is determined either by neutronics limits, thermal/hydraulic limits, or fuel damage limits, whichever yields the largest mass. RSMASS requires the reactor power and energy, 24 reactor parameters, and 20 shield parameters to be specified. This parametric approach should be applicable to a very broad range of reactor types. Reactor and shield masses calculated by RSMASS were found to be in good agreement with the masses obtained from detailed calculations.
Ultra High Mass Range Mass Spectrometer System
Reilly, Peter T. A. [Knoxville, TN
2005-12-06T23:59:59.000Z
Applicant's present invention comprises mass spectrometer systems that operate in a mass range from 1 to 10.sup.16 DA. The mass spectrometer system comprising an inlet system comprising an aerodynamic lens system, a reverse jet being a gas flux generated in an annulus moving in a reverse direction and a multipole ion guide; a digital ion trap; and a thermal vaporization/ionization detector system. Applicant's present invention further comprises a quadrupole mass spectrometer system comprising an inlet system having a quadrupole mass filter and a thermal vaporization/ionization detector system. Applicant's present invention further comprises an inlet system for use with a mass spectrometer system, a method for slowing energetic particles using an inlet system. Applicant's present invention also comprises a detector device and a method for detecting high mass charged particles.
Effective Mass and Energy-Mass Relationship
Viktor Ariel
2012-05-14T23:59:59.000Z
The particle effective mass is often a challenging concept in solid state physics due to the many different definitions of the effective mass that are routinely used. Also, the most commonly used theoretical definition of the effective mass was derived from the assumption of a parabolic energy-momentum relationship, E(p), and therefore should not be applied to non-parabolic materials. In this paper, we use wave-particle duality to derive a definition of the effective mass and the energy-mass approximation suitable for non-parabolic materials. The new energy-mass relationship can be considered a generalization of Einstein's E=mc^2 suitable for arbitrary E(p) and therefore applicable to solid state materials and devices. We show that the resulting definition of the effective mass seems suitable for non-paraboic solid state materials such as HgCdTe, GaAs, and graphene.
Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, M.; Adams, T.; Agelou, M.; Agram, J.-L.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G.A.; Anastasoaie, M.; Andeen, T.; Anderson, S.; Andrieu, B.; Arnoud, Y.; Askew, A.; /Buenos Aires U. /Rio de Janeiro, CBPF /Rio de Janeiro State U. /Sao
2005-04-01T23:59:59.000Z
We present a measurement of the top quark pair (t{bar t}) production cross section ({sigma}{sub t{bar t}}) in p{bar p} collisions at a center-of-mass energy of 1.96 TeV using 230 pb{sub -1} of data collected by the D0 detector at the Fermilab Tevatron Collider. We select events with one charged lepton (electron or muon), large missing transverse energy, and at least four jets, and extract the t{bar t} content of the sample based on the kinematic characteristics of the events. For a top quark mass of 175 GeV, we measure {sigma}{sub t{bar t}} = 6.7{sub -1.3}{sup +1.4}(stat){sub -1.1}{sup +1.6}(syst) {+-} 0.4(lumi)pb, in good agreement with the standard model prediction.
W? Production and Limits on Anomalous WW? Couplings in pp? Collisions at ?s=1.96 TeV
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Abazov, V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G. A.; Aoki, M.; Arov, M.; Askew, A.; Ĺsman, B.; Atkins, S.; Atramentov, O.; Augsten, K.; Avila, C.; BackusMayes, J.; Badaud, F.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Barberis, E.; Baringer, P.; Barreto, J.; Bartlett, J. F.; Bassler, U.; Bazterra, V.; Bean, A.; Begalli, M.; Begel, M.; Belanger-Champagne, C.; Bellantoni, L.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besançon, M.; Beuselinck, R.; Bezzubov, V. A.; Bhat, P. C.; Bhatnagar, V.; Blazey, G.; Blessing, S.; Bloom, K.; Boehnlein, A.; Boline, D.; Boos, E. E.; Borissov, G.; Bose, T.; Brandt, A.; Brandt, O.; Brock, R.; Brooijmans, G.; Bross, A.; Brown, D.; Brown, J.; Bu, X. B.; Buehler, M.; Buescher, V.; Bunichev, V.; Burdin, S.; Burnett, T. H.; Buszello, C. P.; Calpas, B.; Camacho-Pérez, E.; Carrasco-Lizarraga, M. A.; Casey, B. C. K.; Castilla-Valdez, H.; Chakrabarti, S.; Chakraborty, D.; Chan, K. M.; Chandra, A.; Chapon, E.; Chen, G.; Chevalier-Théry, S.; Cho, D. K.; Cho, S. W.; Choi, S.; Choudhary, B.; Cihangir, S.; Claes, D.; Clutter, J.; Cooke, M.; Cooper, W. E.; Corcoran, M.; Couderc, F.; Cousinou, M.-C.; Croc, A.; Cutts, D.; Das, A.; Davies, G.; De, K.; de Jong, S. J.; De La Cruz-Burelo, E.; Déliot, F.; Demarteau, M.; Demina, R.; Denisov, D.; Denisov, S. P.; Desai, S.; Deterre, C.; DeVaughan, K.; Diehl, H. T.; Diesburg, M.; Ding, P. F.; Dominguez, A.; Dorland, T.; Dubey, A.; Dudko, L. V.; Duggan, D.; Duperrin, A.; Dutt, S.; Dyshkant, A.; Eads, M.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Enari, Y.; Evans, H.; Evdokimov, A.; Evdokimov, V. N.; Facini, G.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Fortner, M.; Fox, H.; Fuess, S.; Garcia-Bellido, A.; García-Guerra, G. A.; Gavrilov, V.; Gay, P.; Geng, W.; Gerbaudo, D.; Gerber, C. E.; Gershtein, Y.; Ginther, G.; Golovanov, G.; Goussiou, A.; Grannis, P. D.; Greder, S.; Greenlee, H.; Greenwood, Z. D.; Gregores, E. M.; Grenier, G.; Gris, Ph.; Grivaz, J.-F.; Grohsjean, A.; Grünendahl, S.; Grünewald, M. W.; Guillemin, T.; Gutierrez, G.; Gutierrez, P.; Haas, A.; Hagopian, S.; Haley, J.; Han, L.; Harder, K.; Harel, A.; Hauptman, J. M.; Hays, J.; Head, T.; Hebbeker, T.; Hedin, D.; Hegab, H.; Heinson, A. P.; Heintz, U.; Hensel, C.; Heredia-De La Cruz, I.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hoang, T.; Hobbs, J. D.; Hoeneisen, B.; Hohlfeld, M.; Hubacek, Z.; Huske, N.; Hynek, V.; Iashvili, I.; Ilchenko, Y.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffré, M.; Jamin, D.; Jayasinghe, A.; Jesik, R.; Jiang, P.; Johns, K.; Johnson, M.; Jonckheere, A.; Jonsson, P.; Joshi, J.; Jung, A. W.; Juste, A.; Kaadze, K.; Kajfasz, E.; Karmanov, D.; Kasper, P. A.; Katsanos, I.; Kehoe, R.; Kermiche, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. N.; Kohli, J. M.; Kozelov, A. V.; Kraus, J.; Kulikov, S.; Kumar, A.; Kupco, A.; Kur?a, T.; Kuzmin, V. A.; Kvita, J.; Lammers, S.; Landsberg, G.; Lebrun, P.; Lee, H. S.; Lee, S. W.; Lee, W. M.; Lellouch, J.; Li, L.; Li, Q. Z.; Lietti, S. M.; Lim, J. K.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, Y.; Lobodenko, A.; Lokajicek, M.; Lopes de Sa, R.; Lubatti, H. J.; Luna-Garcia, R.; Lyon, A. L.; Maciel, A. K. A.; Mackin, D.; Madar, R.; Magańa-Villalba, R.; Malik, S.; Malyshev, V. L.; Maravin, Y.; Martínez-Ortega, J.; McCarthy, R.; McGivern, C. L.; Meijer, M. M.; Melnitchouk, A.; Menezes, D.; Mercadante, P. G.; Merkin, M.; Meyer, A.; Meyer, J.; Miconi, F.; Mondal, N. K.; Muanza, G. S.; Mulhearn, M.; Nagy, E.; Naimuddin, M.; Narain, M.; Nayyar, R.; Neal, H. A.; Negret, J. P.; Neustroev, P.; Novaes, S. F.; Nunnemann, T.; Obrant, G.; Orduna, J.; Osman, N.; Osta, J.; Otero y Garzón, G. J.; Padilla, M.; Pal, A.; Parashar, N.; Parihar, V.; Park, S. K.; Parsons, J.; Partridge, R.; Parua, N.; Patwa, A.; Penning, B.; Perfilov, M.; Peters, K.; Peters, Y.; Petridis, K.; Petrillo, G.; Pétroff, P.; Piegaia, R.; Pleier, M.-A.; Podesta-Lerma, P. L. M.; Podstavkov, V. M.; Polozov, P.; Popov, A. V.; Prewitt, M.; Price, D.; Prokopenko, N.; Protopopescu, S.; Qian, J.; Quadt, A.; Quinn, B.; Rangel, M. S.; Ranjan, K.; Ratoff, P. N.; Razumov, I.; Renkel, P.; Rijssenbeek, M.; Ripp-Baudot, I.; Rizatdinova, F.; Rominsky, M.; Ross, A.; Royon, C.; Rubinov, P.; Ruchti, R.; Safronov, G.; Sajot, G.; Salcido, P.; Sánchez-Hernández, A.; Sanders, M. P.; Sanghi, B.; Santos, A. S.; Savage, G.; Sawyer, L.; Scanlon, T.; Schamberger, R. D.; Scheglov, Y.; Schellman, H.; Schliephake, T.; Schlobohm, S.; Schwanenberger, C.; Schwienhorst, R.; Sekaric, J.; Severini, H.; Shabalina, E.; Shary, V.; Shchukin, A. A.; Shivpuri, R. K.; Simak, V.; Sirotenko, V.; Skubic, P.; Slattery, P.; Smirnov, D.
2011-12-01T23:59:59.000Z
We measure the cross section and the difference in rapidities between photons and charged leptons for inclusive W(?l?)+? production in e? and ?? final states. Using data corresponding to an integrated luminosity of 4.2 fb?š collected with the D0 detector at the Fermilab Tevatron Collider, the measured cross section times branching fraction for the process pp??W?+X?l??+X and the distribution of the charge-signed photon-lepton rapidity difference are found to be in agreement with the standard model. These results provide the most stringent limits on anomalous WW? couplings for data from hadron colliders: -0.4??<0.07 at the 95% C.L.
Maier, Andreas Alexander; The ATLAS collaboration
2015-01-01T23:59:59.000Z
The top quark mass in dileptonic top quark pair decays was measured using $4.7~\\mathrm{fb}^{-1}$ of $\\sqrt{s}=7~\\mathrm{TeV}$ proton-proton ($pp$) collision data recorded by the ATLAS experiment at the LHC in 2011. The event topology is characterised by the presence of two charged leptons, at least two neutrinos and several jets, two of which originate from bottom quarks. Using the template method and the m$_{\\ell b}$ observable, defined as the average invariant mass of the two charged lepton plus $b$-jet pairs in each event, the top quark mass is measured to be $173.09 \\pm 0.64~(\\mathrm{stat}) \\pm 1.50~(\\mathrm{syst})~\\mathrm{GeV}$. This proceeding is based on a preliminary result, which has been superseded meanwhile.
Paredes Hernandez, Daniela; The ATLAS collaboration
2015-01-01T23:59:59.000Z
Search for new light gauge boson in Higgs boson decays to four-lepton events in pp collisions at 8 TeV with the ATLAS detector
Guesswork for Dirac and Majorana neutrino mass matrices
W. Krolikowski
2004-01-14T23:59:59.000Z
In the framework of seesaw mechanism with three neutrino flavors, we propose tentatively an efficient parametrization for the spectra of Dirac and righthanded Majorana neutrino mass matrices in terms of three free parameters. Two of them are related to (and determined by) the corresponding parameters introduced previously for the mass spectra of charged leptons and up and down quarks. The third is determined from the experimental estimate of solar $\\Delta m^2_{21}$. Then, the atmospheric $\\Delta m^2_{32}$ is {\\it predicted} close to its experimental estimation. With the use of these three parameters all light active-neutrino masses $ m_1 < m_2 < m_3$ and heavy sterile-neutrino masses $ M_1 < M_2 < M_3$ are readily evaluated. The latter turn out much more {\\it hierarchical} than the former. The lightest heavy mass $ M_1$ comes out to be of the order $O(10^6 {\\rm GeV})$ so, it is too light to imply that the mechanism of baryogenesis through thermal leptogenesis might work.
Precision Top-Quark Mass Measurements at CDF
Aaltonen, T.; /Helsinki Inst. of Phys.; Alvarez Gonzalez, B.; /Oviedo U. /Cantabria Inst. of Phys.; Amerio, S.; /INFN, Padua; Amidei, D.; /Michigan U.; Anastassov, A.; /Northwestern U. /Fermilab; Annovi, A.; /Frascati; Antos, J.; /Comenius U.; Apollinari, G.; /Fermilab; Appel, J.A.; /Fermilab; Arisawa, T.; /Waseda U.; Artikov, A.; /Dubna, JINR /Texas A-M
2012-07-01T23:59:59.000Z
We present a precision measurement of the top-quark mass using the full sample of Tevatron {radical}s = 1.96 TeV proton-antiproton collisions collected by the CDF II detector, corresponding to an integrated luminosity of 8.7 fb{sup -1}. Using a sample of t{bar t} candidate events decaying into the lepton+jets channel, we obtain distributions of the top-quark masses and the invariant mass of two jets from the W boson decays from data. We then compare these distributions to templates derived from signal and background samples to extract the top-quark mass and the energy scale of the calorimeter jets with in situ calibration. The likelihood fit of the templates from signal and background events to the data yields the single most-precise measurement of the top-quark mass, mtop = 172.85 {+-} 0.71 (stat) {+-} 0.85 (syst) GeV/c{sup 2}.
Mass spectrometric immunoassay
Nelson, Randall W; Williams, Peter; Krone, Jennifer Reeve
2013-07-16T23:59:59.000Z
Rapid mass spectrometric immunoassay methods for detecting and/or quantifying antibody and antigen analytes utilizing affinity capture to isolate the analytes and internal reference species (for quantification) followed by mass spectrometric analysis of the isolated analyte/internal reference species. Quantification is obtained by normalizing and calibrating obtained mass spectrum against the mass spectrum obtained for an antibody/antigen of known concentration.
Mass spectrometric immunoassay
Nelson, Randall W (Phoenix, AZ); Williams, Peter (Phoenix, AZ); Krone, Jennifer Reeve (Granbury, TX)
2007-12-04T23:59:59.000Z
Rapid mass spectrometric immunoassay methods for detecting and/or quantifying antibody and antigen analytes utilizing affinity capture to isolate the analytes and internal reference species (for quantification) followed by mass spectrometric analysis of the isolated analyte/internal reference species. Quantification is obtained by normalizing and calibrating obtained mass spectrum against the mass spectrum obtained for an antibody/antigen of known concentration.
Darmann, Francis Anthony
2013-10-08T23:59:59.000Z
A fault current limiter (FCL) includes a series of high permeability posts for collectively define a core for the FCL. A DC coil, for the purposes of saturating a portion of the high permeability posts, surrounds the complete structure outside of an enclosure in the form of a vessel. The vessel contains a dielectric insulation medium. AC coils, for transporting AC current, are wound on insulating formers and electrically interconnected to each other in a manner such that the senses of the magnetic field produced by each AC coil in the corresponding high permeability core are opposing. There are insulation barriers between phases to improve dielectric withstand properties of the dielectric medium.
(Limiting the greenhouse effect)
Rayner, S.
1991-01-07T23:59:59.000Z
Traveler attended the Dahlem Research Conference organized by the Freien Universitat, Berlin. The subject of the conference was Limiting the Greenhouse Effect: Options for Controlling Atmospheric CO{sub 2} Accumulation. Like all Dahlem workshops, this was a meeting of scientific experts, although the disciplines represented were broader than usual, ranging across anthropology, economics, international relations, forestry, engineering, and atmospheric chemistry. Participation by scientists from developing countries was limited. The conference was divided into four multidisciplinary working groups. Traveler acted as moderator for Group 3 which examined the question What knowledge is required to tackle the principal social and institutional barriers to reducing CO{sub 2} emissions'' The working rapporteur was Jesse Ausubel of Rockefeller University. Other working groups examined the economic costs, benefits, and technical feasibility of options to reduce emissions per unit of energy service; the options for reducing energy use per unit of GNP; and the significant of linkage between strategies to reduce CO{sub 2} emissions and other goals. Draft reports of the working groups are appended. Overall, the conference identified a number of important research needs in all four areas. It may prove particularly important in bringing the social and institutional research needs relevant to climate change closer to the forefront of the scientific and policy communities than hitherto.
Baryonic Dark Matter: Limits from HST and ISO
Gerard Gilmore; IoA Cambridge; UK
1998-12-15T23:59:59.000Z
Recent HST and ISO observations provide very severe limits on any compact baryonic contributions to galactic (dark) halos. When combined with Milky Way Galaxy microlensing results, almost the entire plausible range of massive compact baryonic objects is excluded by direct observation. Deep direct imaging at 7mu and 15mu with ISOCAM on the ISO spacecraft directly excludes hydrogen-burning stars of any mass above the hydrogen-burning limit, and of any chemical abundance, from being the predominant explanation of the dark halos of external spiral galaxies. In the Milky Way Galaxy, HST has provided luminosity functions to the hydrogen-burning limit in several globular clusters. The resulting mass functions do not provide any support for dominance by very low-mass stars. This is consistent with field surveys for sub-stellar mass brown dwarfs, which show such objects to be relatively rare. These results are complemented by very deep HST luminosity functions in the Large Magellanic Cloud, providing strong support for the (near)-universality of the stellar mass function. Very recent HST results are available for the nearby dSph galaxy UMi. This galaxy, the most dark-matter dominated object known on kpc scales, has a normal stellar mass function at low masses. The prospects are bright for dark elementary particles.
Imaging mass spectrometer with mass tags
Felton, James S.; Wu, Kuang Jen; Knize, Mark G.; Kulp, Kristen S.; Gray, Joe W.
2010-06-01T23:59:59.000Z
A method of analyzing biological material by exposing the biological material to a recognition element, that is coupled to a mass tag element, directing an ion beam of a mass spectrometer to the biological material, interrogating at least one region of interest area from the biological material and producing data, and distributing the data in plots.
Imaging mass spectrometer with mass tags
Felton, James S.; Wu, Kuang Jen J.; Knize, Mark G.; Kulp, Kristen S.; Gray, Joe W.
2013-01-29T23:59:59.000Z
A method of analyzing biological material by exposing the biological material to a recognition element, that is coupled to a mass tag element, directing an ion beam of a mass spectrometer to the biological material, interrogating at least one region of interest area from the biological material and producing data, and distributing the data in plots.
Neutrino mixings and leptonic CP violation from CKM matrix and Majorana phases
Agarwalla, Sanjib Kumar; Parida, M. K.; Mohapatra, R. N.; Rajasekaran, G. [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019 (India); Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Institute of Mathematical Sciences, Chennai 600113 (India)
2007-02-01T23:59:59.000Z
The high scale mixing unification hypothesis recently proposed by three of us (R. N. M., M. K. P. and G. R.) states that if at the seesaw scale the quark and lepton mixing matrices are equal, then for quasidegenerate neutrinos radiative corrections can lead to large solar and atmospheric mixings and small reactor angle at the weak scale in agreement with data. Evidence for quasidegenerate neutrinos could, within this framework, be interpreted as being consistent with quark-lepton unification at high scale. In the current work, we extend this model to show that the hypothesis works quite successfully in the presence of CP-violating phases (which were set to zero in the first paper). In the case where the Pontecorvo-Maki-Nakagawa-Sakata matrix is identical to the Cabibbo-Kobayashi-Maskawa quark-mixing matrix at the seesaw scale, with a Dirac phase but no Majorana phase, the low energy Dirac phase is predicted to be ({approx_equal}0.3 deg.) and leptonic CP-violation parameter J{sub CP}{approx_equal}(4-8)x10{sup -5} and {theta}{sub 13}=3.5 deg. If on the other hand, the Pontecorvo-Maki-Nakagawa-Sakata matrix is assumed to also have non-negligible Majorana phase(s) initially, the resulting theory damps radiative magnification phenomenon for a large range of parameters but nevertheless has enough parameter space to give the two necessary large neutrino mixing angles. In this case, one has {theta}{sub 13}=3.5 deg. -10 deg. and vertical bar J{sub CP} vertical bar as large as 0.02-0.04 which are accessible to long baseline neutrino oscillation experiments.
Neutrino Mixings and Leptonic CP Violation from CKM Matrix and Majorana Phases
S. K. Agarwalla; M. K. Parida; R. N. Mohapatra; G. Rajasekaran
2007-04-11T23:59:59.000Z
The high scale mixing unification hypothesis recently proposed by three of us (R. N. M., M. K. P. and G. R.) states that if at the seesaw scale, the quark and lepton mixing matrices are equal then for quasi-degenerate neutrinos, radiative corrections can lead to large solar and atmospheric mixings and small reactor angle at the weak scale in agreement with data. Evidence for quasi-degenerate neutrinos could, within this framework, be interpreted as a sign of quark-lepton unification at high scale. In the current work, we extend this model to show that the hypothesis works quite successfully in the presence of CP violating phases (which were set to zero in the first paper). In the case where the PMNS matrix is identical to the CKM matrix at the seesaw scale, with a Dirac phase but no Majorana phase, the low energy Dirac phase is predicted to be ($\\simeq 0.3^{\\circ}$) and leptonic CP-violation parameter $J_{CP} \\simeq (4 - 8)\\times 10^{-5}$ and $\\theta_{13} = 3.5^{\\circ}$. If on the other hand, the PMNS matrix is assumed to also have Majorana phases initially, the resulting theory damps radiative magnification phenomenon for a large range of parameters but nevertheless has enough parameter space to give the two necessary large neutrino mixing angles. In this case, one has $\\theta_{13} = 3.5^{\\circ} - 10^{\\circ}$ and $|J_{CP}|$ as large as $0.02-0.04$ which are accessible to long baseline neutrino oscillation experiments.
Ideal Quantum Gases with Planck Scale Limitations
Rainer Collier
2015-03-14T23:59:59.000Z
A thermodynamic system of non-interacting quantum particles changes its statistical distribution formulas if there is a universal limitation for the size of energetic quantum leaps (magnitude of quantum leaps smaller than Planck energy). By means of a restriction of the a priori equiprobability postulate one can reach a thermodynamic foundation of these corrected distribution formulas. The number of microstates is determined by means of a suitable counting method and combined with thermodynamics via the Boltzmann principle. The result is that, for particle energies that come close to the Planck energy, the thermodynamic difference between fermion and boson distribution vanishes. Both distributions then approximate a Boltzmann distribution. The wave and particle character of the quantum particles, too, can be influenced by choosing the size of the temperature and particle energy parameters relative to the Planck energy, as you can see from the associated fluctuation formulas. In the case of non-relativistic degeneration, the critical parameters Fermi momentum (fermions) and Einstein temperature (bosons) vanish as soon as the rest energy of the quantum particles reaches the Planck energy. For the Bose-Einstein condensation there exists, in the condensation range, a finite upper limit for the number of particles in the ground state, which is determined by the ratio of Planck mass to the rest mass of the quantum particles. In the relativistic high-temperature range, the energy densities of photon and neutrino radiation have finite limit values, which is of interest with regard to the start of cosmic expansion.
Caldwell, R.R.; Linder, Eric V.
2005-05-24T23:59:59.000Z
We present evidence that the simplest particle-physics scalar-field models of dynamical dark energy can be separated into distinct behaviors based on the acceleration or deceleration of the field as it evolves down its potential towards a zero minimum. We show that these models occupy narrow regions in the phase-plane of w and w', the dark energy equation-of-state and its time-derivative in units of the Hubble time. Restricting an energy scale of the dark energy microphysics limits how closely a scalar field can resemble a cosmological constant. These results, indicating a desired measurement resolution of order \\sigma(w')\\approx (1+w), define firm targets for observational tests of the physics of dark energy.
AN in inclusive lepton-proton collisions: TMD and twist-3 approaches
Prokudin, Alexey [JLAB
2015-01-01T23:59:59.000Z
We consider the inclusive production of hadrons in lepton-nucleon scattering. For a transversely polarized nucleon this reaction shows a left-right azimuthal asymmetry, which we compute this asymmetry in both TMD and in twist-3 collinear factorization formalisms. All non-perturbative parton correlators of the calculation are fixed through information from other hard processes. Our results for the left-right asymmetry agree in sign with recent data for charged pion production from the HERMES Collaboration and from Jefferson Lab. We discuss similarities and differences of two formalisms.
Black Hole Interior Mass Formula
Parthapratim Pradhan
2014-05-06T23:59:59.000Z
We argue by explicit computations that, although the area product, horizon radii product, entropy product and \\emph {irreducible mass product} of the event horizon and Cauchy horizon are universal, the \\emph{surface gravity product}, \\emph{surface temperature product} and \\emph{Komar energy product} of the said horizons do not seem to be universal for Kerr-Newman (KN) black hole space-time. We show the black hole mass formula on the \\emph{Cauchy horizon} following the seminal work by Smarr\\cite{smarr} for the outer horizon. We also prescribed the \\emph{four} laws of black hole mechanics for the \\emph{inner horizon}. New definition of the extremal limit of a black hole is discussed.
More on the renormalization group limit cycle in QCD
Evgeny Epelbaum; Hans-Werner Hammer; Ulf-G. Meissner; Andreas Nogga
2006-02-26T23:59:59.000Z
We present a detailed study of the recently conjectured infrared renormalization group limit cycle in QCD using chiral effective field theory. We show that small increases in the up and down quark masses, corresponding to a pion mass around 200 MeV, can move QCD to the critical renormalization group trajectory for an infrared limit cycle in the three-nucleon system. At the critical values of the quark masses, the binding energies of the deuteron and its spin-singlet partner are tuned to zero and the triton has infinitely many excited states with an accumulation point at the three-nucleon threshold. At next-to-leading order in the chiral counting, we find three parameter sets where this effect occurs. For one of them, we study the structure of the three-nucleon system using both chiral and contact effective field theories in detail. Furthermore, we calculate the influence of the limit cycle on scattering observables.
The HERMES collaboration; A. Airapetian
2010-01-22T23:59:59.000Z
The nuclear-mass dependence of azimuthal cross section asymmetries with respect to charge and longitudinal polarization of the lepton beam is studiedfor hard exclusive electroproduction of real photons. The observed beam-charge and beam-helicity asymmetries are attributed to the interference between the Bethe-Heitler and deeply virtual Compton scattering processes. For various nuclei, the asymmetries are extracted for both coherent and incoherent-enriched regions, which involve different (combinations of) generalized parton distributions. For both regions, the asymmetries are compared to those for a free proton, and no nuclear-mass dependence is found.
Running of Radiative Neutrino Masses: The Scotogenic Model
Romain Bouchand; Alexander Merle
2012-04-30T23:59:59.000Z
We study the renormalization group equations of Ma's scotogenic model, which generates an active neutrino mass at 1-loop level. In addition to other benefits, the main advantage of the mechanism exploited in this model is to lead to a natural loop-suppression of the neutrino mass, and therefore to an explanation for its smallness. However, since the structure of the neutrino mass matrix is altered compared to the ordinary type I seesaw case, the corresponding running is altered as well. We have derived the full set of renormalization group equations for the scotogenic model which, to our knowledge, had not been presented previously in the literature. This set of equations reflects some interesting structural properties of the model, and it is an illustrative example for how the running of neutrino parameters in radiative models is modified compared to models with tree-level mass generation. We also study a simplified numerical example to illustrate some general tendencies of the running. Interestingly, the structure of the RGEs can be exploited such that a bimaximal leptonic mixing pattern at the high-energy scale is translated into a valid mixing pattern at low energies, featuring a large value of \\theta_{13}. This suggests very interesting connections to flavour symmetries.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
mass-spectrometry Proteomics Capabilities High resolution and mass accuracy Fourier-transform ion cyclotron resonance (FT-ICR) spectrometers, from 6 Tesla (T) to 15T and 21T in...
Updated fit to three neutrino mixing: status of leptonic CP violation
M. C. Gonzalez-Garcia; Michele Maltoni; Thomas Schwetz
2014-12-16T23:59:59.000Z
We present a global analysis of solar, atmospheric, reactor and accelerator neutrino data in the framework of three-neutrino oscillations based on data available in summer 2014. We provide the allowed ranges of the six oscillation parameters and show that their determination is stable with respect to uncertainties related to reactor neutrino and solar neutrino flux predictions. We find that the maximal possible value of the Jarlskog invariant in the lepton sector is $0.0329 \\pm 0.0009$ ($\\pm 0.0027$) at the $1\\sigma$ ($3\\sigma$) level and we use leptonic unitarity triangles to illustrate the ability of global oscillation data to obtain information on CP violation. We discuss "tendencies and tensions" of the global fit related to the octant of $\\theta_{23}$ as well as the CP violating phase $\\delta_\\mathrm{CP}$. The favored values of $\\delta_\\mathrm{CP}$ are around $3\\pi/2$ while values around $\\pi/2$ are disfavored at about $\\Delta\\chi^2 \\simeq 6$. We comment on the non-trivial task to assign a confidence level to this $\\Delta\\chi^2$ value by performing a Monte Carlo study of T2K data.
Horizon-Scale Lepton Acceleration in Jets: Explaining the Compact Radio Emission in M87
Tchekhovskoy, Alexander
2015-01-01T23:59:59.000Z
It has now become clear that the radio jet in the giant elliptical galaxy M87 must turn on very close to the black hole. This implies the efficient acceleration of leptons within the jet at scales much smaller than feasible by the typical dissipative events usually invoked to explain jet synchrotron emission. Here we show that the stagnation surface, the separatrix between material that falls back into the black hole and material that is accelerated outward forming the jet, is a natural site of pair formation and particle acceleration. This occurs via an inverse-Compton pair catastrophe driven by unscreened electric fields within the charge-starved region about the stagnation surface and substantially amplified by a post-gap cascade. For typical estimates of the jet properties in M87, we find excellent quantitive agreement between the predicted relativistic lepton densities and those required by recent high-frequency radio observations of M87. This mechanism fails to adequately fill a putative jet from Sagitt...
Effective Hamiltonian for non-leptonic |Delta F| = 1 decays at NNLO in QCD
Gorbahn, Martin; /Durham U., IPPP; Haisch, Ulrich; /Fermilab
2004-11-01T23:59:59.000Z
The authors compute the effective hamiltonian for non-leptonic |{Delta}F| = 1 decays in the standard model including next-to-next-to-leading order QCD corrections. In particular, they present the complete three-loop anomalous dimension matrix describing the mixing of current-current and QCD penguin operators. The calculation is performed in an operator basis which allows to consistently use fully anticommuting {gamma}{sub 5} in dimensional regularization at an arbitrary number of loops. The renormalization scheme dependences and their cancellation in physical quantities is discussed in detail. Furthermore, they demonstrate how the results are transformed to a different basis of effective operators which is frequently adopted in phenomenological applications. They give all necessary two-loop constant terms which allow to obtain the three-loop anomalous dimensions and the corresponding initial conditions of the two-loop Wilson coefficients in the latter scheme. Finally, they solve the renormalization group equation and given the analytic expressions for the low-energy Wilson coefficients relevant for non-leptonic B meson decays beyond next-to-leading order in both renormalization schemes.
McFarland, Andrew R. (College Station, TX); Rodgers, John C. (Santa Fe, NM); Ortiz, Carlos A. (Bryan, TX); Nelson, David C. (Santa Fe, NM)
1994-01-01T23:59:59.000Z
Elbow mass flow meter. The present invention includes a combination of an elbow pressure drop generator and a shunt-type mass flow sensor for providing an output which gives the mass flow rate of a gas that is nearly independent of the density of the gas. For air, the output is also approximately independent of humidity.
Fermion masses and mixings from dihedral flavor symmetries with preserved subgroups
Blum, A.; Hagedorn, C.; Lindner, M. [Max-Planck-Institut fuer Kernphysik, Postfach 10 39 80, 69029 Heidelberg (Germany)
2008-04-01T23:59:59.000Z
We perform a systematic study of dihedral groups used as flavor symmetry. The key feature here is the fact that we do not allow the dihedral groups to be broken in an arbitrary way, but in all cases some (nontrivial) subgroup has to be preserved. In this way we arrive at only five possible (Dirac) mass matrix structures which can arise, if we require that the matrix has to have a nonvanishing determinant and that at least two of the three generations of left-handed (conjugate) fermions are placed into an irreducible two-dimensional representation of the flavor group. We show that there is no difference between the mass matrix structures for single- and double-valued dihedral groups. Furthermore, we comment on possible forms of Majorana mass matrices. As a first application we find a way to express the Cabibbo angle, i.e. the Cabibbo-Kobayashi-Maskawa matrix element |V{sub us}|, in terms of group theory quantities only, the group index n, the representation index j and the index m{sub u,d} of the different preserved subgroups in the up and down quark sector: |V{sub us}|=|cos(({pi}(m{sub u}-m{sub d})j/n))| which is |cos((3{pi}/7))|{approx_equal}0.2225 for n=7, j=1, m{sub u}=3 and m{sub d}=0. We prove that two successful models which lead to maximal atmospheric mixing and vanishing {theta}{sub 13} in the lepton sector are based on the fact that the flavor symmetry is broken in the charged lepton, Dirac neutrino and Majorana neutrino sector down to different preserved subgroups whose mismatch results in the prediction of these mixing angles. This also demonstrates the power of preserved subgroups in connection with the prediction of mixing angles in the quark as well as in the lepton sector.
Infrared cutoffs and the adiabatic limit in noncommutative spacetime
Claus Doescher; Jochen Zahn
2005-12-02T23:59:59.000Z
We discuss appropriate infrared cutoffs and their adiabatic limit for field theories on the noncommutative Minkowski space in the Yang-Feldman formalism. In order to do this, we consider a mass term as interaction term. We show that an infrared cutoff can be defined quite analogously to the commutative case and that the adiabatic limit of the two-point function exists and coincides with the expectation, to all orders.
Infrared cutoffs and the adiabatic limit in noncommutative spacetime
Doescher, Claus; Zahn, Jochen [II. Institut fuer Theoretische Physik, Universitaet Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); Zentrum fuer Mathematische Physik, Universitaet Hamburg, Bundesstrasse 55, 20146 Hamburg (Germany)
2006-02-15T23:59:59.000Z
We discuss appropriate infrared cutoffs and their adiabatic limit for field theories on the noncommutative Minkowski space in the Yang-Feldman formalism. In order to do this, we consider a mass term as interaction term. We show that an infrared cutoff can be defined quite analogously to the commutative case and that the adiabatic limit of the two-point function exists and coincides with the expectation, to all orders.
COMMENTARY:Limits to adaptation
Preston, Benjamin L [ORNL
2013-01-01T23:59:59.000Z
An actor-centered, risk-based approach to defining limits to social adaptation provides a useful analytic framing for identifying and anticipating these limits and informing debates over society s responses to climate change.
Tritium--helium-3 mass difference using the Penning trap mass spectroscopy
Van Dyck, R.S. Jr.; Farnham, D.L.; Schwinberg, P.B. (Department of Physics, FM-15, University of Washington, Seattle, Washington 98195 (United States))
1993-05-10T23:59:59.000Z
The atomic masses of both [sup 3]H and [sup 3]He have been measured with a Penning trap mass spectrometer that utilizes a frequency-shift detector to observe ion cyclotron resonances. Present resolution exceeds 1 part in 10[sup 9] and is limited only by the stability of the magnetic field. The leading systematic shift (at [approx lt]1 part in 10[sup 10]) is due to the residual quadratic [bold B] field dependence. The atomic masses have been combined to yield [Delta][ital Mc][sup 2]([sup 3]H[minus][sup 3]He)=18 590.1(1.7) eV. The excellent agreement with recent results from [beta] spectrometers lends strong support for new limits on the neutrino's rest mass.
Neutrino masses in SU(4){sub L}?U(1){sub X} gauge models
Palcu, Adrian [Faculty of Exact Sciences - Aurel Vlaicu University Arad, Str. Elena Dr?goi 2, Arad - 310330 (Romania)
2013-11-13T23:59:59.000Z
Neutrino masses are obtained within SU(4){sub L}?U(1){sub X} electroweak gauge models with spontaneous symmetry breaking by simply exploiting the tree level realization of certain dimension-five effective operators. The scalar sector needs not to be enlarged, since these operators are constructed as direct products among scalar multiplets already existing in the model. There is a unique generic matrix for Yukawa couplings in the neutrino sector, while the charged leptons are already in their diagonal basis. The experimentally observed phenomenology in the neutrino sector is obtained as a natural consequence of this particular approach.
Conceptual design of the Mu2e production solenoid cold mass
Kashikhin, V.V.; Ambrosio, G.; Andreev, N.; Lamm, M.; Mokhov, N.V.; Nicol, T.H.; Page, T.M.; Pronskikh, V.; /Fermilab
2011-06-01T23:59:59.000Z
The Muon-to-Electron conversion experiment (Mu2e), under development at Fermilab, seeks to detect direct muon to electron conversion to provide evidence for a process violating muon and electron lepton number conservation that cannot be explained by the Standard Model of particle physics. The required magnetic field is produced by a series of superconducting solenoids of various apertures and lengths. This paper describes the conceptual design of the 5 T, 4 m long solenoid cold mass with 1.67 m bore with the emphasis on the magnetic, radiation and thermal analyses.
Total Matrix Intercomparison: A Method for Determining the Geometry of Water-Mass Pathways
Gebbie, Geoffrey
Ocean tracer distributions have long been used to decompose the deep ocean into constituent water masses, but previous inverse methods have generally been limited to just a few water masses that have been defined by a ...
Mass ejected by impacts with materials of various strengths
Canavan, G.H.
1997-02-01T23:59:59.000Z
Similarity solutions are used to discuss impacts on asteroids of various strengths, concentrating on the voids produced, the mass ejected, and its thermodynamic and mechanical state. Numerical calculations have advantages and limitations for the next step in complexity.
RESEARCH Open Access Impact of physical incompatibility on drug mass
Paris-Sud XI, Université de
RESEARCH Open Access Impact of physical incompatibility on drug mass flow rates: example drugs simultaneously but through limited venous accesses. Several intravenous therapies have rates of drugs infused simultaneously to the patient, through an in vitro study. Methods: Furosemide
Bound states for Overlap and Fixed Point Actions close to the chiral limit
Stefan Haeusler; C. B. Lang
2001-05-16T23:59:59.000Z
We study the overlap and the fixed point Dirac operators for massive fermions in the two-flavor lattice Schwinger model. The masses of the triplet (pion) and singlet (eta) bound states are determined down to small fermion masses and the mass dependence is compared with various continuum model approximations. Near the chiral limit, at very small fermion masses the fixed point operator has stability problems, which in this study are dominated by finite size effects,
Constraints on the tau neutrino mass and mixing from precise measurements of tau decay rates
John Swain; Lucas Taylor
1996-10-04T23:59:59.000Z
We have derived constraints on the tau neutrino mass and fourth generation mixing from an analysis of the partial widths of tau lepton decays, in particular: tau -> e nu nu_tau, tau -> mu nu nu_tau, tau -> pi nu_tau, tau -> K nu_tau. We present predictions for the tau decay widths, allowing for a non-zero tau neutrino mass, m(nu_tau), and for mixing with a neutrino of mass m(nu_L) > M_Z/2, which is parametrised using a Cabibbo-like mixing angle, theta_L. By comparison of these theoretical predictions with the experimental measurements, we obtain the following bounds at the 90% confidence level: m(nu_tau) < 42 MeV and sin^2(theta_L) < 0.014.
Universal SU(2/1) and the Higgs and fermion masses
Ne`eman, Y. [Tel Aviv Univ. (Israel). Sackler Faculty of Exact Sciences
1992-12-31T23:59:59.000Z
We review the SU(2/1) internal supersymmetry suggested by D. Fairlie and the author in 1979. The initial apparent difficulties were resolved when, with J. Thierry-Mieg, we understood that the gauging of a supergroup implies taking the usual Yang-Mills-like Principal (Double) Fibre Bundle as a ``scaffold`` and using its Grassmann algebra as parameter manifold for the supergauge. SU(2/1) Universality fixes the masses of the Higgs scalar field and the ``top`` quark around 100--200 GeV, in the same region as the W and Z masses. A ``unified``` supergauge, enclosing SU(3)colour x SU(2) x U(l), predicts a fourth lepton generation in which the neutrino mass is of the same order.
The In-medium Mass and Widths of Light Vector Mesons
Djalali, C.; Paolone, M. [University of South Carolina, Department of Physics and Astronomy, Columbia, SC 29208 (United States); Weygand, D. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Wood, M. H. [Canisius College, Department of Physics, Buffalo, NY 14208 (United States); Nasseripour, R. [George Washington University, Department of Physics, Washington, DC 20052 (United States)
2011-05-23T23:59:59.000Z
Partial restoration of chiral symmetry in ordinary nuclear matter suggests the modification of properties of vector mesons, such as a shift in mass and/or a change of width. Photoproduction of vector mesons off nuclei were performed at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). The properties of the {rho}, {omega} and {phi} mesons were investigated via their rare leptonic decay to e+e-. This decay channel has an advantage over hadronic modes as it eliminates final state interactions in the nuclear matter. After subtracting the combinatorial background, the meson mass distributions were extracted for each of the nuclear targets. No significant mass shift is observed, however substantial increase in the widths of the mesons is reported.
Neutrino mixing based on mass matrices with a 2{r_reversible}3 symmetry
Koide, Yoshio; Takasugi, Eiichi [Institute for Higher Education Research and Practice, Osaka University, 1-16 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan)
2008-01-01T23:59:59.000Z
Under an assumption that the 2{r_reversible}3 symmetry is broken only through phases, we give a systematic investigation of possible lepton mass matrix forms without referring to explicit parameter values. Two types of the 2{r_reversible}3 symmetry are investigated: one is that the left- and right-handed fields (f{sub L},f{sub R}) obey the symmetry, and another one is that only f{sub L} obeys the symmetry. In the latter case, in spite of no 2{r_reversible}3 symmetry in the Majorana mass matrix M{sub R} for {nu}{sub R}, the neutrino seesaw mass matrix still obeys the 2{r_reversible}3 symmetry. Possible phenomenology is discussed.
Running of Low-Energy Neutrino Masses, Mixing Angles and CP Violation
John Ellis; Andi Hektor; Mario Kadastik; Kristjan Kannike; Martti Raidal
2005-06-13T23:59:59.000Z
We calculate the running of low-energy neutrino parameters from the bottom up, parameterizing the unknown seesaw parameters in terms of the dominance matrix $R$. We find significant running only if the $R$ matrix is non-trivial and the light-neutrino masses are moderately degenerate. If the light-neutrino masses are very hierarchical, the quark-lepton complementarity relation $\\theta_c + \\theta_{12} = \\pi/4$ is quite stable, but $\\theta_{13,23}$ may run beyond their likely future experimental errors. The running of the oscillation phase $\\delta$ is enhanced by the smallness of $\\theta_{13}$, and jumps in the mixing angles occur in cases where the light-neutrino mass eigenstates cross.
Measurable neutrino mass scale in A{sub 4}xSU(5)
Antusch, S.; Spinrath, M. [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Foehringer Ring 6, D-80805 Muenchen (Germany); King, Stephen F. [School of Physics and Astronomy, University of Southampton, SO17 1BJ Southampton (United Kingdom)
2011-01-01T23:59:59.000Z
We propose a supersymmetric A{sub 4}xSU(5) model of quasidegenerate neutrinos which predicts the effective neutrino mass m{sub ee} relevant for neutrinoless double beta decay to be proportional to the neutrino mass scale, thereby allowing its determination approximately independently of unknown Majorana phases. Such a natural quasidegeneracy is achieved by using A{sub 4} family symmetry (as an example of a non-Abelian family symmetry with real triplet representations) to enforce a contribution to the neutrino mass matrix proportional to the identity. Tribimaximal neutrino mixing as well as quark CP violation with {alpha}{approx_equal}90 deg. d a leptonic CP phase {delta}{sub MNS{approx_equal}}90 deg. arise from the breaking of the A{sub 4} family symmetry by the vacuum expectation values of four 'flavon' fields pointing in specific postulated directions in flavor space.
Tuna, Alexander Naip; The ATLAS collaboration
2015-01-01T23:59:59.000Z
Recent results on the search for Higgs boson decays to tau leptons with the ATLAS detector are presented based on approximately 25 $\\text{fb}^{-1}$ of proton-proton collision data collected at $\\sqrt{s}=$ 7 and 8 TeV. Prospects of future measurements with proposed ATLAS upgrades at the High Luminosity LHC are also presented.
Apyan, Aram
A search for anomalous production of events with three or more isolated leptons and bottom-quark jets produced in pp collisions at ?s = 8??TeV is presented. The analysis is based on a data sample corresponding to an ...
Fermilab
CDF note 10582 Search for SM Higgs boson production in association with tÂŻt using no lepton final is that tÂŻt decay all hadronic mode (all t decay into bqq ). In both cases we consider that the Higgs boson discriminant variable from different neural network to discriminate the Higgs boson signal from remained
Quigg, Chris
V collected using CDF II detector at the Fermilab Tevatron. We find 15 ETb events versus an expectation of 14 production of ETb events, and the results of a search for tÂŻt events in a semi-leptonic channel using 929 pb
Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, M.; Adams, T.; Agelou, M.; Agram, J.-L.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G.A.; Anastasoaie, M.; Andeen, T.; Anderson, S.; Andrieu, B.; Arnoud, Y.; Askew, A.; /Buenos Aires U. /Rio de Janeiro, CBPF /Rio de Janeiro State U. /Sao
2005-04-01T23:59:59.000Z
We present a measurement of the top quark pair (t{bar t}) production cross section ({sigma}{sub t{bar t}}) in p{bar p} collisions at {radical}s = 1.96 TeV using 230 pb{sup -1} of data collected by the D0 experiment at the Fermilab Tevatron Collider. We select events with one charged lepton (electron or muon), missing transverse energy, and jets in the final state. We employ lifetime-based b-jet identification techniques to further enhance the t{bar t} purity of the selected sample. For a top quark mass of 175 GeV, we measure {sigma}{sub t{bar t}} = 8.6{sub -1.5}{sup +1.6}(stat. + syst.) {+-} 0.6 (lumi.) pb, in agreement with the standard model expectation.
MassMass transfer andtransfer and MassMass transfer andtransfer and
Zevenhoven, Ron
Heat conductivity T'1 Heat flux h" (W/m2), local and overall heat transfer coeffients h1 Heat transfer coefficientcoefficient /1/1 Mass flow species A:interface a p A = A mol/s M f1 (L) 2 (G) Mass transfer rate per area: A = A/a = "A mol/(m2ˇs) 1 (L) 2 (G) xi C1.i M t f ffi i t k x C y 1.i AA !!! Mass transfer coefficients
Hindawai, S. M.
2010-01-01T23:59:59.000Z
- 1 - MASS AND HEAT RECOVERY SYSTEM SALAH MAHMOUD HINDAWI DIRECTOR HINDAWI FOR ENGINEERING SERVICES & CONTRACTING NEW DAMIETTA , EGYPT ABSTRACT : In the last few years heat recovery was under spot . and in air conditioning fields... ) as a heat recovery . and I use the water as a mass recovery . The source of mass and heat recovery is the condensate water which we were dispose and connect it to the drain lines . THE BENEFIT OF THIS SYSTEM ARE : 1) Using the heat energy from...
Electroweak corrections to lepton pair production in association with two hard jets at the LHC
Ansgar Denner; Lars Hofer; Andreas Scharf; Sandro Uccirati
2014-11-04T23:59:59.000Z
We compute the next-to-leading order corrections of $O(\\alpha_s^2\\alpha^3)$ to the hadronic production of two oppositely charged leptons and two hard jets, $p p \\to j j l^- l^+$, using Recola and Collier. We include electroweak and QCD corrections at the given order and all off-shell effects. We provide detailed predictions for the LHC operating at 13 TeV and obtain per-cent-level corrections for the total cross section. For differential distributions we find significant non-uniform distortions in high-energy tails at the level of several ten per cent due to electroweak Sudakov logarithms and deformations at the level of a few per cent for angular variables.
Chiral sum rules and vacuum condensates from tau-lepton decay data
C. A. Dominguez; L. A. Hernandez; K. Schilcher; H. Spiesberger
2015-02-16T23:59:59.000Z
QCD finite energy sum rules, together with the latest updated ALEPH data on hadronic decays of the tau-lepton are used in order to determine the vacuum condensates of dimension $d=2$ and $d=4$. These data are also used to check the validity of the Weinberg sum rules, and to determine the chiral condensates of dimension $d=6$ and $d=8$, as well as the chiral correlator at zero momentum, proportional to the counter term of the ${\\cal{O}}(p^4)$ Lagrangian of chiral perturbation theory, $\\bar{L}_{10}$. Suitable (pinched) integration kernels are introduced in the sum rules in order to suppress potential quark-hadron duality violations. We find no compelling indications of duality violations in the kinematic region above $s \\simeq 2.2$ GeV$^2$ after using pinched integration kernels.
Events with Isolated Leptons and Missing Transverse Momentum in ep Collisions at HERA
G. Brandt
2007-01-28T23:59:59.000Z
The analysis of events with isolated leptons and missing transverse momentum in the H1 experiment is discussed for the electron, muon and tau channels. In the Standard Model (SM) framework, production of real W-bosons gives rise to such topologies. Contributions to the background are dominated by QCD processes. An excess of observed signal over background presents a chance of the discovery of new physics. The results using the HERA 1994-2006 data set corresponding to 341 pb^-1 are presented. While the e- p sample shows good agreement between data and SM expectation, in e+ p collisions an excess over the SM expectation with 3.4 sigma significance is observed at high hadronic transverse momentum.
Examining the geometrical model with inverted mass hierarchy for neutrinos
Honda, Mizue; Tanimoto, Morimitsu [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Department of Physics, Niigata University, Niigata 950-2181 (Japan)
2007-05-01T23:59:59.000Z
The comprehensive analyses are presented in the model with the inverted mass hierarchy for neutrinos, which follows from a geometrical structure of a (1+5) dimensional space-time where two extra dimensions are compactified on the T{sup 2}/Z{sub 3} orbifold. The model gives two large lepton flavor mixings due to the S{sub 3} structure in the (1+5) dimensional space-time. It also predicts the lightest neutrino mass as m{sub 3}=(1-50)x10{sup -5} eV and the effective neutrino mass responsible for neutrinoless double beta decays as
Nuclear Masses in Astrophysics
Christine Weber; Klaus Blaum; Hendrik Schatz
2008-12-09T23:59:59.000Z
Among all nuclear ground-state properties, atomic masses are highly specific for each particular combination of N and Z and the data obtained apply to a variety of physics topics. One of the most crucial questions to be addressed in mass spectrometry of unstable radionuclides is the one of understanding the processes of element formation in the Universe. To this end, accurate atomic mass values of a large number of exotic nuclei participating in nucleosynthesis are among the key input data in large-scale reaction network calculations. In this paper, a review on the latest achievements in mass spectrometry for nuclear astrophysics is given.
B. Jegerlehner
1997-08-29T23:59:59.000Z
We present a general method to construct multiple mass solvers from standard algorithms. As an example, the BiCGstab-M algorithm is derived.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
MS) with high mass resolution (m&61636;m100,000). Solvent mixtures of acetonitrilewater and acetonitriletoluene were used to extract and ionize polar and non-polar...