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Sample records for leptons leptons leptons

  1. Summary of Lepton Photon 2011

    SciTech Connect (OSTI)

    Peskin, Michael E.; /SLAC

    2012-03-14

    In this lecture, I summarize developments presented at the Lepton Photon 2011 conference and give my perspective on the current situation in high-energy physics. I am grateful to the organizers of Lepton Photon 2011 for providing us a very pleasant and simulating week in Mumbai. This year's Lepton Photon conference has covered the full range of subjects that fall within the scope of high-energy physics, including connections to cosmology, nuclear physics, and atomic physics. The experiments that were discussed detect particles ranging in energy from radio frequencies to EeV.

  2. Weak scale radiative lepton mass

    SciTech Connect (OSTI)

    Wong, G.; Hou, W. (Department of Physics, National Taiwan University, Taipei, Taiwan 10764 (Taiwan, Province of China))

    1994-09-01

    We construct a [ital Z][sub 8] model for leptons where all Yukawa couplings are of order unity, but known lepton masses are generated radiatively, [ital order] [ital by] [ital order]. The seed is provided by fourth generation leptons [ital E] and [ital N], and two additional Higgs doublets are introduced to give nearest-neighbor Yukawa couplings. Loop masses are generated when [ital Z][sub 8] is [ital softly] broken down to [ital Z][sub 2], while [ital m][sub [ital e

  3. Search for neutrinoless decays of the ? lepton

    E-Print Network [OSTI]

    Baringer, Philip S.

    1990-02-01

    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...

  4. Testing minimal lepton flavor violation with extra vector-like leptons at the LHC

    E-Print Network [OSTI]

    Eilam Gross; Daniel Grossman; Yosef Nir; Ofer Vitells

    2010-01-17

    Models of minimal lepton flavor violation where the seesaw scale is higher than the relevant flavor scale predict that all lepton flavor violation is proportional to the charged lepton Yukawa matrix. If extra vector-like leptons are within the reach of the LHC, it will be possible to test the resulting predictions in ATLAS/CMS.

  5. Lepton asymmetry and the cosmic QCD transition

    E-Print Network [OSTI]

    Dominik J Schwarz; Maik Stuke

    2010-09-29

    We study the influence of lepton asymmetry on the evolution of the early Universe. The lepton asymmetry $l$ is poorly constrained by observations and might be orders of magnitude larger than the baryon asymmetry $b$, $|l|/b \\leq 2\\times 10^8$. We find that lepton asymmetries that are large compared to the tiny baryon asymmetry, can influence the dynamics of the QCD phase transition significantly. The cosmic trajectory in the $\\mu_B-T$ phase diagram of strongly interacting matter becomes a function of lepton (flavour) asymmetry. Large lepton asymmetry could lead to a cosmic QCD phase transition of first order.

  6. Lepton-flavored dark matter

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kile, Jennifer; Kobach, Andrew; Soni, Amarjit

    2015-05-01

    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 GeV–1 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(10–100 TeV), whereas the 3.6? deviation of the muon g – 2 from the standard model can be explained by a new physics scale more »TeV). 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 GeV–1 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)« less

  7. Lepton-flavored dark matter

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kile, Jennifer; Kobach, Andrew; Soni, Amarjit

    2015-05-01

    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 GeV–1 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(10–100 TeV), whereas the 3.6? deviation of the muon g – 2 from the standard model can be explained by a new physics scale 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 GeV–1 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)

  8. Lepton-mediated electroweak baryogenesis

    SciTech Connect (OSTI)

    Chung, Daniel J. H.; Garbrecht, Bjorn [University of Wisconsin, Madison, Wisconsin, 53706-1390 (United States); Ramsey-Musolf, Michael J. [University of Wisconsin, Madison, Wisconsin, 53706-1390 (United States); California Institute of Technology, Pasadena, California 91125 (United States); Tulin, Sean [California Institute of Technology, Pasadena, California 91125 (United States)

    2010-03-15

    We investigate the impact of the tau and bottom Yukawa couplings on the transport dynamics for electroweak baryogenesis in supersymmetric extensions of the standard model. Although it has generally been assumed in the literature that all Yukawa interactions except those involving the top quark are negligible, we find that the tau and bottom Yukawa interaction rates are too fast to be neglected. We identify an illustrative 'lepton-mediated electroweak baryogenesis' scenario in which the baryon asymmetry is induced mainly through the presence of a left-handed leptonic charge. We derive analytic formulas for the computation of the baryon asymmetry that, in light of these effects, are qualitatively different from those in the established literature. In this scenario, for fixed CP-violating phases, the baryon asymmetry has opposite sign compared to that calculated using established formulas.

  9. Natural fourth generation of leptons

    E-Print Network [OSTI]

    Oleg Antipin; Matti Heikinheimo; Kimmo Tuominen

    2009-09-14

    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.

  10. Lepton Photon Symposium 2005: Summary and Outlook

    E-Print Network [OSTI]

    Francis Halzen

    2005-11-02

    Lepton Photon 2005 told the saga of the Standard Model which is still exhilarating because it leaves all questions of consequence unanswered.

  11. Symmetrical parametrizations of the lepton mixing matrix

    SciTech Connect (OSTI)

    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)

    2011-10-01

    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.

  12. Universality of Quark-Lepton Mass Matrix

    E-Print Network [OSTI]

    Takeshi Fukuyama; Hiroyuki Nishiura

    2013-01-22

    The recently observed lepton mixing angle $\\theta_{13}$ of the MNS mixing matrix is well incorporated in a universal mixing hypothesis between quark and lepton sectors. This hypothesis asserts that, in the charged lepton diagonal base, all other mass matrices for up- and down-type quarks and light neutrinos are diagonalized by the same unitary matrix except for the phase elements. It is expressed as $V_{CKM}= U_{MNS}(\\delta^\\prime)^\\dagger P U_{MNS}(\\delta)$ for quark mixing matrix $V_{CKM}$ and lepton mixing matrix $U_{MNS}(\\delta)$ in the phenomenological level. Here $P$ is a diagonal phase mass matrix. $\\delta^\\prime$ is a slightly different phase parameter from the Dirac CP violating phase $\\delta=1.1\\pi$ (best fit) in the MNS lepton mixing matrix.

  13. Lepton Flavor Mixing and CP Symmetry

    E-Print Network [OSTI]

    Peng Chen; Cai-Chang Li; Gui-Jun Ding

    2014-12-29

    The strategy of constraining the lepton flavor mixing from remnant CP symmetry is investigated in a rather general way. The neutrino mass matrix generally admits four remnant CP transformations which can be derived from the measured lepton mixing matrix in the charged lepton diagonal basis. Conversely, the lepton mixing matrix can be reconstructed from the postulated remnant CP transformations. All mixing angles and CP violating phases can be completely determined by the full set of remnant CP transformations or three of them. When one or two remnant CP transformations are preserved, the resulting lepton mixing matrix would depend on three real parameters or one real parameter respectively in addition to the parameters characterizing the remnant CP, and the concrete form of the mixing matrix is presented. The phenomenological predictions for the mixing parameters are discussed. The conditions leading to vanishing or maximal Dirac CP violation are studied.

  14. New textures for the lepton mass matrices

    E-Print Network [OSTI]

    P. M. Ferreira; L. Lavoura

    2014-12-02

    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.

  15. New textures for the lepton mass matrices

    E-Print Network [OSTI]

    Ferreira, P M

    2014-01-01

    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.

  16. Probing lepton asymmetry with 21 cm fluctuations

    SciTech Connect (OSTI)

    Kohri, Kazunori; Oyama, Yoshihiko [The Graduate University for Advanced Studies (Sokendai), 1-1 Oho, Tsukuba 305-0801 (Japan); Sekiguchi, Toyokazu [Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602 (Japan); Takahashi, Tomo, E-mail: kohri@post.kek.jp, E-mail: oyamayo@post.kek.jp, E-mail: toyokazu.sekiguchi@helsinki.fi, E-mail: tomot@cc.saga-u.ac.jp [Department of Physics, Saga University, Saga 840-8502 (Japan)

    2014-09-01

    We investigate the issue of how accurately we can constrain the lepton number asymmetry ?{sub ?}=?{sub ?}/T{sub ?} in the Universe by using future observations of 21 cm line fluctuations and cosmic microwave background (CMB). We find that combinations of the 21 cm line and the CMB observations can constrain the lepton asymmetry better than big-bang nucleosynthesis (BBN). Additionally, we also discuss constraints on ?{sub ?} in the presence of some extra radiation, and show that the 21 cm line observations can substantially improve the constraints obtained by CMB alone, and allow us to distinguish the effects of the lepton asymmetry from the ones of extra radiation.

  17. Lepton Flavor Violating Decays - Review & Outlook

    E-Print Network [OSTI]

    Toshinori Mori

    2006-05-31

    Here I review the status and prospects of experimental investigations into lepton flavor violation (LFV) in charged leptons. Rare LFV processes are naturally expected to occur through loops of TeV scale particles predicted by supersymmetric theories or other models beyond the Standard Model. In contrast to physics of quark flavors that is dominated by the Cabibbo-Kobayashi-Maskawa matrix, LFV in charged leptons is a definitive signal of new physics. Currently active researches are rare tau decay searches at the B factories. The MEG experiment will soon start a sensitive search for the LFV muon decay, mu to e gamma. Prospects for searches at the LHC, a possibility of a fixed target LFV experiment with high energy muons, and a sensitivity of leptonic kaon decays to LFV are also briefly discussed.

  18. Fourth Lepton Family is Natural in Technicolor

    E-Print Network [OSTI]

    Mads T. Frandsen; Isabella Masina; Francesco Sannino

    2009-05-10

    Imagine to discover a new fourth family of leptons at the Large Hadron Collider (LHC) but no signs of an associated fourth family of quarks. What would that imply? An intriguing possibility is that the new fermions needed to compensate for the new leptons gauge anomalies simultaneously address the big hierarchy problem of the Standard Model. A natural way to accomplish such a scenario is to have the Higgs itself be composite of these new fermions. This is the setup we are going to investigate in this paper using as a template Minimal Walking Technicolor. We analyze a general heavy neutrino mass structure with and without mixing with the Standard Model families. We also analyze the LHC potential to observe the fourth lepton family in tandem with the new composite Higgs dynamics. We finally introduce a model uniting the fourth lepton family and the technifermion sector at higher energies.

  19. Exotic Leptons. Higgs, Flavor and Collider Phenomenology

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Altmannshofer, Wolfgang; Bauer, Martin; Carena, Marcela

    2014-01-15

    We study extensions of the standard model by one generation of vector-like leptons with non-standard hypercharges, which allow for a sizable modification of the h ? ?? decay rate for new lepton masses in the 300 GeV-1 TeV range. We also analyze vacuum stability implications for different hypercharges. Effects in h ? Z? are typically much smaller than in h ? ??, but distinct among the considered hypercharge assignments. Non-standard hypercharges constrain or entirely forbid possible mixing operators with standard model leptons. As a consequence, the leading contributions to the experimentally strongly constrained electric dipole moments of standard model fermionsmore »are only generated at the two loop level by the new CP violating sources of the considered setups. Furthermore, we derive the bounds from dipole moments, electro-weak precision observables and lepton flavor violating processes, and discuss their implications. Finally, we examine the production and decay channels of the vector-like leptons at the LHC, and find that signatures with multiple light leptons or taus are already probing interesting regions of parameter space.« less

  20. The Lepton Sector of a Fourth Generation

    E-Print Network [OSTI]

    Gustavo Burdman; Leandro Da Rold; Ricardo D. Matheus

    2010-05-10

    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.

  1. Lepton flavor violation in Higgs boson decays under the rare...

    Office of Scientific and Technical Information (OSTI)

    Lepton flavor violation in Higgs boson decays under the rare tau decay results Citation Details In-Document Search Title: Lepton flavor violation in Higgs boson decays under the...

  2. Probing lepton number violation on three frontiers

    SciTech Connect (OSTI)

    Deppisch, Frank F. [Department of Physics and Astronomy, University College London (United Kingdom)

    2013-12-30

    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.

  3. Limits on tau lepton flavor violating decays in three charged leptons

    SciTech Connect (OSTI)

    Cervelli, Alberto

    2010-04-29

    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.

  4. Search for lepton-flavor and lepton-number-violating ? ? ?hh' decay modes

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Miyazaki, Y.; Hayasaka, K.; Adachi, I.; Aihara, H.; Asner, D.M.; Aulchenko, V.; Aushev, T.; Bakich, A.M.; Bay, A.; Bhardwaj, V.; et al

    2013-02-01

    We search for lepton-flavor and lepton-number-violating ? decays into a lepton (? = electron or muon) and two charged mesons (h,h'=?± or K±) using 854 fb?¹of data collected with the Belle detector at the KEKB asymmetric-energy e?e? collider. We obtain 90% confidence level upper limits on the ???hh' branching fractions in the range (2.0–8.4)×10??. These results improve upon our previously published upper limits by factors of about 1.8 on average.

  5. Measurement of the Inclusive Leptonic Asymmetry in Top-Quark Pairs that Decay to Two Charged Leptons at CDF

    E-Print Network [OSTI]

    Gomez-Ceballos, Guillelmo

    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 ...

  6. Tau Lepton Production in ep Collisions at HERA

    E-Print Network [OSTI]

    H1 Collaboration

    2006-04-11

    The production of tau leptons in ep collisions is investigated using data recorded by the H1 detector at HERA in the period 1994-2000. Tau leptons are identified by detecting their decay products, using leptonic and hadronic decay modes. The cross section for the production of tau lepton pairs is measured for the first time at HERA. Furthermore, a search for events with an energetic isolated tau lepton and with large missing transverse momentum is performed. The results are found to be in agreement with the Standard Model predictions.

  7. Test of lepton universality and search for lepton flavor violation in Upsilon(1S,2S,3S) decays at CLEO

    E-Print Network [OSTI]

    Istvan Danko; for the CLEO Collaboration

    2006-01-18

    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.

  8. Leptonic Decays of Charged Pseudoscalar Mesons - 2015

    E-Print Network [OSTI]

    Jonathan L. Rosner; Sheldon Stone; Ruth S. Van de Water

    2015-09-07

    We review the physics of purely leptonic decays of $\\pi^\\pm$, $K^\\pm$, $D^{\\pm}$, $D_s^\\pm$, and $B^\\pm$ pseudoscalar mesons. The measured decay rates are related to the product of the relevant weak-interaction-based CKM matrix element of the constituent quarks and a strong interaction parameter related to the overlap of the quark and antiquark wave-functions in the meson, called the decay constant $f_P$. The leptonic decay constants for $\\pi^\\pm$, $K^\\pm$, $D^{\\pm}$, $D_s^\\pm$, and $B^\\pm$ mesons can be obtained with controlled theoretical uncertainties and high precision from {\\it ab initio} lattice-QCD simulations. The combination of experimental leptonic decay-rate measurements and theoretical decay-constant calculations enables the determination of several elements of the CKM matrix within the standard model. These determinations are competitive with those obtained from semileptonic decays, and also complementary because they are sensitive to different quark flavor-changing currents. They can also be used to test the unitarity of the first and second rows of the CKM matrix. Conversely, taking the CKM elements predicted by unitarity, one can infer "experimental" values for $f_P$ that can be compared with theory. These provide tests of lattice-QCD methods, provided new-physics contributions to leptonic decays are negligible at the current level of precision. This review is the basis of the article in the Particle Data Group's 2016 edition, updating the versions in Refs. [1-3].

  9. Lepton sector of a fourth generation

    SciTech Connect (OSTI)

    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)

    2010-09-01

    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.

  10. Leptonic Decays of Charged Pseudoscalar Mesons - 2015

    E-Print Network [OSTI]

    Rosner, Jonathan L; Van de Water, Ruth S

    2015-01-01

    We review the physics of purely leptonic decays of $\\pi^\\pm$, $K^\\pm$, $D^{\\pm}$, $D_s^\\pm$, and $B^\\pm$ pseudoscalar mesons. The measured decay rates are related to the product of the relevant weak-interaction-based CKM matrix element of the constituent quarks and a strong interaction parameter related to the overlap of the quark and antiquark wave-functions in the meson, called the decay constant $f_P$. The leptonic decay constants for $\\pi^\\pm$, $K^\\pm$, $D^{\\pm}$, $D_s^\\pm$, and $B^\\pm$ mesons can be obtained with controlled theoretical uncertainties and high precision from {\\it ab initio} lattice-QCD simulations. The combination of experimental leptonic decay-rate measurements and theoretical decay-constant calculations enables the determination of several elements of the CKM matrix within the standard model. These determinations are competitive with those obtained from semileptonic decays, and also complementary because they are sensitive to different quark flavor-changing currents. They can also be use...

  11. Leptonic mixing, family symmetries, and neutrino phenomenology

    SciTech Connect (OSTI)

    Medeiros Varzielas, I. de [Departamento de Fisica and Centro de Fisica Teorica de Particulas, Instituto Superior Tecnico, Avenida Rovisco Pais, 1049-001 Lisboa (Portugal); Fakultaet fuer Physik, Technische Universitaet Dortmund D-44221 Dortmund (Germany); Gonzalez Felipe, R. [Departamento de Fisica and Centro de Fisica Teorica de Particulas, Instituto Superior Tecnico, Avenida Rovisco Pais, 1049-001 Lisboa (Portugal); Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emidio Navarro, 1959-007 Lisboa (Portugal); Serodio, H. [Departamento de Fisica and Centro de Fisica Teorica de Particulas, Instituto Superior Tecnico, Avenida Rovisco Pais, 1049-001 Lisboa (Portugal)

    2011-02-01

    Tribimaximal leptonic mixing is a mass-independent mixing scheme consistent with the present solar and atmospheric neutrino data. By conveniently decomposing the effective neutrino mass matrix associated to it, we derive generic predictions in terms of the parameters governing the neutrino masses. We extend this phenomenological analysis to other mass-independent mixing schemes which are related to the tribimaximal form by a unitary transformation. We classify models that produce tribimaximal leptonic mixing through the group structure of their family symmetries in order to point out that there is often a direct connection between the group structure and the phenomenological analysis. The type of seesaw mechanism responsible for neutrino masses plays a role here, as it restricts the choices of family representations and affects the viability of leptogenesis. We also present a recipe to generalize a given tribimaximal model to an associated model with a different mass-independent mixing scheme, which preserves the connection between the group structure and phenomenology as in the original model. This procedure is explicitly illustrated by constructing toy models with the transpose tribimaximal, bimaximal, golden ratio, and hexagonal leptonic mixing patterns.

  12. Leptophobic boson signals with leptons, jets and missing energy

    E-Print Network [OSTI]

    Dobrescu, Bogdan A

    2015-01-01

    Color-singlet gauge bosons with renormalizable couplings to quarks but not to leptons must interact with additional fermions ("anomalons") required to cancel the gauge anomalies. Analyzing the decays of such leptophobic bosons into anomalons, I show that they produce final states involving leptons at the LHC. Resonant production of a flavor-universal leptophobic $Z'$ boson leads to cascade decays via anomalons, whose signatures include a leptonically decaying $Z$, missing energy and several jets. A $Z'$ boson that couples to the right-handed quarks of the first and second generations undergoes cascade decays that violate lepton universality and include signals with two leptons and jets, or with a Higgs boson, a lepton, a $W$ and missing energy.

  13. Exploring new physics through contact interactions in lepton...

    Office of Scientific and Technical Information (OSTI)

    Conference: Exploring new physics through contact interactions in lepton pair production at a linear collider Citation Details In-Document Search Title: Exploring new physics...

  14. Lepton universality violation and lepton flavor conservation in $B$-meson decays

    E-Print Network [OSTI]

    Rodrigo Alonso; Benjamín Grinstein; Jorge Martin Camalich

    2015-05-19

    Anomalies in (semi)leptonic $B$-meson decays present interesting patterns that might be revealing the shape of the new physics to come. In order to understand the experimental data, we explore symmetry arguments that lead to the hypothesis of minimal flavor violation. In particular, under the assumption of negligible neutrino mass effects in charged lepton processes, the presence of lepton universality violation without lepton flavor violation naturally arises. This can account for a deficit of $B^+\\to K^+\\mu\\mu$ over $B^+\\to K^+ee$ decays with new physics coupled predominantly to muons and a new physics scale of a few TeV. A prediction of this scenario is the modification of processes involving the third generation. In particular, accounting for the above ratio implies a large enhancement, by a factor $\\sim10^3$ with respect to the standard model, of all the $b\\to s\\tau\\tau$ decay rates. Although these are still below current experimental limits, they should be easily at reach in future experiments at $B$-factories. Another important consequence is the prediction of sizable effects in charge-current $B$ tauonic decays which could also explain the enhancements that have been observed in the $B\\to D^{(*)}\\tau\\bar \

  15. Tera-Leptons Shadows over Sinister Universe

    E-Print Network [OSTI]

    D. Fargion; M. Khlopov

    2005-07-07

    The role of Sinister Heavy Fermions in recent Glashow's SU(3)*SU(2)*SU(2)'*U(1) model is to offer in a unique frame relic Helium-like products (an ingenious candidate to the dark matter puzzle), a solution to the See-Saw mechanism for light neutrino masses as well as to strong CP violation problem in QCD. The Sinister model requires a three additional families of leptons and quarks, but only the lightest of them Heavy U-quark and E-"electron" are stable. Final neutral Helium-like UUUEE state is an ideal evanescent dark-matter candidate. However it is reached by multi-body interactions along a tail of more manifest secondary frozen blocks. They should be now here polluting the surrounding matter. Moreover, in opposition to effective pair quark annihilations, there is no such an early or late tera-lepton pairs suppressions, because:a) electromagnetic interactions are "weaker" than nuclear ones and b) helium ion 4He++ is able to attract and capture, E-, fixing it into a hybrid tera helium "ion" trap. This leads to a pile up of relic (4HeE)+ traces, a lethal compound for any Sinister Universe. This capture leaves no Tera-Lepton frozen in Ep relic (otherwise an ideal catalyzer to achieve effective late E+E- annihilations possibly saving the model). The (4HeE)+ Coulomb screening is also avoiding the synthesis of the desired UUUEE hidden dark matter gas. The e(4HeE)+ behave chemically like an anomalous hydrogen isotope.Also tera-positronium (eE+) relics are over-abundant and they behave like an anomalous hydrogen atom: these gases do not fit by many orders of magnitude known severe bounds on hydrogen anomalous isotope, making grave shadows over a Sinister Universe. However a surprising and resolver role for Tera-Pions in UHECR astrophysics has been revealed.

  16. Tensor mesons produced in tau lepton decays

    SciTech Connect (OSTI)

    Lopez Castro, G.; Munoz, J. H.

    2011-05-01

    Light tensor mesons (T=a{sub 2}, f{sub 2} and K{sub 2}*) can be produced in decays of {tau} leptons. In this paper we compute the branching ratios of {tau}{yields}T{pi}{nu} decays by assuming the dominance of intermediate virtual states to model the form factors involved in the relevant hadronic matrix elements. The exclusive f{sub 2}(1270){pi}{sup -} decay mode turns out to have the largest branching ratio, of O(10{sup -4}). Our results indicate that the contribution of tensor meson intermediate states to the three-pseudoscalar channels of {tau} decays are rather small.

  17. INCIDENT CONTAMINATION LEPTON DOSES MEASURED USING RADIOCHROMIC FILM IN

    E-Print Network [OSTI]

    Yu, Peter K.N.

    INCIDENT CONTAMINATION LEPTON DOSES MEASURED USING RADIOCHROMIC FILM IN RADIOTHERAPY MARTIN J) AbstractÐMeasurement of lepton contamination is achieved across a radiotherapy photon beam and peripheral in air to measure incident contamination without the eects of phantom scatter. Surface dose was measured

  18. First search for CP violation in tau lepton decay

    E-Print Network [OSTI]

    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.

    1998-11-01

    We have performed the first search for CP violation in tau lepton decay. CP violation in lepton decay does not occur in the minimal standard model but can occur in extensions such as the multi-Higgs doublet model. It appears as a characteristic...

  19. Radiative Transmission of Lepton Flavor Hierarchies

    E-Print Network [OSTI]

    Adisorn Adulpravitchai; Manfred Lindner; Alexander Merle; Rabindra N. Mohapatra

    2009-08-04

    We discuss a one loop model for neutrino masses which leads to a seesaw-like formula with the difference that the charged lepton masses replace the unknown Dirac mass matrix present in the usual seesaw case. This is a considerable reduction of parameters in the neutrino sector and predicts a strong hierarchical pattern in the right handed neutrino mass matrix that is easily derived from a $U(1)_H$ family symmetry. The model is based on the left-right gauge group with an additional $Z_4$ discrete symmetry which gives vanishing neutrino Dirac masses and finite Majorana masses arising at the one loop level. Furthermore, it is one of the few models that naturally allow for large (but not necessarily maximal) mixing angles in the lepton sector. A generalization of the model to the quark sector requires three iso-spin singlet vector-like down type quarks, as in $E_6$. The model predicts an inert doublet type scalar dark matter.

  20. Detecting Exotic Heavy Leptons at the Large Hadron Collider

    E-Print Network [OSTI]

    B. C. Allanach; C. M. Harris; M. A. Parker; P. Richardson; B. R. Webber

    2001-08-10

    New almost-degenerate charged and neutral heavy leptons are a feature of a number of theories of physics beyond the Standard Model. The prospects for detecting these at the Large Hadron Collider using a time-of-flight technique are considered, along with any cosmological or experimental constraints on their masses. Based on a discovery criterion of 10 detected exotic leptons we conclude that, with an integrated luminosity of 100 fb-1, it should be possible to detect such leptons provided their masses are less than 950 GeV. It should also be possible to use the angular distribution of the produced particles to distinguish these exotic leptons from supersymmetric scalar leptons, at a better than 90% confidence level, for masses up to 580 GeV.

  1. New Paradigm for Baryon and Lepton Number Violation

    E-Print Network [OSTI]

    Pavel Fileviez Perez

    2015-08-17

    The possible discovery of proton decay, neutron-antineutron oscillation, neutrinoless beta decay in low energy experiments, and exotic signals related to the violation of the baryon and lepton numbers at collider experiments will change our understanding of the conservation of fundamental symmetries in nature. In this review we discuss the rare processes due to the existence of baryon and lepton number violating interactions. The simplest grand unified theories and the neutrino mass generation mechanisms are discussed. The theories where the baryon and lepton numbers are defined as local gauge symmetries spontaneously broken at the low scale are discussed in detail. The simplest supersymmetric gauge theory which predicts the existence of lepton number violating processes at the low scale is investigated. The main goal of this review is to discuss the main implications of baryon and lepton number violation in physics beyond the Standard Model.

  2. CP nonconservation in the leptonic sector

    E-Print Network [OSTI]

    Petre Dita

    2006-09-22

    In this paper we use an exact method to impose unitarity on moduli of the neutrino PMNS matrix recently determined, and show how one could obtain information on CP non-conservation from a limited experimental information. One suggests a novel type of global fit by expressing all the theoretical quantities in terms of convention independent parameters: the Jarlskog invariant $J$ and the moduli $|U_{\\alpha i}|$, able to resolve the positivity problem of $|U_{e 3}|$. In this way the fit will directly provide a value for $J$, and if it is different from zero it will prove the existence of CP violation in the available experimental data. If the best fit result, $|U_{e3}|^2<0$, from M. Maltoni {\\em et al}, New J.Phys. {\\bf 6} (2004) 122 is confirmed, it will imply a new physics in the leptonic sector.

  3. CP nonconservation in the leptonic sector

    E-Print Network [OSTI]

    Petre Dita

    2011-01-21

    In this paper we use an exact method to impose unitarity on moduli of neutrino PMNS matrix recently determined, and show how one could obtain information on CP nonconservation from a limited experimental information. One suggests a novel type of global fit by expressing all theoretical quantities in terms of convention independent parameters: the Jarlskog invariant $J$ and the moduli $|U_{\\alpha i}|$, able to resolve the positivity problem of $|U_{e 3}|$. In this way the fit will directly provide a value for $J$, and if it is different from zero it will prove the existence of CP violation in the available experimental data. If the best fit result, $|U_{e3}|^2<0$, from M. Maltoni {\\em et al}, [New J.Phys. {\\bf 6} (2004) 122] is confirmed, it will imply a new physics in the leptonic sector.

  4. Light Leptonic New Physics at the Precision Frontier

    E-Print Network [OSTI]

    Matthias Le Dall

    2015-09-25

    Precision probes of new physics are often interpreted through their indirect sensitivity to short-distance scales. In this proceedings contribution, we focus on the question of which precision observables, at current sensitivity levels, allow for an interpretation via either short-distance new physics or consistent models of long-distance new physics, weakly coupled to the Standard Model. The electroweak scale is chosen to set the dividing line between these scenarios. In particular, we find that inverse see-saw models of neutrino mass allow for light new physics interpretations of most precision leptonic observables, such as lepton universality, lepton flavor violation, but not for the electron EDM.

  5. Lepton Number Violation and the Baryon Asymmetry of the Universe

    E-Print Network [OSTI]

    Harz, Julia; Päs, Heinrich

    2015-01-01

    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.

  6. Measurements of heavy quark production via single leptons at PHENIX

    E-Print Network [OSTI]

    Donald Hornback; for the PHENIX Collaboration

    2008-04-30

    The measurement of single leptons from the semi-leptonic decay of heavy-flavor hadrons has long been a means for studying heavy-quark production. PHENIX has measured single muons in pp collisions at forward rapidity and single electrons in both pp and AuAu collisions at mid-rapidity at sqrt(s_NN)=200 GeV. The most recent PHENIX single lepton results are presented in the context of state-of-the-art pQCD calculations. An updated azimuthal anisotropy, v2(pT), measurement for heavy-flavor single electrons in AuAu collisions is also presented.

  7. Survey of lepton number violation via effective operators

    SciTech Connect (OSTI)

    Gouvea, Andre de; Jenkins, James [Northwestern University, Department of Physics and Astronomy, 2145 Sheridan Road, Evanston, Illinois 60208 (United States)

    2008-01-01

    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.

  8. Leptonic B Decays at BaBar

    SciTech Connect (OSTI)

    Monorchio, Diego; /INFN, Naples /Naples U.

    2011-09-13

    The authors will present the most recent results on leptonic B decays B{sup {+-}(0)} {yields} K*{sup {+-}(0)} {nu}{bar {nu}} and B{sup {+-}} {yields} {mu}{sup {+-}}{nu}, based on the data collected by the BaBar detector at PEP-II, an asymmetric e{sup +}e{sup -} collider at the center of mass energy of the {Upsilon}(4S) resonance. Rare B decays have always been a standard probe for New Physics (NP) searches. The very low Standard Model (SM) rate of these decays often make them unaccessible with the present experimental datasets, unless NP effects enhance the rate up to the current experimental sensitivity. Moreover, as NP effects can modify the decay kinematic, particular attention must be payed in order to perform a model independent analysis. A B-Factory provides an unique environment where to investigate these processes. The high number of B{bar B} pairs produced by a B-Factory often allows to approach the needed experimental sensitivity. Moreover, the clean environment and the closed kinematic of the initial state enable to obtaining a very pure sample where to look for these decays.

  9. Leptonic B Decays at BaBar

    SciTech Connect (OSTI)

    Baracchini, Elisabetta; /Rome U. /INFN, Rome

    2011-11-10

    We will present the most recent results on leptonic B decays B{sup {+-}(0)} {yields} K*{sup {+-}(0)}{nu}{bar {nu}} and B{sup {+-}} {yields} {mu}{sup {+-}}{nu}, based on the data collected by the BaBar detector at PEP-II, an asymmetric e{sup +}e{sup -} collider at the center of mass energy of the {Upsilon}(4S) resonance. Rare B decays have always been a standard probe for New Physics (NP) searches. The very low Standard Model (SM) rate of these decays often make them unaccessible with the present experimental datasets, unless NP effects enhance the rate up to the current experimental sensitivity. Moreover, as NP effects can modify the decay kinematic, particular attention must be paid in order to perform a model independent analysis. A B-Factory provides an unique environment to investigate these processes. The high number of B{bar B} pairs produced by a B-Factory often allows to approach the needed experimental sensitivity. Moreover, the clean environment and the closed kinematic of the initial state enable to obtaining a very pure sample where to look for these decays.

  10. Search for doubly charged Higgs bosons with lepton-flavour-violating decays involving tau leptons

    SciTech Connect (OSTI)

    Aaltonen, T.

    2007-12-01

    The authors search for pair production of doubly charged Higgs particles (H{sup {+-}{+-}}) followed by decays into electron-tau (e{tau}) and muon-tau ({mu}{tau}) pairs using a data set corresponding to an integrated luminosity of 350 pb{sup -1} collected from {bar p}p collisions at {radical}s = 1.96 TeV by the CDF II experiment. They search separately for cases where three or four final-state leptons are detected, and then combine the results into limits for each exclusive flavor decay mode of the H{sup {+-}{+-}}. Assuming 100% branching ratios of the H{sup {+-}{+-}} to left-handed e{tau} ({mu}{tau}) pairs, they set an H{sup {+-}{+-}} lower mass limit of 114 (112) GeV/c{sup 2} at the 95% confidence level (C.L.).

  11. A new bridge between leptonic CP violation and leptogenesis

    E-Print Network [OSTI]

    G. C. Branco; R. Gonzalez Felipe; F. R. Joaquim

    2006-09-28

    Flavor effects due to lepton interactions in the early Universe may have played an important role in the generation of the cosmological baryon asymmetry through leptogenesis. If the only source of high-energy CP violation comes from the left-handed leptonic sector, then it is possible to establish a bridge between flavored leptogenesis and low-energy leptonic CP violation. We explore this connection taking into account our present knowledge about low-energy neutrino parameters and the matter-antimatter asymmetry observed in the Universe. In this framework, we find that leptogenesis favors a hierarchical light neutrino mass spectrum, while for quasi-degenerate and inverted hierarchical neutrino masses there is a very narrow allowed window. The absolute neutrino mass scale turns out to be m < 0.1 eV.

  12. Electric Dipole Moments of Charged Leptons with Sterile Fermions

    E-Print Network [OSTI]

    Abada, Asmaa

    2015-01-01

    We address the impact of sterile fermions on charged lepton electric dipole moments. Any experimental signal of these observables calls for scenarios of physics beyond the Standard Model providing new sources of CP violation. In this work, we consider a minimal extension of the Standard Model via the addition of sterile fermions which mix with active neutrinos and we derive the corresponding analytical expressions for the electric dipole moments of charged leptons at two-loop order. Our study reveals that, in order to have a non-vanishing contribution in this framework, the minimal extension necessitates the addition of at least 2 sterile fermion states to the Standard Model field content. Our conclusion is that sterile neutrinos can give significant contributions to the charged lepton electric dipole moments, some of them lying within present and future experimental sensitivity if the masses of the non-degenerate sterile states are both above the electroweak scale. The Majorana nature of neutrinos is also im...

  13. Nonzero $?_{13}$ in $SO(3) \\rightarrow A_4$ lepton models

    E-Print Network [OSTI]

    Yuval Grossman; Wee Hao Ng

    2015-03-25

    The simplest neutrino mass models based on $A_4$ symmetry predict $\\theta_{13} = 0$ at tree level, a value that contradicts recent data. We study models that arise from the spontaneous breaking of an $SO(3)$ symmetry to its $A_4$ subgroup, and find that such models can naturally accommodate a nonzero $\\theta_{13}$ at tree level. Standard Model charged leptons mix with additional heavy ones to generate a $\\theta_{13}$ that scales with the ratio of the $A_4$-breaking to $SO(3)$-breaking scales. A suitable choice of energy scales hence allows one to reproduce the correct lepton mixing angles. We also consider an alternative approach where we modify the alignment of flavons associated with the charged lepton masses, and find that the effects on $\\theta_{13}$ are enhanced by a factor that scales as $m_\\tau/m_\\mu$.

  14. Nuclear PDF for neutrino and charged lepton data

    E-Print Network [OSTI]

    K. Kovarik

    2010-12-13

    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.

  15. Leptonic Decays of the Charged B Meson

    SciTech Connect (OSTI)

    Corwin, Luke A.; /Ohio State U.; ,

    2010-06-11

    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.).

  16. Lepton and Quark Mixing Patterns from Finite Flavor Symmetries

    E-Print Network [OSTI]

    Chang-Yuan Yao; Gui-Jun Ding

    2015-05-14

    We perform a systematical and analytical study of lepton mixing which can be derived from the subgroups of $SU(3)$ under the assumption that neutrinos are Dirac particles. We find that type D groups can predict lepton mixing patterns compatible with the experimental data at $3\\sigma$ level. The lepton mixing matrix turns out to be of the trimaximal form, and the Dirac CP violating phase is trivial. Moreover, we extend the flavor symmetry to the quark sector. The Cabibbo mixing between the first two generations of quarks can be generated by type D groups. Since all the finite subgroups of $U(3)$ which are not the subgroups of $SU(3)$ have not been classified, an exhaustive scan over all finite discrete groups up to order 2000 is performed with the help of the computer algebra system \\texttt{GAP}. We find that only 90 (10) groups for Dirac (Majorana) neutrinos can generate the lepton mixing angles in the experimentally preferred ranges. The lepton mixing matrix is still the trimaximal pattern and the Dirac CP phase remains trivial. The smallest groups which lead to viable mixing angles are $[162, 10]$, $[162, 12]$ and $[162, 14]$. For quark flavor mixing, the correct order of magnitude of the CKM matrix elements can not be generated. Only the Cabibbo mixing is allowed even if we impose very loose constraints $0.1\\leq|\\left(V_{CKM}\\right)_{12}|\\leq0.3$ and $|\\left(V_{CKM}\\right)_{13}|\\leq|\\left(V_{CKM}\\right)_{23}|right)_{12}|$. The group $\\Delta(6\\cdot7^2)$ can predict a Cabibbo angle $\\theta_q=\\pi/14$ in good agreement with the best fit value. The groups which can give rise to both phenomenologically viable lepton mixing angles and acceptable Cabibbo angle are discussed, and the groups $\\Delta(6\\cdot9^2)$, $[648, 259]$, $[648, 260]$, $[648, 266]$ and $\\Delta(6\\cdot14^2)$ are especially promising.

  17. Search for lepton-flavour-violating decays of the Higgs boson...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Search for lepton-flavour-violating decays of the Higgs boson Citation Details In-Document Search Title: Search for lepton-flavour-violating decays of the Higgs...

  18. Search for Low Mass Exotic leptonic or bosonic structures

    E-Print Network [OSTI]

    B. Tatischeff; E. Tomasi-Gustafsson

    2007-07-09

    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.

  19. Leptons and Quarks from a Discrete Flavor Symmetry

    E-Print Network [OSTI]

    Y. H. Ahn

    2013-03-20

    We propose a new model of leptons and quarks based on the discrete flavor symmetry $T'$, the double covering of $A_4$, in which the hierarchies of charged fermion masses and the mildness of neutrino masses are responsible for Higgs scalars. After spontaneous breaking of flavor symmetry, with the constraint of renormalizability in the Lagrangian, the leptons have $m_{e}=0$ and the quarks have the Cabibbo-Kobayashi-Maskawa (CKM) mixing angles $\\theta^{q}_{12}=13^{\\circ}, \\theta^{q}_{23}=0^{\\circ}$ and $\\theta^{q}_{13}=0^{\\circ}$. Thus, certain effective dimension-5 operators are introduced, which induce $m_{e}\

  20. A Search for Neutrinoless Tau Decays to Three Leptons

    SciTech Connect (OSTI)

    Kolb, Jeffrey A.; /Oregon U. /SLAC; ,

    2008-09-24

    Using approximately 350 million {tau}{sup +}{tau}{sup -} pair events recorded with the BaBar detector at the Stanford Linear Accelerator Center between 1999 and 2006, a search has been made for neutrinoless, lepton-flavor violating tau decays to three lighter leptons. All six decay modes consistent with conservation of electric charge and energy have been considered. With signal selection efficiencies of 5-12%, we obtain 90% confidence level upper limits on the branching fraction {Beta}({tau} {yields} {ell}{ell}{ell}) in the range (4-8) x 10{sup -8}.

  1. Neutrinoless Double Beta Decay and Lepton Flavor Violation

    E-Print Network [OSTI]

    V. Cirigliano; A. Kurylov; M. J. Ramsey-Musolf; P. Vogel

    2004-06-17

    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.

  2. Relating quarks and leptons with the T7 flavour group

    E-Print Network [OSTI]

    Bonilla, Cesar; Peinado, Eduardo; Valle, Jose W F

    2014-01-01

    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.

  3. Bounds on R-parity violating supersymmetric couplings from leptonic and semileptonic meson decays

    SciTech Connect (OSTI)

    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)

    2007-06-01

    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.

  4. Leptonic Dirac CP Violation Predictions from Residual Discrete Symmetries

    E-Print Network [OSTI]

    Girardi, I; Stuart, Alexander J; Titov, A V

    2015-01-01

    Assuming that the observed pattern of 3-neutrino mixing is related to the existence of a (lepton) flavour symmetry, corresponding to a non-Abelian discrete symmetry group $G_f$, and that $G_f$ is broken to specific residual symmetries $G_e$ and $G_\

  5. Leptonic Dirac CP Violation Predictions from Residual Discrete Symmetries

    E-Print Network [OSTI]

    I. Girardi; S. T. Petcov; Alexander J. Stuart; A. V. Titov

    2015-09-08

    Assuming that the observed pattern of 3-neutrino mixing is related to the existence of a (lepton) flavour symmetry, corresponding to a non-Abelian discrete symmetry group $G_f$, and that $G_f$ is broken to specific residual symmetries $G_e$ and $G_\

  6. Hadronic decays of the tau lepton: Theoretical outlook

    E-Print Network [OSTI]

    J. Portoles

    2007-02-18

    The structure of the form factors stemmed from the hadronization of QCD currents in the energy region of the resonances can be explored through the analyses of exclusive hadronic decays of the tau lepton. I give a short review on the later theoretical progress achieved in the description of experimental data.

  7. Weak interactions of quarks and leptons: experimental status

    SciTech Connect (OSTI)

    Wojcicki, S.

    1984-09-01

    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)

  8. Tau decays into three charged leptons and two neutrinos

    E-Print Network [OSTI]

    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

    1996-04-01

    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...

  9. Partial Quark-Lepton Universality and Neutrino CP Violation

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Liao, Jiajun; Marfatia, D.; Whisnant, K.

    2015-01-01

    We study a model with partial quark-lepton universality that can naturally arise in grand unified theories. We find that constraints on the model can be reduced to a single condition on the Dirac CP phase ? in the neutrino sector. Using our current knowledge of the CKM and PMNS mixing matrices, we predict - 32 . 4 ° ? ? ? 32 . 0 ° at 2 ? .

  10. Lepton flavour violating processes at the International Linear Collider

    E-Print Network [OSTI]

    P. M. Ferreira; R. B. Guedes; R. Santos

    2007-02-13

    We study the effects of dimension six effective operators on the flavour violating production and decay of leptons at the International Linear Collider. Analytic expressions for the cross sections, decay widths and asymmetries of all flavour changing processes will be presented, as well as an analysis of the feasibility of their observation at the ILC.

  11. Lepton Mixing Predictions from (Generalised) CP and Discrete Flavour Symmetry

    E-Print Network [OSTI]

    Thomas Neder

    2015-03-31

    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.

  12. Search for Charged Lepton Violation in Narrow Upsilon Decays

    SciTech Connect (OSTI)

    Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E.; /Barcelona U., ECM; Martinelli, M.; Palano, A.; Pappagallo, M.; /Bari U. /INFN, Bari; Eigen, G.; Stugu, B.; Sun, L.; /Bergen U.; Battaglia, M.; Brown, D.N.; Hooberman, B.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Osipenkov, I.L.; Tanabe, T.; /LBL, Berkeley /UC, Berkeley; Hawkes, C.M.; /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. /Ferrara U. /INFN, Ferrara /Frascati /Columbus Supercond., Genova /INFN, Genoa /Indian Inst. Tech., Guwahati /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State 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 /McGill U. /Consorzio Milano Ricerche /INFN, Milan /Mississippi U. /Montreal U. /Napoli Seconda U. /INFN, Naples /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /Padua U. /INFN, Padua /Paris U., VI-VII /Perugia U. /INFN, Perugia /INFN, Pisa /Princeton U. /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 /Turin U. /INFN, Turin /Trieste U. /INFN, Trieste /Valencia U., IFIC /Victoria U. /Warwick U. /Wisconsin U., Madison

    2011-08-19

    Charged lepton flavor violating processes are unobservable in the standard model, but they are predicted to be enhanced in several extensions to the standard model, including supersymmetry and models with leptoquarks or compositeness. We present a search for such processes in a sample of 99 x 10{sup 6} {Upsilon}(2S) decays and 117 x 10{sup 6} {Upsilon}(3S) decays collected with the BABAR detector. We place upper limits on the branching fractions {Beta}({Upsilon}(nS) {yields} e{sup {+-}}{tau}{sup {-+}}) and {Beta}({Upsilon}(nS) {yields} {mu}{sup {+-}}{tau}{sup {-+}}) (n = 2, 3) at the 10{sup -6} level and use these results to place lower limits of order 1 TeV on the mass scale of charged lepton flavor violating effective operators.

  13. Lepton Number Violation within the Conformal Inverse Seesaw

    E-Print Network [OSTI]

    Humbert, Pascal; Patra, Sudhanwa; Smirnov, Juri

    2015-01-01

    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.

  14. 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

    2012-06-26

    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 3–4 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 »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.« less

  15. Statistical Understanding of Quark and Lepton Masses in Gaussian Landscapes

    E-Print Network [OSTI]

    Lawrence J. Hall; Michael P. Salem; Taizan Watari

    2007-08-10

    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.

  16. Future Possibilities for Lepton-Hadron Collider Physics and Detectors

    E-Print Network [OSTI]

    Fleming, G; Lammers, S; Magill, S

    2001-01-01

    We have considered the physics opportunities of future lepton-hadron colliders and how these opportunities might be realized in a possible polarized eRHIC facility and an e-p collider as part of a staged or final version VLHC. We evaluated the physics priorities based on experience at HERA and, using simulated data for e-p collisions with sqrt(s) > 1 TeV, showed how detector designs would be impacted by the physics.

  17. Future Possibilities for Lepton-Hadron Collider Physics and Detectors

    E-Print Network [OSTI]

    G. Fleming; E. Kinney; S. Lammers; S. Magill

    2002-01-29

    We have considered the physics opportunities of future lepton-hadron colliders and how these opportunities might be realized in a possible polarized eRHIC facility and an e-p collider as part of a staged or final version VLHC. We evaluated the physics priorities based on experience at HERA and, using simulated data for e-p collisions with sqrt(s) > 1 TeV, showed how detector designs would be impacted by the physics.

  18. Electroweak Penguin and Leptonic Decays at BaBar

    SciTech Connect (OSTI)

    Bucci, F.; /Pisa U. /INFN, Pisa

    2005-08-26

    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}}.

  19. Clues for flavor from rare lepton and quark decays

    E-Print Network [OSTI]

    Ivo de Medeiros Varzielas; Gudrun Hiller

    2015-06-08

    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 $h \\to \\ell \\ell^\\prime$.

  20. The Cabibbo angle as a universal seed for quark and lepton mixings

    E-Print Network [OSTI]

    S. Roy; S. Morisi; N. N. Singh; J. W. F. Valle

    2014-10-14

    A model-independent ansatz to describe lepton and quark mixing in a unified way is suggested based upon the Cabibbo angle. In our framework neutrinos mix in a "Bi-Large" fashion, while the charged leptons mix as the "down-type" quarks do. In addition to the standard Wolfenstein parameters (lambda, A) two other free parameters are needed to specify the physical lepton mixing matrix. Through this simple assumption one makes specific predictions for the atmospheric angle as well as leptonic CP violation in good agreement with current observations.

  1. Constraints on Majorana dark matter from a fourth lepton family

    SciTech Connect (OSTI)

    Hapola, Tuomas [Institute for Particle Physics Phenomenology, Durham University, South Road, Durham DH1 3LE (United Kingdom); Järvinen, Matti [Crete Center for Theoretical Physics, University of Crete, 71003 Heraklion (Greece); Kouvaris, Chris; Panci, Paolo; Virkajärvi, Jussi, E-mail: t.a.hapola@durham.ac.uk, E-mail: mjarvine@physics.uoc.gr, E-mail: kouvaris@cp3.dias.sdu.dk, E-mail: panci@cp3-origins.net, E-mail: virkajarvi@cp3-origins.net [CP "3-Origins and DIAS, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark)

    2014-02-01

    We study the possibility of dark matter in the form of heavy neutrinos from a fourth lepton family with helicity suppressed couplings such that dark matter is produced thermally via annihilations in the early Universe. We present all possible constraints for this scenario coming from LHC and collider physics, underground direct detectors, neutrino telescopes, and indirect astrophysical searches. Although we embed the WIMP candidate within a model of composite dynamics, the majority of our results are model independent and applicable to all models where heavy neutrinos with suppressed couplings account for the dark matter abundance.

  2. Searches for Leptonic B Decays at BaBar

    SciTech Connect (OSTI)

    Nelson, Silke; /SLAC

    2012-04-25

    Measurements of the branching fractions of purely leptonic decays of B-mesons translate into constraints in the plane of the charged Higgs mass versus tan {beta} which are relatively insensitive to the particular theoretical model. Using the full BABAR dataset of 450 million B-decays we search for these decays. No significant signal is found in the decays into electrons or muons and we set upper limits on the branching fractions of the order of a 10{sup -6} at 90% confidence level. We measure the branching fraction of B {yields} {tau}{mu} to be (1.7 {+-} 0.6) x 10{sup -4}.

  3. On the Potential of Leptonic Minimal Flavour Violation

    E-Print Network [OSTI]

    R. Alonso; M. B. Gavela; D. Hernández; L. Merlo

    2012-07-29

    Minimal Flavour Violation can be realized in several ways in the lepton sector due to the possibility of Majorana neutrino mass terms. We derive the scalar potential for the fields whose background values are the Yukawa couplings, for the simplest See-Saw model with just two right-handed neutrinos, and explore its minima. The Majorana character plays a distinctive role: the minimum of the potential allows for large mixing angles -in contrast to the simplest quark case- and predicts a maximal Majorana phase. This points in turn to a strong correlation between neutrino mass hierarchy and mixing pattern.

  4. Muon g-2 Anomaly and Dark Leptonic Gauge Boson

    SciTech Connect (OSTI)

    Lee, Hye-Sung [W& M

    2014-11-01

    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.

  5. Lepton-pair production in nuclear collisions - past, present, future

    E-Print Network [OSTI]

    H. J. Specht

    2007-10-29

    The key results on lepton-pair production in ultra-relativistic nuclear collisions are shortly reviewed, starting at the roots of pp collisions in the seventies, and ending at the perspectives of the colliders RHIC and LHC. The presence is dominated by the recent precision results from NA60 at the CERN SPS, culminating in the first measurement of the in-medium rho spectral function and the transverse flow of the associated thermal radiation. The seeming cut-off of the flow above the rho may well be the first direct hint for thermal radiation of partonic origin in nuclear collisions. The major milestones in the theoretical developments are also covered.

  6. Electron generation of leptons and hadrons with reciprocal -quantized lifetimes and masses

    E-Print Network [OSTI]

    1 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 the generation of hadron masses. In fact, the role of the electron in generating lepton masses has never been

  7. Measurement of the Top Quark Mass in the Lepton+Jets Channel Using the Lepton Transverse Momentum

    SciTech Connect (OSTI)

    Aaltonen, T.; Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J.A.; Apresyan, A.; /Purdue U. /Waseda U. /Dubna, JINR

    2011-01-01

    This letter reports a measurement of the top quark mass, M{sub top}, in data from p{bar p} collisions at {radical}s = 1.96 TeV corresponding to 2.7 fb{sup -1} of integrated luminosity at the Fermilab Tevatron using the CDF II detector. Events with the lepton+jets topology are selected. An unbinned likelihood is constructed based on the dependence of the lepton transverse momentum, P{sub T}, on M{sub top}. A maximum likelihood fit to the data yields a measured mass M{sub top} = 176.9 {+-} 8.0{sub stat} {+-} 2.7{sub syst} GeV/c{sup 2}. In this measurement, the contribution by the jet energy scale uncertainty to the systematic error is negligible. The result provides an important consistency test for other M{sub top} measurements where explicit use of the jet energy is made for deriving the top quark mass.

  8. The Ds and D+ Leptonic Decay Constants from Lattice QCD

    E-Print Network [OSTI]

    A. Bazavov; C. Bernard; C. DeTar; E. D. Freeland; E. Gamiz; Steven Gottlieb; U. M. Heller; J. E. Hetrick; A. X. El-Khadra; A. S. Kronfeld; J. Laiho; L. Levkova; P. B. Mackenzie; M. B. Oktay; M. Di Pierro; J. N. Simone; R. Sugar; D. Toussaint; R. S. Van de Water

    2009-12-28

    We present the leptonic decay constants fDs and fD+ computed on the MILC collaboration's 2+1 flavor asqtad gauge ensembles. We use clover heavy quarks with the Fermilab interpretation and improved staggered light quarks. The simultaneous chiral and continuum extrapolation, which determines both decay constants, includes partially-quenched lattice results at lattice spacings a ~ 0:09, 0:12 and 0:15 fm. We have made several recent improvements in our analysis: a) we include terms in the fit describing leading order heavy-quark discretization effects, b) we have adopted a more precise input r1 value consistent with our other D and B meson studies, c) we have retuned the input bare charm masses based upon the new r1. Our preliminary results are fDs = 260 +/-10 MeV and fD+ = 217 +/-10 MeV.

  9. Form factors for semi-leptonic B decays

    E-Print Network [OSTI]

    Ran Zhou; Steven Gottlieb; Jon A. Bailey; Daping Du; Aida X. El-Khadra; R. D. Jain; Andreas S. Kronfeld; Ruth S. Van de Water; Yuzhi Liu; Yannick Meurice; for the Fermilab Lattice; MILC Collaborations

    2012-11-06

    We report on form factors for the B->K l^+ l^- semi-leptonic decay process. We use several lattice spacings from a=0.12 fm down to 0.06 fm and a variety of dynamical quark masses with 2+1 flavors of asqtad quarks provided by the MILC Collaboration. These ensembles allow good control of the chiral and continuum extrapolations. The b-quark is treated as a clover quark with the Fermilab interpretation. We update our results for f_\\parallel and f_\\perp, or, equivalently, f_+ and f_0. In addition, we present new results for the tensor form factor f_T. Model independent results are obtained based upon the z-expansion.

  10. PDF Nuclear Corrections for Charged Lepton and Neutrino Deep Inelastic Scattering Processes

    E-Print Network [OSTI]

    I. Schienbein; J. Y. Yu; K. Kovarik; C. Keppel; J. G. Morfin; F. Olness; J. F. Owens

    2010-02-11

    We perform a \\chi^2-analysis of Nuclear Parton Distribution Functions (NPDFs) using neutral current charged-lepton Deeply Inelastic Scattering (DIS) and Drell-Yan data for several nuclear targets. The nuclear A dependence of the NPDFs is extracted in a next-to-leading order fit. We compare the nuclear corrections factors F2(Fe)/F2(D) for this 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.

  11. Falsifying High-Scale Baryogenesis with Neutrinoless Double Beta Decay and Lepton Flavor Violation

    E-Print Network [OSTI]

    Deppisch, Frank F; Hirsch, Martin; Huang, Wei-Chih; Päs, Heinrich

    2015-01-01

    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.

  12. Falsifying High-Scale Baryogenesis with Neutrinoless Double Beta Decay and Lepton Flavor Violation

    E-Print Network [OSTI]

    Frank F. Deppisch; Julia Harz; Martin Hirsch; Wei-Chih Huang; Heinrich Päs

    2015-09-11

    Interactions that manifest themselves as lepton number violating processes at low energies in combination with sphaleron transitions typically erase any preexisting baryon asymmetry of the Universe. In this article, 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 other than the standard light neutrino exchange 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.

  13. Falsifying High-Scale Baryogenesis with Neutrinoless Double Beta Decay and Lepton Flavor Violation

    E-Print Network [OSTI]

    Frank F. Deppisch; Julia Harz; Martin Hirsch; Wei-Chih Huang; Heinrich Päs

    2015-03-16

    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.

  14. Lepton number asymmetry via inflaton decay in a modified radiative seesaw model

    E-Print Network [OSTI]

    Kashiwase, Shoichi

    2015-01-01

    We propose a non-thermal scenario for the generation of baryon number asymmetry in a radiative neutrino mass model which is modified to realize inflation at the early Universe. In this scenario, inflaton plays a crucial role in both generation of neutrino masses and lepton number asymmetry. Lepton number asymmetry is firstly generated in the dark matter sector through direct decay of inflaton. It is transferred to the lepton sector via the dark matter annihilation and then converted to the baryon number asymmetry due to the sphaleron interaction. All of the neutrino masses, the baryon number asymmetry and the dark matter are intimately connected to each other through the inflaton.

  15. Search for new ?[superscript 0]-like particles produced in association with a ?-lepton pair

    E-Print Network [OSTI]

    Lees, J.?P.

    We report on a search in e[superscript +]e[superscript -] annihilations for new ?[superscript 0]-like particles produced in association with a ?-lepton pair. These objects, with a similar mass and similar decay modes to ...

  16. Precision measurement of the top quark mass in the lepton + jets...

    Office of Scientific and Technical Information (OSTI)

    Precision measurement of the top quark mass in the lepton + jets channel using a matrix element method with Quasi-Monte Carlo integration Citation Details In-Document Search...

  17. Monte Carlo simulation of baryon and lepton number violating processes at high energies

    E-Print Network [OSTI]

    M. J. Gibbs; A. Ringwald; B. R. Webber; J. T Zadrozny

    1994-06-09

    We report results obtained with the first complete event generator for electroweak baryon and lepton number violating interactions at supercolliders. We find that baryon number violation would be very difficult to establish, but lepton number violation can be seen provided at least a few hundred L violating events are available with good electron or muon identification in the energy range 10 GeV to 1 TeV.

  18. Test of Lepton Flavour Universality in K+ --> l+nu Decays

    E-Print Network [OSTI]

    C. Lazzeroni et al.

    2011-03-01

    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.

  19. Study of predominant hadronic modes of $?$-lepton using a Monte Carlo generator TAUOLA

    E-Print Network [OSTI]

    O. Shekhovtsova

    2015-08-22

    TAUOLA is a Monte Carlo generator dedicated to generating tau-lepton decays and it is used in the analysis of experimental data both at B-factories and LHC. TAUOLA is a long-term project that started in the 90's and has been under development up to now. In this note we discuss the status of the predominant hadronic tau-lepton decays into two ($Br \\simeq 25.52\\%$) and three pions ($Br \\simeq 18.67\\%$).

  20. Lepton Flavor Violation in Predictive SUSY-GUT Models

    SciTech Connect (OSTI)

    Albright, Carl H.; /Northern Illinois U. /Fermilab; Chen, Mu-Chun; /UC, Irvine

    2008-02-01

    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.

  1. Kubo relations and radiative corrections for lepton number washout

    SciTech Connect (OSTI)

    Bödeker, Dietrich; Laine, M. E-mail: laine@itp.unibe.ch

    2014-05-01

    The rates for lepton number washout in extensions of the Standard Model containing right-handed neutrinos are key ingredients in scenarios for baryogenesis through leptogenesis. We relate these rates to real-time correlation functions at finite temperature, without making use of any particle approximations. The relations are valid to quadratic order in neutrino Yukawa couplings and to all orders in Standard Model couplings. They take into account all spectator processes, and apply both in the symmetric and in the Higgs phase of the electroweak theory. We use the relations to compute washout rates at next-to-leading order in g, where g denotes a Standard Model gauge or Yukawa coupling, both in the non-relativistic and in the relativistic regime. Even in the non-relativistic regime the parametrically dominant radiative corrections are only suppressed by a single power of g. In the non-relativistic regime radiative corrections increase the washout rate by a few percent at high temperatures, but they are of order unity around the weak scale and in the relativistic regime.

  2. Search for heavy lepton resonances decaying to a Z boson and a lepton in pp collisions at \\( \\sqrt{s}=8 \\) TeV with the ATLAS detector

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aad, G.

    2015-09-16

    In this study, a search for heavy leptons decaying to a Z boson and an electron or a muon is presented. The search is based on pp collision data taken at \\( \\sqrt{s}=8 \\) TeV by the ATLAS experiment at the CERN Large Hadron Collider, corresponding to an integrated luminosity of 20.3 fb?¹. Three high-transverse-momentum electrons or muons are selected, with two of them required to be consistent with originating from a Z boson decay. No significant excess above Standard Model background predictions is observed, and 95% confidence level limits on the production cross section of high-mass trilepton resonances aremore »derived. The results are interpreted in the context of vector-like lepton and type-III seesaw models. For the vector-like lepton model, most heavy lepton mass values in the range 114–176 GeV are excluded. For the type-III seesaw model, most mass values in the range 100–468 GeV are excluded.« less

  3. The double mass hierarchy pattern: simultaneously understanding quark and lepton mixing

    E-Print Network [OSTI]

    Wolfgang Gregor Hollik; Ulises Jesus Saldana Salazar

    2015-01-21

    The charged fermion masses of the three generations exhibit the two strong hierarchies m_3 >> m_2 >> m_1. We assume that also neutrino masses satisfy m_{nu 3} > m_{nu 2} > m_{nu 1} and derive the consequences of the hierarchical spectra on the fermionic mixing patterns. The quark and lepton mixing matrices are built in a general framework with their matrix elements expressed in terms of the four fermion mass ratios m_u/m_c, m_c/m_t, m_d/m_s, and m_s/m_b and m_e/m_mu, m_mu/m_tau, m_{nu 1}/m_{nu 2}, and m_{nu 2}/m_{nu 3}, for the quark and lepton sector, respectively. In this framework, we show that the resulting mixing matrices are consistent with data for both quarks and leptons, despite the large leptonic mixing angles. The minimal assumption we take is the one of hierarchical masses and minimal flavour symmetry breaking that strongly follows from phenomenology. No special structure of the mass matrices has to be assumed that cannot be motivated by this minimal assumption. This analysis allows us to predict the neutrino mass spectrum and set the mass of the lightest neutrino well below 0.01 eV. The method also gives the 1 sigma allowed ranges for the leptonic mixing matrix elements. Contrary to the common expectation, leptonic mixing angles are found to be determined solely by the four leptonic mass ratios without any relation to symmetry considerations as commonly used in flavor model building. Still, our formulae can be used to build up a flavor model that predicts the observed hierarchies in the masses---the mixing follows then from the procedure which is developed in this work.

  4. Parametrization of lepton mixing matrix in terms of deviations from bi-maximal and tri-bimaximl mixing

    E-Print Network [OSTI]

    Chandan Duarah; K. Sashikanta Singh; N. Nimai Singh

    2015-03-26

    We parametrize lepton mixing matrix, known as PMNS matrix, in terms of three parameters which account deviations of three mixing angles from their bi-maximal or tri-bimaximal values. On the basis of this parametrization we can determine corresponding charged lepton mixing matrix in terms of those three parameters which can deviate bi-maximal or tri-bimaximal mixing. We find that the charged lepton mixing matrices which can deviate bi-maximal mixing matrix and tri-bimaximal mixing matrix exhibit similar structures. Numerical analysis shows that these charged lepton mixing matrices are close to CKM matrix of quark sector.

  5. Exclusion of an Exotic Top Quark with -4/3 Electric Charge Using Soft Lepton Tagging

    SciTech Connect (OSTI)

    Aaltonen, T.; Adelman, J.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J.; Apresyan, A.; /Purdue U. /Waseda U.

    2010-06-01

    We present a measurement of the electric charge of the top quark using p{bar p} collisions corresponding to an integrated luminosity of 2.7 fb{sup -1} at the CDF II detector. We reconstruct t{bar t} events in the lepton+jets final state and use kinematic information to determine which b-jet is associated with the leptonically- or hadronically-decaying t-quark. Soft lepton taggers are used to determine the b-jet flavor. Along with the charge of the W boson decay lepton, this information permits the reconstruction of the top quark's electric charge. Out of 45 reconstructed events with 2.4 {+-} 0.8 expected background events, 29 are reconstructed as tt with the standard model +2/3 charge, whereas 16 are reconstructed as t{bar t} with an exotic -4/3 charge. This is consistent with the standard model and excludes the exotic scenario at 95% confidence level. This is the strongest exclusion of the exotic charge scenario and the first to use soft leptons for this purpose.

  6. Polarized Lepton-Nucleon Elastic Scattering and a Search for a Light Scalar Boson

    E-Print Network [OSTI]

    Yu-Sheng Liu; Gerald A. Miller

    2015-07-15

    Lepton-nucleon elastic scattering, using the one-photon and one-scalar-boson exchange mechanisms considering all possible polarizations, is used to study searches for a new scalar boson and suggest new measurements of the nucleon form factors. A new light scalar boson, which feebly couples to leptons and nucleons, may account for the proton radius and muon $g-2$ puzzles. We show that the scalar boson produces relatively large effects in certain kinematic region when using sufficient control of lepton and nucleon spin polarization. We generalize current techniques to measure the ratio $G_E/G_M$ and present a new method to separately measure $G_M^2$ and $G_E^2$ using polarized incoming and outgoing muons.

  7. Search for anomalous production of multiple leptons in association with $W$ and $Z$ bosons at CDF

    SciTech Connect (OSTI)

    Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J.A.; Arisawa, T.; Artikov, A.; /Dubna, JINR /Texas A-M

    2012-02-01

    This paper presents a search for anomalous production of multiple low-energy leptons in association with a W or Z boson using events collected at the CDF experiment corresponding to 5.1 fb{sup -1} of integrated luminosity. This search is sensitive to a wide range of topologies with low-momentum leptons, including those with the leptons near one another. The observed rates of production of additional electrons and muons are compared with the standard model predictions. No indications of phenomena beyond the standard model are found. A 95% confidence level limit is presented on the production cross section for a benchmark model of supersymmetric hidden-valley Higgs production. Particle identification efficiencies are also provided to enable the calculation of limits on additional models.

  8. Lepton Flavor Non-Universality in B-meson Decays from a U(2) Flavor Model

    E-Print Network [OSTI]

    Falkowski, Adam; Ziegler, Robert

    2015-01-01

    We address the recent anomalies in semi-leptonic $B$-meson decays using a model of fermion masses based on the $U(2)$ flavor symmetry. The new contributions to $b \\to s \\ell \\ell$ transitions arise due to a tree-level exchange of a $Z^\\prime$ vector boson gauging a $U(1)$ subgroup of the flavor symmetry. They are controlled by a single parameter and are approximately aligned to the Standard Model prediction, with constructive interference in the $e$-channel and destructive interference in the $\\mu$-channel. The current experimental data on semi-leptonic $B$-meson decays can be very well reproduced without violating existing constraints from flavor violation in the quark and lepton sectors. Our model will be tested by new measurements of $b \\to s \\ell \\ell$ transitions and also by future electroweak precision tests, direct $Z^\\prime$ searches, and $\\mu$-$e$ conversion in nuclei.

  9. Lepton Flavor Non-Universality in B-meson Decays from a U(2) Flavor Model

    E-Print Network [OSTI]

    Adam Falkowski; Marco Nardecchia; Robert Ziegler

    2015-09-03

    We address the recent anomalies in semi-leptonic $B$-meson decays using a model of fermion masses based on the $U(2)$ flavor symmetry. The new contributions to $b \\to s \\ell \\ell$ transitions arise due to a tree-level exchange of a $Z^\\prime$ vector boson gauging a $U(1)$ subgroup of the flavor symmetry. They are controlled by a single parameter and are approximately aligned to the Standard Model prediction, with constructive interference in the $e$-channel and destructive interference in the $\\mu$-channel. The current experimental data on semi-leptonic $B$-meson decays can be very well reproduced without violating existing constraints from flavor violation in the quark and lepton sectors. Our model will be tested by new measurements of $b \\to s \\ell \\ell$ transitions and also by future electroweak precision tests, direct $Z^\\prime$ searches, and $\\mu$-$e$ conversion in nuclei.

  10. Measurements of Four-Lepton Production at the Z Resonance in pp Collisions at ?s = 7 and 8 TeV with ATLAS

    E-Print Network [OSTI]

    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 ?+??] ...

  11. Angular correlations of lepton pairs from vector boson and top quark decays in Monte Carlo simulations

    E-Print Network [OSTI]

    S. Frixione; E. Laenen; P. Motylinski; B. R. Webber

    2007-02-20

    We explain how angular correlations in leptonic decays of vector bosons and top quarks can be included in Monte Carlo parton showers, in particular those matched to NLO QCD computations. We consider the production of $n$ pairs of leptons, originating from the decays of $n$ electroweak vector bosons or of $n$ top quarks, in the narrow-width approximation. In the latter case, the information on the $n$ $b$ quarks emerging from the decays is also retained. We give results of implementing this procedure in MC@NLO

  12. Leptogenesis from right-handed neutrino decays to right-handed leptons

    E-Print Network [OSTI]

    Thomas Hambye

    2006-06-16

    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.

  13. Hadron-Pair Photoproduction in Longitudinally Polarized Lepton-Nucleon Collisions

    E-Print Network [OSTI]

    Hendlmeier, C; Schäfer, A

    2006-01-01

    We present a detailed phenomenological study of photoproduction of two hadrons, both with high transverse momentum, in longitudinally polarized lepton-nucleon collisions. We consistently include ``direct'' and ``resolved'' photon contributions and examine the sensitivity of the relevant spin asymmetries to the gluon polarization in the nucleon and to the completely unknown parton content of circularly polarized photons. Our results are relevant for the COMPASS and HERMES fixed-target experiments as well as for a possible future polarized lepton-proton collider like eRHIC at BNL. So far, all studies are limited to the lowest order approximation of QCD.

  14. Hadron-Pair Photoproduction in Longitudinally Polarized Lepton-Nucleon Collisions

    E-Print Network [OSTI]

    C. Hendlmeier; M. Stratmann; A. Schafer

    2006-06-08

    We present a detailed phenomenological study of photoproduction of two hadrons, both with high transverse momentum, in longitudinally polarized lepton-nucleon collisions. We consistently include ``direct'' and ``resolved'' photon contributions and examine the sensitivity of the relevant spin asymmetries to the gluon polarization in the nucleon and to the completely unknown parton content of circularly polarized photons. Our results are relevant for the COMPASS and HERMES fixed-target experiments as well as for a possible future polarized lepton-proton collider like eRHIC at BNL. So far, all studies are limited to the lowest order approximation of QCD.

  15. Searching for Single Production of Charged Heavy Leptons via Anomalous Interactions at CLIC

    E-Print Network [OSTI]

    A. T. Tasci; A. Senol

    2013-01-07

    We consider the possible discovery potential for single production of charged heavy leptons via anomalous interactions at the envisaged Compact Linear Collider (CLIC) by taking into account initial state radiation (ISR) and beamstrahlung effects. We calculate the production cross sections and decay widths of charged heavy leptons in the context of anomalous interactions at center of mass energies $\\sqrt{s}=1$ and 3 TeV. The signal and corresponding backgrounds are studied in detail for the mass range 300-1900 GeV.

  16. Search for Lepton Flavor Violating Decays tau--->l-Ks0 with the BABAR Experiment

    E-Print Network [OSTI]

    Fisher, Peter H.

    A search for the lepton flavor violating decays tau--->l-KS0 (l=e or mu) has been performed using a data sample corresponding to an integrated luminosity of 469??fb[superscript -1], collected with the BABAR detector at the ...

  17. DIFFRACTION 2000 SESSION: `Di raction in lepton-hadron collisions I'

    E-Print Network [OSTI]

    DIFFRACTION 2000 SESSION: `Di#11;raction in lepton-hadron collisions I' September 2 - 7, 2000; Conclusions #12; DIFFRACTION 2000 Paul Thompson Why measure open charm in di#11;raction ? #15; Charm mass Interactions? September 2000 2 #12; DIFFRACTION 2000 Paul Thompson Event Kinematics x IP = M 2 X +Q 2 W 2 +Q 2

  18. A wave equation including leptons and quarks for the standard model of quantum physics in

    E-Print Network [OSTI]

    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

  19. Novel inclusive search for the Higgs boson in the four-lepton final state at CDF

    E-Print Network [OSTI]

    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 ...

  20. Inclusive Higgs Boson Searches in Four-Lepton Final States at the LHC

    E-Print Network [OSTI]

    Evelyne Delmeire

    2007-05-15

    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.

  1. Discrimination of models including doubly charged scalar bosons by using tau lepton decay distributions

    E-Print Network [OSTI]

    Hiroaki Sugiyama; Koji Tsumura; Hiroshi Yokoya

    2012-10-05

    The doubly charged scalar boson (H^{\\pm\\pm}) is introduced in several models of the new physics beyond the standard model. The H^{\\pm\\pm} has Yukawa interactions with two left-handed charged leptons or two right-handed charged leptons depending on the models. We study kinematical properties of H^{\\pm\\pm} decay products through tau leptons in order to discriminate the chiral structures of the new Yukawa interaction. The chirality of tau leptons can be measured by the energy distributions of the tau decay products, and thus the chiral structure of the new Yukawa interaction can be traced in the invariant-mass distributions of the H^{\\pm\\pm} decay products. We perform simulation studies for the typical decay patterns of the H^{\\pm\\pm} with simple event selections and tau-tagging procedures, and show that the chiral structure of the Yukawa interactions of H^{\\pm\\pm} can be distinguished by measuring the invariant-mass distributions.

  2. The double mass hierarchy pattern: simultaneously understanding quark and lepton mixing

    E-Print Network [OSTI]

    Hollik, Wolfgang Gregor

    2015-01-01

    The charged fermion masses of the three generations exhibit the two strong hierarchies m_3 >> m_2 >> m_1. We assume that also neutrino masses satisfy m_{nu 3} > m_{nu 2} > m_{nu 1} and derive the consequences of the hierarchical spectra on the fermionic mixing patterns. The quark and lepton mixing matrices are built in a general framework with their matrix elements expressed in terms of the four fermion mass ratios m_u/m_c, m_c/m_t, m_d/m_s, and m_s/m_b and m_e/m_mu, m_mu/m_tau, m_{nu 1}/m_{nu 2}, and m_{nu 2}/m_{nu 3}, for the quark and lepton sector, respectively. In this framework, we show that the resulting mixing matrices are consistent with data for both quarks and leptons, despite the large leptonic mixing angles. The minimal assumption we take is the one of hierarchical masses and minimal flavour symmetry breaking that strongly follows from phenomenology. No special structure of the mass matrices has to be assumed that cannot be motivated by this minimal assumption. This analysis allows us to predict ...

  3. Non-perturbative Heavy Quark Effective Theory: An application to semi-leptonic B-decays

    E-Print Network [OSTI]

    Michele Della Morte; Jochen Heitger; Hubert Simma; Rainer Sommer

    2015-01-14

    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.

  4. Evidence for the 125 GeV Higgs boson decaying to a pair of ? leptons

    E-Print Network [OSTI]

    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 ...

  5. Search for WW and WZ production in lepton plus jets final state at CDF

    E-Print Network [OSTI]

    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 ...

  6. Forschung an Lepton Collidern Abbildung 49: Perspektivische Ansicht des TESLA-Detektors.

    E-Print Network [OSTI]

    Forschung an Lepton Collidern Abbildung 49: Perspektivische Ansicht des TESLA-Detektors. 86 #12An- strengung vieler Gruppen und Institute der ,,Tech- nical Design Report" für TESLA veröffentlicht wer- den von TESLA, besonders in Bereichen, die im TDR nicht ausreichend behandelt werden konnten, und die

  7. Drell-Yan Lepton pair production at NNLO QCD with parton showers

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hoeche, Stefan; Li, Ye; Prestel, Stefan

    2015-04-13

    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.

  8. Measurement of the Top Quark Mass Simultaneously in Dilepton and Lepton + Jets Decay Channels

    SciTech Connect (OSTI)

    Fedorko, Wojciech T.; /Chicago U.

    2008-09-01

    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.

  9. Electroweak quark-lepton symmetry and weak topological-charge confinement in the Standard Model with Dirac neutrinos

    E-Print Network [OSTI]

    Ernesto A. Matute

    2007-09-25

    The standard electroweak model with Dirac neutrinos is extended by way of the principles of electroweak quark-lepton symmetry and weak topological-charge confinement to account for quark-lepton charge relations which, if not accidental, are indicative of charge structures. A mixing in quarks and leptons of underlying integer local charges with integer weak topological charges associated with an additive group Z_3, fixed by the anomaly cancellation requirement, is discussed. It is found that the electroweak difference between topological quarks and leptons is the nonequivalence between the topological vacua of their weak field configurations, produced by a four-instanton which carries the topological charge, induces the universal fractional piece of charge distinguishing quarks from leptons, and breaks the underlying symmetry. The constituent quarks of the standard model appear as coming from topological quarks, via the weak four-instanton event. Dual transitions occur for leptons. It is shown that several other fundamental problems left open in the standard electroweak model with Dirac neutrinos are solved: the one-to-one correspondence between quark and lepton flavors, the existence of three generations, the conservation and ungauging of B-L, the electric charge quantization, and the confinement of fractional electric charges.

  10. A Search for Prompt Lepton-Jets in pp Collisions at ?s = 7 TeV with the ATLAS Detector

    E-Print Network [OSTI]

    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 ...

  11. Search for excited leptons in proton-proton collisions at ?s=7??TeV with the ATLAS detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    The ATLAS detector is used to search for excited leptons in the electromagnetic radiative decay channel ?*???. Results are presented based on the analysis of pp collisions at a center-of-mass energy of 7 TeV corresponding ...

  12. Search for type-III seesaw heavy leptons in pp collisions at s=8 TeVwith the ATLAS detector

    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

    2015-08-03

    A search for the pair production of heavy leptons (N?,L±) predicted by the type-III seesaw theory formulated to explain the origin of small neutrino masses is presented. The decay channels N??W±l? (?=e,?,?) and L±?W±? (?=?e,??,??) are considered. The analysis is performed using the final state that contains two leptons (electrons or muons), two jets from a hadronically decaying W boson and large missing transverse momentum. The data used in the measurement correspond to an integrated luminosity of 20.3 fb?¹ of pp collisions at s?=8 TeV collected by the ATLAS detector at the LHC. No evidence of heavy lepton pair productionmore »is observed. Heavy leptons with masses below 325–540 GeV are excluded at the 95% confidence level, depending on the theoretical scenario considered.« less

  13. Search for new physics in final states with a lepton and missing transverse energy in pp collisions at the LHC

    E-Print Network [OSTI]

    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 ...

  14. Search for type-III seesaw heavy leptons inppcollisions ats=8 TeVwith the ATLAS detector

    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

    2015-08-01

    A search for the pair production of heavy leptons (N?,L±) predicted by the type-III seesaw theory formulated to explain the origin of small neutrino masses is presented. The decay channels N??W±l? (?=e,?,?) and L±?W±? (?=?e,??,??) are considered. The analysis is performed using the final state that contains two leptons (electrons or muons), two jets from a hadronically decaying W boson and large missing transverse momentum. The data used in the measurement correspond to an integrated luminosity of 20.3??fb?¹ of pp collisions at s?=8??TeV collected by the ATLAS detector at the LHC. No evidence of heavy lepton pair production is observed.more »Heavy leptons with masses below 325–540 GeV are excluded at the 95% confidence level, depending on the theoretical scenario considered.« less

  15. Search for new physics in final states with a lepton and missing transverse energy in pp collisions at the LHC

    E-Print Network [OSTI]

    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.

    2013-04-08

    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 ...

  16. Search for the standard model Higgs boson in tau lepton pair final states

    E-Print Network [OSTI]

    D0 Collaboration

    2012-05-16

    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.

  17. CPT and lepton number violation in neutrino sector: Modified mass matrix and oscillation due to gravity

    E-Print Network [OSTI]

    Monika Sinha; Banibrata Mukhopadhyay

    2007-11-21

    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.

  18. Transverse self-modulation of ultra-relativistic lepton beams in the plasma wakefield accelerator

    E-Print Network [OSTI]

    Vieira, J; Mori, W B; Silva, L O; Muggli, P

    2015-01-01

    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.

  19. Fourth Generation Lepton Sectors with Stable Majorana Neutrinos: From LEP to LHC

    E-Print Network [OSTI]

    Linda M. Carpenter

    2010-10-26

    I analyze a fourth generation lepton sector in which the lightest particle is a stable Majorana neutrino. In this scenario fourth generation neutrinos have both a Dirac and Majorana mass, resulting in two Majorana neutrino mass eigenstates. A reanalysis of LEP's lower mass bound is performed on stable Majorana neutrinos from the Z width and the lower mass bound is loosened. I also extrapolate LEP's SUSY squark search with a 2 jet plus missing missing energy final state to the production and decay of a pair of heavy Majorana neutrinos; here it is expected that significant regions of the neutrino mass plane may be ruled out. Finally, a search strategy is proposed for heavy fourth generation neutrino pairs at LHC in the four lepton plus missing energy channel. Exclusions are set in the neutrino mass plane for 30 inverse fb of data at LHC for 13 TeV.

  20. Sneutrino Higgs models explain lepton non-universality in eejj, e?jj excesses

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Berger, Joshua; Dror, Jeff Asaf; Ng, Wee Hao

    2015-09-23

    Recent searches for first-generation leptoquarks and heavy right-handed WR bosons have seen excesses in final states with electrons and jets. A bizarre property of these excesses is that they appear to violate lepton universality. With these results in mind, we study the phenomenology of supersymmetric models in which the Higgs arises as the sneutrino in an electron supermultiplet. Since the electron is singled out in this approach, one can naturally account for the lepton flavor structure of the excesses. In this work, we show that in such a framework, one can significantly alleviate the tension between the Standard Model andmore »the data and yet evade current constraints from other searches. Finally we point out that correlated excesses are expected to be seen in future multilepton searches.« less

  1. Search for the Higgs boson in lepton, tau and jets final states

    E-Print Network [OSTI]

    D0 Collaboration

    2013-01-28

    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.

  2. Search for the Higgs boson in lepton, tau, and jets final states

    SciTech Connect (OSTI)

    Abazov, V. M.; et al.

    2013-09-01

    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.

  3. Search for the standard model Higgs boson in tau lepton final states

    SciTech Connect (OSTI)

    Abazov, Victor Mukhamedovich; et al.

    2012-08-01

    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.

  4. ERL-BASED LEPTON-HADRON COLLIDERS: eRHIC AND LHeC

    E-Print Network [OSTI]

    Zimmermann, F

    2013-01-01

    Two hadron-ERL colliders are being proposed. The Large Hadron electron Collider (LHeC) plans to collide the high-energy protons and heavy ions in the Large Hadron Collider (LHC) at CERN with 60-GeV polarized electrons or positrons. The baseline scheme for this facility adds to the LHC a separate recirculating superconducting (SC) lepton linac with energy recovery, delivering a lepton current of 6.4mA. The electron-hadron collider project eRHIC aims to collide polarized (and unpolarized) electrons with a current of 50 (220) mA and energies in the range 5–30 GeV with a variety of hadron beams— heavy ions as well as polarized light ions— stored in the existing Relativistic Heavy Ion Collider (RHIC) at BNL. The eRHIC electron beam will be generated in an energy recovery linac (ERL) installed inside the RHIC tunnel.

  5. Lepton-flavor-violating decay {tau}{yields}{mu}{mu}{mu} at the CERN LHC

    SciTech Connect (OSTI)

    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)

    2008-04-01

    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.

  6. Lepton universality test in the photoproduction of $e^- e^+$ versus $?^- ?^+$ pairs on a proton target

    E-Print Network [OSTI]

    Vladyslav Pauk; Marc Vanderhaeghen

    2015-03-04

    In view of the significantly different proton charge radius extracted from muonic hydrogen Lamb shift measurements as compared to electronic hydrogen spectroscopy or electron scattering experiments, we study in this work the photoproduction of a lepton pair on a proton target in the limit of very small momentum transfer as a way to provide a test of the lepton universality when extracting the proton charge form factor. By detecting the recoiling proton in the $\\gamma p \\to l^- l^+ p$ reaction, we show that a measurement of a ratio of $e^-e^+ + \\mu^-\\mu^+$ over $e^-e^+$ cross sections with a relative precision of around 2%, would allow for a test to distinguish between the two different proton charge radii currently extracted from muonic and electronic observables.

  7. Sneutrino Higgs models explain lepton non-universality in CMS excesses

    E-Print Network [OSTI]

    Joshua Berger; Jeff Asaf Dror; Wee Hao Ng

    2015-07-08

    Recent searches for first-generation leptoquarks and heavy right-handed $W_R$ bosons have seen excesses in final states with electrons and jets. A bizarre property of these excesses is that they appear to violate lepton universality. With these results in mind, we study the phenomenology of supersymmetric models in which the Higgs arises as the sneutrino in an electron supermultiplet. Since the electron is singled out in this approach, one can naturally account for the lepton flavor structure of the excesses. In this work, we show that in such a framework, one can significantly alleviate the tension between the Standard Model and the data and yet evade current constraints from other searches. Lastly we point out that correlated excesses are expected to be seen in future multilepton searches.

  8. QCD Corrections to Pair Production of Type III Seesaw Leptons at Hadron Colliders

    E-Print Network [OSTI]

    Richard Ruiz

    2015-09-17

    If kinematically accessible, hadron collider experiments provide an ideal laboratory for the direct production of heavy lepton partners in Seesaw models. In the context of the Type III Seesaw Mechanism, the $\\mathcal{O}(\\alpha_s)$ rate and shape corrections are presented for the pair production of hypothetical, heavy $SU(2)_L$ triplet leptons in $pp$ collisions at $\\sqrt{s}=13,$ 14, and 100 TeV. The next-to-leading order (NLO) $K$-factors span, approximately, $K^{NLO}=1.1 - 1.4$ for both charged current and neutral current processes over a triplet mass range $m_T = 100~\\text{GeV}-2\\text{TeV}$. Total production cross sections exhibit a $^{+5\\%}_{-6\\%}$ scale dependence at 14 TeV and $\\pm1\\%$ at 100 TeV. The NLO differential $K$-factors for heavy lepton kinematics are largely flat, suggesting that na\\"ive scaling by the total $K^{NLO}$ is reasonably justified. The resummed transverse momentum distribution of the dilepton system is presented at leading logarithmic (LL) accuracy. The effects of resummation are large in TeV-scale dilepton systems. Discovery potential to heavy lepton pairs at 14 and 100 TeV is briefly explored: At the High-Luminosity LHC, we estimate a $4.8-6.3\\sigma$ discovery potential maximally for $m_T = 1.5-1.6~\\text{TeV}$ after 3000 fb$^{-1}$. With 300 (3000) fb$^{-1}$, there is $2\\sigma$ sensitivity up to $m_T = 1.3-1.4~\\text{TeV}~(1.7-1.8~\\text{TeV})$ in the individual channels. At 100 TeV and with 10 fb$^{-1}$, a $5\\sigma$ discovery can be achieved for $m_T=1.4-1.6~\\text{TeV}$.

  9. $S_3$ as a unified family theory for quarks and leptons

    E-Print Network [OSTI]

    Canales, F González; Salazar, U J Saldaña; Velasco-Sevilla, L

    2012-01-01

    We present an $S_3$-invariant extension of the SM which is able to account for the mixing both in the quark and the lepton sector. We focus here on the quark sector and present different realizations of the model, according to how many Higgs fields are involved. We then confront the models with the up-to-date values of masses and mixing in the quark sector.

  10. Search for the associated production of chargino and neutralino in the final state with three leptons

    SciTech Connect (OSTI)

    Canepa, Anadi; /Purdue U.

    2006-02-01

    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.

  11. Statistical Constraints on the Error of the Leptonic CP Violation of Neutrinos

    E-Print Network [OSTI]

    Fu, Kai

    2015-01-01

    A constraint on the error of leptonic CP violation, which require the phase $\\delta_{CP}$ to be less than $\\pi/4$ for it to be distinguishable on a $2\\pi$ cycle, is presented. Under this constraint, the effects of neutrino detector 's distance, beam energy, and energy resolution are discussed with reference to the present values of these parameters in experiments. Although an optimized detector performances can minimize the deviation to yield a larger distinguishable range of the leptonic CP phase on a $2\\pi$ cycle, it is not possible to determine an arbitrary leptonic CP phase in the range of $2\\pi$ with the statistics from a single detector because of the existence of two singular points. An efficiency factor $\\eta$ is defined to characterize the distinguishable range of $\\delta_{CP}$. To cover the entire possible $\\delta_{CP}$ range, a combined efficiency factor $\\eta^*$ corresponding to multiple sets of detection parameters with different neutrino beam energies and distances is proposed. The combined effi...

  12. Statistical Constraints on the Error of the Leptonic CP Violation of Neutrinos

    E-Print Network [OSTI]

    Kai Fu; Ying Zhang

    2015-04-28

    A constraint on the error of leptonic CP violation, which require the phase $\\delta_{CP}$ to be less than $\\pi/4$ for it to be distinguishable on a $2\\pi$ cycle, is presented. Under this constraint, the effects of neutrino detector 's distance, beam energy, and energy resolution are discussed with reference to the present values of these parameters in experiments. Although an optimized detector performances can minimize the deviation to yield a larger distinguishable range of the leptonic CP phase on a $2\\pi$ cycle, it is not possible to determine an arbitrary leptonic CP phase in the range of $2\\pi$ with the statistics from a single detector because of the existence of two singular points. An efficiency factor $\\eta$ is defined to characterize the distinguishable range of $\\delta_{CP}$. To cover the entire possible $\\delta_{CP}$ range, a combined efficiency factor $\\eta^*$ corresponding to multiple sets of detection parameters with different neutrino beam energies and distances is proposed. The combined efficiency factors $\\eta^*$ of various major experiments are also presented.

  13. Search for lepton flavor violating decay $\\tau^- \\to \\ell^- \\ell^ \\ell^-$ at BaBar

    SciTech Connect (OSTI)

    Cervelli, Alberto; /Pisa U.

    2010-05-26

    The Standard Model (SM) is one of the most tested and verified physical theories of all time, present experimental observations are consistent with SM expectations. On the other hand SM can not explain many physical observations: the cosmological observations possibly infer the presence of dark matter which is clearly beyond the SM expectations; the SM Higgs model, while explaining the generation of fermion masses, can not explain the hierarchy problem and a non natural fine tuning of SM is needed to cancel out quadratic divergences in the Higgs boson mass. New physics (NP) beyond SM should hence be investigated: rising the energy above NP processes thresholds, and detecting new particles or new effects not predicted by the standard model directly, is one of the possible approaches; another approach is to make precision measurements of well known processes or looking for rare processes which involve higher order contribution from NP processes, this approach need higher luminosities with respect to the previous approach but lower beam energies. Search for Lepton Flavor Violation (LFV) in charged lepton decays is promising: neutrino physics provides indeed a clear and unambiguous evidence of LFV in the neutral lepton sector via mixing processes, which have been observed for the first time by the Homestake collaboration. We expect LFV in the charged sector as well, both in {mu} and {tau} sector, but current experimental searches for LFV processes did not find any evidence for those processes, and more results are expected to come from new experiments in the coming years.

  14. HERBVI - a program for simulation of baryon- and lepton- number violating processes

    E-Print Network [OSTI]

    M. J. Gibbs; B. R. Webber

    1995-04-05

    We describe a Monte Carlo event generator for the simulation of baryon- and lepton-number violating processes at supercolliders. The package, {\\HERBVI}, is designed as a hard-process generator interfacing to the general hadronic event simulation program {\\HW}. In view of the very high multiplicity of gauge bosons expected in such processes, particular attention is paid to the efficient generation of multiparticle phase space. The program also takes account of the expected colour structure of baryon-number violating vertices, which has important implications for the hadronization of the final state.

  15. AN in inclusive lepton-proton collisions: TMD and twist-3 approaches

    SciTech Connect (OSTI)

    Prokudin, Alexey [JLAB

    2015-01-01

    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.

  16. $A_N$ in inclusive lepton-proton collisions: TMD and twist-3 approaches

    E-Print Network [OSTI]

    Alexei Prokudin

    2014-10-14

    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.

  17. AN in inclusive lepton-proton collisions: TMD and twist-3 approaches

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Prokudin, Alexei

    2015-01-23

    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. As a result, we discuss similarities and differences of two formalisms.

  18. Dark Matter and Lepton Flavour Violation in a Hybrid Neutrino Mass Model

    E-Print Network [OSTI]

    Deppisch, Frank F

    2014-01-01

    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.

  19. Further Evidence of Narrow Baryonic Structures with Hadronic as Well as Leptonic Probes

    E-Print Network [OSTI]

    B. Tatischeff; E. Tomasi-Gustafsson

    2004-11-22

    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.

  20. Model independent interpretation of recent CR lepton data after AMS-02

    SciTech Connect (OSTI)

    Gaggero, Daniele; Maccione, Luca E-mail: luca.maccione@lmu.de

    2013-12-01

    We model the CR leptonic fluxes above 20 GeV in terms of a superposition of a standard and a charge symmetric extra component, which we generically describe as power-laws in momentum. We investigate under these hypotheses the compatibility between AMS-02, Fermi-LAT and PAMELA datasets on positron fraction, electron+positron spectrum and electron spectrum respectively. We find that it is possible to reconcile AMS and Fermi-LAT data within uncertainties, if energy-dependent effects are present in Fermi-LAT systematics. We also study possible deviations from charge symmetry in the extra component and find no compelling evidence for them.

  1. The SUSY seesaw model and lepton-flavor violation at a future electron-positron linear collider

    E-Print Network [OSTI]

    F. Deppisch; H. Päs; A. Redelbach; R. Rückl; Y. Shimizu

    2004-05-11

    We study lepton-flavor violating slepton production and decay at a future e^+e^- linear collider in context with the seesaw mechanism in mSUGRA post-LEP benchmark scenarios. The present knowledge in the neutrino sector as well as improved future measurements are taken into account. We calculate the signal cross-sections \\sigma(e^{+/-}e^- -> l_{\\beta}^{+/-} l_{\\alpha}^- \\tilde{\\chi}_b^0 \\tilde{\\chi}_a^0); l_{\\delta}=e, \\mu, \\tau; \\alpha =|= \\beta and estimate the main background processes. Furthermore, we investigate the correlations of these signals with the corresponding lepton-flavor violating rare decays l_{\\alpha} -> l_{\\beta} \\gamma. It is shown that these correlations are relatively weakly affected by uncertainties in the neutrino data, but very sensitive to the model parameters. Hence, they are particularly suited for probing the origin of lepton-flavor violation.

  2. The Effects of Fourth Generation on the double Lepton Polarization in B \\rar K \\ell^+ \\ell^- decay

    E-Print Network [OSTI]

    V. Bashiry; S. M. Zebarjad; F. Falahati; K. Azizi

    2008-04-30

    This study investigates the influence of the fourth generation quarks on the double lepton polarizations in B \\rar K \\ell^+ \\ell^- decay. Taking |V_{t's}V_{t'b}|\\sim \\{0.01-0.03\\} with phase about 100^\\circ, which is consistent with the b\\to s\\ell^+\\ell^- rate and the B_s mixing parameter Delta m_{B_s}$, we obtain that the double lepton(muon and tau) polarizations are quite sensitive to the existence of fourth generation. It can serve as a good tool to search for new physics effects, precisely, to indirect search for the fourth generation quarks(t', b').

  3. Neutrino Masses, Lepton Flavor Mixing and Leptogenesis in the Minimal Seesaw Model

    E-Print Network [OSTI]

    Wan-lei Guo; Zhi-zhong Xing; Shun Zhou

    2006-12-05

    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.

  4. A Direct Top-Quark Width Measurement from Lepton + Jets Events at CDF II

    SciTech Connect (OSTI)

    Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J.A.; Apresyan, A.; Arisawa, T.; /Waseda U. /Dubna, JINR

    2010-08-01

    We present a measurement of the top-quark width using t{bar t} events produced in p{bar p} collisions at Fermilab's Tevatron collider and collected by the CDF II detector. In the mode where the top quark decays to a W boson and a bottom quark, we select events in which one W decays leptonically and the other hadronically (lepton + jets channel) . From a data sample corresponding to 4.3 fb{sup -1} of integrated luminosity, we identify 756 candidate events. The top-quark mass and the mass of W boson that decays hadronically are reconstructed for each event and compared with templates of different top-quark widths ({Lambda}{sub t}) and deviations from nominal jet energy scale ({Delta}{sub JES}) to perform a simultaneous fit for both parameters, where {Delta}{sub JES} is used for the in situ calibration of the jet energy scale. By applying a Feldman-Cousins approach, we establish an upper limit at 95% confidence level (CL) of {Lambda}{sub t} < 7.6 GeV and a two-sided 68% CL interval of 0.3 GeV < {Lambda}{sub t} < 4.4 GeV for a top-quark mass of 172.5 GeV/c{sup 2}, which are consistant with the standard model prediction. This is the first direct measurement of {Lambda}{sub t} to set a lower limit with 68% CL.

  5. Updated fit to three neutrino mixing: status of leptonic CP violation

    E-Print Network [OSTI]

    M. C. Gonzalez-Garcia; Michele Maltoni; Thomas Schwetz

    2014-12-16

    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.

  6. Horizon-Scale Lepton Acceleration in Jets: Explaining the Compact Radio Emission in M87

    E-Print Network [OSTI]

    Tchekhovskoy, Alexander

    2015-01-01

    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...

  7. Low and high energy phenomenology of quark-lepton complementarity scenarios

    SciTech Connect (OSTI)

    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)

    2007-04-01

    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.

  8. Lepton flavor violation in the supersymmetric seesaw model after the LHC 8 TeV run

    E-Print Network [OSTI]

    Toru Goto; Yasuhiro Okada; Tetsuo Shindou; Minoru Tanaka; Ryoutaro Watanabe

    2014-12-08

    We study the lepton flavor violation in the supersymmetric seesaw model taking into account recent experimental improvements, especially for the Higgs boson mass measurement, direct searches of superpartners and the rare decay of B_s -> mu+ mu- at the LHC, the neutrino mixing angle of theta_{13} at the neutrino experiments, and the search of mu -> e gamma at the MEG experiment. We obtain the latest constraints on the parameters in the supersymmetry breaking terms and study the effect on the lepton flavor violating decays of tau -> mu gamma and mu -> e gamma. In particular, we consider two kinds of assumption on the structures in the Majorana mass matrix and the neutrino Yukawa matrix. In the case of the Majorana mass matrix proportional to the unit matrix, allowing non-vanishing CP violating parameters in the neutrino Yukawa matrix, we find that the branching ratio of tau -> mu gamma can be larger than 10^{-9} within the improved experimental limit of mu -> e gamma. We also consider the neutrino Yukawa matrix that includes the mixing only in the second and third generations, and find that a larger branching ratio of tau -> mu gamma than 10^{-9} is possible with satisfying the recent constraints.

  9. NLO QCD and electroweak corrections to W+? production with leptonic W-boson decays

    E-Print Network [OSTI]

    Ansgar Denner; Stefan Dittmaier; Markus Hecht; Christian Pasold

    2015-11-12

    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.

  10. Lepton production at the LHC from singly- and doubly-charged bilepton

    SciTech Connect (OSTI)

    Sa Borges, J. [Instituto de Fisica, UERJ, Rio de Janeiro, RJ (Brazil); Coutinho, Y. A. [Instituto de Fisica, UFRJ, Rio de Janeiro, RJ (Brazil); Barreto, E. R. [C C N H, UFABC, Santo Andre, SP (Brazil)

    2013-03-25

    Some extensions of the standard model predict the existence of particles having two units of leptonic charge, known as bileptons. One of such models is based on the SU(3){sub c} Multiplication-Sign SU(3){sub L} Multiplication-Sign U(1){sub X} symmetry group (3-3-1). Our search uses the minimal version of this model, having exotic charges for the quarks and gauge bosons. It predicts the existence of bileptons as vector particles having one unit of electric charge (V{sup {+-}}) or two units of electric charge (Y{sup {+-}{+-}}). Our aim is to establish the signatures for the production of four fermions in pp collisions at the LHC for 7 TeV center of mass energy. We present the total cross section and we show the leptons invariant mass and transverse momentum distributions. We conclude that LHC collider can show a clear signature for a process induced by bileptons as a signal of new physics.

  11. Indirect Probe of Electroweak-Interacting Particles at Future Lepton Colliders

    E-Print Network [OSTI]

    Harigaya, Keisuke; Kundu, Anirban; Matsumoto, Shigeki; Shirai, Satoshi

    2015-01-01

    Various types of electroweak-interacting particles, which have non-trivial charges under the $\\mathrm{SU}(2)_L \\times \\mathrm{U}(1)_Y$ gauge symmetry, appear in various extensions of the Standard Model. These particles are good targets of future lepton colliders, such as the International Linear Collider (ILC), the Compact LInear Collider (CLIC) and the Future Circular Collider of electrons and positrons (FCC-ee). An advantage of the experiments is that, even if their beam energies are below the threshold of the production of the new particles, quantum effects of the particles can be detected through high precision measurements. We estimate the capability of future lepton colliders to probe electroweak-interacting particles through the quantum effects, with particular focus on the wino, the Higgsino and the so-called minimal dark matters, and found that a particle whose mass is greater than the beam energy by 100-1000 GeV is detectable by measuring di-fermion production cross sections with $O(0.1)$\\% accuracy...

  12. Indirect Probe of Electroweak-Interacting Particles at Future Lepton Colliders

    E-Print Network [OSTI]

    Keisuke Harigaya; Koji Ichikawa; Anirban Kundu; Shigeki Matsumoto; Satoshi Shirai

    2015-04-14

    Various types of electroweak-interacting particles, which have non-trivial charges under the $\\mathrm{SU}(2)_L \\times \\mathrm{U}(1)_Y$ gauge symmetry, appear in various extensions of the Standard Model. These particles are good targets of future lepton colliders, such as the International Linear Collider (ILC), the Compact LInear Collider (CLIC) and the Future Circular Collider of electrons and positrons (FCC-ee). An advantage of the experiments is that, even if their beam energies are below the threshold of the production of the new particles, quantum effects of the particles can be detected through high precision measurements. We estimate the capability of future lepton colliders to probe electroweak-interacting particles through the quantum effects, with particular focus on the wino, the Higgsino and the so-called minimal dark matters, and found that a particle whose mass is greater than the beam energy by 100-1000 GeV is detectable by measuring di-fermion production cross sections with $O(0.1)$\\% accuracy. In addition, with the use of the same analysis, we also discuss the sensitivity of the future colliders to model independent higher dimensional operators, and found that the cutoff scales corresponding to the operators can be probed up to a few ten TeV.

  13. Search for neutral MSSM Higgs bosons decaying to a pair of tau leptons in pp collisions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Khachatryan, V.

    2014-10-28

    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 MSSMmore »parameter space for different benchmark scenarios, mhmax, mhmod+ , mhmod– , light-stop, light-stau, ?-phobic, and low-mH. Upper limits on the cross section times branching fraction for gluon fusion and b-quark associated Higgs boson production are also given.« less

  14. Search for neutral MSSM Higgs bosons decaying to a pair of tau leptons in pp collisions

    SciTech Connect (OSTI)

    Khachatryan, V.

    2014-10-28

    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, mhmax, mhmod+ , mhmod– , light-stop, light-stau, ?-phobic, and low-mH. Upper limits on the cross section times branching fraction for gluon fusion and b-quark associated Higgs boson production are also given.

  15. A Novel Technique to Reconstruct the $Z$ mass in $WZ/ZZ$ Events with Lepton(s), Missing Transverse Energy and Three Jets at CDFII

    SciTech Connect (OSTI)

    Trovato, Marco; Vernieri, Caterina

    2012-01-01

    Observing WZ/ZZ production at the Tevatron in a final state with a lepton, missing transverse energy and jets is extremely difficult because of the low signal rate and the huge background. In an attempt to increase the acceptance we study the sample where three high-energy jets are reconstructed, where about 1/3 of the diboson signal events are expected to end. Rather than choosing the two E{sub T}-leading jets to detect a Z signal, we make use of the information carried by all jets. To qualify the potential of our method, we estimate the probability of observing an inclusive diboson signal at the three standard deviations level (P{sub 3{sigma}}) to be about four times larger than when using the two leading jets only. Aiming at applying the method to the search for the exclusive WZ/ZZ {yields} {ell}{nu}q{bar q} channel in the three jets sample, we analyzed separately the sample with at least one b-tagged jet and the sample with no tags. In WZ/ZZ {yields} {ell}{nu}b{bar b} search, we observe a modest improvement in sensitivity over the option of building the Z-mass from the two leading jets in E{sub T}. Studies for improving the method further are on-going.

  16. The first measurement of $B$ meson semi-leptonic decay contribution to non-photonic electrons at RHIC

    E-Print Network [OSTI]

    Xiaoyan Lin

    2007-01-30

    We present the first measurement for the $B$ meson semi-leptonic decay contribution to non-photonic electrons at RHIC using non-photonic electron azimuthal correlations with charged hadrons in p+p collisions at $\\sqrt{s_{NN}} = 200$ GeV from STAR.

  17. CDF note 10582 Search for SM Higgs boson production in association with tt using no lepton final state

    E-Print Network [OSTI]

    Fermilab

    CDF note 10582 Search for SM Higgs boson production in association with t¯t using no lepton final is that t¯t 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

  18. Search for Top Squarks in R-Parity-Violating Supersymmetry Using Three or More Leptons and b-Tagged Jets

    E-Print Network [OSTI]

    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 ...

  19. The Effect of Lepton Mass on the Energy and Bond Length of the Hydrogen Molecule Ion Frank Rioux

    E-Print Network [OSTI]

    Rioux, Frank

    The Effect of Lepton Mass on the Energy and Bond Length of the Hydrogen Molecule Ion Frank Rioux geometry (bond length) and energy of the hydrogen molecule ion. The electron has several heavy weight). The molecular orbital for the hydrogen molecule ion is formed as a linear combination of scaled hydrogenic 1s

  20. Measurements of four-lepton production in pp collisions at ?s=8 TeV with the ATLAS Detector

    E-Print Network [OSTI]

    Orlando, Nicola; The ATLAS collaboration

    2015-01-01

    The observation of a new particle consistent with the Standard Model (SM) Higgs boson reported by the ATLAS and CMS Collaborations, is a long-sought achievement of modern physics and represents a new starting point for investigating all the fundamental open questions in particle physics and cosmology. The study of four–lepton production in ATLAS at LHC provides a clean experimental environment for investigating the properties of the Higgs boson, for searching for exotic particles, and for precision tests of the SM gauge symmetry. The inclusive four–lepton line shape measurement (4l, where l = e or ?) in proton-proton collisions at 8 TeV with the ATLAS experiment at LHC, is presented. The measurement is performed in four final states: e+e?e+e? (4e), e+e??+?? (2e2?), ?+??e+e? (2?2e) and ?+ ?? ?+ ?? (4?), where the first lepton pair is defined to be the one with invariant mass closest to the Z boson mass. The analysis considers all four–leptons production modes in the invariant ...

  1. Search for Lepton Flavour Violating Decays Tau -> l Ks with the BABAR Detector

    SciTech Connect (OSTI)

    Cenci, Riccardo; /SLAC

    2009-03-20

    We present the search for the lepton flavour violating decay {tau} {yields} lK{sup 0}{sub s} with the BaBar experiment data. This process and many other lepton flavour violating {tau} decays, like {tau} {yields} {mu}{gamma} and {tau} {yields} lll, are one of the most promising channel to search for evidence of new physics. According to the Standard Model and the neutrino mixing parameters, branching fractions are estimated well below 10{sup -14}, but many models of new physics allow for branching fractions values close to the present experimental sensitivity. This analysis is based on a data sample of 469fb{sup -1} collected by BABAR detector at the PEP-II storage ring from 1999 to 2007, equivalent to 431 millions of {tau} pairs. the BABAR experiment, initially designed for studying CP violation in B mesons, has demonstrated to be one of the most suitable environments for studying {tau} decays. The tracking system, the calorimeter and the particle identification of BABAR, together with the knowledge of the {tau} initial energy, allow an extremely powerful rejection of background events that, for this analysis, is better than 10{sup -9}. Being {tau} {yields} lK{sup 0}{sub s} a decay mode without neutrinos, the signal {tau} decay can be fully reconstructed. Kinematical constraints are used in a fit that provides a decay tree reconstruction with a high resolution. For this analysis MC simulated events play a decisive role for estimating the signal efficiency and study the residual background. High statistics MC sample are produced simulating detector conditions for different periods of data collection, in order to reduce any discrepancies with the data. When discrepancies can not be removed, we perform studies to compute a correction factor or an estimation of systematic errors that need to be included in the final measurement. A significant improvement of the current result can be reached only with a higher statistics and, therefore, with a new collider providing a luminosity from 10 to 100 times more than PEP-II. A new detector, with improved performance and able to collect data in a high background environment, is also requested to fully exploit the capability of such amount of data. In fact, only keeping the efficiency and the background as similar as possible to present ones, we will be able to scale almost linearly the estimated upper limit according to the luminosity. The strong potential of improvement for the search of lepton flavour violation {tau} decays makes the building of such a machine highly desirable.

  2. Electromagnetic Heavy Lepton Pair Production in Relativistic Heavy-Ion Collisions

    E-Print Network [OSTI]

    Sengul, M Y; Mercan, O; Karakus, N G

    2015-01-01

    We calculate the cross sections of electromagnetic productions of muon and tauon pair productions from the ultra-relativistic heavy ion collisions. Since the Compton wavelengths of muon and tauon are comparable to the radius of the colliding ions, nuclear form factors play important roles for calculating the cross sections. Recent measurement [1] indicates that the neutrons are differently distributed from the protons therefore this affects the cross section of the heavy lepton pair production. In order to see the effects of the neutron distributions in the nucleus, we used analytical expression of the Fourier transforms of the Wood-Saxon distribution. Cross section calculations show that Wood-Saxon distribution function is more sensitive to the parameter R compare to the parameter a.

  3. Multi-wavelength constraints on cosmic-ray leptons in the Galaxy

    E-Print Network [OSTI]

    Orlando, E; Moskalenko, I V; Dickinson, C; Digel, S; Jaffe, T R; Jóhannesson, G; Leahy, J P; Porter, T A; Vidal, M

    2015-01-01

    Cosmic rays (CRs) interact with the gas, the radiation field and the magnetic field in the Milky Way, producing diffuse emission from radio to gamma rays. Observations of this diffuse emission and comparison with detailed predictions are powerful tools to unveil the CR properties and to study CR propagation. We present various GALPROP CR propagation scenarios based on current CR measurements. The predicted synchrotron emission is compared to radio surveys, and synchrotron temperature maps from WMAP and Planck, while the predicted interstellar gamma-ray emission is compared to Fermi-LAT observations. We show how multi-wavelength observations of the Galactic diffuse emission can be used to help constrain the CR lepton spectrum and propagation. Finally we discuss how radio and microwave data could be used in understanding the diffuse Galactic gamma-ray emission observed with Fermi-LAT, especially at low energies.

  4. Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aad, G.

    2015-04-21

    Results of a search for H ? ?? decays are presented, based on the full set of proton-proton collision data recorded by the ATLAS experiment at the LHC during 2011 and 2012. The data correspond to integrated luminosities of 4.5 fb–1 and 20.3 fb–1 at centre-of-mass energies of ?s=7 TeV and ?s=8 TeV respectively. All combinations of leptonic (? ? ???¯ with ? = e, ?) and hadronic (? ? hadrons ?) tau decays are considered. An excess of events over the expected background from other Standard Model processes is found with an observed (expected) significance of 4.5 (3.4) standardmore »deviations. This excess provides evidence for the direct coupling of the recently discovered Higgs boson to fermions. The measured signal strength, normalized to the Standard Model expectation, of ? = 1.43–0.37+0.43 is consistent with the predicted Yukawa coupling strength in the Standard Model.« less

  5. The tau leptons theory and experimental data: Monte Carlo, fits, software and systematic errors

    E-Print Network [OSTI]

    Zbigniew Was

    2014-12-09

    Status of tau lepton decay Monte Carlo generator TAUOLA is reviewed. Recent efforts on development of new hadronic currents are presented. Multitude new channels for anomalous tau decay modes and parametrization based on defaults used by BaBar collaboration are introduced. Also parametrization based on theoretical considerations are presented as an alternative. Lesson from comparison and fits to the BaBar and Belle data is recalled. It was found that as in the past, in particular at a time of comparisons with CLEO and ALEPH data, proper fitting, to as detailed as possible representation of the experimental data, is essential for appropriate developments of models of tau decays. In the later part of the presentation, use of the TAUOLA program for phenomenology of W,Z,H decays at LHC is adressed. Some new results, relevant for QED bremsstrahlung in such decays are presented as well.

  6. 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

    2011-08-09

    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 ± 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 ± 1.49 GeV for a total integrated luminosity of 3.6 fb-1.

  7. Precision measurement of the top-quark mass in lepton$+$jets final states

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Abazov, Victor Mukhamedovich

    2015-06-04

    We measure the mass of the top quark in lepton þ jets final states using the full sample of pp¯ collision data collected by the D0 experiment in Run II of the Fermilab Tevatron Collider at ffiffi s p ¼ 1.96 TeV, corresponding to 9.7 fb-1 of integrated luminosity. We also use a matrix element technique that calculates the probabilities for each event to result from t¯t production or background. Furthermore, the overall jet energy scale is constrained in situ by the mass of the W boson. We measure mt ¼ 174.98 0.76 GeV. This constitutes the most precise singlemore »measurement of the top-quark mass.« less

  8. PDF uncertainties on the W boson mass measurement from the lepton transverse momentum distribution

    E-Print Network [OSTI]

    Giuseppe Bozzi; Luca Citelli; Alessandro Vicini

    2015-05-22

    We study the charged current Drell-Yan process and we evaluate the proton parton densities uncertainties on the lepton transverse momentum distribution and their impact on the determination of the W-boson mass. We consider the global PDF sets CT10, MSTW2008CPdeut, NNPDF2.3, NNPDF3.0, MMHT2014, and apply the PDF4LHC recipe to combine the individual results, obtaining an uncertainty on MW that ranges between +-18 and +-24 MeV, depending on the final state, collider energy and kind. We discuss the dependence of the uncertainty on the acceptance cuts and the role of the individual parton densities in the final result. We remark that some PDF sets predict an uncertainty on MW of O(10 MeV); this encouraging result is spoiled, in the combined analysis of the different sets, by an important spread of the central values predicted by each group.

  9. PDF uncertainties on the W boson mass measurement from the lepton transverse momentum distribution

    E-Print Network [OSTI]

    Bozzi, Giuseppe; Vicini, Alessandro

    2015-01-01

    We study the charged current Drell-Yan process and we evaluate the proton parton densities uncertainties on the lepton transverse momentum distribution and their impact on the determination of the W-boson mass. We consider the global PDF sets CT10, MSTW2008CPdeut, NNPDF2.3, NNPDF3.0, MMHT2014, and apply the PDF4LHC recipe to combine the individual results, obtaining an uncertainty on MW that ranges between +-18 and +-24 MeV, depending on the final state, collider energy and kind. We discuss the dependence of the uncertainty on the acceptance cuts and the role of the individual parton densities in the final result. We remark that some PDF sets predict an uncertainty on MW of O(10 MeV); this encouraging result is spoiled, in the combined analysis of the different sets, by an important spread of the central values predicted by each group.

  10. The Leptonic CP Phase from Muon Decay at Rest with Two Detectors

    E-Print Network [OSTI]

    Emilio Ciuffoli; Jarah Evslin; Xinmin Zhang

    2014-03-10

    We propose a novel experimental setup for the determination of the leptonic CP-violating phase delta using the decay at rest (DAR) of mu+ from a single source located at distances of 10 and 30 km from two 20 kton organic liquid scintillator detectors. The mu+ are created by bombarding a target with a 9 mA beam of 800 MeV protons. With this proposal delta can be determined with a precision of about 20 (15) degrees in 6 (12) years. In contrast with the DAEdALUS project, only a single source is required and it runs with a duty factor of 100 percent. Therefore 9 mA is the maximum instanteous current, greatly reducing both the technological challenges and the costs.

  11. Leptonic dark matter annihilation in the evolving universe: constraints and implications

    E-Print Network [OSTI]

    Yuan, Qiang; Bi, Xiaojun; Chen, Xuelei; Zhang, Xinmin

    2009-01-01

    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...

  12. 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

    2011-08-09

    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 ± 1.64 GeV. Combining this result with a previous result obtained on an independent data set, wemore »measure a top-quark mass of mt = 174.94 ± 1.49 GeV for a total integrated luminosity of 3.6 fb-1.« less

  13. Measurement of charm production cross-section and leptons from its semileptonic decay at RHIC

    E-Print Network [OSTI]

    Yifei Zhang

    2008-09-09

    In this thesis, we present the measurements of $D^{0}\\to K\\pi$ at low $p_T$ ($p_T\\leq2$ GeV/$c$) and non-photonic electron spectra ($0.9\\leq p_T\\leq5$ GeV/$c$) from $D^0$ semi-leptonic decay. In addition, we use a newly proposed technique to identify muons from charm decays at low $p_T$. The combination of all these three measurements stringently constrains the total charm production cross-section at mid-rapidity at RHIC. They also allow the extraction of the charmed hadron spectral shape and a study of possible charm radial flow in Au+Au collisions.

  14. Measurement of Angular Correlations in Drell–Yan Lepton Pairs to Probe Z/?[superscript ?] Boson Transverse Momentum at ?s = 7 TeV with the ATLAS Detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    A measurement of angular correlations in Drell–Yan lepton pairs via the ?[* over ?] observable is presented. This variable probes the same physics as the Z/?[superscript ?] boson transverse momentum with a better experimental ...

  15. Searches for supersymmetry with the ATLAS detector using final states with two leptons and missing transverse momentum in ?s = 7 TeV proton–proton collisions

    E-Print Network [OSTI]

    Taylor, Frank E.

    Results of three searches are presented for the production of supersymmetric particles decaying into final states with missing transverse momentum and exactly two isolated leptons, e or ?. The analysis uses a data sample ...

  16. Search for physics beyond the standard model in events with two leptons, jets, and missing transverse momentum in pp collisions at ?s = 8 TeV

    E-Print Network [OSTI]

    Apyan, Aram

    A search is presented for physics beyond the standard model in final states with two opposite-sign same-flavor leptons, jets, and missing transverse momentum. The data sample corresponds to an integrated luminosity of 19.4 ...

  17. Search for heavy lepton partners of neutrinos in proton–proton collisions in the context of the type III seesaw mechanism

    E-Print Network [OSTI]

    Apyan, Aram

    A search is presented in proton–proton collisions at ?s = 7 TeV for fermionic triplet states expected in type III seesaw models. The search is performed using final states with three isolated charged leptons and an imbalance ...

  18. Search for stealth supersymmetry in events with jets, either photons or leptons, and low missing transverse momentum in pp collisions at 8 TeV

    E-Print Network [OSTI]

    Apyan, Aram

    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 a ...

  19. Measurement of the t[bar over t] production cross section in pp collisions at ?s = 8 TeV in dilepton final states containing one ? lepton

    E-Print Network [OSTI]

    Zhukova, Victoria

    The top-quark pair production cross section is measured in final states with one electron or muon and one hadronically decaying ? lepton from the process t[bar over t] ? (??[subscript ?])(??[subscript ?])b[bar over b], ...

  20. Search for TeV-scale gravity signatures in final states with leptons and jets with the ATLAS detector at ?s = 7 TeV

    E-Print Network [OSTI]

    Taylor, Frank E.

    The production of events with multiple high transverse momentum particles including charged leptons and jets is measured, using 1.04 fb[superscript ?1] of proton–proton collision data recorded by the ATLAS detector during ...

  1. Search for Supersymmetry in Events with Four or More Leptons in ?s = 8 TeV pp Collisions with the ATLAS Detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    Results from a search for supersymmetry in events with four or more leptons including electrons, muons and taus are presented. The analysis uses a data sample corresponding to 20.3??fb[superscript ?1] of proton-proton ...

  2. Measurement of Hadron and Lepton-Pair Production in e+e- Collisions at sqrt{s}=192-208GeV at LEP

    E-Print Network [OSTI]

    L3 Collaboration

    2006-03-10

    Hadron production and lepton-pair production in e+e- collisions are studied with data collected with the L3 detector at LEP at centre-of-mass energies sqrt{s}=192-208GeV. Using a total integrated luminosity of 453/pb, 36057 hadronic events and 12863 lepton-pair events are selected. The cross sections for hadron production and lepton-pair production are measured for the full sample and for events where no high-energy initial-state-radiation photon is emitted prior to the collisions. Lepton-pair events are further investigated and forward-backward asymmetries are measured. Finally, the differential cross sections for electron-positron pair-production is determined as a function of the scattering angle. An overall good agreement is found with Standard Model predictions.

  3. Study of top quark production and decays involving a tau lepton at CDF and limits on a charged Higgs boson contribution

    E-Print Network [OSTI]

    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 ...

  4. Measurement of the lepton charge asymmetry in inclusive $W$ production in pp collisions at sqrt(s) = 7 TeV

    SciTech Connect (OSTI)

    Chatrchyan, V.; et al.,

    2011-04-01

    A measurement of the lepton charge asymmetry in inclusive pp to WX production at sqrt(s)= 7 TeV is presented based on data recorded by the CMS detector at the LHC and corresponding to an integrated luminosity of 36 inverse picobarns. This high precision measurement of the lepton charge asymmetry, performed in both the W to e nu and W to mu nu channels, provides new insights into parton distribution functions.

  5. The Effects of Fourth Generation on the Total Branching Ratio and the Lepton Polarization in $?_b \\rar ?\\ell^+ \\ell^-$ decay

    E-Print Network [OSTI]

    V. Bashiry; K. Azizi

    2007-07-09

    This study investigates the influence of the fourth generation quarks on the total branching ratio and the single lepton polarizations in \\Lambda_b --> \\Lambda \\ell^+ \\ell^- decay. Taking $|V_{t's}V_{t'b}| {0.01-0.03} with phase just below $90^\\circ$, which is consistent with the b\\to s\\ell^+\\ell^- rate and the B_s mixing parameter \\Delta m_{B_s}, we obtain that the total branching ratio and the single lepton(\\mu, \\tau) polarizations are quite sensitive to the existence of fourth generation. It can serve as a good tool to search for new physics effects, precisely, to search for the fourth generation quarks(t', b').

  6. Ansatz of Leptonic Mixing: The Alliance of Bi-Maximal Mixing with a Single-Angle Rotation

    E-Print Network [OSTI]

    Siyeon, Kim

    2012-01-01

    We introduce an ansatz of the PMNS matrix that consists of specific types of transformations. Bi-maximal mixing is taken for the neutrino masses, while a single-angle rotation in the 1-2 block is taken for the charged lepton masses. Motivated by the implications of the recent results on neutrino oscillations, $\\theta_{23}$ in the first octant and non-zero $\\theta_{13}$ are predicted by the ansatz. Three physical mixing angles are expressed in terms of a single variable, the 1-2 angle of charged leptons, so that a simple relation among the angles has been obtained: $\\tan\\theta_{13}=\\sqrt{2}(\\sin\\theta_{23}-\\sin\\theta_{12})$. It follows that a model of the inverted hierarchy that can produce the given ansatz is proposed.

  7. Search for lepton--flavour--violating $H\\to\\mu\\tau$ decays of the Higgs boson with the ATLAS detector

    E-Print Network [OSTI]

    ,; ATLAS Collaboration

    2015-01-01

    A direct search for lepton--flavour--violating (LFV) $H\\to\\mu\\tau$ decays of the recently discovered Higgs boson with the ATLAS detector at the LHC is presented. The analysis is performed in the $H\\to\\mu\\tau_{\\mathrm{had}}$ channel, where $\\tau_{\\mathrm{had}}$ is a hadronically decaying $\\tau$--lepton. The search is based on the data sample of proton--proton collisions collected by the ATLAS experiment corresponding to an integrated luminosity of 20.3~fb$^{-1}$ at a centre--of--mass energy of $\\sqrt{s}=8$ TeV. No statistically significant excess of data over the predicted background is observed. The observed (expected) 95% confidence--level upper limit on the branching fraction, Br($H\\to\\mu\\tau$), is 1.85% (1.24%).

  8. The two-loop helicity amplitudes for $q \\bar q' \\to V_1 V_2 \\to 4~\\mathrm{leptons}$

    E-Print Network [OSTI]

    Thomas Gehrmann; Andreas von Manteuffel; Lorenzo Tancredi

    2015-09-11

    We compute the two-loop massless QCD corrections to the helicity amplitudes for the production of two massive vector bosons in quark-antiquark annihilation, allowing for an arbitrary virtuality of the vector bosons: $q \\bar q' \\to V_1V_2$. Combining with the leptonic decay currents, we obtain the full two-loop QCD description of the corresponding electroweak four-lepton production processes. The calculation is performed by projecting the two-loop diagrams onto an appropriate basis of Lorentz structures. All two-loop Feynman integrals are reduced to a basis of master integrals, which are then computed using the differential equations method and optimised for numerical performance. We provide a public C++ code which allows for fast and precise numerical evaluations of the amplitudes.

  9. Two-stage acceleration of interstellar ions due to the interaction of high-energy lepton plasma flow

    E-Print Network [OSTI]

    Cui, Yun-Qian; Lu, Quan-Ming; Li, Yu-Tong; Zhang, Jie

    2015-01-01

    We present the particle-in-cell (PIC) simulation results of the interaction of a high-energy lepton plasma flow with background electron-proton plasma and focus on the acceleration processes of the protons. It is found that the acceleration follows a two-stage processes. In the first stage, protons are accelerated transversely (perpendicular to the lepton flow) by the turbulent magnetic field "islands" generated via the strong Weibel-type instabilities. The accelerated protons shows a perfect inverse-power energy spectrum. As the interaction continues, a shockwave structure forms and the protons in front of the shockwave are reflected at twice of the shock speed, resulting in a quasi-monoenergetic peak located near 200MeV under the simulation parameters.

  10. Study of two- and three-meson decay modes of tau-lepton with Monte Carlo generator TAUOLA

    E-Print Network [OSTI]

    Shekhovtsova, Olga

    2015-01-01

    The study of the $\\tau$-lepton decays into hadrons has contributed to a better understanding of non-perturbative QCD and light-quark meson spectroscopy, as well as to the search of new physics beyond the Standard Model. The two- and three-meson decay modes, considering only those permitted by the Standard Model, are the predominant decays and together with the one-pion mode compose more than $85\\%$ of the hadronic $\\tau$-lepton decay width. In this note we review the theoretical results for these modes implemented in the Monte Carlo event generator TAUOLA and present at the same time a comparison with the Belle Collaboration data for the two-pion decay mode and the BaBar preliminary data for the three-pion decay mode as well for the decay mode into two-kaon and one-pion.

  11. DELAYED ONSET OF HIGH-ENERGY EMISSIONS IN LEPTONIC AND HADRONIC MODELS OF GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    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)

    2012-10-01

    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.

  12. Inclusive tau lepton hadronic decay in vector and axial-vector channels within dispersive approach to QCD

    E-Print Network [OSTI]

    Nesterenko, A V

    2015-01-01

    The dispersive approach to QCD, which properly embodies the intrinsically nonperturbative constraints originating in the kinematic restrictions on relevant physical processes and extends the applicability range of perturbation theory towards the infrared domain, is briefly overviewed. The study of OPAL (update 2012) and ALEPH (update 2014) experimental data on inclusive tau lepton hadronic decay in vector and axial-vector channels within dispersive approach is presented.

  13. Top quark pair production cross section in the lepton+jets channel using b-tagging at D0

    SciTech Connect (OSTI)

    Yoo, H.D.; /Brown U.

    2008-05-01

    The top quark pair production cross section measurement in the lepton+jets channel with b-tagging algorithm is described. About 900 pb{sup -1} data collected by the D0 detector at the Fermilab Tevatron are used for this analysis. In this thesis, event selection, background estimation, and cross section calculation are discussed in detail. In addition, calibration of the Luminosity Monitor readout electronics and a new b-tagging algorithm, the SLTNN tagger, are also discussed in this thesis.

  14. Searching for Lepton Flavor Violation at a Future High Energy Electron-Positron Collider

    E-Print Network [OSTI]

    Brandon Murakami; Tim M. P. Tait

    2014-10-06

    We consider theories where lepton flavor is violated, in particular concentrating on the four fermion operator consisting of three electrons and a tau. Strong constraints are available from existing searches for tau -> eee, requiring the scale of the contact interaction to be less than ~(9 TeV)^-2. We reexamine this type of physics, assuming that the particles responsible are heavy (with masses greater than ~TeV) such that a contact interaction description continues to be applicable at the energies for a future e+e- collider. We find that the process e+e- -> e tau can be a very sensitive probe of this kind of physics (even for very conservative assumptions about the detector performance), already improving upon the tau decay bounds to less than ~(11 TeV)^-2 at collider energy sqrt(s) 500 GeV, or reaching beyond ~(35 TeV)^-2 for sqrt(s) = 3 TeV. Even stronger bounds are possible at e-e- colliders in the same energy range.

  15. Search for Lepton-Number Violating Processes in B+ to h- l+ l+ Decays

    SciTech Connect (OSTI)

    Lees, J.P.

    2012-05-17

    We have searched for the lepton-number violating processes B{sup +} {yields} h{sup -}{ell}{sup +}{ell}{sup +} with h{sup -} = K{sup -}/{pi}{sup -} and {ell}{sup +} = e{sup +}/{mu}{sup +}, using a sample of 471 {+-} 3 million B{bar B} events collected with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory. We find no evidence for these decays and place 90% confidence level upper limits on their branching fractions B (B{sup +} {yields} {pi}{sup -}e{sup +}e{sup +}) < 2.3 x 10{sup -8}, {Beta}(B{sup +} {yields} K{sup -}e{sup +}e{sup +}) < 3.0 x 10{sup -8}, {Beta}(B{sup +} {yields} {pi}{sup -}{mu}{sup +}{mu}{sup +}) < 10.7 x 10{sup -8}, and {Beta}(B{sup +} {yields} K{sup -}{mu}{sup +}{mu}{sup +}) < 6.7 x 10{sup -8}.

  16. Search for Rare Multi-Pion Decays of the Tau Lepton Using the BABAR Detector

    SciTech Connect (OSTI)

    Ter-Antonyan, Ruben

    2007-09-18

    A search for the decay of the {tau} lepton to rare multi-pion final states is performed using the BABAR detector at the PEP-II asymmetric-energy e+e- collider. The analysis uses 232 fb-1 of data at center-of-mass energies on or near the {Upsilon}(4S) resonance. In the search for the {tau}- {yields} 3{pi}-2{pi}+2{pi}{sup 0}{nu}{sub {tau}} decay, we observe 10 events with an expected background of 6.5{sup +2.0}{sub -1.4} events. In the absence of a signal, we calculate the decay branching ratio upper limit {beta}({tau}- {yields} 3{pi}-2{pi}+2{pi}{sup 0}{nu}{sub {tau}}) < 3.4 x 10{sup -6} at the 90% confidence level. This is more than a factor of 30 improvement over the previously established limit. In addition, we search for the exclusive decay mode {tau}- {yields} 2{omega}{pi}-{nu}{sub {tau}} with the further decay of {omega} {yields} {pi}-{pi}+{pi}{sup 0}. We observe 1 event, expecting 0.4{sup +1.0}{sub -0.4} background events, and calculate the upper limit {beta}{tau}-{yields} 2{omega}{pi}-{nu}{sub {tau}} < 5.4 x 10{sup -7} at the 90% confidence level. This is the first upper limit for this mode.

  17. Time-space symmetry as a solution to the mass hierarchy of charged lepton generations

    E-Print Network [OSTI]

    Vo Van Thuan

    2015-07-27

    Based on an extended time-space symmetry, a cylindrical model of gravitational geometrical dynamics with two time-like extra-dimensions leads to a microscopic geodesic description of the curved space-time. Due to interaction of a Higgs-like cosmological potential with individual space-time fluctuations, the original time-space symmetry is spontaneously broken, inducing a strong time-like curvature and a weak space-like deviation curve. As a result, the basic Klein-Gordon-Fock equation of a free massive elementary particle was derived, which implies a duality between the quantum mechanics equation and a microscopic geodesic description in the frame of general relativity. Consequently, Heisenberg inequalities are determined explicitly by the space-time curvatures. Moreover, extending curvatures to higher time-like dimensional hyper-spherical surfaces than one of the basic common cylindrical configuration, we found reasonable mass ratios of all charged leptons and succeeded to fix the number of their generations to be three. Following to concepts of the standard cosmological model, a possible experimental verification of mass ratio variation is proposed.

  18. Time-space symmetry as a solution to the mass hierarchy of charged lepton generations

    E-Print Network [OSTI]

    Van Thuan, Vo

    2015-01-01

    Based on an extended time-space symmetry, a cylindrical model of gravitational geometrical dynamics with two time-like extra-dimensions leads to a microscopic geodesic description of the curved space-time. Due to interaction of a Higgs-like cosmological potential with individual space-time fluctuations, the original time-space symmetry is spontaneously broken, inducing a strong time-like curvature and a weak space-like deviation curve. As a result, the basic Klein-Gordon-Fock equation of a free massive elementary particle was derived, which implies a duality between the quantum mechanics equation and a microscopic geodesic description in the frame of general relativity. Consequently, Heisenberg inequalities are determined explicitly by the space-time curvatures. Moreover, extending curvatures to higher time-like dimensional hyper-spherical surfaces than one of the basic common cylindrical configuration, we found reasonable mass ratios of all charged leptons and succeeded to fix the number of their generations...

  19. Neutrino properties deduced from the study of lepton number violating processes at low and high energies

    SciTech Connect (OSTI)

    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)

    2012-11-20

    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.

  20. Lepton number violating processes mediated by Majorana neutrinos at hadron colliders

    SciTech Connect (OSTI)

    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)

    2009-10-01

    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.

  1. Limits on the Higgs boson lifetime and width from its decay to four charged leptons

    E-Print Network [OSTI]

    CMS Collaboration

    2015-07-23

    Constraints on the lifetime and width of the Higgs boson are obtained from H to ZZ to 4 lepton events using data recorded by the CMS experiment during the LHC run 1 with an integrated luminosity of 5.1 and 19.7 inverse femtobarns at a center-of-mass energy of 7 and 8 TeV, respectively. The measurement of the Higgs boson lifetime is derived from its flight distance in the CMS detector with an upper bound of tau[H] 3.5E-9 MeV. The measurement of the width is obtained from an off-shell production technique, generalized to include anomalous couplings of the Higgs boson to two electroweak bosons. From this measurement, a joint constraint is set on the Higgs boson width and a parameter f[LQ] that expresses an anomalous coupling contribution as an on-shell cross-section fraction. The limit on the Higgs boson width is Gamma[H] Higgs boson width.

  2. Discovery and Characterization of a Higgs boson using four-lepton events from the CMS experiment

    E-Print Network [OSTI]

    AUTHOR|(SzGeCERN)678846

    2015-01-01

    A new particle decaying to a pair of vector bosons was discovered in 2012 by the ATLAS and CMS experiments at the Large Hadron Collider. In the wake of this discovery a rush of measurements was made to characterize this particle. The four-lepton final state has been instrumental in both the discovery and characterization of this new particle. With only about 20 events seen in the resonance peak at 125GeV the CMS experiment has been able to make considerable progress in characterizing the Higgs-like boson using the wealth of information in this final state in concert with other decay modes. In addition to the search for this new boson we present three recent results in the study of the Higgs-like boson properties: studies of the production mode, total width, and spin-parity quantum numbers. First we present the search for this new resonance using the H to ZZ to 4l decay channel. Then we discuss the production mode measurement using this final state. Next, we present two results that provided breakthroughs in t...

  3. Quark-Lepton Complementarity Predictions for $\\theta_{23}^{pmns}$ and CP Violation

    E-Print Network [OSTI]

    Sharma, Gazal

    2015-01-01

    In the light of recent experimental results on $\\theta_{13}^{pmns}$, we re-investigate the complementarity between the quark and lepton mixing matrices and obtain predictions with updated global data fits. This paper is motivated by our previous work where in a QLC model we predicted the value for $\\theta_{13}^{pmns}=(9{^{+1}_{-2}})^\\circ$, which was found to be in strong agreement with the experimental results. In the QLC model the non-trivial correlation between CKM and PMNS mixing matrices is given by a correlation matrix ($V_{c}$). We do numerical simulation and estimate the texture of the $V_{c}$ and in our findings we get a small deviation from the Tri-Bi-Maximal (TBM) texture and a large from the Bi-Maximal one, which is consistent with the work already reported in literature. In the further investigation we obtain quite constrained limits for $sin^2{\\theta_{23}^{pmns}}= 0.4235_{-0.0043}^{+0.0032}$ that is narrower to the existing ones. We also obtain the constrained limits for the three CP violating p...

  4. Identification and energy calibration of hadronically decaying tau leptons with the ATLAS experiment in pp collisions at ?s = 8 TeV

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aad, G.

    2015-07-02

    This study 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 ?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 2–4%, depending on transverse energy and pseudorapidity, is achieved using two independent methods. The offline tau identification efficiency is measured withmore »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 2–8%, 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.« less

  5. Measurement of the top quark mass in the tt¯? lepton+jets and tt¯? dilepton channels using ?s = 7   TeV ATLAS data

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aad, G.

    2015-07-17

    The top quark mass was measured in the channels tt¯? lepton+jets and tt¯? dilepton (lepton = e,?) based on ATLAS data recorded in 2011. The data were taken at the LHC with a proton–proton centre-of-mass energy of ?s = 7 TeV and correspond to an integrated luminosity of 4.6 fb–1. The tt¯? lepton+jets analysis uses a three-dimensional template technique which determines the top quark mass together with a global jet energy scale factor (JSF), and a relative b-to-light-jet energy scale factor (bJSF), where the terms b-jets and light-jets refer to jets originating from b-quarks and u, d, c, s-quarks ormore »gluons, respectively. The analysis of the tt¯? dilepton channel exploits a one-dimensional template method using the m?b observable, defined as the average invariant mass of the two lepton+b-jet pairs in each event. The top quark mass is measured to be 172.33 ± 0.75 (stat + JSF + bJSF) ± 1.02(syst) GeV, and 173.79 ± 0.54(stat) ± 1.30(syst) GeV in the tt¯? lepton+jets and tt¯? dilepton channels, respectively. Thus, the combination of the two results yields mtop = 172.99 ± 0.48(stat) ± 0.78(syst) GeV, with a total uncertainty of 0.91 GeV.« less

  6. Monte-Carlo simulation of lepton pair production in "p pbar --> l+l- + X" events at E_beam = 14 GeV

    E-Print Network [OSTI]

    A. N. Skachkova; N. B. Skachkov; G. D. Alexeev

    2011-03-08

    The lepton pair production in collisions of antiproton beam (E_beam = 14 GeV) with proton target is studied on the basis of event samples simulated with PYTHIA6 generator. Two types of quark level subprocesses are considered. The first one goes through the production of virtual photon which converts into lepton pair (q qbar --> gamma* --> l+l-) having a continuous energy spectrum of the final lepton pair invariant mass. The other subprocess proceeds through the J/Psi resonance production (p pbar --> J/Psi + X --> l+l- + X) with the following decay of J/Psi into a pair of leptons. The distributions of different kinematical variables which may be useful for the design of the muon system and the electromagnetic calorimeter of the detector of PANDA experiment at FAIR are presented. The analysis of these distribution shows the possibility to measure the proton structure function in a new kinematical region defined by the time-like values of the square of the momentum transferred 1 processes, are also discussed. The set of cuts which allows one to separate the signal events with lepton pairs from this kind of background events is proposed.

  7. Averages of B-Hadron, C-Hadron, and tau-lepton properties as of early 2012

    SciTech Connect (OSTI)

    Amhis, Y.; et al.

    2012-07-01

    This article reports world averages of measurements of b-hadron, c-hadron, and tau-lepton properties obtained by the Heavy Flavor Averaging Group (HFAG) using results available through the end of 2011. In some cases results available in the early part of 2012 are included. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, CP violation parameters, parameters of semileptonic decays and CKM matrix elements.

  8. Search for baryon-number and lepton-number violating decays of $Lambda$ hyperons using the CLAS detector at Jefferson Laboratory

    SciTech Connect (OSTI)

    McCracken, Michael E.

    2015-10-09

    We present a search for ten baryon-number violating decay modes of $\\Lambda$ hyperons using the CLAS detector at Jefferson Laboratory. Nine of these decay modes result in a single meson and single lepton in the final state ($\\Lambda \\rightarrow m \\ell$) and conserve either the sum or the difference of baryon and lepton number ($B \\pm L$). The tenth decay mode ($\\Lambda \\rightarrow \\bar{p}\\pi^+$) represents a difference in baryon number of two units and no difference in lepton number. We observe no significant signal and set upper limits on the branching fractions of these reactions in the range $(4-200)\\times 10^{-7}$ at the $90\\%$ confidence level.

  9. Search for baryon-number and lepton-number violating decays of $Lambda$ hyperons using the CLAS detector at Jefferson Laboratory

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    McCracken, Michael E.

    2015-10-09

    We present a search for ten baryon-number violating decay modes of $\\Lambda$ hyperons using the CLAS detector at Jefferson Laboratory. Nine of these decay modes result in a single meson and single lepton in the final state ($\\Lambda \\rightarrow m \\ell$) and conserve either the sum or the difference of baryon and lepton number ($B \\pm L$). The tenth decay mode ($\\Lambda \\rightarrow \\bar{p}\\pi^+$) represents a difference in baryon number of two units and no difference in lepton number. We observe no significant signal and set upper limits on the branching fractions of these reactions in the range $(4-200)\\times 10^{-7}$more »at the $90\\%$ confidence level.« less

  10. Search for anomalous production of prompt like-sign lepton pairs at $ \\sqrt{s}=7\\;\\mathrm{TeV} $ with the ATLAS detector

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aad, G.

    2012-12-03

    An inclusive search for anomalous production of two prompt, isolated leptons with the same electric charge is presented. The search is performed in a data sample corresponding to 4.7 fb-1 of integrated luminosity collected in 2011 at ?s = 7 TeV with the ATLAS detector at the LHC. Pairs of leptons (e± e±, e± ?±, and ?± ?±) with large transverse momentum are selected, and the dilepton invariant mass distribution is examined for any deviation from the Standard Model expectation. No excess is found, and upper limits on the production cross section of like-sign lepton pairs from physics processes beyondmore »the Standard Model are placed as a function of the dilepton invariant mass within a fiducial region close to the experimental selection criteria. The 95% confidence level upper limits on the cross section of anomalous e± e±, e± ?±, or ?± ?± production range between 1.7 fb and 64 fb depending on the dilepton mass and flavour combination.« less

  11. Self-sustained asymmetry of lepton-number emission: a new phenomenon during the supernova shock-accretion phase in three dimensions

    SciTech Connect (OSTI)

    Tamborra, Irene; Raffelt, Georg G. [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, D-80805 München (Germany); Hanke, Florian; Janka, Hans-Thomas; Müller, Bernhard [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Marek, Andreas [Rechenzentrum der Max-Planck-Gesellschaft, Boltzmannstr. 2, D-85741 Garching (Germany)

    2014-09-10

    During the stalled-shock phase of our three-dimensional, hydrodynamical core-collapse simulations with energy-dependent, three-flavor neutrino transport, the lepton-number flux (? {sub e} minus ?-bar {sub e}) emerges predominantly in one hemisphere. This novel, spherical-symmetry breaking neutrino-hydrodynamical instability is termed LESA for 'Lepton-number Emission Self-sustained Asymmetry'. While the individual ? {sub e} and ?-bar {sub e} fluxes show a pronounced dipole pattern, the heavy-flavor neutrino fluxes and the overall luminosity are almost spherically symmetric. Initially, LESA seems to develop stochastically from convective fluctuations. It exists for hundreds of milliseconds or more and persists during violent shock sloshing associated with the standing accretion shock instability. The ? {sub e} minus ?-bar {sub e} flux asymmetry originates predominantly below the neutrinosphere in a region of pronounced proto-neutron star (PNS) convection, which is stronger in the hemisphere of enhanced lepton-number flux. On this side of the PNS, the mass accretion rate of lepton-rich matter is larger, amplifying the lepton-emission asymmetry, because the spherical stellar infall deflects on a dipolar deformation of the stalled shock. The increased shock radius in the hemisphere of less mass accretion and minimal lepton-number flux ( ?-bar {sub e} flux maximum) is sustained by stronger convection on this side, which is boosted by stronger neutrino heating due to ??{sub ?-bar{sub e}}?>??{sub ?{sub e}}?. Asymmetric heating thus supports the global deformation despite extremely nonstationary convective overturn behind the shock. While these different elements of the LESA phenomenon form a consistent picture, a full understanding remains elusive at present. There may be important implications for neutrino-flavor oscillations, the neutron-to-proton ratio in the neutrino-heated supernova ejecta, and neutron-star kicks, which remain to be explored.

  12. arXiv:0708.1344v1[hep-ph]9Aug2007 NUHEP-TH/07-10 A Survey of Lepton Number Violation Via Effective Operators

    E-Print Network [OSTI]

    number violating phenomena. These include searches for neutrinoless double-beta decay and rare meson 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

  13. Improving estimates of the number of fake leptons and other mis-reconstructed objects in hadron collider events: BoB's your UNCLE

    E-Print Network [OSTI]

    Gillam, Thomas P. S.; Lester, Christopher G.

    2014-11-06

    with missing transverse momentum and at least three b-jets using 20.1 fb?1 of pp collisions at ?s = 8 TeV with the ATLAS detector,ATLAS-CONF-2013-061, CERN, Geneva Switzerland (2013) [INSPIRE]. [2] ATLAS collaboration, Background studies for top-pair production... in lepton plus jets final states in ?s = 7 TeV ATLAS data, ATLAS-CONF-2010-087, CERN, Geneva Switzerland (2010) [INSPIRE]. [3] ATLAS collaboration, Search for supersymmetry using final states with one lepton, jets and missing transverse momentum...

  14. Implications of the Diboson Excess for Neutrinoless Double Beta Decay and Lepton Flavor Violation in TeV Scale Left Right Symmetric Model

    E-Print Network [OSTI]

    Awasthi, Ram Lal; Mitra, Manimala

    2015-01-01

    Inspired by the recent diboson excess observed at the LHC and possible interpretation within a TeV-scale Left-Right symmetric framework, we explore its implications for low-energy experiments searching for lepton number and flavor violation. Assuming a simple Type-II seesaw mechanism for neutrino masses, we show that for the right-handed (RH) gauge boson mass and coupling values required to explain the LHC anomalies, the RH contribution to the lepton number violating process of neutrinoless double beta decay ($0\

  15. Search for high-mass states with one lepton plus missing transverse momentum in proton–proton collisions at ?s = 7 TeV with the ATLAS detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    The ATLAS detector is used to search for high-mass states, such as heavy charged gauge bosons (W?,W*), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of pp ...

  16. Search for Flavor-Changing Neutral Current and Lepton-Flavor Violating Decays of D[superscript 0]-->l+l-

    E-Print Network [OSTI]

    Cowan, Ray Franklin

    We report on a search for the flavor-changing neutral current decays D0?e+e- and D0??+?-, and the lepton-flavor violating decay D0?e±??. The measurement is based on 122??fb-1 of data collected by the BABAR detector at the ...

  17. NLO QCD corrections to off-shell top-antitop production with leptonic decays in association with a Higgs boson at the LHC

    E-Print Network [OSTI]

    Denner, Ansgar

    2015-01-01

    We compute the hadronic production of top-antitop pairs in association with a Higgs boson at next-to-leading-order QCD, including the decay of the top and antitop quark into bottom quarks and leptons. Our computation is based on full leading and next-to-leading-order matrix elements for $e^+ \

  18. Search for standard model production of four top quarks in the lepton + jets channel in pp collisions at ?s = 8 TeV

    E-Print Network [OSTI]

    CMS Collaboration

    A search is presented for standard model (SM) production of four top quarks (tt¯tt¯) in pp collisions in the lepton + jets channel. The data correspond to an integrated luminosity of 19.6 fb[superscript ?1] recorded at a ...

  19. Search for pair production of scalar top quarks decaying to a tau lepton and a b quark in 1.96 TeV ppbar collisions

    SciTech Connect (OSTI)

    Khotilovich, Vadim, G.; /Texas A-M

    2008-05-01

    I present the results of a search for pair production of scalar top quarks ({tilde t}{sub 1}) in an R-parity violating supersymmetric scenario using 322 pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV collected by the upgraded Collider Detector at Fermilab. I assume each {tilde t}{sub 1} decays into a {tau} lepton and a b quark, with branching ratio {beta}, 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 final selection criteria, consistent with the expectation from standard model processes. I present upper limits on the cross section times branching ratio squared {sigma}({tilde t}{sub 1}{bar {tilde t}}{sub 1}) x {beta}{sup 2} as a function of the stop mass m({tilde t}{sub 1}). Assuming {beta} = 1, I set a 95% confidence level limit m({tilde t}{sub 1}) > 153 GeV=c{sup 2}. These limits are also fully applicable to the case of a pair produced third generation scalar leptoquark that decays into a {tau} lepton and a b quark.

  20. Search for new phenomena in events with three charged leptons at sqrt[s]=7??TeV with the ATLAS detector

    E-Print Network [OSTI]

    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 ...

  1. Measurement of R = B(t?Wb)/B(t?Wq) in top-quark-pair decays using lepton+jets events and the full CDF run II dataset

    E-Print Network [OSTI]

    Gomez-Ceballos, Guillelmo

    We present a measurement of the ratio of the top-quark branching fractions R=B(t?Wb)/ B(t?Wq), where q represents quarks of type b, s, or d, in the final state with a lepton and hadronic jets. The measurement uses ?s=1.96??TeV ...

  2. Herwig++ Monte Carlo At Next-To-Leading Order for e+e- annihilation and lepton pair production.

    E-Print Network [OSTI]

    Latunde-Dada, Oluseyi

    . They are the emission of a gluon, q + q¯ ? V + g and the QCD Compton subprocess, q + g ? V + q. Both are illustrated in Figure 4. q _p pq pV pg q q V g _ Vq g q pV pqpg pq ’ Figure 4: NLO diagrams for lepton pair production. – 3 – The generic MC@NLO method is described... S 2? CF ( 3 (1? x)+ ? 6? 4x + 2(1 + x2) ( ln(1? x) 1? x ) + + ( 1 + 4 3 ?2 ) ?(1? x) )) ?Mqq¯ } + FV gMqq¯] . (7.3) where J = Jq ?Jq¯. A similar procedure can be adopted for the Compton subprocess which as discussed has one jet region. In this case...

  3. PIC simulation study of the interaction between a relativistically moving leptonic micro-cloud and ambient electrons

    E-Print Network [OSTI]

    Dieckmann, M E; Markoff, S; Borghesi, M; Zepf, M

    2015-01-01

    The jets of compact accreting objects are composed of electrons and a mixture of positrons and ions. These outflows impinge on the interstellar or intergalactic medium and both plasmas interact via collisionless processes. Filamentation (beam-Weibel) instabilities give rise to the growth of strong electromagnetic fields. These fields thermalize the interpenetrating plasmas. Hitherto, the effects imposed by a spatial non-uniformity on filamentation instabilities have remained unexplored. We examine the interaction between spatially uniform background electrons and a minuscule cloud of electrons and positrons. A square micro-cloud of equally dense electrons and positrons impinges in our particle-in-cell (PIC) simulation on a spatially uniform plasma at rest. The mean speed of the micro-cloud corresponds to a relativistic factor of 15, which is relevant for laboratory experiments and for relativistic astrophysical outflows. The spatial distributions of the leptons and of the electromagnetic fields are examined a...

  4. Search for supersymmetry with jets, missing transverse momentum and at least one hadronically decaying ? lepton in proton–proton collisions at ?s = 7 TeV with the ATLAS detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    A search for production of supersymmetric particles in final states containing jets, missing transverse momentum, and at least one hadronically decaying ? lepton is presented. The data were recorded by the ATLAS experiment ...

  5. Search for Gluinos in Events with Two Same-Sign Leptons, Jets, and Missing Transverse Momentum with the ATLAS Detector in pp Collisions at ?s=7??TeV

    E-Print Network [OSTI]

    Taylor, Frank E.

    A search is presented for gluinos decaying via the supersymmetric partner of the top quark using events with two same-sign leptons, jets, and missing transverse momentum. The analysis is performed with 2.05??fb-1 of ...

  6. Search for top squark pair production in final states with one isolated lepton, jets, and missing transverse momentum in ?s = 8 TeV pp collisions with the ATLAS detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    The results of a search for top squark (stop) pair production in final states with one isolated lepton, jets, and missing transverse momentum are reported. The analysis is performed with proton-proton collision data at ?s ...

  7. Search for physics beyond the standard model in events with two leptons, jets, and missing transverse momentum in pp collisions at ?s = 8 TeV

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Khachatryan, V.; et al.

    2015-04-22

    A search is presented for physics beyond the standard model in final states with two opposite-sign same-flavor leptons, jets, and missing transverse momentum. The data sample corresponds to an integrated luminosity of 19.4 fb-1 of proton-proton collisions at ?s¯ = 8 TeV collected with the CMS detector at the CERN LHC in 2012. The analysis focuses on searches for a kinematic edge in the invariant mass distribution of the oppositesign same-flavor lepton pair and for final states with an on-shell Z boson. The observations are consistent with expectations from standard model processes and are interpreted in terms of upper limitsmore »on the production of supersymmetric particles.« less

  8. Measurement of $ZZ$ production in leptonic final states at $\\surd{s}$ of 1.96 TeV at CDF

    SciTech Connect (OSTI)

    Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J.A.; Arisawa, T.; Artikov, A.; /Dubna, JINR /Texas A-M

    2011-12-01

    In this paper we present a precise measurement of the total ZZ production cross section in p{bar p} collisions at {radical}s = 1.96 TeV, using data collected with the CDF II detector corresponding to an integrated luminosity of approximately 6 fb{sup -1}. The result is obtained by combining separate measurements in the four-charged ({ell}{ell}{ell}{prime}{ell}{prime}), and two-charged-lepton and two-neutral-lepton ({ell}{ell}{nu}{nu}) decay modes of the Z. The combined measured cross section for p{bar p} {yields} ZZ is 1.64{sub -0.38}{sup +0.44} pb. This is the most precise measurement of the ZZ production cross section in 1.96 TeV p{bar p} collisions to date.

  9. Light Vector Meson Photoproduction off of 1H at Jefferson Lab and p-w Interference in the Leptonic Decay Channel

    SciTech Connect (OSTI)

    Djalali, Chaden; Paolone, Michael; Weygand, Dennis; Wood, Mike H.

    2014-09-01

    Although the phenomena of r – w interference has been studied at great length in pionic decay channel over the past 50 years, a study of the interference in a purely electromagnetic production and decay channel has never been performed on an elementary proton target until now. The only published photo-production data of the r - w leptonic decay channel was obtained in the early seventies on C and Be. An investigation of the r - w interference on a Hydrogen was recently completed at Jefferson Lab with the CLAS detector. The di-lepton spectra was fit with two inter- fering relativistic Breit-Wigner functions, and the interference phase was extracted. Preliminary results will be compared to the previous experimental studies in nuclei.

  10. Search for squark production in events with jets, hadronically decaying tau leptons and missing transverse energy at s**(1/2) = 1.96-TeV

    SciTech Connect (OSTI)

    Abazov, V.M.; /Dubna, JINR; Abbott, B.; /Oklahoma U.; Abolins, M.; /Michigan State U.; Acharya, B.S.; /Tata Inst.; Adams, M.; /Illinois U., Chicago; Adams, T.; /Florida State U.; Aguilo, E.; /Alberta U. /Simon Fraser U. /York U., Canada /McGill U.; Ahsan, M.; /Kansas State U.; Alexeev, G.D.; /Dubna, JINR; Alkhazov, G.; /St. Petersburg, INP; Alton, A.; /Michigan U. /Northeastern U.

    2009-05-01

    A search for supersymmetric partners of quarks is performed in the topology of multijet events accompanied by at least one tau lepton decaying hadronically and large missing transverse energy. Approximately 1 fb-1 of ppbar collision data from the Fermilab Tevatron Collider at a center of mass energy of 1.96 TeV recorded by the D0 detector is analyzed. Results are combined with the previously published D0 inclusive search for squarks and gluinos. No evidence of physics beyond the standard model is found and lower limits on the squark mass up to 410 GeV are derived in the framework of minimal supergravity with tan(beta)=15, A{sub 0}=-2m{sub 0} and mu<0, in the region where decays to tau leptons dominate. Gaugino masses m{sub 1/2} are excluded up to 172 GeV.

  11. Phenomenology of the SU(3){sub c}xSU(3){sub L}xU(1){sub X} model with exotic charged leptons

    SciTech Connect (OSTI)

    Salazar, Juan C.; Ponce, William A.; Gutierrez, Diego A.

    2007-04-01

    A phenomenological analysis of the three-family model based on the local gauge group SU(3){sub c}xSU(3){sub L}xU(1){sub X} with exotic charged leptons, is carried out. Instead of using the minimal scalar sector able to break the symmetry in a proper way, we introduce an alternative set of four Higgs scalar triplets, which combined with an anomaly-free discrete symmetry, produce quark and charged lepton mass spectrum without hierarchies in the Yukawa coupling constants. We also embed the structure into a simple gauge group and show some conditions to achieve a low energy gauge coupling unification, avoiding possible conflict with proton decay bounds. By using experimental results from the CERN-LEP, SLAC linear collider, and atomic parity violation data, we update constraints on several parameters of the model.

  12. Search for anomalous production of events with three or more leptons in pp collisions at sqrt(s) = 8 TeV

    SciTech Connect (OSTI)

    Chatrchyan, S.; et al.,

    2014-08-01

    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.

  13. Self-sustained asymmetry of lepton-number emission: A new phenomenon during the supernova shock-accretion phase in three dimensions

    E-Print Network [OSTI]

    Tamborra, Irene; Janka, Hans-Thomas; Mueller, Bernhard; Raffelt, Georg G; Marek, Andreas

    2014-01-01

    During the stalled-shock phase of our 3D hydrodynamical core-collapse simulations with energy-dependent, 3-flavor neutrino transport, the lepton-number flux (nu_e minus anti-nu_e) emerges predominantly in one hemisphere. This novel, spherical-symmetry breaking neutrino-hydrodynamical instability is termed LESA for "Lepton-number Emission Self-sustained Asymmetry." While the individual nu_e and anti-nu_e fluxes show a pronounced dipole pattern, the heavy-flavor neutrino fluxes and the overall luminosity are almost spherically symmetric. LESA seems to develop stochastically from convective fluctuations, it exists for hundreds of milliseconds or more, and it persists during violent shock sloshing associated with the standing accretion shock instability. The nu_e minus anti-nu_e flux asymmetry originates predominantly below the neutrinosphere in a region of pronounced proto-neutron star (PNS) convection, which is stronger in the hemisphere of enhanced lepton-number flux. On this side of the PNS, the mass-accretio...

  14. Search for Resonant Top-antitop Production in the Semi-leptonic Decay Mode Using the Full CDF Data Set

    E-Print Network [OSTI]

    Aaltonen, T; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Bae, T; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Bland, K R; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brigliadori, L; Bromberg, C; Brucken, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Butti, P; Buzatu, A; Calamba, A; Camarda, S; Campanelli, M; Canelli, F; Carls, B; Carlsmith, D; Carosi, R; Carrillo, 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; Chokheli, D; Cho, K; Clark, A; Clarke, C; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Cremonesi, M; Cruz, D; Cuevas, J; Culbertson, R; d'Ascenzo, N; Datta, M; de Barbaro, P; Demortier, L; Deninno, M; d'Errico, M; Devoto, F; Di Canto, A; Di Ruzza, B; Dittmann, J R; Donati, S; D'Onofrio, M; Dorigo, M; Driutti, A; Ebina, K; Edgar, R; Elagin, A; Erbacher, R; Errede, S; Esham, B; Eusebi, R; Farrington, S; Fernandez Ramos, J P; Field, R; Flanagan, G; Forrest, R; Franklin, M; Freeman, J C; Frisch, H; Funakoshi, Y; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Giurgiu, G; Glagolev, V; Glenzinski, D; Goldin, D; Gold, M; Golossanov, A; Gomez-Ceballos, G; Gomez, G; Goncharov, M; Gonzalez Lopez, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gramellini, E; Grinstein, S; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Hahn, S R; Han, J Y; Happacher, F; Hara, K; Hare, M; Harrington-Taber, T; Harr, R F; Hatakeyama, K; Hays, C; Heinrich, J; Herndon, M; Hocker, A; Hong, Z; Hopkins, W; Hou, S; Hughes, R E; Husemann, U; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Junk, T R; Jun, S Y; Kambeitz, M; Kamon, T; Karchin, P E; Kasmi, A; Kato, Y; Ketchum, W; Keung, J; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kimura, N; Kim, Y J; Kim, Y K; Kirby, M; Knoepfel, K; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kreps, M; Kroll, J; Kruse, M; Kuhr, T; Kurata, M; Laasanen, A T; Lammel, S; Lancaster, M; Lannon, K; Latino, G; Lee, H S; Lee, J S; Leone, S; Lewis, J D; Limosani, A; Lipeles, E; Liu, H; Liu, Q; Liu, T; Lockwitz, S; Loginov, A; Lucchesi, D; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lysak, R; Lys, J; Madrak, R; Maestro, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, P; Martinez, M; Matera, K; Mattson, M E; Mazzacane, A; Mazzanti, P; McNulty, R; Mehta, A; Mehtala, P; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Moon, C S; Moore, R; Morello, M J; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Nigmanov, T; Nodulman, L; Noh, S Y; Norniella, O; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagliarone, C; Palencia, E; Palni, P; Papadimitriou, V; Parker, W; Pauletta, G; Paulini, M; Paus, C; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Poprocki, S; Potamianos, K; Pranko, A; Prokoshin, F; Ptohos, F; Punzi, G; Ranjan, N; Redondo Fernandez, I; Renton, P; Rescigno, M; Riddick, T; Rimondi, F; Ristori, L; Robson, A; Rodriguez, T; Rolli, S; Ronzani, M; Roser, R; Rosner, J L; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Safonov, A; Sakumoto, W K; Sakurai, Y; Santi, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, E E; Schwarz, T; Scodellaro, L; Seidel, S; Seiya, Y; Semenov, A; Sforza, F; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shochet, M; Shreyber-Tecker, I; Simonenko, A; Sinervo, P; Sliwa, K; Smith, J R; Snider, F D; Song, H; Sorin, V; Stancari, M; St. Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Sudo, Y; Sukhanov, A; Suslov, I; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thomson, E; Thukral, V; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Ukegawa, F; Uozumi, S; Vazquez, F; Velev, G; Vellidis, C; Vernieri, C; Vidal, M; Vilar, R; Vizan, J; Vogel, M; Volpi, G; Wagner, P; Wallny, R; Wang, S M; Warburton, A; Waters, D; Wester, W C, III; Whiteson, D; Wicklund, A B; Wilbur, S; Williams, H H; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, H; Wright, T; Wu, X; Wu, Z; Yamamoto, K; Yamato, D; Yang, T; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yi, K; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Zanetti, A M; Zeng, Y; Zhou, C; Zucchelli, S

    2013-01-01

    This Letter reports a search for a narrow resonant state decaying into two $W$ bosons and a bottom-antibottom quark pair where one $W$ boson decays leptonically and the other decays into a quark-antiquark pair. The search is particularly sensitive to top-antitop resonant production. We use the full data sample of proton-antiproton collisions at a center-of-mass energy of 1.96 TeV collected by the CDF II detector at the Fermilab Tevatron, corresponding to an integrated luminosity of 9.45 fb$^{-1}$. No evidence for resonant production is found and upper limits on the production cross section times branching ratio for a narrow resonant state are extracted. Within a specific benchmark model, we exclude a $Z'$ boson with mass below 915 GeV/$c^2$ decaying into a top-antitop pair at the 95% credibility level assuming a $Z'$ boson decay width of $\\Gamma_{Z'} = 0.012 M_{Z'}$. This is the most sensitive search for a narrow $\\ensuremath{q\\bar{q}}$-initiated $\\ensuremath{t\\bar{t}}$ resonance in the mass region below 750 ...

  15. Nuclear geometry effect and transport coefficient in semi-inclusive lepton-production of hadrons off nuclei

    E-Print Network [OSTI]

    Na Liu; Wen-Dan Miao; Li-Hua Song; Chun-Gui Duan

    2015-11-03

    Hadron production in semi-inclusive deep-inelastic scattering of leptons from nuclei is an ideal tool to determine and constrain the transport coefficient in cold nuclear matter. The leading-order computations for hadron multiplicity ratios are performed by means of the SW quenching weights and the analytic parameterizations of quenching weights based on BDMPS formalism. The theoretical results are compared to the HERMES positively charged pions production data with the quarks hadronization occurring outside the nucleus. With considering the nuclear geometry effect on hadron production, our predictions are in good agreement with the experimental measurements. The extracted transport parameter from the global fit is shown to be $\\hat{q} = 0.74\\pm0.03 GeV^2/fm$ for the SW quenching weight without the finite energy corrections. As for the analytic parameterization of BDMPS quenching weight without the quark energy E dependence, the computed transport coefficient is $\\hat{q} = 0.20\\pm0.02 GeV^2/fm$. It is found that the nuclear geometry effect has a significant impact on the transport coefficient in cold nuclear matter. It is necessary to consider the detailed nuclear geometry in studying the semi-inclusive hadron production in deep inelastic scattering on nuclear targets.

  16. The role of primary point defects in the degradation of silicon detectors due to hadron and lepton irradiation

    E-Print Network [OSTI]

    I. Lazanu; S. Lazanu

    2006-03-20

    The principal obstacle to long-time operation of silicon detectors at the highest energies in the next generation of experiments arises from bulk displacement damage which causes significant degradation of their macroscopic properties. The analysis of the behaviour of silicon detectors after irradiation conduces to a good or reasonable agreement between theoretical calculations and experimental data for the time evolution of the leakage current and effective carrier concentration after lepton and gamma irradiation and large discrepancies after hadron irradiation and this in conditions where a reasonable agreement is obtained between experimental and calculated concentrations of complex defects. In this contribution, we argue that the main discrepancies could be solved naturally considering as primary defects the self-interstitials, classical vacancies and the new predicted fourfold coordinated silicon pseudo-vacancy defects. This new defect is supposed to be introduced uniformly in the bulk during irradiation, has deep energy level(s) in the gap and it is stable in time. Considering the mechanisms of production of defects and their kinetics, it was possible to determine indirectly the characteristics of the SiFFCD defect: energy level in the band gap and cross section for minority carrier capture. In the frame of the model, the effects of primary defects on the degradation of silicon detectors are important in conditions of continuous long time irradiation and /or high fluences.

  17. Search for the Standard Model Higgs Boson in the H -> WW -> lepton+neutrino+q'qbar Decay Channel

    SciTech Connect (OSTI)

    Abazov, Victor Mukhamedovich; et al.

    2011-04-01

    We present a search for the standard model Higgs boson (H) in ppbar collisions at sqrt{s}=1.96 TeV in events containing a charged lepton (ell), missing transverse energy, and at least two jets, using 5.4 fb^-1 of integrated luminosity recorded with the D0 detector at the Fermilab Tevatron Collider. This analysis is sensitive primarily to Higgs bosons produced through the fusion of two gluons or two electroweak bosons, with subsequent decay H->WW->ell+nu+q'qbar, where ell is an electron or muon. The search is also sensitive to contributions from other production channels, such as WH->ell+nu+bbbar In the absence of signal, we set limits at the 95% C.L. on the cross section for H production sigma(ppbar->H+X) in these final states. For a mass of MH=160 GeV, the limit is a factor of 3.9 larger than the cross section in the standard model, and consistent with expectation.

  18. Light top squarks in $U(1)_{R}$-lepton number model with a right handed neutrino and the LHC

    E-Print Network [OSTI]

    Chakraborty, Sabyasachi; Huitu, Katri; Roy, Sourov; Waltari, Harri

    2015-01-01

    We investigate the phenomenology of top squarks at the Large Hadron Collider (LHC) in a supersymmetric model where lepton number is identified with an approximate $U(1)_R$ symmetry in such a way that one of the left chiral sneutrinos can acquire a large vacuum expectation value ($vev$) and can play the role of the down-type Higgs. This $R$-symmetry allows a subset of trilinear $R$-parity violating interactions, which determine the collider phenomenology of this model in a significant way. The gauginos are Dirac particles and gluinos are relatively heavy in this class of models. The model contains a right handed neutrino superfield, which gives a tree level mass to one of the active neutrinos. An order one neutrino Yukawa coupling also helps enhance the Higgs boson mass at the tree level and results in a very light bino-like neutralino ($\\widetilde \\chi_2^0$) with mass around a few hundred MeV, which is a carrier of missing (transverse) energy (\\met). The model can accommodate two rather light top squarks, com...

  19. Search for lepton-flavour-violating decays of the Higgs boson to etau and emu at sqrt(s)=8 TeV

    E-Print Network [OSTI]

    CMS Collaboration

    2015-01-01

    A direct search for lepton-flavour-violating decays of a Higgs boson ($m_{\\textrm{H}}$ = 125 GeV) is described. The search is performed for the $\\textrm{H} \\rightarrow \\textrm{e} \\tau_{\\mu}$, $\\textrm{H} \\rightarrow \\textrm{e} \\tau_{h}$, and $\\textrm{H} \\rightarrow \\textrm{e} \\mu$ decays, where $\\tau_{h}$ and $\\tau_{\\mu}$ are taus reconstructed in the hadronic and muonic decay channels, respectively. The data sample used in the search corresponds to an integrated

  20. Double semi-leptonic charm decay in helios-I 450 GeV/c p-Be data. Appendix 1

    SciTech Connect (OSTI)

    Pierre, A. [Montreal Univ., PQ (Canada). Dept. of Physics; Pomianowski, P.A. [Pittsburgh Univ., PA (United States). Dept. of Physics

    1992-12-31

    Data taken in 1989 by HELIOS-I (NA34) at the CERN SPS (450 GeV/c proton beam on Be target) have been examined for e{sup {plus_minus}} {mu}{sup {minus_plus}} or {mu}{sup {plus_minus}} {mu}{sup {minus_plus}} pairs with associated missing energy. Such pairs arise from semi-leptonic decay of both members of a c{bar c} pair. The e{mu} and {mu}{mu} samples are consistent with expectations from charm decay, allowing a quantitative limit to be placed on other physics.

  1. Collider Detector at Fermilab (CDF): Data from W, Z bosons and Drell Yan lepton pairs research of the CDF Electroweak Group

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    The Collider Detector at Fermilab (CDF) is a Tevatron experiment at Fermilab. The Tevatron, a powerful particle accelerator, accelerates protons and antiprotons close to the speed of light, and then makes them collide head-on inside the CDF detector. The CDF detector is used to study the products of such collisions. The CDF Physics Group at Fermilab is organized into six working groups, each with a specific focus. The Electroweak group studies production and properties of W, Z bosons and Drell Yan lepton pairs. Their public web page makes data and numerous figures available from both CDF Runs I and II.

  2. Search for High-Mass States with One Lepton Plus Missing Transverse Momentum in Proton-Proton Collisions at $\\sqrt{s} with the ATLAS Detector

    SciTech Connect (OSTI)

    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

    2012-06-20

    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.

  3. Search for an excess of events with an identical flavour lepton pair and significant missing transverse momentum in sqrt{s} = 7 TeV proton-proton collisions with the ATLAS detector

    E-Print Network [OSTI]

    The ATLAS Collaboration

    2011-03-31

    Results are presented of a search for supersymmetric particles decaying into final states with significant missing transverse momentum and exactly two identical flavour leptons (e or mu) of opposite charge in sqrt{s}=7 TeV collisions at the Large Hadron Collider. This channel is particularly sensitive to supersymmetric particle cascade decays producing flavour correlated lepton pairs. Flavour uncorrelated backgrounds are subtracted using a sample of opposite flavour lepton pair events. Observation of an excess beyond Standard Model expectations following this subtraction procedure would offer one of the best routes to measuring the masses of supersymmetric particles. In a data sample corresponding to an integrated luminosity of 35 pb-1 no such excess is observed. Model-independent limits are set on the contribution to these final states from new physics and are used to exclude regions of a phenomenological supersymmetric parameter space.

  4. Search for an excess of events with an identical flavour lepton pair and significant missing transverse momentum in ?s = 7 TeV proton-proton collisions with the ATLAS detector

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aad, G.

    2011-07-09

    Results are presented of a search for supersymmetric particles decaying into final states with significant missing transverse momentum and exactly two identical flavour leptons (e, ?) of opposite charge in ?s = 7 TeV collisions at the Large Hadron Collider. This channel is particularly sensitive to supersymmetric particle cascade decays producing flavour correlated lepton pairs. Flavour uncorrelated backgrounds are subtracted using a sample of opposite flavour lepton pair events. Observation of an excess beyond Standard Model expectations following this subtraction procedure would offer one of the best routes to measuring the masses of supersymmetric particles. In a data sample correspondingmore »to an integrated luminosity of 35 pb?¹ no such excess is observed. Model-independent limits are set on the contribution to these final states from new physics and are used to exclude regions of a phenomenological supersymmetric parameter space.« less

  5. Measurement of the top-quark mass in the lepton+jets channel using a matrix element technique with the CDF II detector

    SciTech Connect (OSTI)

    Aaltonen, T; Alvarez Gonzalez, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A

    2011-10-14

    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 = 172.4± 1.4 (stat + ?JES) ± 1.3 (syst) GeV/c2.

  6. Measurement of the top-quark mass in the lepton+jets channel using a matrix element technique with the CDF II detector

    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

    2011-10-14

    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 = 172.4± 1.4 (stat + ?JES) ± 1.3 (syst) GeV/c2.

  7. Measurement of the top-quark mass in the lepton+jets channel using a matrix element technique with the CDF II detector

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aaltonen, T.

    2011-10-14

    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 »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 = 172.4± 1.4 (stat + ?JES) ± 1.3 (syst) GeV/c2.« less

  8. Measurements of four-lepton production in $pp$ collisions at $\\sqrt{s}=$ 8 TeV with the ATLAS detector

    E-Print Network [OSTI]

    ATLAS Collaboration

    2015-09-25

    The four-lepton ($4\\ell$, $\\ell = e, \\mu$) production cross section is measured in the mass range from 80 to 1000 GeV using 20.3 fb$^{-1}$ of data in $pp$ collisions at $\\sqrt{s}=8$ TeV collected with the ATLAS detector at the LHC. The $4\\ell$ events are produced in the decays of resonant $Z$ and Higgs bosons and the non-resonant $ZZ$ continuum originating from $q\\bar q$, $gg$, and $qg$ initial states. A total of 476 signal candidate events are observed with a background expectation of $26.2 \\pm 3.6$ events, enabling the measurement of the integrated cross section and the differential cross section as a function of the invariant mass and transverse momentum of the four-lepton system. In the mass range above $180$ GeV, assuming the theoretical constraint on the $q\\bar q$ production cross section calculated with perturbative NNLO QCD and NLO electroweak corrections, the signal strength of the gluon-fusion component relative to its leading-order prediction is determined to be $\\mu_{gg}=2.4 \\pm 1.0 (stat.) \\pm 0.5 (syst.)\\pm 0.8 (theory)$.

  9. Search for tt¯ resonances in the lepton plus jets final state with ATLAS using 4.7 fb?¹ of pp collisions at ?s=7 TeV

    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.; Åkesson, 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.; Åsman, 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 Guimarães 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.

    2013-07-01

    A search for new particles that decay into top quark pairs (tt¯) is performed with the ATLAS experiment at the LHC using an integrated luminosity of 4.7 fb?¹ of proton–proton (pp ) collision data collected at a center-of-mass energy ?s =7 TeV . In the tt¯ ?WbWb decay, the lepton plus jets final state is used, where one W boson decays leptonically and the other hadronically. The tt¯ 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 tt¯ invariant mass spectrum is performed. No evidence for a tt¯ 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 Kaluza–Klein excitation of the gluon in a Randall–Sundrum model is excluded for masses below 2.07 TeV.

  10. Gravitating lepton bag model

    E-Print Network [OSTI]

    Burinskii, Alexander

    2015-01-01

    As is known, the gravitational and electromagnetic (EM) field of the Dirac electron is described by an over-extremal Kerr-Newman (KN) black hole (BH) solution which has the naked singular ring and two-sheeted topology. This space is regulated by the formation of a regular source based on the Higgs mechanism of broken symmetry. This source shares much in common with the known MIT- and SLAC-bag models, but has the important advantage, of being in accordance with gravitational and electromagnetic field of the external KN solution. The KN bag model is flexible. At rotations, it takes the shape of a thin disk, and similar to other bag models, under deformations it creates a string-like structure which is positioned along the sharp border of the disk.

  11. Gravitating lepton bag model

    E-Print Network [OSTI]

    Alexander Burinskii

    2015-04-30

    As is known, the gravitational and electromagnetic (EM) field of the Dirac electron is described by an over-extremal Kerr-Newman (KN) black hole (BH) solution which has the naked singular ring and two-sheeted topology. This space is regulated by the formation of a regular source based on the Higgs mechanism of broken symmetry. This source shares much in common with the known MIT- and SLAC-bag models, but has the important advantage, of being in accordance with gravitational and electromagnetic field of the external KN solution. The KN bag model is flexible. At rotations, it takes the shape of a thin disk, and similar to other bag models, under deformations it creates a string-like structure which is positioned along the sharp border of the disk.

  12. Search for a heavy gauge boson decaying to a charged lepton and a neutrino in 1 fb[superscript ?1] of pp collisions at ?s = 7 TeV using the ATLAS detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    The ATLAS detector at the LHC is used to search for high-mass states, such as heavy charged gauge bosons (W?), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of ...

  13. Search for direct slepton and gaugino production in final states with two leptons and missing transverse momentum with the ATLAS detector in pp collisions at ?s = 7 TeV

    E-Print Network [OSTI]

    Taylor, Frank E.

    A search for the electroweak pair production of charged sleptons and weak gauginos decaying into final states with two leptons is performed using 4.7 fb[superscript ?1] of proton–proton collision data at ?s = 7 TeV recorded ...

  14. Search for events with large missing transverse momentum, jets, and at least two tau leptons in 7 TeV proton–proton collision data with the ATLAS detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    A search for events with large missing transverse momentum, jets, and at least two tau leptons has been performed using 2 fb[superscript ?1] of proton–proton collision data at ?s = 7 TeV recorded with the ATLAS detector ...

  15. An Inclusive Search for the Higgs Boson in the Four Lepton Final State The Higgs boson is the last undiscovered particle of the Standard Model of Particle Physics (SM).

    E-Print Network [OSTI]

    Fermilab

    An Inclusive Search for the Higgs Boson in the Four Lepton Final State The Higgs boson is the last undiscovered particle of the Standard Model of Particle Physics (SM). A search for SM Higgs boson decays transverse energy. Our search is optimized for Higgs boson decays to Z-boson pairs but is sensitive, due

  16. Search for Pair Production of Scalar Top Quarks Decaying to a tau Lepton and a b Quark in ppbar Collisions at sqrt{s}=1.96 TeV

    SciTech Connect (OSTI)

    Brigliadori, L.; Zheng, Y.; Zucchelli, S.; /Taiwan, Inst. Phys. /Bologna U. /Argonne /Barcelona, IFAE /Baylor U., Math. Dept. /Bologna U. /Brandeis U. /UC, Davis /UCLA /UC, San Diego /UC, Santa Barbara /Cantabria U., Santander /Carnegie Mellon U.

    2008-02-01

    We present the results of a search for pair production of scalar top quarks ({tilde t}{sub 1}) in an R-parity violating supersymmetric scenario using 322 pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV collected by the upgraded Collider Detector at Fermilab. We assume each {tilde t}{sub 1} decays into a {tau} lepton and a b quark with a branching ratio {beta}, and that the final state contains 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 our final selection criteria, consistent with the expectation from standard model processes. We present upper limits on the cross section times branching ratio squared {sigma}({tilde t}{sub 1}{bar {tilde t}}{sub 1}) x {beta}{sup 2} as a function of the stop mass m({tilde t}{sub 1}). Assuming {beta} = 1, we set a 95% confidence level limit m({tilde t}{sub 1}) > 153 GeV=c{sup 2} obtained using a next-to-leading order cross section. These limits are also fully applicable to the case of a pair produced third generation scalar leptoquark decaying into a {tau} lepton and a b quark.

  17. Search for the standard model Higgs boson in the decay channel $H$ to $Z Z$ to 4 leptons in $pp$ collisions at $\\sqrt{s}=7$ TeV

    SciTech Connect (OSTI)

    Chatrchyan, Serguei; et al.

    2012-03-01

    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.

  18. Search for the production of ZW and ZZ boson pairs decaying into charged leptons and jets in p[bar over p] collisions at ?s = 1.96??TeV

    E-Print Network [OSTI]

    Gomez-Ceballos, Guillelmo

    We present a measurement of the production cross section for ZW and ZZ boson pairs in final states with a pair of charged leptons, from the decay of a Z boson, and at least two jets, from the decay of a W or Z boson, using ...

  19. Search for production of WW / WZ resonances decaying to a lepton, neutrino and jets in pp collisions at ?s = 8 TeV with the ATLAS detector

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aad, G.

    2015-05-12

    In this study, a search is presented for narrow diboson resonances decaying to WW or WZ in the final state where one W boson decays leptonically (to an electron or a muon plus a neutrino) and the other W/Z boson decays hadronically. The analysis is performed using an integrated luminosity of 20.3 fb–1 of pp collisions at ?s = 8 TeV collected by the ATLAS detector at the large hadron collider. No evidence for resonant diboson production is observed, and resonance masses below 700 and 1490 GeV are excluded at 95% confidence level for the spin-2 Randall–Sundrum bulk graviton G*more »with coupling constant of 1.0 and the extended gauge model W' boson respectively.« less

  20. Search for standard model production of four top quarks in the lepton + jets channel in pp collisions at ? = 8 TeV

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Khachatryan, Vardan

    2014-11-27

    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?¹ 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 »on the cross section for producing four top quarks in the SM, where a limit of 32 ± 17 fb is expected.« less

  1. Measurement of the fraction of top quark pair events produced via gluon-gluon fusion at the Tevatron in lepton+jets final states

    E-Print Network [OSTI]

    Sungwoong Cho; Suyong Choi; Sehwook Lee; JaeHoon Lim; SungWoo Youn

    2014-11-30

    We report a measurement of the fraction of top quark pair events produced via gluon-gluon fusion in $p\\bar{p}$ collisions at $\\sqrt{s} = 1.96 ~\\rm TeV$ in lepton+jets final states using the full RunII data set corresponding to $9.7 ~\\rm fb^{-1}$ of integrated luminosity collected by the D\\O\\ experiment. We utilize a boosted decision tree to distinguish top quark pair events produced by $q\\bar{q}$ annihilation and $gg$ fusion. We perform a template fit to extract the $t\\bar{t}$ production fraction via $gg$ fusion and find $f_{gg} = 0.096 \\pm 0.039 ~(\\rm stat.) ~^{+0.077}_{-0.062} ~(\\rm syst.)$.

  2. Search for standard model production of four top quarks in the lepton + jets channel in pp collisions at ? = 8 TeV

    SciTech Connect (OSTI)

    Khachatryan, Vardan

    2014-11-27

    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?¹ 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 ± 17 fb is expected.

  3. Search for standard model production of four top quarks in the lepton + jets channel in pp collisions at ? = 8 TeV

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Khachatryan, Vardan [Yerevan Physics Inst. (YerPhI) (Armenia)

    2014-11-01

    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?¹ 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 ± 17 fb is expected.

  4. Searches for electroweak production of charginos, neutralinos, and sleptons decaying to leptons and W, Z, and Higgs bosons in pp collisions at 8 TeV

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Khachatryan, Vardan

    2014-09-26

    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 »details.« less

  5. Searches for electroweak production of charginos, neutralinos, and sleptons decaying to leptons and W, Z, and Higgs bosons in pp collisions at 8 TeV

    SciTech Connect (OSTI)

    Khachatryan, Vardan [Yerevan Physics Institute (Armenia); et al.,

    2014-09-01

    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.

  6. Search for standard model production of four top quarks in the lepton + jets channel in pp collisions at ? = 8 TeV

    SciTech Connect (OSTI)

    Khachatryan, Vardan [Yerevan Physics Inst. (YerPhI) (Armenia)

    2014-11-01

    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?¹ 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 ± 17 fb is expected.

  7. Searches for electroweak production of charginos, neutralinos, and sleptons decaying to leptons and W, Z, and Higgs bosons in pp collisions at 8 TeV

    SciTech Connect (OSTI)

    Khachatryan, Vardan

    2014-09-26

    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.

  8. Search for supersymmetry in pp collisions at sqrt(s)=7 TeV in events with a single lepton, jets, and missing transverse momentum

    SciTech Connect (OSTI)

    Chatrchyan, Serguei; et al.

    2011-08-01

    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.

  9. ATLAS search for a heavy gauge boson decaying to a charged lepton and a neutrino in pp collisions at ?s = 7 TeV

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aad, G.

    2012-12-08

    The ATLAS detector at the LHC is used to search for high-mass states, such as heavy charged gauge bosons (W'), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of pp collisions at a centre-of-mass energy of 7 TeV corresponding to an integrated luminosity of 4.7 fb-1. No excess beyond Standard Model expectations is observed. A W' with Sequential Standard Model couplings is excluded at the 95% credibility level for masses up to 2.55 TeV. Excited chiral bosons (W*) with equivalent coupling strength are excluded for masses up to 2.42 TeV.

  10. Search for vectorlike B quarks in events with one isolated lepton, missing transverse momentum, and jets at ?s = 8 TeV with the ATLAS detector

    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

    2015-06-19

    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 »TeV, corresponding to an integrated luminosity of 20.3 fb?¹. 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).« less

  11. Search for tt¯ resonances in the lepton plus jets final state with ATLAS using 4.7 fb?¹ of pp collisions at ?s=7 TeV

    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.; et al

    2013-07-23

    A search for new particles that decay into top quark pairs (tt¯) is performed with the ATLAS experiment at the LHC using an integrated luminosity of 4.7 fb?¹ of proton–proton (pp ) collision data collected at a center-of-mass energy ?s =7 TeV . In the tt¯ ?WbWb decay, the lepton plus jets final state is used, where one W boson decays leptonically and the other hadronically. The tt¯ 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 themore »Standard Model expectation in the tt¯ invariant mass spectrum is performed. No evidence for a tt¯ 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 Kaluza–Klein excitation of the gluon in a Randall–Sundrum model is excluded for masses below 2.07 TeV.« less

  12. Search for vectorlike B quarks in events with one isolated lepton, missing transverse momentum, and jets at ?s = 8 TeV with the ATLAS detector

    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.; Åkesson, 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.; Åsman, 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 Guimarães 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.

    2015-06-01

    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?¹. 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).

  13. Measurement of the production and lepton charge asymmetry of W bosons in Pb+Pb collisions at ?sNN = 2.76 TeV with the ATLAS detector

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aad, G.

    2015-01-22

    A measurement of W boson production in lead-lead collisions at ?sNN=2.76 TeV is presented. It is based on the analysis of data collected with the ATLAS detector at the LHC in 2011 corresponding to an integrated luminosity of 0.14 nb–1 and 0.15 nb–1 in the muon and electron decay channels, respectively. The differential production yields and lepton charge asymmetry are each measured as a function of the average number of participating nucleons (Npart) and absolute pseudorapidity of the charged lepton. The results are compared to predictions based on next-to-leading-order QCD calculations. As a result, these measurements are, in principle, sensitivemore »to possible nuclear modifications to the parton distribution functions and also provide information on scaling of W boson production in multi-nucleon systems.« less

  14. Measurement of the production and lepton charge asymmetry of $\\textit{W}$ bosons in Pb+Pb collisions at $\\sqrt{s_{\\mathrm{\\mathbf{NN}}}}=$ 2.76 TeV with the ATLAS detector

    E-Print Network [OSTI]

    ATLAS Collaboration

    2015-01-26

    A measurement of $\\textit{W}$ boson production in lead-lead collisions at $\\sqrt{s_{\\mathrm{NN}}}=$2.76 TeV is presented. It is based on the analysis of data collected with the ATLAS detector at the LHC in 2011 corresponding to an integrated luminosity of 0.14 $\\mathrm{nb}^{-1}$ and 0.15 $\\mathrm{nb}^{-1}$ in the muon and electron decay channels, respectively. The differential production yields and lepton charge asymmetry are each measured as a function of the average number of participating nucleons $$ and absolute pseudorapidity of the charged lepton. The results are compared to predictions based on next-to-leading-order QCD calculations. These measurements are, in principle, sensitive to possible nuclear modifications to the parton distribution functions and also provide information on scaling of $\\textit{W}$ boson production in multi-nucleon systems.

  15. The opportunity offered by the ESSnuSB project to exploit the larger leptonic CP violation signal at the second oscillation maximum and the requirements of this project on the ESS accelerator complex

    E-Print Network [OSTI]

    Elena Wildner; Michel Martini; Horst Schonauer; Alexander Burgman; Joakim Cederkall; Peter Christiansen; Tord Ekelof; Maja Olvegard

    2015-10-02

    Very intense neutrino beams and large neutrino detectors will be needed to enable the discovery of CP violation in the leptonic sector. The European Spallation Source (ESS), currently under construction in Lund, Sweden, is a research center that will provide, by 2023, the world's most powerful neutron source. The average power will be 5 MW. Pulsing this linac at higher frequency, at the same instantaneous power, will make it possible to raise the average beam power to 10 MW to produce, in parallel with the spallation neutron production, a high performance neutrino Super Beam of about 0.4 GeV mean neutrino energy. The ESS neutrino Super Beam, ESSnuSB, operated with a 2.0 GeV linac proton beam, together with a large underground Water Cherenkov detector located at 540 km from Lund, close to the second oscillation maximum, will make it possible to discover leptonic CP violation at 5 sigma significance level in 56 percent (65 percent for an upgrade to 2.5 GeV beam energy) of the leptonic Dirac CP-violating phase range after 10 years of data taking. The paper gives an overview of the proposed facility and presents the outstanding physics reach possible for CP violation with ESSnuSB.

  16. Measurement of differential and integrated fiducial cross sections for Higgs boson production in the four-lepton decay channel in pp collisions at sqrt(s) = 7 and 8 TeV

    E-Print Network [OSTI]

    CMS Collaboration

    2015-12-28

    Differential and integrated fiducial cross sections for the production of four leptons via the H to 4l decays (l = e, mu) are measured in pp collisions at sqrt(s) = 7 and 8 TeV. Measurements are performed with data corresponding to integrated luminosities of 5.1 inverse-femtobarns at 7 TeV, and 19.7 inverse-femtobarns at 8 TeV, collected with the CMS experiment at the LHC. Differential cross sections are determined as functions of the transverse momentum and rapidity of the four-lepton system, accompanying jet multiplicity, transverse momentum of the leading jet, and difference in rapidity between the Higgs boson candidate and the leading jet. A measurement of the Z to 4l cross section, and its ratio to the H to 4l cross section is also performed. All cross sections are measured within a fiducial phase space defined by the requirements on lepton kinematics and event topology. The integrated H to 4l fiducial cross section is measured to be 0.56 +0.67-0.44 (stat) +0.21-0.06 (syst) fb at 7 TeV, and 1.11 +0.41-0.35 (stat) +0.14-0.10 (syst) fb at 8 TeV. The measurements are found to be compatible with theoretical calculations based on the standard model.

  17. The opportunity offered by the ESSnuSB project to exploit the larger leptonic CP violation signal at the second oscillation maximum and the requirements of this project on the ESS accelerator complex

    E-Print Network [OSTI]

    Wildner, Elena; Schonauer, Horst; Burgman, Alexander; Cederkall, Joachim; Christiansen, Peter; Ekelof, Tord; Olvegard, Maja

    2015-01-01

    Very intense neutrino beams and large neutrino detectors will be needed to enable the discovery of CP violation in the leptonic sector. The European Spallation Source (ESS), currently under construction in Lund, Sweden, is a research center that will provide, by 2023, the world's most powerful neutron source. The average power will be 5 MW. Pulsing this linac at higher frequency, at the same instantaneous power, will make it possible to raise the average beam power to 10 MW to produce, in parallel with the spallation neutron production, a high performance neutrino Super Beam of about 0.4 GeV mean neutrino energy. The ESS neutrino Super Beam, ESSnuSB, operated with a 2.0 GeV linac proton beam, together with a large underground Water Cherenkov detector located at 540 km from Lund, close to the second oscillation maximum, will make it possible to discover leptonic CP violation at 5 sigma significance level in 56 percent (65 percent for an upgrade to 2.5 GeV beam energy) of the leptonic Dirac CP-violating phase r...

  18. Search for stealth supersymmetry in events with jets, either photons or leptons, and low missing transverse momentum in pp collisions at 8 TeV

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Khachatryan, Vardan [Yerevan Physics Institute (Armenia); et al.,

    2015-04-01

    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.

  19. Dependence of the leptonic decays of H^- on the neutrino mixing angles theta_{13} and theta_{23} in models with neutrinophilic charged scalars

    E-Print Network [OSTI]

    A. G. Akeroyd; S. Moretti; Hiroaki Sugiyama

    2013-12-19

    In the Higgs Triplet Model and the neutrinophilic Two-Higgs-Doublet Model the observed neutrinos obtain mass from a vacuum expectation value which is much smaller than the vacuum expectation value of the Higgs boson in the Standard Model. Both models contain a singly charged Higgs boson (H^-) whose Yukawa coupling is directly related to the neutrino mass (i.e. a "neutrinophilic charged Higgs"). The partial decay widths of H^- into a charged lepton and a neutrino (H^- to l^- nu) depend identically on the neutrino masses and mixings in the two models. We quantify the impact of the recent measurement of sin^2(2theta_{13}), which plays a crucial role in determining the magnitude of the branching ratio of H^- to e^- nu for the case of a normal neutrino mass ordering if the lightest neutrino mass m_0 eV. We also discuss the sizeable dependence of H^- to mu^- nu and H^- to tau^- nu on sin^2(theta_{23}), which would enable information to be obtained on sin^2(theta_{23}) and the sign of \\Delta m^2_{31} if these decays are measured. Such information would help neutrino oscillation experiments to determine the CP-violating phase \\delta.

  20. Search for stealth supersymmetry in events with jets, either photons or leptons, and low missing transverse momentum in pp collisions at 8 TeV

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Khachatryan, Vardan; et al.,

    2015-04-01

    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 »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.« less

  1. Measurement of the top quark mass using the template method in the lepton plus jets channel with in situ W ---> j j calibration at CDF-II

    SciTech Connect (OSTI)

    Adelman, Jahred A.; Arguin, J.F.; Bellettini, G.; Brubaker, E.; Budagov, J.; Chlachidze, G.; Demortier, L.; Gibson, A.; Kim, S.; Kim, Y.K.; Maruyama, T.; Sato, K.; Shochet, M.; Sinervo, P.; Tomura, T.; Velev, G.; Xie, S.; Yang, U.K.; /Chicago U. /Toronto U. /INFN, Pisa /Dubna, JINR /Rockefeller U. /LBL, Berkeley /Tsukuba U. /Fermilab

    2006-05-01

    We report an updated measurement of the top quark mass in the lepton plus jets channel of t{bar t} events from p{bar p} collisions at {radical}s = 1.96 TeV. This measurement uses a dataset with integrated luminosity of 680 pb{sup -1}, containing 360 t{bar t} candidates separated into four subsamples. A top quark mass is reconstructed for each event by using energy and momentum constraints on the top quark pair decay products. We also employ the reconstructed mass of hadronic W boson decays W {yields} jj to constrain in situ the largest systematic uncertainty of the top quark mass measurement: the jet energy scale. Monte Carlo templates of the reconstructed top quark and W boson mass are produced as a function of the true top quark mass and the jet energy scale. The distribution of reconstructed top quark and W boson mass in the data are compared to the Monte Carlo templates using a likelihood fit to obtain: M{sub top} = 173.4 {+-} 2.8 GeV/c{sup 2}.

  2. UHE Leptons and Neutrons feeding Precessing gamma Jet in GRBs - SGRs: A SGR 1806-20 link to EeV C.R.?

    E-Print Network [OSTI]

    D. Fargion; M. Grossi

    2005-05-09

    Soft Gamma Repeaters are widely believed to occur as isotropic Magnetar explosion. We suggest on the contrary that they may be described by thin collimated spinning and precessing Gamma Jets flashing and blazing along the line of sight. The Jet (for SGRs) maybe powered by an accretion disk in binary system and it reproduces huge outflow and oscillating blazing mode as the observed ones in Giant Flare SGR 1806-20. The precessing and spinning blazing nature reflects at smaller intensity the same behavior observed in brief GRBs Jetted Supernova, as well as re-brightening and bumps in afterglows. The SGR gamma beam maybe powered by Inverse Compton Scattering or by Synchrotron Radiation of electron pair beam respectively at GeVs or PeVs energies. In the latter case tens PeVs leptons (muons and later decaying PeVs electrons) might be originated while EeV nucleons Jets (protons-neutrons) are in photo-pion equilibrium with infrared photons surrounding the source. The neutron Jet might survive and remain collimated. It maybe already detected as an EeV cosmic ray anisotropy in present AGASA map pointing toward known (North Hemisphere) SGRs : SGR 1900 +14 and SGR 1806-20. If the SGR-EeV connection is correct a parasite traces of PeVs neutrino as well PeV-TeVs gamma rays might be found in present or future data records, among the others C.R. array detectors, inside the Amanda and Milagro volumes.

  3. Structure Functions in Deep Inelastic Lepton Scattering: Data from DOE laboratory experiments as compiled in data reviews by the Durham High Energy Physics Database Group

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Gehrmann, T; Roberts, R. G.; Whalley, M. R.; Durham HEP Database Group

    Gehrmann, Roberts, and Whalley in their 1999 paper, A Compilation of Structure Functions in Deep Inelastic Scattering, published in volume 25 of Journal of Physics G (Nuclear and Particle Physics) note that these data will continue to be relevant to the next generation of hadron colliders. They present data on the unpolarized structure functions F2 and xF3, R D ._L=_T /, the virtual photon asymmetries A1 and A2 and the polarized structure functions g1 and g2, from deep inelastic lepton scattering off protons, deuterium and nuclei. Data are presented in both tabular and graphical format and include predictions based on the MRST98 and CTEQ4 parton distribution functionsö as well. The data gathered from the relevant collaborations at DOE's Fermilab, SLAC, and JLAB are available, and so are data from related collaborations based at CERN and DESY. The Durham High Energy Physics (HEP) Database Group makes these data, extracted from papers and data reviews, available in one place in an easy-to-access format. These data are also include in the Durham HEP Reaction Data Database which can be searched at http://hepdata.cedar.ac.uk/reaction

  4. $ttW$ and $ttZ$ production cross section in leptonic final states at 8 TeV with ATLAS

    E-Print Network [OSTI]

    Suster, Carl Joseph Edmund; The ATLAS collaboration

    2015-01-01

    A measurement of the production cross section of a pair of top quarks in association with a $W$ or $Z$ boson is presented, using $20.3 \\,\\mathrm{fb}^{-1}$ of $pp$ collision data collected by the ATLAS detector at $\\sqrt{s} = 8 \\,\\mathrm{TeV}$. The measurement combines four separate analyses which consider final states with two opposite sign, two same sign, three and four leptons. A simultaneous fit to data of the $t\\bar{t}W$ and $t\\bar{t}Z$ signals measures their cross sections to be $\\sigma_{t\\bar{t}Z} = 176^{+58}_{-52} \\;\\mathrm{fb}$ and $\\sigma_{t\\bar{t}W} = 369^{+100}_{-91}\\;\\mathrm{fb}$, consistent with next-to-leading order theoretical calculations. Tested against the background-only hypothesis, these correspond to an observed (expected) significance of $4.2\\sigma$ ($4.5\\sigma$) for $t\\bar{t}Z$ and $5.0\\sigma$ ($3.2\\sigma$) for $t\\bar{t}W$.

  5. Search for massive resonances decaying into pairs of boosted bosons in semi-leptonic final states at $\\sqrt{s} =$ 8 TeV

    SciTech Connect (OSTI)

    Khachatryan, Vardan; et al.,

    2014-08-01

    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.

  6. Search for High-Mass Resonances Decaying into Leptons of Different Flavor (e mu, e tau, mu tau) in p anti-p Collisions at sqrt(s) = 1.96 TeV

    SciTech Connect (OSTI)

    Tu, Yanjun; /Pennsylvania U.

    2008-10-01

    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}.

  7. Search for a heavy gauge boson decaying to a charged lepton and a neutrino in 1 fb-1 of pp collisions at ?s=7 TeV using the ATLAS detector

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aad, G.

    2011-11-01

    The ATLAS detector at the LHC is used to search for heavy charged gauge bosons (W'), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of pp collisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 1.04 fb?¹. No excess beyond Standard Model expectations is observed. A W' with Sequential Standard Model couplings is excluded at the 95% confidence level for masses up to 2.15 TeV.

  8. Search for new physics in lepton + photon + X events with 305 pb**-1 of p anti-p collisions at s**(1/2) = 1.96-TeV

    SciTech Connect (OSTI)

    Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D.; Amerio, S.; Amidei, D.; Anastassov, A.; Anikeev, K.; /Taiwan, Inst. Phys. /Argonne /Barcelona, IFAE /Baylor U. /INFN, Bologna /Bologna U. /Brandeis U. /UC, Davis /UCLA /UC, San Diego /UC, Santa Barbara

    2006-05-01

    The authors present results of a search for anomalous production of events containing a charged lepton ({ell}, either e or {mu}) and a photon ({gamma}), both with high transverse momentum, accompanied by additional signatures, X, including missing transverse energy (E{sub T}) and additional leptons and photons. We use the same kinematic selection criteria as in a previous CDF search, but with a substantially larger data set, 305 pb{sup -1}, a p{bar p} collision energy of 1.96 TeV, and the upgraded CDF II detector. We find 42 {ell}{gamma}E{sub T} events versus a standard model expectation of 37.3 {+-} 5.4 events. The level of excess observed in Run I, 16 events with an expectation of 7.6 {+-} 0.7 events (corresponding to a 2.7{sigma} effect), is not supported by the new data. In the signature of {ell}{ell}{gamma} + X we observe 31 events versus an expectation of 23.0 {+-} 2.7 events. In this sample we find no events with an extra photon or E{sub T} and so find no events like the one ee{gamma}{gamma}E{sub T} event observed in Run I.

  9. Measurement of the Single Top Quark Cross Section in the Lepton Plus Jets Final State in Proton-Antiproton Collisions at a Center of Mass Energy of 1.96 TeV Using the CDF II Detector

    SciTech Connect (OSTI)

    Wu, Zhenbin

    2012-01-01

    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.

  10. Search for the Standard Model Higgs boson produced in association with a W Boson in the isolated-track charged-lepton channel using the Collider Detector at Fermilab

    SciTech Connect (OSTI)

    Buzatu, Adrian; /McGill U.

    2011-08-01

    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

  11. Tau lepton physics at LEP

    E-Print Network [OSTI]

    Z. Zhang; the ALEPH; DELPHI; OPAL Collaboration

    2006-02-24

    The talk covers three contributions on (i) the final measurement of branching ratios and spectral functions of t decays using the full LEP-I data from ALEPH, (ii) a preliminary measurement of the t hadronic branching ratios from DELPHI and (iii) a measurement of the strange spectral function in hadronic t decays from OPAL. These measurements are discussed and the relevant physics topics are briefly reviewed.

  12. Search for the standard model Higgs boson decaying to a $W$ pair in the fully leptonic final state in $pp$ collisions at $\\sqrt{s}=7$ TeV

    SciTech Connect (OSTI)

    Chatrchyan, Serguei; et al.

    2012-03-01

    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.

  13. Top physics: measurement of the tt-bar production cross section in p anti-p collisions at s**(1/2) = 1.96 tev using lepton + jets events with secondary vertex b-tagging

    SciTech Connect (OSTI)

    Acosta, D.; The CDF Collaboration

    2005-04-07

    We present a measurement of the t{bar t} production cross section using events with one charged lepton and jets from p{bar p} collisions at a center-of-mass energy of 1.96TeV. In these events, heavy flavor quarks from top quark decay are identified with a secondary vertex tagging algorithm. From 162 pb{sup -1} of data collected by the Collider Detector at Fermilab, a total of 48 candidate events are selected, where 13.5 {+-} 1.8 events are expected from background contributions. We measure a t{bar t} production cross section of 5.6{sub -1.1}{sup _1.2}(stat.){sub -0.6}{sup +0.9}(syst.)pb.

  14. Search for the Production of Dark Matter in Association with Top-Quark Pairs in the Single-Lepton Final State in Proton-Proton Collisions at $\\sqrt{s}$ = 8 TeV

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.

    2015-06-17

    A search is presented for particle dark matter produced in association with a pair of top quarks in pp collisions at a centre-of-mass energy of s?=8 TeV. The data were collected with the CMS detector at the LHC and correspond to an integrated luminosity of 19.7 fb?1. This search requires the presence of one lepton, multiple jets, and large missing transverse energy. No excess of events is found above the SM expectation, and upper limits are derived on the production cross section. Interpreting the findings in the context of a scalar contact interaction between fermionic dark matter particles and topmore »quarks, lower limits on the interaction scale are set. These limits are also interpreted in terms of the dark matter-nucleon scattering cross sections for the spin-independent scalar operator and they complement direct searches for dark matter particles in the low mass region.« less

  15. A search for \\( t\\overline{t} \\) resonances using lepton-plus-jets events in proton-proton collisions at \\( \\sqrt{s}=8 \\) TeV with the ATLAS detector

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aad, G.

    2015-08-28

    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}^{+}b{W}^{-}\\overline{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 pairmore »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 ?/m = 15% decaying to \\( t\\overline{t} \\). These range from 4.8 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.« less

  16. Measurement of Spin Correlations in $t\\bar{t}$ Events from $pp$ Collisions at $\\sqrt{s}$ = 7 TeV in the Lepton + Jets Final State with the ATLAS Detector

    E-Print Network [OSTI]

    Boris Lemmer

    2014-10-05

    The top quark decays before it hadronises. Before its spin state can be changed in a process of strong interaction, it is directly transferred to the top quark decay products. The top quark spin can be deduced by studying angular distributions of the decay products. The Standard Model predicts the top/anti-top quark ($t\\bar{t}$) pairs to have correlated spins. The degree is sensitive to the spin and the production mechanisms of the top quark. Measuring the spin correlation allows to test the predictions. New physics effects can be reflected in deviations from the prediction. In this thesis the spin correlation of $t\\bar{t}$ pairs, produced at a centre-of-mass energy of $\\sqrt{s} = 7\\,$TeV and reconstructed with the ATLAS detector, is measured. The dataset corresponds to an integrated luminosity of $4.6~\\text{fb}^{-1}$. $t\\bar{t}$ pairs are reconstructed in the $\\ell$+jets channel using a kinematic likelihood fit offering the identification of light up- and down-type quarks from the $t \\rightarrow bW \\rightarrow bq\\bar{q}'$ decay. The spin correlation is measured via the distribution of the azimuthal angle $\\Delta\\phi$ between two top quark spin analyzers in the laboratory frame. It is expressed as the degree of $t\\bar{t}$ spin correlation predicted by the Standard Model, $f_{\\text{SM}}$. The results of \\begin{align*} &f_{\\text{SM}}( \\Delta\\phi(\\text{charged lepton, down-type quark} )) &= 1.53 \\pm 0.14\\,\\text{(stat.)} \\pm 0.32\\,\\text{(syst.)}, \\\\ &f_{\\text{SM}} ( \\Delta\\phi(\\text{charged lepton, b-quark} )) &= 0.53 \\pm 0.18\\,\\text{(stat.)} \\pm 0.49\\,\\text{(syst.)}, \\\\ &f_{\\text{SM}} ( \\Delta\\phi(\\text{combined})) &= 1.12 \\pm 0.11\\,\\text{(stat.)} \\pm 0.22\\,\\text{(syst.)}, \\end{align*} are consistent with the Standard Model prediction of $f_{\\text{SM}}= 1.0$.

  17. Measurement of the t-tbar production cross section in p-pbar collisions at s**(1/2) = 1.96 TeV using lepton+jets events in the CDF detector at Fermilab

    SciTech Connect (OSTI)

    Palencia, Enrique; /Cantabria Inst. of Phys. /Cantabria U., Santander

    2006-12-01

    The top quark is the most massive fundamental particle observed so far, and the study of its properties is interesting for several reasons ranging from its possible special role in electroweak symmetry breaking to its sensitivity to physics beyond the standard model (SM). In particular, the measurement of the top quark pair production cross section {sigma}{sub t{bar t}} is of interest as a test of QCD predictions. Recent QCD calculations done with perturbation theory to next-to-leading order predict {sigma}{sub t{bar t}} with an uncertainty of less than 15%, which motivate measurements of comparable precision. In this thesis, the author reports a measurement of the cross section for pair production of top quarks in the lepton+jets channel in 318 pb{sup -1} of p{bar p} collision data at {radical}s = 1.96 TeV. The data were recorded between March 2002 and September 2004, during Run II of the Tevatron, by the CDF II detector, a general purpose detector which combines charged particle trackers, sampling calorimeters, and muon detectors. processes in which a W boson is produced in association with several jets with large transverse momentum can be misidentified at t{bar t}, since they have the same signature. In order to separate the t{bar t} events from this background, they develop a method to tag b-jets based on tracking information from the silicon detector. The main event selection requires at least one tight (more restrictive) b tag in the event. As a cross check, they also measure the cross section using events with a loose (less restrictive) b tag and events which have at least two tight or at least two loose b tags. Background contributions from heavy flavor production processes, such as Wb{bar b}, Wc{bar c} or Wc, misidentified W bosons, electroweak processes, single top production, and mistagged jets are estimated using a combination of Monte Carlo calculations and independent measurements in control data samples. An excess over background in the number of events that contain a lepton, missing energy and three or more jets with at least one b-tag is assumed to be a signal of t{bar t} production and is used to measure the production cross section {sigma}{sub t{bar t}}.

  18. Search for physics beyond the standard model in final states with a lepton and missing transverse energy in proton-proton collisions at $\\sqrt{s}$ = 8 TeV

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Khachatryan, Vardan

    2015-05-22

    A search for new physics in proton-proton collisions having final states with an electron or muon and missing transverse energy is presented. The analysis uses data collected in 2012 with the CMS detector, at an LHC center-of-mass energy of 8 TeV, and corresponding to an integrated luminosity of 19.7 fb$^{-1}$. No significant deviation of the transverse mass distribution of the charged lepton-neutrino system from the standard model prediction is found. Mass exclusion limits of up to 3.28 TeV at a 95% confidence level for a W$^{\\prime}$ boson with the same couplings as that of the standard model W boson aremore »determined. Results are also derived in the framework of split universal extra dimensions, and exclusion limits on Kaluza-Klein W$^{(2)}_{{\\rm KK}}$ states are found. The final state with large missing transverse energy also enables a search for dark matter production with a recoiling W boson, with limits set on the mass and the production cross section of potential candidates. Finally, limits are established for a model including interference between a left-handed W$^{\\prime}$ boson and the standard model W boson, and for a compositeness model.« less

  19. Search for the production of ZW and ZZ boson pairs decaying into charged leptons and jets in proton-antiproton collisions at sqrt[s]=1.96 TeV

    SciTech Connect (OSTI)

    Aaltonen, Timo Antero; et al,

    2013-11-01

    We present a measurement of the production cross section for ZW and ZZ boson pairs in final states with a pair of charged leptons, from the decay of a Z boson, and at least two jets, from the decay of a W or Z boson, using the full sample of proton-antiproton collisions recorded with the CDF II detector at the Tevatron, corresponding to 8.9 fb^(-1) of integrated luminosity. We increase the sensitivity to vector boson decays into pairs of quarks using a neural network discriminant that exploits the differences between the spatial spread of energy depositions and charged-particle momenta contained within the jet of particles originating from quarks and gluons. Additionally, we employ new jet energy corrections to Monte Carlo simulations that account for differences in the observed energy scales for quark and gluon jets. The number of signal events is extracted through a simultaneous fit to the dijet mass spectrum in three classes of events: events likely to contain jets with a heavy-quark decay, events likely to contain jets originating from light quarks, and events that fail these identification criteria. We determine the production cross section to be 2.5 +2.0 -1.0 pb (< 6.1 pb at the 95% confidence level), consistent with the standard model prediction of 5.1 pb.

  20. Search for physics beyond the standard model in final states with a lepton and missing transverse energy in proton-proton collisions at $\\sqrt{s}$ = 8 TeV

    SciTech Connect (OSTI)

    Khachatryan, Vardan

    2015-05-22

    A search for new physics in proton-proton collisions having final states with an electron or muon and missing transverse energy is presented. The analysis uses data collected in 2012 with the CMS detector, at an LHC center-of-mass energy of 8 TeV, and corresponding to an integrated luminosity of 19.7 fb$^{-1}$. No significant deviation of the transverse mass distribution of the charged lepton-neutrino system from the standard model prediction is found. Mass exclusion limits of up to 3.28 TeV at a 95% confidence level for a W$^{\\prime}$ boson with the same couplings as that of the standard model W boson are determined. Results are also derived in the framework of split universal extra dimensions, and exclusion limits on Kaluza-Klein W$^{(2)}_{{\\rm KK}}$ states are found. The final state with large missing transverse energy also enables a search for dark matter production with a recoiling W boson, with limits set on the mass and the production cross section of potential candidates. Finally, limits are established for a model including interference between a left-handed W$^{\\prime}$ boson and the standard model W boson, and for a compositeness model.

  1. Measurement of the charge asymmetry in top-quark pair production in the lepton-plus-jets final state in $pp$ collision data at $\\sqrt{s}=8$ TeV with the ATLAS detector

    E-Print Network [OSTI]

    ATLAS Collaboration

    2015-01-01

    This paper reports inclusive and differential measurements of the $t\\bar{t}$ charge asymmetry $A_{\\text{C}}$ in 20.3 fb$^{-1}$ of $\\sqrt{s} = 8$ TeV $pp$ collisions recorded by the ATLAS experiment at the Large Hadron Collider at CERN. Three differential measurements are performed as a function of the invariant mass, transverse momentum and longitudinal boost of the $t\\bar{t}$ system. The $t\\bar{t}$ pairs are selected in the single-lepton channels ($e$ or $\\mu$) with at least four jets, and a likelihood fit is used to reconstruct the $t\\bar{t}$ event kinematics. A Bayesian unfolding procedure is performed to infer the asymmetry at parton level from the observed data distribution. The inclusive $t\\bar{t}$ charge asymmetry is measured to be $A_{\\text{C}} = 0.009 \\pm 0.005$ (stat.$+$syst.). The inclusive and differential measurements are compatible with the values predicted by the Standard Model.

  2. Search for WW and WZ production in lepton, neutrino plus jets final states at CDF Run II and Silicon module production and detector control system for the ATLAS SemiConductor Tracker

    SciTech Connect (OSTI)

    Sfyrla, Anna; /Geneva U.

    2008-03-01

    In the first part of this work, we present a search for WW and WZ production in charged lepton, neutrino plus jets final states produced in p{bar p} collisions with {radical}s = 1.96 TeV at the Fermilab Tevatron, using 1.2 fb{sup -1} of data accumulated with the CDF II detector. This channel is yet to be observed in hadron colliders due to the large singleWplus jets background. However, this decay mode has a much larger branching fraction than the cleaner fully leptonic mode making it more sensitive to anomalous triple gauge couplings that manifest themselves at higher transverse W momentum. Because the final state is topologically similar to associated production of a Higgs boson with a W, the techniques developed in this analysis are also applicable in that search. An Artificial Neural Network has been used for the event selection optimization. The theoretical prediction for the cross section is {sigma}{sub WW/WZ}{sup theory} x Br(W {yields} {ell}{nu}; W/Z {yields} jj) = 2.09 {+-} 0.14 pb. They measured N{sub Signal} = 410 {+-} 212(stat) {+-} 102(sys) signal events that correspond to a cross section {sigma}{sub WW/WZ} x Br(W {yields} {ell}{nu}; W/Z {yields} jj) = 1.47 {+-} 0.77(stat) {+-} 0.38(sys) pb. The 95% CL upper limit to the cross section is estimated to be {sigma} x Br(W {yields} {ell}{nu}; W/Z {yields} jj) < 2.88 pb. The second part of the present work is technical and concerns the ATLAS SemiConductor Tracker (SCT) assembly phase. Although technical, the work in the SCT assembly phase is of prime importance for the good performance of the detector during data taking. The production at the University of Geneva of approximately one third of the silicon microstrip end-cap modules is presented. This collaborative effort of the university of Geneva group that lasted two years, resulted in 655 produced modules, 97% of which were good modules, constructed within the mechanical and electrical specifications and delivered in the SCT collaboration for assembly on the end-cap disks. The SCT end-caps and barrels consist of 4088 silicon modules, with a total of 6.3 million readout channels. The coherent and safe operation of the SCT during commissioning and subsequent operation is the essential task of the Detector Control System (DCS). The main building blocks of the DCS are the cooling system, the power supplies and the environmental system. The DCS has been initially developed for the SCT assembly phase and this system is described in the present work. Particular emphasis is given in the environmental hardware and software components, that were my major contributions. Results from the DCS testing during the assembly phase are also reported.

  3. Search for production of vector-like quark pairs and of four top quarks in the lepton-plus-jets final state in pp collisions at ?s = 8 TeV with the ATLAS detector

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aad, G.

    2015-08-20

    A search for pair production of vector-like quarks, both up-type (T) and down-type (B), as well as for four-top-quark production, is presented. The search is based on pp collisions at \\( \\sqrt{s}=8 \\) TeV recorded in 2012 with the ATLAS detector at the CERN Large Hadron Collider and corresponding to an integrated luminosity of 20.3 fb–1. Data are analysed in the lepton-plus-jets final state, characterised by an isolated electron or muon with high transverse momentum, large missing transverse momentum and multiple jets. Dedicated analyses are performed targeting three cases: a T quark with significant branching ratio to a W bosonmore »and a b-quark \\( \\left(T\\overline{T}\\to Wb+\\mathrm{X}\\right) \\), and both a T quark and a B quark with significant branching ratio to a Higgs boson and a third-generation quark (\\( T\\overline{T}\\to Ht+X\\;\\mathrm{and}\\;B\\overline{B}\\to Hb+\\mathrm{X} \\) respectively). No significant excess of events above the Standard Model expectation is observed, and 95% CL lower limits are derived on the masses of the vector-like T and B quarks under several branching ratio hypotheses assuming contributions from T ? Wb, Zt, Ht and B ? Wt, Zb, Hb decays. The 95% CL observed lower limits on the T quark mass range between 715 GeV and 950 GeV for all possible values of the branching ratios into the three decay modes, and are the most stringent constraints to date. In addition, the most restrictive upper bounds on four-top-quark production are set in a number of new physics scenarios.« less

  4. Search for top squark pair production in final states with one isolated lepton, jets, and missing transverse momentum in ?s = 8 TeV pp collisions with the ATLAS detector

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aad, G.

    2014-11-21

    The results of a search for top squark (stop) pair production in final states with one isolated lepton, jets, and missing transverse momentum are reported. The analysis is performed with proton-proton collision data at ?s = 8 TeV collected with the ATLAS detector at the LHC in 2012 corresponding to an integrated luminosity of 20 fb–1. The lightest supersymmetric particle (LSP) is taken to be the lightest neutralino which only interacts weakly and is assumed to be stable. The stop decay modes considered are those to a top quark and the LSP as well as to a bottom quark andmore »the lightest chargino, where the chargino decays to the LSP by emitting a W boson. A wide range of scenarios with different mass splittings between the stop, the lightest neutralino and the lightest chargino are considered, including cases where the W bosons or the top quarks are off-shell. Decay modes involving the heavier charginos and neutralinos are addressed using a set of phenomenological models of supersymmetry. No significant excess over the Standard Model prediction is observed. A stop with a mass between 210 and 640 GeV decaying directly to a top quark and a massless LSP is excluded at 95% confidence level, and in models where the mass of the lightest chargino is twice that of the LSP, stops are excluded at 95% confidence level up to a mass of 500 GeV for an LSP mass in the range of 100 to 150 GeV. As a result, stringent exclusion limits are derived for all other stop decay modes considered, and model-independent upper limits are set on the visible cross-section for processes beyond the Standard Model.« less

  5. Search for top squark pair production in final states with one isolated lepton, jets, and missing transverse momentum in ?s = 8 TeV pp collisions with the ATLAS detector

    SciTech Connect (OSTI)

    Aad, G.

    2014-11-21

    The results of a search for top squark (stop) pair production in final states with one isolated lepton, jets, and missing transverse momentum are reported. The analysis is performed with proton-proton collision data at ?s = 8 TeV collected with the ATLAS detector at the LHC in 2012 corresponding to an integrated luminosity of 20 fb–1. The lightest supersymmetric particle (LSP) is taken to be the lightest neutralino which only interacts weakly and is assumed to be stable. The stop decay modes considered are those to a top quark and the LSP as well as to a bottom quark and the lightest chargino, where the chargino decays to the LSP by emitting a W boson. A wide range of scenarios with different mass splittings between the stop, the lightest neutralino and the lightest chargino are considered, including cases where the W bosons or the top quarks are off-shell. Decay modes involving the heavier charginos and neutralinos are addressed using a set of phenomenological models of supersymmetry. No significant excess over the Standard Model prediction is observed. A stop with a mass between 210 and 640 GeV decaying directly to a top quark and a massless LSP is excluded at 95% confidence level, and in models where the mass of the lightest chargino is twice that of the LSP, stops are excluded at 95% confidence level up to a mass of 500 GeV for an LSP mass in the range of 100 to 150 GeV. As a result, stringent exclusion limits are derived for all other stop decay modes considered, and model-independent upper limits are set on the visible cross-section for processes beyond the Standard Model.

  6. Search for production of vector-like quark pairs and of four top quarks in the lepton-plus-jets final state in pp collisions at ?s = 8 TeV with the ATLAS detector

    SciTech Connect (OSTI)

    Aad, G.

    2015-08-20

    A search for pair production of vector-like quarks, both up-type (T) and down-type (B), as well as for four-top-quark production, is presented. The search is based on pp collisions at \\( \\sqrt{s}=8 \\) TeV recorded in 2012 with the ATLAS detector at the CERN Large Hadron Collider and corresponding to an integrated luminosity of 20.3 fb–1. Data are analysed in the lepton-plus-jets final state, characterised by an isolated electron or muon with high transverse momentum, large missing transverse momentum and multiple jets. Dedicated analyses are performed targeting three cases: a T quark with significant branching ratio to a W boson and a b-quark \\( \\left(T\\overline{T}\\to Wb+\\mathrm{X}\\right) \\), and both a T quark and a B quark with significant branching ratio to a Higgs boson and a third-generation quark (\\( T\\overline{T}\\to Ht+X\\;\\mathrm{and}\\;B\\overline{B}\\to Hb+\\mathrm{X} \\) respectively). No significant excess of events above the Standard Model expectation is observed, and 95% CL lower limits are derived on the masses of the vector-like T and B quarks under several branching ratio hypotheses assuming contributions from T ? Wb, Zt, Ht and B ? Wt, Zb, Hb decays. The 95% CL observed lower limits on the T quark mass range between 715 GeV and 950 GeV for all possible values of the branching ratios into the three decay modes, and are the most stringent constraints to date. In addition, the most restrictive upper bounds on four-top-quark production are set in a number of new physics scenarios.

  7. Supersymmetric Dark Matter and Lepton Flavor Violation

    E-Print Network [OSTI]

    Soleimani, Ali

    2010-05-07

    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 1.5 Notation and Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 1.6 Flavor violation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 1.6.1 Quark sector flavor....3) LHiggs = |Dµ?|2 +µ2?†???(?†?)2, (1.4) and LYukawa = summationdisplay generations bracketleftBig ?fe¯L·?eR ?fd ¯Q·?dR ?fuepsilon1ab ¯Qa?†buR + h.c. bracketrightBig . (1.5) Here, Gµ?A , Wµ?A , Bµ? are the color, weak isospin and hypercharge field tensors...

  8. Search for ? mesons in ? lepton decay

    E-Print Network [OSTI]

    Baringer, Philip S.

    1997-02-01

    ¯m and Em the momentum and energy of the event. All charged tracks are assumed to be pions. @19# R.A. Fisher, Ann. Eugen. 7, 179 ~1936!. @20# B. Flury and H. Ridewyl, Multivariate Statistics, A Practical Approach ~New York, Chapman and Hall, 1988!. @21# S... of information on a possible four-quark state @C~1480!# with a mass 1480 MeV/c2 and JPC5122 @3,4# which decays into fp . Building on the work of Ref. @5#, Eidelman and Ivanchenko @6# estimate the branching fraction of t2!fp2n t assuming that the C~1480...

  9. Electronic branching ratio of the ? lepton

    E-Print Network [OSTI]

    Ammar, Raymond G.; Baringer, Philip S.; Coppage, Don; Davis, Robin E. P.; Kelly, M.; Kwak, Nowhan; Lam, H.

    1992-06-01

    - duction processes. In addition, it also contained events due to beam interactions with residual gas in the beam pipe ("beam-gas" events). We studied these backgrounds using Monte Carlo techniques and, whenever possible, the data themselves. In the Monte... that the angle between the net momentum of the event and the beam axis, 0„,„„ satisfied ~cos8,„,„,~ (0.80 for events where P~ was less than 0.5 (GeV/c) . Monte Carlo studies indicated that these cuts retained approximately 90% of r pairs satisfy- ing all other...

  10. DECAYS OF THE HEAVY LEPTON, TAU (1785)

    E-Print Network [OSTI]

    Blocker, Craig Alan

    2010-01-01

    f f i c i e n c y using the EGS shower Monte C a r l o t o dshower Monte Carlo had an EGS it was 4% of the real photonsp the liquid argon modules EGS, were narrow it v;~s f o u n

  11. Rare semi-leptonic B meson decays 

    E-Print Network [OSTI]

    Lyon, James David

    2014-06-28

    In this thesis, novel corrections to B ? X? and B ? Xl+l- decays, where X is a pseudoscalar or vector meson, are presented. These are the chromomagnetic matrix element, weak annihilation in a general four-quark operator basis and a long...

  12. Martin Perl and the Tau Lepton

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousandReport)PriceHistoricEnergyAprilMartin D. Kamen, 1995 TheMartin

  13. CLNS 99/1634 Observation of Radiative Leptonic Decay of the Tau Lepton

    E-Print Network [OSTI]

    \\Gamma ! š ø ¯ \\Gamma š ¯ fl and ø \\Gamma ! š ø e \\Gamma š e fl. For a 10 MeV minimum photon energy, Ottawa, Ontario, Canada K1S 5B6 and the Institute of Particle Physics, Canada 3 McGill University, Montr'eal

  14. Towards a realistic model of quarks and leptons, leptonic CP violation and neutrinoless $??$-decay

    E-Print Network [OSTI]

    Y. H. Ahn; Paolo Gondolo

    2014-12-09

    In order to explain the fermion masses and mixings naturally, we introduce a specific flavor symmetry and mass suppression pattern that constrain the flavor structure of the fermion Yukawa couplings. Our model describes why the hierarchy of neutrino masses is milder than the hierarchy of charged fermion masses in terms of successive powers of flavon fields. We investigate CP violation and neutrinoless double beta ($0\

  15. Measurements of the Top Quark Pair Production Cross Section in Lepton + Jets Final States using a Topological Multivariate Technique as well as Lifetime b-Tagging in Proton - Anti-proton Collisions at s**(1/2)=1.96 TeV with the D0 Detector at the Tevatron

    SciTech Connect (OSTI)

    Golling, Tobias F

    2005-01-01

    Two alternative measurements of the t{bar t} production cross section at {radical}s = 1.96 TeV in proton-antiproton collisions in the lepton+jets channel are presented. The t{bar t} production cross section is extracted by combining the kinematic event information in a multivariate discriminant. The measurement yields {sigma}{sub p{bar p} {yields} t{bar t} + x} = 5.13{sub -1.57}{sup +1.76}(stat){sub -1.10}{sup +0.96}(syst) {+-} 0.33 (lumi) pb in the muon+jets channel, using 229.1 pb{sup -1}, and in the combination with the electron+jets channel 226.3 pb{sup -1} {sigma}{sub p{bar p} {yields} t{bar t} + x} = 6.60{sub -1.28}{sup +1.37}(stat){sub -1.11}{sup +1.25}(syst) {+-} 0.43 (lumi) pb. The second measurement presented reconstructs explicitly secondary vertices to d lifetime b-tagging. The measurement combines the muon+jets and the electron+jets channel, using 158.4 pb{sup -1} and 168.8 pb{sup -1}, respectively: {sigma}{sub p{bar p} {yields} t{bar t} + x} = 8.24{sub -1.25}{sup +1.34}(stat){sub -1.63}{sup +1.89}(syst) {+-} 0.54 (lumi) pb.

  16. Neutrino mass, lepton number, and the origin of matter

    E-Print Network [OSTI]

    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

  17. Phenomenology of Maximal and Near-Maximal Lepton Mixing

    E-Print Network [OSTI]

    M. C. Gonzalez-Garcia; C. Peña-Garay; Y. Nir; A. Yu. Smirnov

    2000-09-18

    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|neutrinoless double beta decay.

  18. Summary and Outlook: 2015 Lepton-Photon Symposium

    E-Print Network [OSTI]

    John Ellis

    2015-09-24

    What life is there after Higgs? Specifically, what physics lies beyond the Standard Model (SM)? These are the biggest questions in particle physics today, and my talk is oriented towards efforts to answer them at the LHC and elsewhere.

  19. Summary and Outlook: 2015 Lepton-Photon Symposium

    E-Print Network [OSTI]

    Ellis, John

    2015-01-01

    What life is there after Higgs? Specifically, what physics lies beyond the Standard Model (SM)? These are the biggest questions in particle physics today, and my talk is oriented towards efforts to answer them at the LHC and elsewhere.

  20. Electromagnetic Field Creation During EWPT Nucleation With Lepton Currents

    E-Print Network [OSTI]

    Leonard S. Kisslinger; Sameer Walawalkar; Ernest M. Henley; Mikkel B. Johnson

    2005-10-11

    We include the electromagnetic currents from fermion degrees of freedom in the equations of motion for electroweak MSSM with a right-handed Stop that we have recently investigated. It is found that near the surface of the bubble walls there are important effects on the electromagnetic fields produced during bubble nucleation.

  1. Probing the fermionic Higgs portal at lepton colliders

    E-Print Network [OSTI]

    Fedderke, Michael A; Wang, Lian-Tao

    2015-01-01

    We study the sensitivity of future electron-positron colliders to UV completions of the fermionic Higgs portal operator $H^\\dagger H \\bar \\chi \\chi$. Measurements of precision electroweak $S$ and $T$ parameters and the $e^+e^- \\to Zh$ cross section at the CEPC, FCC-ee, and ILC are considered. The scalar completion of the fermionic Higgs portal is closely related to the scalar Higgs portal, and we summarize existing results. We devote the bulk of our analysis to a singlet-doublet fermion completion. Assuming the doublet is sufficiently heavy, we construct the effective field theory (EFT) at dimension-6 in order to compute contributions to the observables. We also provide full one-loop results for $S$ and $T$ in the general mass parameter space. In both completions, future precision measurements can probe the new states at the (multi-)TeV scale, beyond the direct reach of the LHC.

  2. Probing the fermionic Higgs portal at lepton colliders

    E-Print Network [OSTI]

    Michael A. Fedderke; Tongyan Lin; Lian-Tao Wang

    2015-06-17

    We study the sensitivity of future electron-positron colliders to UV completions of the fermionic Higgs portal operator $H^\\dagger H \\bar \\chi \\chi$. Measurements of precision electroweak $S$ and $T$ parameters and the $e^+e^- \\to Zh$ cross section at the CEPC, FCC-ee, and ILC are considered. The scalar completion of the fermionic Higgs portal is closely related to the scalar Higgs portal, and we summarize existing results. We devote the bulk of our analysis to a singlet-doublet fermion completion. Assuming the doublet is sufficiently heavy, we construct the effective field theory (EFT) at dimension-6 in order to compute contributions to the observables. We also provide full one-loop results for $S$ and $T$ in the general mass parameter space. In both completions, future precision measurements can probe the new states at the (multi-)TeV scale, beyond the direct reach of the LHC.

  3. Search for neutrinoless decays of the tau lepton

    E-Print Network [OSTI]

    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.

    1994-10-01

    . The upper limits obtained for 22 decay branching fractions are several times more stringent than those set previously....

  4. New Physics Models Facing Lepton Flavor Violating Higgs Decays

    E-Print Network [OSTI]

    Košnik, Nejc

    2015-01-01

    We speculate about the possible interpretations of the recently observed excess in the $h \\to \\tau \\mu$ decay. We derive a robust lower bound on the Higgs boson coupling strength to a tau and a muon, even in presence of the most general new physics affecting other Higgs properties. Then we reevaluate complementary indirect constraints coming from low energy observables as well as from theoretical considerations. In particular, the tentative signal should lead to $\\tau \\to \\mu \\gamma$ at rates which could be observed at Belle II. In turn we show that, barring fine-tuned cancellations, the effect can be accommodated within models with an extended scalar sector. These general conclusions are demonstrated in explicit new physics models. Finally we show how, given the $h \\to \\tau \\mu$ signal, the current and future searches for $\\mu \\to e \\gamma$ and $\\mu \\to e$ nuclear conversions unambiguously constrain the allowed rates for $h \\to \\tau e$.

  5. Lineshape of the Higgs boson in future lepton colliders

    E-Print Network [OSTI]

    Jadach, S

    2015-01-01

    The effect of the photon emission (bremsstrahlung) in the cross section of the process of direct production of the Higgs boson in the future high luminosity electron and muon colliders is calculated. It was found that cross section at the top of the Higgs boson resonance peak is reduced by factor 0.347 for the electron collider and 0.548 for the muon collider. Machine spread of the centre of the mass energy of 4.2MeV (equal to the Higgs width) would reduce peak cross section further, by factor 0.170 and 0.256 (QED and energy spread) for electron and muon beams respectively. Possible uncertainties in the resummed QED calculations are discussed. Numerical results for the lineshape cross section including QED and many values of the machine energy spread are provided.

  6. Anomalous magnetic moments of free and bound leptons

    E-Print Network [OSTI]

    Pachucki, Krzysztof

    ]. An almost simultaneous calculation by Schwinger [2] showed how the electron self-interaction explains. Jentschura. Max­Planck­Institut f¨ur Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany. e-mail: Ulrich.Jentschura@mpi-hd.mpg to know this part with the maximum possible accuracy. Schwinger's calculation included a single virtual

  7. Software for physics of tau lepton decay in LHC experiments

    E-Print Network [OSTI]

    Tomasz Przedzinski

    2010-09-20

    Software development in high energy physics experiments offers unique experience with rapidly changing environment and variety of different standards and frameworks that software must be adapted to. As such, regular methods of software development are hard to use as they do not take into account how greatly some of these changes influence the whole structure. The following thesis summarizes development of TAUOLA C++ Interface introducing tau decays to new event record standard. Documentation of the program is already published. That is why it is not recalled here again. We focus on the development cycle and methodology used in the project, starting from the definition of the expectations through planning and designing the abstract model and concluding with the implementation. In the last part of the paper we present installation of the software within different experiments surrounding Large Hadron Collider and the problems that emerged during this process.

  8. TESLA*HERA as Lepton (Photon)-Hadron Collider

    E-Print Network [OSTI]

    O. Yavas; A. K. Ciftci; S. Sultansoy

    2000-04-11

    New facilities for particle and nuclear physics research, which will be available due to constructing the TESLA linear electron-positron collider tangentially to the HERA proton ring, are discussed.

  9. A 233 km tunnel for lepton and hadron colliders

    SciTech Connect (OSTI)

    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)

    2012-12-21

    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.

  10. A_N in inclusive lepton-proton collisions

    SciTech Connect (OSTI)

    Prokudin, Alexey; Anselmino, Mauro; Boglione, Mariaelena; D'Alesio, Umberto; Melis, Stefano; Murgia, Francesco

    2014-11-01

    Some estimates for the transverse single spin asymmetry, A_N, in the inclusive processes l p(transv. Pol.) -> h X are compared with new experimental data. The calculations are based on the Sivers and Collins functions as extracted from SIDIS azimuthal asymmetries, within a transverse momentum dependent factorization approach. The values of A_N thus obtained agree in sign and shape with the data. Predictions for future experiments are also given.

  11. Probing Baryon Asymmetry of the Universe by Using Lepton Universality

    E-Print Network [OSTI]

    Asaka, Takehiko; Takeda, Kazuhiro

    2015-01-01

    We study the model with three right-handed neutrinos which masses are smaller than the weak scale ${\\cal O}(10^2)$ GeV (called as the $\

  12. R. Tayloe, Indiana University Lepton-Photon '07 1

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMassR&D100 Winners * Impacts on Global Technology OUTSIDE FRONT COVER

  13. Exploring new physics through contact interactions in lepton pair

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(Journal Article) |

  14. Exploring new physics through contact interactions in lepton pair

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(Journal Article) |production at a linear collider (Conference) | SciTech Connect

  15. Reconstruction and identification of $\tau$ lepton decays to hadrons and

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech ConnectSpeedingConnect(Conference) | SciTechelectrodes. (Technical$\nu_\tau$ at

  16. Reconstruction and identification of $\tau$ lepton decays to hadrons and

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech ConnectSpeedingConnect(Conference) | SciTechelectrodes. (Technical$\nu_\tau$

  17. Tau Lepton Mass Measurements (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference)Feedback SystemGimbaled X-Ray HeadSTRATIFICATION(JournalConnect

  18. Towards a realistic model of quarks and leptons, leptonic CP violation and neutrinoless $\\beta\\beta$-decay

    E-Print Network [OSTI]

    Ahn, Y H

    2014-01-01

    In order to explain the fermion masses and mixings naturally, we introduce a specific flavor symmetry and mass suppression pattern that constrain the flavor structure of the fermion Yukawa couplings. Our model describes why the hierarchy of neutrino masses is milder than the hierarchy of charged fermion masses in terms of successive powers of flavon fields. We investigate CP violation and neutrinoless double beta ($0\

  19. SEARCH FOR CHARGED HIGGS DECAYS OF THE TOP QUARK USING HADRONIC DECAYS OF THE TAU LEPTON

    E-Print Network [OSTI]

    Quigg, Chris

    ­Wagner, 7 K. L. Byrum, 1 J. Cammerata, 15 C. Campagnari, 7 M. Campbell, 19 A. Caner, 26 W. Carithers, 17 D

  20. Direct CP, Lepton Flavor, and Isospin Asymmetries in the Decays B-->K(*)l+l-

    E-Print Network [OSTI]

    Cowan, Ray Franklin

    We measure branching fractions and integrated rate asymmetries for the rare decays B?K(*)l+l-, where l+l- is either e+e- or ?+?-, using a sample of 384×10(6) BB? events collected with the BABAR detector at the PEP-II e+e- ...

  1. Observation and examination of a Higgs boson in the ZZ to four lepton channel

    E-Print Network [OSTI]

    Ralph, Duncan (Duncan Kelley)

    2014-01-01

    Results are presented on 5.1 fb- 1 of proton-proton collisions at a center of mass energy of 7 TeV and 19.7 fb- 1 at 8 TeV in a search for decays of the Standard Model (SM) Higgs boson to two Z bosons to four charged ...

  2. Discovery of a Higgs Boson in the H to ZZ to 4 leptons channel /

    E-Print Network [OSTI]

    Vartak, Adish Pradeep

    2014-01-01

    1.2 History of Higgs Boson Searches . . . . . . . . . . .Implications of a 125 GeV Higgs Boson 7.7 Concluding1.3.4 Higgs Boson Decays . . . . . . . . . . . . . . 1.3.5

  3. Measurement of the properties of a Higgs boson in the four-lepton final state

    E-Print Network [OSTI]

    Apyan, Aram

    The properties of a Higgs boson candidate are measured in the H ? ZZ ? 4? decay channel, with ? = e, ?, using data from pp collisions corresponding to an integrated luminosity of 5.1??fb[superscript ?1] at the center-of-mass ...

  4. First Measurements of Spin Correlation Using Semi-leptonic $t\\bar{t}$ Events at ATLAS

    E-Print Network [OSTI]

    Boris Lemmer; for the ATLAS Collaboration

    2014-11-20

    The top quark decays before it hadronizes. Before its spin state can be changed in a process of strong interaction, it is directly transferred to the top quark decay products. The top quark spin can be deduced by studying angular distributions of the decay products. The Standard Model predicts the top/anti-top quark ($t\\bar{t}$) pairs to have correlated spins. The degree is sensitive to the spin and the production mechanisms of the top quark. Measuring the spin correlation allows to test the predictions. New physics effects can be reflected in deviations from the prediction. The measurement of the spin correlation of $t\\bar{t}$ pairs, produced at the LHC with a center-of-mass energy of $\\sqrt{s} = 7$ TeV and reconstructed with the ATLAS detector, is presented. The dataset corresponds to an integrated luminosity of 4.6 $\\textrm{fb}^{-1}$. $t\\bar{t}$ pairs are reconstructed in the $\\ell$+jets channel using a kinematic likelihood fit offering the identification of light up- and down-type quarks from the $t \\rightarrow bW \\rightarrow bq\\bar{q}'$ decay. The spin correlation is measured via the distribution of the azimuthal angle $\\Delta \\phi$ between two top quark spin analyzers in the laboratory frame. It is expressed as the degree of $t\\bar{t}$ spin correlation predicted by the Standard Model, $f_{\\textrm{SM}}$. The result of $f_{\\textrm{SM}}= 1.12 \\pm 0.11\\,\\text{(stat.)} \\pm 0.22\\,\\text{(syst.)}$ is consistent with the Standard Model prediction of $f_{\\textrm{SM}}= 1.0$.

  5. Numerical Implementation of lepton-nucleus interactions and its effect on neutrino oscillation analysis

    E-Print Network [OSTI]

    C. -M. Jen; A. Ankowski; O. Benhar; A. P. Furmanski; L. N. Kalousis; C. Mariani

    2014-10-13

    We discuss the implementation of the nuclear model based on realistic nuclear spectral functions in the GENIE neutrino interaction generator. Besides improving on the Fermi gas description of the nuclear ground state, our scheme involves a new prescription for $Q^2$ selection, meant to efficiently enforce energy momentum conservation. The results of our simulations, validated through comparison to electron scattering data, have been obtained for a variety of target nuclei, ranging from carbon to argon, and cover the kinematical region in which quasi elastic scattering is the dominant reaction mechanism. We also analyse the influence of the adopted nuclear model on the determination of neutrino oscillation parameters.

  6. Limits on the Higgs boson lifetime and width from its decay to four charged leptons

    E-Print Network [OSTI]

    Khachatryan, Vardan; Tumasyan, Armen; Adam, Wolfgang; A??lar, Ece; Bergauer, Thomas; Brandstetter, Johannes; Brondolin, Erica; Dragicevic, Marko; Erö, Janos; Flechl, Martin; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hartl, Christian; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Knünz, Valentin; König, Axel; Krammer, Manfred; Krätschmer, Ilse; Liko, Dietrich; Matsushita, Takashi; Mikulec, Ivan; Rabady, Dinyar; Rahbaran, Babak; Rohringer, Herbert; Schieck, Jochen; Schöfbeck, Robert; Strauss, Josef; Treberer-Treberspurg, Wolfgang; Waltenberger, Wolfgang; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Alderweireldt, Sara; Cornelis, Tom; De Wolf, Eddi A; Janssen, Xavier; Knutsson, Albert; Lauwers, Jasper; Luyckx, Sten; Ochesanu, Silvia; Rougny, Romain; Van De Klundert, Merijn; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Van Spilbeeck, Alex; Abu Zeid, Shimaa; Blekman, Freya; D'Hondt, Jorgen; Daci, Nadir; De Bruyn, Isabelle; Deroover, Kevin; Heracleous, Natalie; Keaveney, James; Lowette, Steven; Moreels, Lieselotte; Olbrechts, Annik; Python, Quentin; Strom, Derek; Tavernier, Stefaan; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Van Parijs, Isis; Barria, Patrizia; Caillol, Cécile; Clerbaux, Barbara; De Lentdecker, Gilles; Delannoy, Hugo; Fasanella, Giuseppe; Favart, Laurent; Gay, Arnaud; Grebenyuk, Anastasia; Lenzi, Thomas; Léonard, Alexandre; Maerschalk, Thierry; Marinov, Andrey; Perniè, Luca; Randle-conde, Aidan; Reis, Thomas; Seva, Tomislav; Vander Velde, Catherine; Vanlaer, Pascal; Yonamine, Ryo; Zenoni, Florian; Zhang, Fengwangdong; Beernaert, Kelly; Benucci, Leonardo; Cimmino, Anna; Crucy, Shannon; Dobur, Didar; Fagot, Alexis; Garcia, Guillaume; Gul, Muhammad; Mccartin, Joseph; Ocampo Rios, Alberto Andres; Poyraz, Deniz; Ryckbosch, Dirk; Salva Diblen, Sinem; Sigamani, Michael; Strobbe, Nadja; Tytgat, Michael; Van Driessche, Ward; Yazgan, Efe; Zaganidis, Nicolas; Basegmez, Suzan; Beluffi, Camille; Bondu, Olivier; Brochet, Sébastien; Bruno, Giacomo; Castello, Roberto; Caudron, Adrien; Ceard, Ludivine; Da Silveira, Gustavo Gil; Delaere, Christophe; Favart, Denis; Forthomme, Laurent; Giammanco, Andrea; Hollar, Jonathan; Jafari, Abideh; Jez, Pavel; Komm, Matthias; Lemaitre, Vincent; Mertens, Alexandre; Nuttens, Claude; Perrini, Lucia; Pin, Arnaud; Piotrzkowski, Krzysztof; Popov, Andrey; Quertenmont, Loic; Selvaggi, Michele; Vidal Marono, Miguel; Beliy, Nikita; Hammad, Gregory Habib; Aldá Júnior, Walter Luiz; Alves, Gilvan; Brito, Lucas; Correa Martins Junior, Marcos; Hamer, Matthias; Hensel, Carsten; Mora Herrera, Clemencia; Moraes, Arthur; Pol, Maria Elena; Rebello Teles, Patricia; Belchior Batista Das Chagas, Ewerton; Carvalho, Wagner; Chinellato, Jose; Custódio, Analu; Da Costa, Eliza Melo; De Jesus Damiao, Dilson; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Huertas Guativa, Lina Milena; Malbouisson, Helena; Matos Figueiredo, Diego; Mundim, Luiz; Nogima, Helio; Prado Da Silva, Wanda Lucia; Santoro, Alberto; Sznajder, Andre; Tonelli Manganote, Edmilson José; Vilela Pereira, Antonio; Ahuja, Sudha; Bernardes, Cesar Augusto; De Souza Santos, Angelo; Dogra, Sunil; Tomei, Thiago; De Moraes Gregores, Eduardo; Mercadante, Pedro G; Moon, Chang-Seong; Novaes, Sergio F; Padula, Sandra; Romero Abad, David; Ruiz Vargas, José Cupertino; Aleksandrov, Aleksandar; Genchev, Vladimir; Hadjiiska, Roumyana; Iaydjiev, Plamen; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Vutova, Mariana; Dimitrov, Anton; Glushkov, Ivan; Litov, Leander; Pavlov, Borislav; Petkov, Peicho; Ahmad, Muhammad; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Chen, Mingshui; Cheng, Tongguang; Du, Ran; Jiang, Chun-Hua; Plestina, Roko; Romeo, Francesco; Shaheen, Sarmad Masood; Tao, Junquan; Wang, Chunjie; Wang, Zheng; Zhang, Huaqiao; Asawatangtrakuldee, Chayanit; Ban, Yong; Li, Qiang; Liu, Shuai; Mao, Yajun; Qian, Si-Jin; Wang, Dayong; Xu, Zijun; Zou, Wei; Avila, Carlos; Cabrera, Andrés; Chaparro Sierra, Luisa Fernanda; Florez, Carlos; Gomez, Juan Pablo; Gomez Moreno, Bernardo; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Polic, Dunja; Puljak, Ivica; Ribeiro Cipriano, Pedro M; Antunovic, Zeljko; Kovac, Marko; Brigljevic, Vuko; Kadija, Kreso; Luetic, Jelena; Micanovic, Sasa; Sudic, Lucija; Attikis, Alexandros; Mavromanolakis, Georgios; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Rykaczewski, Hans; Bodlak, Martin; Finger, Miroslav; Finger Jr, Michael

    2015-01-01

    Constraints on the lifetime and width of the Higgs boson are obtained from $\\mathrm{H} \\to \\mathrm{ZZ} \\to 4\\ell$ events using data recorded by the CMS experiment during the LHC run 1 with an integrated luminosity of 5.1 and 19.7 fb$^{-1}$ at a center-of-mass energy of 7 and 8 TeV, respectively. The measurement of the Higgs boson lifetime is derived from its flight distance in the CMS detector with an upper bound of $\\tau_{\\mathrm{H}} $ lower than $ 1.9 \\times 10^{-13}$ s at the 95% confidence level (CL), corresponding to a lower bound on the width of $\\Gamma_{\\mathrm{H}} $ larger than $ 3.5 \\times 10^{-9} $ MeV. The measurement of the width is obtained from an off-shell production technique, generalized to include anomalous couplings of the Higgs boson to two electroweak bosons. From this measurement, a joint constraint is set on the Higgs boson width and a parameter $f_{\\Lambda Q}$ that expresses an anomalous coupling contribution as an on-shell cross-section fraction. The limit on the Higgs boson width is ...

  7. PoS(EPS-HEP2013)326 Measurement of the ratio of the leptonic widths

    E-Print Network [OSTI]

    aerogel counters, (5) ToF counters, (6) Liquid krypton calorimeter, (7) Superconducting coil, (8) Magnet

  8. A Measurement of the Mass of the Top Quark in Lepton + Jets Events at CDF

    SciTech Connect (OSTI)

    Brubaker, Erik Matthews

    2004-12-01

    This document presents a measurement of the top quark mass using the CDF run II detector at Fermilab. Colliding beams of protons and anti-protons at Fermilab's Tevatron ({radical}s = 1.96 TeV) produce top/anti-top pairs, which decay to W{sup +}W{sup -} b{bar b}; events are selected where one W decays hadronically, and one W decays to either e or {mu} plus a neutrino. The data sample was collected between March 2002 and September 2003, and corresponds to an integrated luminosity of approximately 162 pb{sup -1}. Thirty-seven candidate t{bar t} events are found with at least one b jet identified by its displaced vertex. In each event, the best fit top quark invariant mass is determined by minimizing a {chi}{sup 2} for the overconstrained kinematic system. A likelihood fit of the reconstructed masses in the data sample to distributions from simulated signal and background events gives a top mass of 174.9{sub -7.7}{sup +7.1}(stat.) {+-} 6.5(syst.) GeV/c{sup 2}. The dominant systematic error is due to uncertainties in the jet energy measurements.

  9. Search for new physics in lepton + photon + x events with 929...

    Office of Scientific and Technical Information (OSTI)

    New Trends in High-Energy Physics: Experiment, Phenomenology, Theory, Yalta, Crimea, Ukraine, 16-23 Sep 2006 Research Org: Fermi National Accelerator Laboratory (FNAL), Batavia,...

  10. Exclusion of an Exotic Top Quark with-4/3 Electric Charge Using Soft Lepton Tagging

    E-Print Network [OSTI]

    Paus, Christoph M. E.

    We present a measurement of the electric charge of the top quark using pp[over-bar] collisions corresponding to an integrated luminosity of 2.7??fb[superscript -1] at the CDF II detector. We reconstruct tt[over-bar] events ...

  11. Measurement of Higgs boson production and properties in the WW decay channel with leptonic final states

    E-Print Network [OSTI]

    Apyan, Aram

    A search for the standard model Higgs boson decaying to a W-boson pair at the LHC is reported. The event sample corresponds to an integrated luminosity of 4.9 fb[superscript ?1] and 19.4 fb[superscript ?1] collected with ...

  12. Search for the Higgs boson in its decay into tau leptons at CMS

    E-Print Network [OSTI]

    Chan, Matthew Hans

    2013-01-01

    A search for the Standard Model Higgs boson in the H --> rr channel is presented. The search is performed on proton collision data collected by the Compact Muon Solenoid at the Large Hadron Collider. The data corresponds ...

  13. Events with an Isolated Lepton and Missing Transverse Momentum and Measurement of W Production at HERA

    E-Print Network [OSTI]

    The H1; ZEUS Collaborations

    2010-07-30

    A search for events containing an isolated electron or muon and missing transverse momentum produced in ep collisions is performed with the H1 and ZEUS detectors at HERA. The data were taken in the period 1994-2007 and correspond to an integrated luminosity of 0.98 fb^-1. The observed event yields are in good overall agreement with the Standard Model prediction, which is dominated by single W production. In the e+p data, at large hadronic transverse momentum PtX >25 GeV, a total of 23 events are observed compared to a prediction of 14.0 \\pm 1.9. The total single W boson production cross section is measured as 1.06 \\pm 0.16 (stat.) \\pm 0.07 (sys) pb, in agreement with an SM expectation of 1.26 \\pm 0.19 pb.

  14. Lattice study of the leptonic decay constant of the pion and its excitations

    SciTech Connect (OSTI)

    Mastropas, Ekaterina; Richard, David

    2014-11-01

    We present a calculation of the decay constant of the pion, and its lowest-lying three excitations, at three values of the pion mass between around 400 and 700 MeV, using anisotropic clover lattices. We use the variational method to determine an optimal interpolating operator for each of the states. We find that the decay constant of the first excitation, and more notably of the second, is suppressed with respect to that of the ground-state pion, but that the suppression shows little dependence on the quark mass.

  15. Search for pair production of excited top quarks in the lepton + jets final state

    E-Print Network [OSTI]

    Apyan, Aram

    A search is performed for pair-produced spin-3/2 excited top quarks (t[superscript ?][¯ over t][superscript ?]), each decaying to a top quark and a gluon. The search uses data collected with the CMS detector from pp ...

  16. 2+1 Flavour Domain Wall QCD: light meson spectrum, leptonic decays and neutral kaon mixing 

    E-Print Network [OSTI]

    Antonio, David J

    2008-01-01

    We study light hadron phenomenology using Lattice QCD. We focus on the calculations of the light pseudoscalar quantities: masses, decay constants and B-parameters; in particular the calculation of the Kaon B-parameter, ...

  17. Top quark mass measurement in the lepton plus jets channel using a modified matrix element method

    E-Print Network [OSTI]

    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 ...

  18. Search for VH ? leptons + b¯b with the ATLAS experiment at the LHC 

    E-Print Network [OSTI]

    Debenedetti, Chiara

    2014-11-27

    The search for a Higgs boson decaying to a b¯b pair is one of the key analyses ongoing at the ATLAS experiment. Despite being the largest branching ratio decay for a Standard Model Higgs boson, a large dataset is necessary ...

  19. Forschung an Lepton Collidern Abbildung38: PhotographiedesHochfeld-MagnetteststandesamDESY

    E-Print Network [OSTI]

    Beschleu- nigers getroffen worden ist. Gleichzeitig wurde der X-FEL, der bisher ein Teil des TESLA Projekts Herbst des Jahres die Arbeit aufnahm. Der Linearbeschleuniger TESLA Im Jahr 2003 nahmen in der Gruppe FLC Konstruktion einer ers- ten Generation von Prototypen. Die Arbeiten um- fassten die Entwicklung und den Bau

  20. Quantum Black Holes and their Lepton Signatures at the LHC with CalCHEP

    E-Print Network [OSTI]

    Alexander Belyaev; Xavier Calmet

    2014-12-08

    We discuss a field theoretical framework to describe the interactions of non-thermal quantum black holes (QBHs) with particles of the Standard Model. We propose a non-local Lagrangian to describe the production of these QBHs which is designed to reproduce the geometrical cross section for black hole production. This model is implemented into CalcHEP package and is publicly available at the High Energy Model Database (HEPMDB) for simulation of QBH events at the LHC and future colliders. We present the first phenomenological application of the QBH@HEPMDB model with spin-0 neutral QBH giving rise the $e^+e^-$ and $e\\mu$ signatures at the LHC@8TeV and LHC@13TeV and produce the respective projections for the LHC in terms of limits on the reduced Planck mass and the number of the extra-dimensions.

  1. Angular correlations of lepton pairs from vector boson and top quark decays in Monte Carlo simulations.

    E-Print Network [OSTI]

    Frixione, Stefano; Laenen, Eric; Motylinski, Patrick; Webber, Bryan R

    -space factorization d?3n+1?(P1 + P2; k1, . . . , k2n, r1, . . . , rn, x) = d?n+1?(P1 + P2; p1, . . . , pn, x) n ? i=1 d?3(pi; k2i?1, k2i, ri) dp2i 2pi , (2.13) with the three-body phase spaces on the r.h.s. accounting for the decays ti(pi) ?? Wi(qi) + bi(ri) ?? li(k2i...

  2. Higher-dimensional effective-potential model of quarks and leptons 

    E-Print Network [OSTI]

    Wirjawan, Johannes Vincentius Djoko

    1993-01-01

    -handed solutions of the ordinary Dirac equation only to the 'right-handed' extra- dimensional solutions, and the left-handed solution of the ordinary Dirac solutions only to the 'left-handed' extra- dimensional solutions. If we treat the 'generalized' electro- weak...

  3. Radiation defects in silicon due to hadrons and leptons, their annealing and influence on detector performance

    E-Print Network [OSTI]

    Ionel Lazanu; Sorina Lazanu

    2002-03-25

    A phenomenological model was developed to explain quantitatively, without free parameters, the production of primary defects in silicon after particle irradiation, the kinetics of their evolution toward equilibrium and their influence on detector parameters. The type of the projectile particle and its energy is considered in the evaluation of the concentration of primary defects. Vacancy-interstitial annihilation, interstitial migration to sinks, vacancy - impurity complexes (VP, VO, V2O), and divacancy (V2) formation are taken into account in different irradiation conditions, for different concentrations of impurities in the semiconductor material, for 20 and 0 degrees C. The model can be extended to include other vacancy and interstitial complexes. The density of the reverse current in the detector after irradiation is estimated. Comparison with experimental measurements is performed. A special application considered in the paper is the modelled case of the behaviour of silicon detectors operating in the pion field estimated for the LHC accelerator, under continuum generation and annealing.

  4. NEUTRON IZATI ON, LEPTON ESCAPE,AND STELLAR HYDRODYNAMICS* W. David Arnett

    E-Print Network [OSTI]

    Boyer, Edmond

    in kinetic and bin- ding energy, PdV the work done by pressure forces and dQ the net energy carried out of the system. This simply states that energy is conserved. With the possibility of composi- tion changing of species i. With these variables the E in eq. (1) becomes energy per mole of nucleons and the Q becomes

  5. Time-reversal symmetry violation in several Lepton-Flavor-Violating processes

    E-Print Network [OSTI]

    Vasquez, Juan Carlos

    2015-01-01

    We compute a T-odd triple vector correlation for the $\\mu\\rightarrow e\\gamma $ decay and the $\\mu\\rightarrow e$ conversion process. We find simple results in terms of the CP violating phases of the effective Hamiltonians. Then we focus on the minimal Left-Right symmetric extension of the Standard Model, which can lead to an appreciable correlation. We show that under rather general assumptions, this correlation can be used to discriminate between Parity or Charge-conjugation as the discrete Left-Right symmetry.

  6. Time-reversal symmetry violation in several Lepton-Flavor-Violating processes

    E-Print Network [OSTI]

    Juan Carlos Vasquez

    2015-04-29

    We compute a T-odd triple vector correlation for the $\\mu\\rightarrow e\\gamma $ decay and the $\\mu\\rightarrow e$ conversion process. We find simple results in terms of the CP violating phases of the effective Hamiltonians. Then we focus on the minimal Left-Right symmetric extension of the Standard Model, which can lead to an appreciable correlation. We show that under rather general assumptions, this correlation can be used to discriminate between Parity or Charge-conjugation as the discrete Left-Right symmetry.

  7. Top Quark Mass Measurement in the Lepton plus Jets Channel Using a Modified Matrix Element Method

    SciTech Connect (OSTI)

    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.

    2008-12-01

    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}.

  8. Search for the Standard Model Higgs boson in the fully leptonic WW decay channel at CMS

    E-Print Network [OSTI]

    LeBourgeois, Matthew; LeBourgeois, Matthew

    2012-01-01

    of the Higgs boson . . . . . . . . . . . . . . . . . . . . .the Higgs boson . . . . . . . . . . . . . . . . . . . . . .5 Search for the Higgs Boson in the WW Decay Channel . . .

  9. Decays of ? leptons to final states containing K(0)S mesons

    E-Print Network [OSTI]

    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

    1996-06-01

    present branching fractions for decays to five final states: t 2!K0h2n t , t 2!K0h2p0n t , t 2!K0K2n t , t 2!K0K2p0n t , and t2!KS0KS0h2nt , where K0h2 de- notes the sum of the processes involving K¯0p2 and K0K2 particle combinations. Substructure and mass... systematic errors. For other modes, selection criteria are less stringent for higher acceptance. A sample of t2!KS0h2nt events is selected by requiring four charged tracks, each with momentum transverse to the beam axis pT.0.05Ebeam and ucosuu,0.8, where u...

  10. From Clifford Algebra of Nonrelativistic Phase Space to Quarks and Leptons of the Standard Model

    E-Print Network [OSTI]

    Piotr ?enczykowski

    2015-05-11

    We review a recently proposed Clifford-algebra approach to elementary particles. We start with: (1) a philosophical background that motivates a maximally symmetric treatment of position and momentum variables, and: (2) an analysis of the minimal conceptual assumptions needed in quark mass extraction procedures. With these points in mind, a variation on Born's reciprocity argument provides us with an unorthodox view on the problem of mass. The idea of space quantization suggests then the linearization of the nonrelativistic quadratic form ${\\bf p}^2 +{\\bf x}^2$ with position and momentum satisfying standard commutation relations. This leads to the 64-dimensional Clifford algebra ${Cl}_{6,0}$ of nonrelativistic phase space within which one identifies the internal quantum numbers of a single Standard Model generation of elementary particles (i.e. weak isospin, hypercharge, and color). The relevant quantum numbers are naturally linked to the symmetries of macroscopic phase space. It is shown that the obtained phase-space-based description of elementary particles gives a subquark-less explanation of the celebrated Harari-Shupe rishon model. Finally, the concept of additivity is used to form novel suggestions as to how hadrons are constructed out of quarks and how macroscopically motivated invariances may be restored at the hadron level.

  11. Leptonic B- and D-meson decay constants with 2+1 flavors of asqtad fermions

    E-Print Network [OSTI]

    Andreas S. Kronfeld; Ethan T. Neil; James N. Simone; Ruth S. Van de Water; for the Fermilab Lattice Collaboration; for the MILC Collaboration

    2015-01-08

    We present the status of our updated D- and B-meson decay-constant analysis, based on the MILC $N_f = 2+1$ asqtad gauge ensembles. Heavy quarks are incorporated using the Wilson clover action with the Fermilab interpretation. This analysis includes ensembles at five lattice spacings from a $\\approx$ 0.045 to 0.15 fm, and light sea-quark masses down to 1/20th of the strange-quark mass. Projected error budgets for ratios of decay constants, in particular between bottom- and charm-meson decay constants, are presented.

  12. Constraints on Lepton Asymmetry from Nucleosynthesis in a Linearly Coasting Cosmology

    E-Print Network [OSTI]

    Parminder Singh; Daksh Lohiya

    2015-05-30

    We study the effect of neutrino degeneracy on primordial nucleosynthesis in a universe in which the cosmological scale factor evolves linearly with time. The degeneracy parameter of electron type neutrinos ($\\xi_e$) determines the $n/p$ (neutron to proton) ratio, which in turn determines the abundance of $^4$He in a manner quite distinct from the Standard Scenario. The observed abundances of $^4$He, $\\mathrm{Y}_P$=0.254$\\pm$0.003, and the minimum metallicity that is essential for fragmentation and cooling processes in star forming prestellar gas clouds (Z = Z$_{cr}$ = 10$^{-6}$Z$_\\odot$), constrain the baryon to photon ratio, $\\eta_B$=(3.927$\\pm$0.292)10$^{-9}$, corresponding to a baryonic matter density, $\\Omega_B$=0.263$\\pm$ 0.026 and $\\xi_e$=-2.165$\\pm$0.171. This closes the dynamic mass estimates of matter in the universe by baryons alone. Useful byproducts are the threshold X(CNO) abundances required to trigger the CNO cycle in the observed low metallicity stars in the universe.

  13. A simple model for NN correlations in quasielastic lepton-nucleus scattering

    E-Print Network [OSTI]

    Barbaro, M B; Donnelly, T W; Molinari, A

    2008-01-01

    We present a covariant extension of the relativistic Fermi gas model which incorporates correlation effects in nuclei. Within this model, inspired by the BCS descriptions of systems of fermions, we obtain the nuclear spectral function and from it the superscaling function for use in treating high-energy quasielastic electroweak processes. Interestingly, this model has the capability to yield the asymmetric tail seen in the experimental scaling function.

  14. Super-PINGU for measurement of the leptonic CP-phase with atmospheric neutrinos

    E-Print Network [OSTI]

    Soebur Razzaque; A. Yu. Smirnov

    2015-05-19

    We explore a possibility to measure the CP-violating phase $\\delta$ using multi-megaton scale ice or water Cherenkov detectors with low, $(0.2 - 1)$ GeV, energy threshold assuming that the neutrino mass hierarchy is identified. We elaborate the relevant theoretical and phenomenological aspects of this possibility. The distributions of the $\

  15. Discovery and Characterization of a Higgs boson using four-lepton...

    Office of Scientific and Technical Information (OSTI)

    Bibtex Format Close 0 pages in this document matching the terms "" Search For Terms: Enter terms in the toolbar above to search the full text of this document for pages...

  16. Application of nuclear density functionals to lepton number violating weak processes

    SciTech Connect (OSTI)

    Rodriguez, Tomas R.; Martinez-Pinedo, Gabriel

    2012-10-20

    We present an application of energy density functional methods with the Gogny interaction to the calculation of nuclear matrix elements (NME) for neutrinoless double beta decay and double electron capture. Beyond mean field effects have been included by particle number and angular momentum restoration and shape mixing within the generator coordinate method (GCM) framework. We analyze in detail the NME for {sup 116}Cd nucleus which is one of the most promising candidates to detect neutrinoless double beta decay.

  17. THE STATUS OF HEAVY-LEPTON SEARCHES*+ Martin L. Per1 Stanford Linear Accelerator Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With LivermoreSustainableDEPARTMENT OF ENERGY Office ofPHYSICSSTATUS

  18. REVIEW OF HEAVY LEPTON PRODUCTION IN e+e- ANNIHILATION* Martin L. Per1

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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  19. Lepton flavor violation in Higgs boson decays under the rare tau decay

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(Journalspectroscopy ofArticle) | SciTech Connect Learning How to Count:

  20. Direct Measurement of the Neutral Weak Dipole Moments of the tau Lepton

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing BacteriaConnectlaser-solidSwitchgrass| SciTechConnectDirac

  1. Direct Measurement of the Neutral Weak Dipole Moments of the tau Lepton

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing BacteriaConnectlaser-solidSwitchgrass| SciTechConnectDirac(Technical Report) |

  2. Discovery and Characterization of a Higgs boson using four-lepton events

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing BacteriaConnectlaser-solidSwitchgrass|FeTe0.55Se0.45SciTech Connectfrom the CMS

  3. Discovery and Characterization of a Higgs boson using four-lepton events

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing BacteriaConnectlaser-solidSwitchgrass|FeTe0.55Se0.45SciTech Connectfrom the

  4. ON THE ENERGY SPECTRA OF GeV/TeV COSMIC RAY LEPTONS (Journal Article) |

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech Connect Nanomechanical switchFlue Gasinelastic scattering at low

  5. On the Energy Spectra of GeV/TeV Cosmic Ray Leptons (Journal Article) |

    Office of Scientific and Technical Information (OSTI)

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  6. On the Energy Spectra of GeV/TeV Cosmic Ray Leptons (Journal Article) |

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech ConnectSpeeding access to science informationArticle) |SciTech Connect Energy

  7. Phenomenology of maximal and near-maximal lepton mixing (Journal Article) |

    Office of Scientific and Technical Information (OSTI)

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  8. Precision measurement of the top quark mass in the lepton + jets channel

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech ConnectSpeeding accessusers'(x≤2) surface: A combinedWavelengths (Journalusing a

  9. Precision measurement of the top quark mass in the lepton + jets channel

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech ConnectSpeeding accessusers'(x≤2) surface: A combinedWavelengths (Journalusing

  10. Radiative and Leptonic B-meson Decays from the B-factories (Conference) |

    Office of Scientific and Technical Information (OSTI)

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  11. Radiative and Leptonic B-meson Decays from the B-factories (Conference) |

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech ConnectSpeedingConnect Pulse energy(Conference)Article)

  12. Search for Bs Mixing with Inclusive Leptons at SLD (Technical Report) |

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference) | SciTechsaturatedcrystals (Journal Article) | SciTech

  13. Search for Bs Mixing with Inclusive Leptons at SLD (Technical Report) |

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference) | SciTechsaturatedcrystals (Journal Article) | SciTechSciTech

  14. Search for anomalous production of events with a high energy lepton and

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference) | SciTechsaturatedcrystals (Journal Article) |EXO-200scalar boson

  15. Search for anomalous production of events with a high energy lepton and

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference) | SciTechsaturatedcrystals (Journal Article) |EXO-200scalar bosonphoton

  16. Search for new physics in lepton + photon + x events with 929 pb**-1 of p

    Office of Scientific and Technical Information (OSTI)

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  17. Search for new physics in lepton + photon + x events with 929 pb**-1 of p

    Office of Scientific and Technical Information (OSTI)

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  18. Searches with Mono-Leptons (Journal Article) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

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  19. Searches with Mono-Leptons (Journal Article) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference) |Janka,Ferrara U./INFN,TaÅŸ, Neslihan"RonSearches for

  20. Soft supersymmetry breaking terms from D{sub 4}xZ{sub 2} lepton flavor

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference)Feedback System in the CERN SPS(Journal

  1. Tau Lepton Flavor Violation Results from BaBar (Conference) | SciTech

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference)Feedback SystemGimbaled X-Ray HeadSTRATIFICATION(JournalConnect Tau

  2. A hadronic-leptonic model for the Fermi bubbles: Cosmic-rays in the galactic halo and radio emission

    SciTech Connect (OSTI)

    Fujita, Yutaka; Ohira, Yutaka; Yamazaki, Ryo

    2014-07-01

    We investigate non-thermal emission from the Fermi bubbles in a hadronic model. Cosmic-ray (CR) protons are accelerated at the forward shock of the bubbles. They interact with the background gas in the Galactic halo and create ?{sup 0}-decay gamma-rays and secondary electrons through proton-proton interaction. We follow the evolution of the CR protons and electrons by calculating their distribution functions. We find that the spectrum and the intensity profiles of ?{sup 0}-decay gamma-rays are consistent with observations. We predict that the shock front is located far ahead of the gamma-ray boundary of the Fermi bubbles. This naturally explains the fact that a clear temperature jump of thermal gas was not discovered at the gamma-ray boundary in recent Suzaku observations. We also consider re-acceleration of the background CRs in the Galactic halo at the shock front. We find that it can significantly affect the gamma-rays from the Fermi bubbles, unless the density of the background CRs is ? 10% of that in the Galactic disk. We indicate that secondary electrons alone cannot produce the observed radio emission from the Fermi bubbles. However, the radio emission from the outermost region of the bubbles can be explained if electrons are directly accelerated at the shock front with an efficiency of ?0.1% of that of protons.

  3. y Vacuum Polarization in Low Energy Physics: g -2 1. g -2 introduction, history, muon properties, lepton moments

    E-Print Network [OSTI]

    Röder, Beate

    y Vacuum Polarization in Low Energy Physics: g - 2 1. g - 2 introduction, history, muon properties light-by-light scattering contribution 7. Summary and Outlook 105-1 #12;Physics of vacuum polarization Frascati, Frascati, Italy ­ November 9-13, 2009 ­ #12;Physics of vacuum polarization ... Basic principle

  4. Measurement of the Branching Fractions of the Radiative Leptonic ? Decays ? ? e??[bar over ?] and ? ? ???[bar over ?] at BABAR

    E-Print Network [OSTI]

    Lees, J.?P.

    We perform a measurement of the ? ? l??[bar over ?] (l = e,?) branching fractions for a minimum photon energy of 10 MeV in the ? rest frame, using 431??fb[superscript -1] of e[superscript +]e[superscript -] collisions ...

  5. Search for Heavy Right-Handed Neutrinos at the LHC and Beyond in the Same-Sign Leptons Final State

    E-Print Network [OSTI]

    Ng, John N; Pan, Bob Wei-Ping

    2015-01-01

    In this study we explore the LHC's Run II potential to discover heavy Majorana neutrinos with luminosities between $30$ and $3000$ fb$^{-1}$ in the $l^{\\pm}l^{\\prime\\pm}j~j$ final state. Given that there are many models for neutrino mass generation, even within the Type I seesaw framework, we use a simplified model approach and assume that a heavy single Majorana neutrino extension of the SM and a limiting case of the left-right symmetric model. We then extend the analysis to a future hadron collider running at $100$ TeV center of mass energies. This extrapolation in energy allows us to study the relative importance of the resonant production versus gauge boson fusion processes in the study of Majorana neutrinos at hadron colliders. We analyze and propose different search strategies designed to maximize the discovery potential in either the resonant production or the gauge boson fusion modes.

  6. Search for Heavy Right-Handed Neutrinos at the LHC and Beyond in the Same-Sign Leptons Final State

    E-Print Network [OSTI]

    John N. Ng; Alejandro de la Puente; Bob Wei-Ping Pan

    2015-05-21

    In this study we explore the LHC's Run II potential to discover heavy Majorana neutrinos with luminosities between $30$ and $3000$ fb$^{-1}$ in the $l^{\\pm}l^{\\prime\\pm}j~j$ final state. Given that there are many models for neutrino mass generation, even within the Type I seesaw framework, we use a simplified model approach and assume that a heavy single Majorana neutrino extension of the SM and a limiting case of the left-right symmetric model. We then extend the analysis to a future hadron collider running at $100$ TeV center of mass energies. This extrapolation in energy allows us to study the relative importance of the resonant production versus gauge boson fusion processes in the study of Majorana neutrinos at hadron colliders. We analyze and propose different search strategies designed to maximize the discovery potential in either the resonant production or the gauge boson fusion modes.

  7. Measurement of the Top Pair Production Cross Section in the Lepton + Jets Channel Using a Jet Flavor Discriminant

    SciTech Connect (OSTI)

    Aaltonen, T; Aaltonen, T; Alvarez Gonzalez, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Apresyan, A

    2011-08-01

    We present a new method to measure the top quark pair production cross section and the background rates with data corresponding to an integrated luminosity of 2.7 fb-1 from p p? collisions at ?s = 1.96 TeV collected with the CDF II Detector. We select events with a single electron or muon candidate, missing transverse energy, and at least one b-tagged jet. We perform a simultaneous fit to a jet flavor discriminant across nine samples defined by the number of jets and b-tags. An advantage of this approach is that many systematic uncertainties are measured in situ and inversely scale with integrated luminosity. We measure a top cross section of ?tt? = 7.64 ± 0.57 (stat + syst) ± 0.45 (luminosity) pb.

  8. Measurement of the top quark mass using the invariant mass of lepton pairs in soft muon b-tagged events

    E-Print Network [OSTI]

    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 ...

  9. Measurement of the WW plus WZ Production Cross Section Using the lepton plus jets Final State at CDF II

    E-Print Network [OSTI]

    Paus, Christoph M. E.

    We report two complementary measurements of the WW+WZ cross section in the final state consisting of an electron or muon, missing transverse energy, and jets, performed using pp[over-bar] collision data at [sqrt]s=1.96??TeV ...

  10. Measurement of ZZ Production in Leptonic Final States at ?s of 1.96 TeV at CDF

    E-Print Network [OSTI]

    Gomez-Ceballos, Guillelmo

    In this Letter, we present a precise measurement of the total ZZ production cross section in pp? collisions at ?s=1.96??TeV, using data collected with the CDF II detector corresponding to an integrated luminosity of ...

  11. Measurement of the WW+WZ Production Cross Section Using the Lepton+Jets Final State at CDF II

    SciTech Connect (OSTI)

    Aaltonen, T.; Adelman, J.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Apresyan, A.; Arisawa, T.; /Waseda U. /Dubna, JINR

    2009-11-01

    We report two complementary measurements of the diboson (WW + WZ) cross section in the final state consisting of an electron or muon, missing transverse energy, and jets, performed using p{bar p} collision data at {radical}s = 1.96 TeV collected by the Collider Detector at Fermilab. The first method uses the dijet invariant mass distribution while the second method uses more of the kinematic information in the event through matrix-element calculations of the signal and background processes and has a higher sensitivity. The result from the second method has a signal significance of 5.4{sigma} and is the first observation of WW + WZ production using this signature. Combining the results from both methods gives {sigma}{sub WW+WZ} = 16.0 {+-} 3.3 pb, in agreement with the standard model prediction.

  12. Measurement of the Top Pair Production Cross Section in the Lepton + Jets Channel Using a Jet Flavor Discriminant

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aaltonen, T; Aaltonen, T; Alvarez Gonzalez, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; et al

    2011-08-01

    We present a new method to measure the top quark pair production cross section and the background rates with data corresponding to an integrated luminosity of 2.7 fb-1 from p p? collisions at ?s = 1.96 TeV collected with the CDF II Detector. We select events with a single electron or muon candidate, missing transverse energy, and at least one b-tagged jet. We perform a simultaneous fit to a jet flavor discriminant across nine samples defined by the number of jets and b-tags. An advantage of this approach is that many systematic uncertainties are measured in situ and inversely scalemore »with integrated luminosity. We measure a top cross section of ?tt? = 7.64 ± 0.57 (stat + syst) ± 0.45 (luminosity) pb.« less

  13. Measurement of the top pair production cross section in the lepton+jets channel using a jet flavor discriminant

    E-Print Network [OSTI]

    Bauer, Gerry P.

    We present a new method to measure the top quark pair production cross section and the background rates with data corresponding to an integrated luminosity of 2.7??fb[superscript -1] from pp? collisions at ?s=1.96??TeV ...

  14. Status of the measurement of K S -> ?e? branching ratio and lepton charge asymmetry with the KLOE detector

    E-Print Network [OSTI]

    D. Kami?ska on behalf of the KLOE-2 collaboration

    2015-07-03

    We present the current status of the analysis of about 1.7 billion K_S K_L pair events collected at DA{\\Phi}NE with the KLOE detector to determine the branching ratio of K_S -> {\\pi}e{\

  15. arXiv:hep-ex/0611046v127Nov2006 New precise determination of the lepton mass at KEDR detector

    E-Print Network [OSTI]

    - inated by the result of the BES collaboration [2] which statistical analysis and uncertainty estima of 1 #12;2 e- e+ e- e- e- HPGe detector VEPP-4M VEPP-3 B-4 p = 40 hours p = 32 mins RFRF KEDR s

  16. Search for W? ? tb decays in the lepton + jets final state in pp collisions at ?s = 8 TeV

    E-Print Network [OSTI]

    Apyan, Aram

    Results are presented from a search for the production of a heavy gauge boson W? decaying into a top and a bottom quark, using a data set collected by the CMS experiment at ?s = 8 TeV and corresponding to an integrated ...

  17. Measurement of the top quark pair production cross-section with ATLAS in the single lepton channel

    E-Print Network [OSTI]

    Taylor, Frank E.

    A measurement of the production cross-section for top quark pairs (t[bar over t]) in pp collisions at ?s = 7 TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected ...

  18. The Working Group M5 on Lepton-Hadron Colliders Conveners: Ilan Ben-Zvi and Georg H. Hoffstaetter

    E-Print Network [OSTI]

    Hoffstaetter, Georg

    ........................................................................... 28 3. eRHIC, Electron-Hadron Collisions with RHIC

  19. Measurement of Branching Ratios for Non-leptonic Cabibbo-suppressed Decays of the Charmed-Strange Baryon Xic+

    SciTech Connect (OSTI)

    Vazquez Jauregui, Eric; /San Luis Potosi U.

    2008-08-01

    We studied several {Xi}{sub c}{sup +} decay modes, most of them with a hyperon in the final state, and determined their branching ratios. The data used in this analysis come from the fixed target experiment SELEX, a multi-stage spectrometer with high acceptance for forward interactions, that took data during 1996 and 1997 at Fermilab with 600 GeV=c (mainly {Sigma}{sup -}, {pi}{sup -}) and 540 GeV/c (mainly p) beams incident on copper and carbon targets. The thesis mainly details the first observation of two Cabibbo-suppressed decay modes, {Xi}{sub c}{sup +} {yields} {Sigma}{sup +}{pi}{sup -}{pi}{sup +} and {Xi}{sub c}{sup +} {yields} {Sigma}{sup -}{pi}{sup +}{pi}{sup +}. The branching ratios of the decays relative to the Cabibbo-favored {Xi}{sub c}{sup +} {yields} {Xi}{sup -}{pi}{sup +}{pi}{sup +} are measured to be: {Lambda}({Xi}{sub c}{sup +} {yields} {Sigma}{sup -}{pi}{sup +}{pi}{sup +})/{Lambda}({Xi}{sub c}{sup +} {yields} {Xi}{sup -}{pi}{sup +}{pi}{sup +}) = 0.184 {+-} 0.086. Systematic studies have been performed in order to check the stability of the measurements varying all cuts used in the selection of events over a wide interval and we do not observe evidence of any trend, so the systematic error is negligible in the final results because the quadrature sum of the total error is not affected. The branching ratios for the same decay modes of the {Lambda}{sub c}{sup +} are measured to check the methodology of the analysis. The branching ratio of the decay mode {Lambda}{sub c}{sup +} {yields} {Sigma}{sup +}{pi}{sup -}{pi}{sup +} is measured relative to {Lambda}{sub c}{sup +} {yields} pK{sup -} {pi}{sup +}, while the one of the decay mode {Lambda}{sub c}{sup +} {yields} {Sigma}{sup -}{pi}{sup +}{pi}{sup +} is relative to {Lambda}{sub c}{sup +} {yields} {Sigma}{sup +}{pi}{sup -}{pi}{sup +}, as they have been reported earlier. The results for the control modes are: {Gamma}({Lambda}{sub c}{sup +} {yields} {Sigma}{sup +}{pi}{sup -}{pi}{sup +})/{Gamma}({Lambda}{sub c}{sup +} {yields} pK{sup -} {pi}{sup +}) = 0.716 {+-} 0.144 and {Gamma}({Lambda}{sub c}{sup +} {yields} {Sigma}{sup -}{pi}{sup +}{pi}{sup +})/{Gamma}({Lambda}{sub c}{sup +} {yields} {Sigma}{sup +}{pi}{sup -}{pi}{sup +}) = 0.382 {+-} 0.104. The branching ratio of the decay mode {Xi}{sub c}{sup +} {yields} pK{sup -} {pi}{sup +} relative to {Xi}{sub c}{sup +} {yields} {Xi}{sup -}{pi}{sup +}{pi}{sup +} is considered as another control mode, the measured value is {Gamma}({Xi}{sub c}{sup +} {yields} pK{sup -}{pi}{sup +})/{Gamma}({Xi}{sub c}{sup +} {yields} {Xi}{sup -}{pi}{sup +}{pi}{sup +}) = 0.194 {+-} 0.054. Systematic studies have been also performed for the control modes and all systematic variations are also small compared to the statistical error. We also report the first observation of two more decay modes, the Cabibbo-suppressed decay {Xi}{sub c}{sup +} {yields} {Xi}{sup -} K{sup +}{pi}{sup +} and the doubly Cabibbo-suppressed decay {Xi}{sub c}{sup +} {yields} {Sigma}{sup +}K{sup +}{pi}{sup -}, but their branching ratios have not been measured up to now.

  20. Search for the Standard Model Higgs Boson in the Lepton + Missing Transverse Energy + Jets Final State in ATLAS

    E-Print Network [OSTI]

    Mark S. Neubauer; for the ATLAS Collaboration

    2011-10-11

    A search for the Standard Model Higgs boson has been performed in the H \\rightarrow WW \\rightarrow l{\

  1. Measurement of the Top Pair Production Cross Section in the Lepton + Jets Channel Using a Jet Flavor Discriminant

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aaltonen, T.; Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J.A.; Apresyan, A.

    2011-08-01

    We present a new method to measure the top quark pair production cross section and the background rates with data corresponding to an integrated luminosity of 2.7 fb-1 from p p? collisions at ?s = 1.96 TeV collected with the CDF II Detector. We select events with a single electron or muon candidate, missing transverse energy, and at least one b-tagged jet. We perform a simultaneous fit to a jet flavor discriminant across nine samples defined by the number of jets and b-tags. An advantage of this approach is that many systematic uncertainties are measured in situ and inversely scale with integrated luminosity. We measure a top cross section of ?tt? = 7.64 ± 0.57 (stat + syst) ± 0.45 (luminosity) pb.

  2. Double semi-leptonic charm decay in helios-I 450 GeV/c p-Be data

    SciTech Connect (OSTI)

    Pierre, A. (Montreal Univ., PQ (Canada). Dept. of Physics); Pomianowski, P.A. (Pittsburgh Univ., PA (United States). Dept. of Physics)

    1992-01-01

    Data taken in 1989 by HELIOS-I (NA34) at the CERN SPS (450 GeV/c proton beam on Be target) have been examined for e[sup [plus minus

  3. Identifying fake leptons in ATLAS while hunting SUSY in 8 TeV proton-proton collisions

    E-Print Network [OSTI]

    Gillam, Thomas P. S.

    2015-04-28

    chamber, and is the outermost com- ponent of the inner detector. Each “straw” is a 4 mm diameter polyimide tube, coated The ATLAS experiment and the LHC 9 internally with aluminium to form a cathode, and enclosing a tungsten wire. Each straw is sealed...

  4. Review of the Microscopic Approach to the Higgs Mechanism and to Quark and Lepton Masses and Mixings

    E-Print Network [OSTI]

    Lampe, Bodo

    2015-01-01

    This review summarizes the results of a series of recent papers, where a microscopic model underlying the physics of elementary particles has been proposed. The model relies on the existence of an internal isospin space, in which an independent physical dynamics takes place. This idea is critically re-considered in the present work. As becomes evident in the course of discussion, the model not only describes electroweak phenomena but also modifies our understanding of other physical topics, like the big bang cosmology and the nature of the strong interactions.

  5. Measurement of the direct $CP$ asymmetry in $\\bar{B}\\rightarrow X_{s+d}?$ decays with a lepton tag

    E-Print Network [OSTI]

    L. Pesántez; P. Urquijo; J. Dingfelder; A. Abdesselam; I. Adachi; K. Adamczyk; H. Aihara; S. Al Said; K. Arinstein; D. M. Asner; V. Aulchenko; T. Aushev; R. Ayad; S. Bahinipati; A. M. Bakich; V. Bansal; E. Barberio; V. Bhardwaj; B. Bhuyan; A. Bobrov; A. Bondar; G. Bonvicini; A. Bozek; M. Bra?ko; T. E. Browder; D. ?ervenkov; V. Chekelian; A. Chen; B. G. Cheon; K. Chilikin; R. Chistov; K. Cho; V. Chobanova; Y. Choi; D. Cinabro; J. Dalseno; Z. Doležal; Z. Drásal; A. Drutskoy; D. Dutta; S. Eidelman; H. Farhat; J. E. Fast; T. Ferber; O. Frost; V. Gaur; N. Gabyshev; S. Ganguly; A. Garmash; D. Getzkow; R. Gillard; Y. M. Goh; B. Golob; J. Haba; J. Hasenbusch; X. H. He; A. Heller; T. Horiguchi; W. -S. Hou; M. Huschle; T. Iijima; K. Inami; A. Ishikawa; R. Itoh; Y. Iwasaki; I. Jaegle; D. Joffe; T. Julius; K. H. Kang; E. Kato; T. Kawasaki; C. Kiesling; D. Y. Kim; J. B. Kim; J. H. Kim; K. T. Kim; M. J. Kim; S. H. Kim; Y. J. Kim; B. R. Ko; P. Kodyš; S. Korpar; P. Križan; P. Krokovny; B. Kronenbitter; T. Kuhr; T. Kumita; A. Kuzmin; Y. -J. Kwon; J. S. Lange; I. S. Lee; Y. Li; L. Li Gioi; J. Libby; D. Liventsev; P. Lukin; D. Matvienko; K. Miyabayashi; H. Miyata; R. Mizuk; G. B. Mohanty; A. Moll; H. K. Moon; E. Nakano; M. Nakao; T. Nanut; Z. Natkaniec; M. Nayak; C. Ng; N. K. Nisar; S. Nishida; S. Ogawa; S. Okuno; S. L. Olsen; C. Oswald; P. Pakhlov; G. Pakhlova; C. W. Park; H. Park; T. K. Pedlar; R. Pestotnik; M. Petri?; L. E. Piilonen; E. Ribežl; M. Ritter; A. Rostomyan; M. Rozanska; Y. Sakai; S. Sandilya; L. Santelj; T. Sanuki; Y. Sato; V. Savinov; O. Schneider; G. Schnell; C. Schwanda; A. J. Schwartz; K. Senyo; O. Seon; M. E. Sevior; V. Shebalin; C. P. Shen; T. -A. Shibata; J. -G. Shiu; B. Shwartz; A. Sibidanov; F. Simon; Y. -S. Sohn; A. Sokolov; E. Solovieva; M. Stari?; M. Steder; T. Sumiyoshi; U. Tamponi; N. Taniguchi; G. Tatishvili; Y. Teramoto; K. Trabelsi; M. Uchida; T. Uglov; Y. Unno; S. Uno; Y. Usov; C. Van Hulse; P. Vanhoefer; G. Varner; A. Vinokurova; V. Vorobyev; M. N. Wagner; B. Wang; C. H. Wang; M. -Z. Wang; P. Wang; Y. Watanabe; K. M. Williams; E. Won; J. Yamaoka; S. Yashchenko; Y. Yook; Z. P. Zhang; V. Zhilich; V. Zhulanov; A. Zupanc for the Belle Collaboration

    2015-06-21

    We report the measurement of the direct $CP$ asymmetry in the radiative $\\bar{B}\\rightarrow X_{s+d}\\gamma$ decay using a data sample of $(772 \\pm 11)\\times 10^6$ $B\\bar{B}$ pairs collected at the $\\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. The $CP$ asymmetry is measured as a function of the photon energy threshold. For $E^{\\rm{*}}_{\\gamma} \\geq 2.1~{\\rm{GeV}}$, where $E^{\\rm{*}}_{\\gamma}$ is the photon energy in the center-of-mass frame, we obtain $\\mathcal{A}_{CP}(\\bar{B}\\rightarrow X_{s+d}\\gamma)= (2.2 \\pm 3.9 \\pm 0.9) \\%$, consistent with the Standard Model prediction.

  6. Measurement of the inclusive and differential tt production cross sections in lepton + jets final states at 13 TeV

    E-Print Network [OSTI]

    CMS Collaboration

    2015-01-01

    The total inclusive and the normalized differential cross sections for the production of top quark pairs in proton-proton collisions at 13\\,TeV are measured based on data collected by the CMS experiment at the LHC corresponding to an integrated luminosity of 42\\,pb$^{-1}$. The measurements are performed in the l+jets decay channels with an electron or a muon in the final state. The differential cross section is measured as a function of transverse momentum and rapidity of the top quarks and as a function of transverse momentum, rapidity, and invariant mass of the top quark pairs, as well as of the jet multiplicity. The measured cross sections are compared to several theoretical calculations. No significant deviation from the standard model prediction is observed.

  7. Lepton asymmetry measurements in B¯?D*l-?¯l and implications for V-A and the form factors

    E-Print Network [OSTI]

    Baringer, Philip S.

    1993-02-01

    ,bl' ~ ((IH+I'+IH I')(1+cos'8)s111 6 +4IHOI s111 Bcos'8* —2Re[H+H' ]sin 6 sin 8"cos2y —Re[(H+ +H )/Ho ]sin26 sin26*cosy +211/[ [ —Re[(H+ H)HO ]s—inB sin28'cosy +(IH I' —IH I')cosB sin 6'] ), where q is the four-momentum transfer squared between the B and the D...,bl' ~ ((IH+I'+IH I')(1+cos'8)s111 6 +4IHOI s111 Bcos'8* —2Re[H+H' ]sin 6 sin 8"cos2y —Re[(H+ +H )/Ho ]sin26 sin26*cosy +211/[ [ —Re[(H+ H)HO ]s—inB sin28'cosy +(IH I' —IH I')cosB sin 6'] ), where q is the four-momentum transfer squared between the B and the D...

  8. Hadronic decays of the tau lepton : {tau}- {yields} ({pi}{pi}{pi})- {nu}{tau} within Resonance Chiral Theory

    SciTech Connect (OSTI)

    Gomez Dumm, D.; Pich, A.; Portoles, J.

    2006-01-12

    {tau} decays into hadrons foresee the study of the hadronization of vector and axial-vector QCD currents, yielding relevant information on the dynamics of the resonances entering into the processes. We analyse {tau} {yields} {pi}{pi}{pi}{nu}{tau} decays within the framework of the Resonance Chiral Theory, comparing this theoretical scheme with the experimental data, namely ALEPH spectral function and branching ratio. Hence we get values for the mass and on-shell width of the a 1 (1260) resonance, and provide the structure functions that have been measured by OPAL and CLEO-II.

  9. Search for excited leptons in proton-proton collisions at sqrt(s) = 8 TeV

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference) | SciTechsaturatedcrystals (Journal Article)

  10. Search for excited leptons in proton-proton collisions at sqrt(s) = 8 TeV

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference) | SciTechsaturatedcrystals (Journal Article)(Journal Article) | SciTech

  11. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    at 1.96 TeV are studied in samples of approx 3-6 fbsup -1 of data using leptons, jets and missing Esub T. Fully leptonic decays as well as semi-leptonic decays are...

  12. Search for physics beyond the standard model in final states with a lepton and missing transverse energy in proton-proton collisions at s = 8 TeV

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Khachatryan, V.; Sirunyan, A.?M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Fabjan, C.; Friedl, M.; Frühwirth, R.; et al

    2015-05-22

    A search for new physics in proton-proton collisions having final states with an electron or muon and missing transverse energy is presented.

  13. Search for WZ resonances in the fully leptonic channel using pp collisions at ?s = 8 TeV with the ATLAS detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    A search for resonant WZ production in the ???[superscript ?]?[superscript ?] (?,?[superscript ?] =e,?) decay channel using 20.3 fb[superscript ?1] of ?s = 8 TeV collision data collected by the ATLAS experiment at LHC is ...

  14. Search for new particles decaying to ZZ using final states with leptons and jets with the ATLAS detector in ?s = 7 TeV proton–proton collisions

    E-Print Network [OSTI]

    Taylor, Frank E.

    A search is presented for a narrow resonance decaying to a pair of Z bosons using data corresponding to 1.02 fb[superscript ?1] of integrated luminosity collected by the ATLAS experiment from pp collisions at ?s = 7 TeV. ...

  15. Top Quark Mass Measurement in the Lepton + Jets Channel Using a Matrix Element Method and \\textit{in situ} Jet Energy Calibration

    SciTech Connect (OSTI)

    Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J.A.; Apresyan, A.; Arisawa, T.; /Waseda U. /Dubna, JINR

    2010-10-01

    A precision measurement of the top quark mass m{sub t} is obtained using a sample of t{bar t} events from p{bar p} collisions at the Fermilab Tevatron with the CDF II detector. Selected events require an electron or muon, large missing transverse energy, and exactly four high-energy jets, at least one of which is tagged as coming from a b quark. A likelihood is calculated using a matrix element method with quasi-Monte Carlo integration taking into account finite detector resolution and jet mass effects. The event likelihood is a function of m{sub t} and a parameter {Delta}{sub JES} used to calibrate the jet energy scale in situ. Using a total of 1087 events, a value of m{sub t} = 173.0 {+-} 1.2 GeV/c{sup 2} is measured.

  16. Top Quark Mass Measurement in the lepton plus jets Channel Using a Matrix Element Method and in situ Jet Energy Calibration

    E-Print Network [OSTI]

    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, ...

  17. Measurement of the Single Top Quark Production Cross Section and |V[subscript tb]| in Events with One Charged Lepton, Large Missing Transverse Energy, and Jets at CDF

    E-Print Network [OSTI]

    Aaltonen, T.

    We report a measurement of single top quark production in proton-antiproton collisions at a center-of-mass energy of ?s = 1.96??TeV using a data set corresponding to 7.5??fb[superscript -1] of integrated luminosity collected ...

  18. Search for the Standard Model Higgs Boson Decaying to a bb? Pair in Events with Two Oppositely Charged Leptons Using the Full CDF Data Set

    E-Print Network [OSTI]

    Gomez-Ceballos, Guillelmo

    We present a search for the standard model Higgs boson produced in association with a Z boson in data collected with the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.45??fb[superscript ...

  19. Search for scalar leptons in e+e- collisions at centre-of-mass energies up to 209GeV

    E-Print Network [OSTI]

    ALEPH Collaboration

    2001-12-07

    A search for selectron, smuon and stau pair production is performed with the data collected by the ALEPH detector at LEP at centre-of-mass energies up to 209 GeV. The numbers of candidate events are consistent with the background predicted by the Standard Model. Final mass limits from ALEPH are reported.

  20. Search for pair-produced heavy quarks decaying to Wq in the two-lepton channel at ?(s)=7??TeV with the ATLAS detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    A search is presented for heavy-quark pair production (QQ?) under the decay hypothesis QQ??W[superscript +]qW[superscript -]q? with q=d, s, b for up-type Q or q=u, c for down-type Q. The search is performed with ...

  1. Nonzero {theta}{sub 13} for neutrino mixing in a supersymmetric B-L gauge model with T{sub 7} lepton flavor symmetry

    SciTech Connect (OSTI)

    Cao Qinghong [Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); High Energy Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, U.S.A (United States); Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637 (United States); Khalil, Shaaban [Centre for Theoretical Physics, The 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); Ma, Ernest [Department of Physics and Astronomy, University of California, Riverside, California 92521 (United States); Okada, Hiroshi [School of Physics, KIAS, Seoul 130-722 (Korea, Republic of)

    2011-10-01

    We discuss how {theta}{sub 13}{ne}0 is accommodated in a recently proposed renormalizable model of neutrino mixing using the non-Abelian discrete symmetry T{sub 7} in the context of a supersymmetric extension of the standard model with gauged U(1){sub B-L}. We predict a correlation between {theta}{sub 13} and {theta}{sub 23}, as well as the effective neutrino mass m{sub ee} in neutrinoless double beta decay.

  2. Search for the standard model Higgs boson decaying to a bb pair in events with two oppositely-charged leptons using the full CDF data set

    E-Print Network [OSTI]

    CDF Collaboration

    2012-07-27

    We present a search for the standard model Higgs boson produced in association with a Z boson in data collected with the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.45/fb. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the Z boson to electron or muon pairs, we set 95% credibility level upper limits on the ZH production cross section times the H -> bb branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125 GeV/c^2 we observe (expect) a limit of 7.1 (3.9) times the standard model value.

  3. Search for physics beyond the standard model in final states with a lepton and missing transverse energy in proton-proton collisions at s = 8 TeV

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Khachatryan, V.; Sirunyan, A.?M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Fabjan, C.; Friedl, M.; Frühwirth, R.; Ghete, V.?M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knünz, V.; Krammer, M.; Krätschmer, I.; Liko, D.; Mikulec, I.; Rabady, D.; Rahbaran, B.; Rohringer, H.; Schöfbeck, R.; Strauss, J.; Taurok, A.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Bansal, M.; Bansal, S.; Cornelis, T.; De Wolf, E.?A.; Janssen, X.; Knutsson, A.; Luyckx, S.; Ochesanu, S.; Roland, B.; Rougny, R.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Blekman, F.; Blyweert, S.; D’Hondt, J.; Daci, N.; Heracleous, N.; Kalogeropoulos, A.; Keaveney, J.; Kim, T.?J.; Lowette, S.; Maes, M.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G.?P.; Villella, I.; Caillol, C.; Clerbaux, B.; De Lentdecker, G.; Dobur, D.; Favart, L.; Gay, A.?P.?R.; Grebenyuk, A.; Léonard, A.; Mohammadi, A.; Perniè, L.; Reis, T.; Seva, T.; Thomas, L.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Adler, V.; Beernaert, K.; Benucci, L.; Cimmino, A.; Costantini, S.; Crucy, S.; Dildick, S.; Fagot, A.; Garcia, G.; Mccartin, J.; Ocampo Rios, A.?A.; Ryckbosch, D.; Salva Diblen, S.; Sigamani, M.; Strobbe, N.; Thyssen, F.; Tytgat, M.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bruno, G.; Castello, R.; Caudron, A.; Ceard, L.; Da Silveira, G.?G.; Delaere, C.; du Pree, T.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Jez, P.; Komm, M.; Lemaitre, V.; Liao, J.; Nuttens, C.; Pagano, D.; Perrini, L.; Pin, A.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Vizan Garcia, J.?M.; Beliy, N.; Caebergs, T.; Daubie, E.; Hammad, G.?H.; Aldá Júnior, W.?L.; Alves, G.?A.; Correa Martins Junior, M.; Dos Reis Martins, T.; Pol, M.?E.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E.?M.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Malbouisson, H.; Malek, M.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Prado Da Silva, W.?L.; Santaolalla, J.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E.?J.; Vilela Pereira, A.; Bernardes, C.?A.; Dias, F.?A.; Fernandez Perez Tomei, T.?R.; Gregores, E.?M.; Mercadante, P.?G.; Novaes, S.?F.; Padula, Sandra S.; Aleksandrov, A.; Genchev, V.; Iaydjiev, P.; Marinov, A.; Piperov, S.; Rodozov, M.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Hadjiiska, R.; Kozhuharov, V.; Litov, L.; Pavlov, B.; Petkov, P.; Bian, J.?G.; Chen, G.?M.; Chen, H.?S.; Chen, M.; Du, R.; Jiang, C.?H.; Liang, D.; Liang, S.; Plestina, R.; Tao, J.; Wang, X.; Wang, Z.; Asawatangtrakuldee, C.; Ban, Y.; Guo, Y.; Li, Q.; Li, W.; Liu, S.; Mao, Y.; Qian, S.?J.; Wang, D.; Zhang, L.; Zou, W.; Avila, C.; Chaparro Sierra, L.?F.; Florez, C.; Gomez, J.?P.; Gomez Moreno, B.; Sanabria, J.?C.; Godinovic, N.; Lelas, D.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Kadija, K.; Luetic, J.; Mekterovic, D.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P.?A.; Bodlak, M.; Finger, M.; Finger, M.; Assran, Y.; Elgammal, S.; Mahmoud, M.?A.; Radi, A.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Eerola, P.; Fedi, G.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Kortelainen, M.?J.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J.?L.; Favaro, C.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Baffioni, S.; Beaudette, F.; Busson, P.; Charlot, C.; Dahms, T.; Dalchenko, M.; Dobrzynski, L.; Filipovic, N.; Florent, A.; Granier de Cassagnac, R.; Mastrolorenzo, L.; Miné, P.; Mironov, C.; Naranjo, I.?N.; Nguyen, M.; Ochando, C.; Paganini, P.; Salerno, R.; Sauvan, J.?B.; Sirois, Y.; Veelken, C.; Yilmaz, Y.; Zabi, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Chabert, E.?C.; Collard, C.; Conte, E.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Goetzmann, C.; Le Bihan, A.-C.; Van Hove, P.; Gadrat, S.; Beauceron, S.; Beaupere, N.; Boudoul, G.; Brochet, S.; Carrillo Montoya, C.?A.; Chasserat, J.; Chierici, R.; Contardo, D.; Depasse, P.; El Mamouni, H.; Fan, J.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Kurca, T.; Lethuillier, M.; Mirabito, L.; Perries, S.; Ruiz Alvarez, J.?D.; Sabes, D.; Sgandurra, L.

    2015-05-01

    A search for new physics in proton-proton collisions having final states with an electron or muon and missing transverse energy is presented.

  4. Charmless non-leptonic B_s decays to PP, PV and VV final states in the pQCD approach

    E-Print Network [OSTI]

    Ahmed Ali; Gustav Kramer; Ying Li; Cai-Dian Lu; Yue-Long Shen; Wei Wang; Yu-Ming Wang

    2007-08-21

    We calculate the CP-averaged branching ratios and CP-violating asymmetries of a number of two-body charmless hadronic decays $\\bar{B_s^0} \\to PP, PV, VV$ in the perturbative QCD (pQCD) approach to leading order in $\\alpha_s$ (here $P$ and $V$ denote light pseudoscalar and vector mesons, respectively). The mixing-induced CP violation parameters are also calculated for these decays. We also predict the polarization fractions of $B_s \\to VV$ decays and find that the transverse polarizations are enhanced in some penguin dominated decays such as $\\bar{B_s^0} \\to K ^{*}\\bar{K^{*}}$, $K ^{*}\\rho$. Some of the predictions worked out here can already be confronted with the recently available data from the CDF collaboration on the branching ratios for the decays $ \\bar{B_s^0} \\to K^+\\pi^-$, $ \\bar{B_s^0} \\to K^+K^-$ and the CP-asymmetry in the decay $ \\bar{B_s^0} \\to K^+\\pi^-$, and are found to be in agreement within the current errors. A large number of predictions for the branching ratios, CP-asymmetries and vector-meson polarizations in $\\bar{B_s^0}$ decays, presented in this paper and compared with the already existing results in other theoretical frameworks, will be put to stringent experimental tests in forthcoming experiments at Fermilab, LHC and Super B-factories.

  5. Search for Quantum Black Hole Production in High-Invariant-Mass Lepton + Jet Final States Using pp Collisions at ?s = 8 TeV and the ATLAS Detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    This Letter presents a search for quantum black-hole production using 20.3??fb[superscript ?1] of data collected with the ATLAS detector in pp collisions at the LHC at ?s = 8??TeV. The quantum black holes are assumed to ...

  6. Further search for supersymmetry at ?s=7??TeV in final states with jets, missing transverse momentum, and isolated leptons with the ATLAS detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    This work presents a new inclusive search for supersymmetry (SUSY) by the ATLAS experiment at the LHC in proton-proton collisions at a center-of-mass energy ?s=7 ??TeV in final states with jets, missing transverse momentum ...

  7. Is There a Real Difference between $|V_{qb}|_{\\rm excl}$ vs. $|V_{qb}|_{\\rm incl}$ from Semi-leptonic $B$ Decays?

    E-Print Network [OSTI]

    Ikaros I. Bigi

    2015-07-12

    For a long time there have been very active discussions about the sizable differences between $|V_{cb}|_{\\rm incl}$ \\& $|V_{cb}|_{\\rm excl}$ and likewise for $|V_{ub}|_{\\rm incl}$ \\& $|V_{ub}|_{\\rm excl}$ \\cite{PhBFacts}. However, the real $|V_{ub}|_{\\rm incl}$ might be smaller than the usually stated ones. The connection of the worlds of hadrons and quarks (\\& gluons) is subtle: we cannot ignore final states with a pair of $\\bar KK$ mesons plus pions: $\\left[ R (B \\to l \

  8. Search for the Higgs Boson Decaying to Two Tau Leptons in Proton-Antiproton Collisions at a Center of Mass Energy of 1.96 TeV 

    E-Print Network [OSTI]

    Elagin, Andrey

    2012-02-14

    . . . . . . . . . . . . . . . . . . . . . . . . . . 35 1. Baseline Hadronic Tau Jet Reconstruction at CDF . . 35 2. Implementation Strategy . . . . . . . . . . . . . . . . 36 3. Response Functions of the CDF Detector Sub-systems 37 4. Computation of the PPFA Likelihood . . . . . . . . . 39 viii... . . . . . . . . . . . . . 84 C. Backgrounds . . . . . . . . . . . . . . . . . . . . . . . . . . 84 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . 84 2. Normalization of the W+jets MC sample. . . . . . . . 86 ix CHAPTER Page a. Jet Counting Scale Factors...

  9. Search for pair production of scalar top quarks decaying to a tau lepton and a b quark in 1.96-tev ppbar collisions 

    E-Print Network [OSTI]

    Khotilovich, Vadim Gennadyevich

    2009-05-15

    of matter. It also contains four kinds of vector gauge bosons which serve as interaction carriers: gluons for the strong interactions, the W and Z bosons for the weak interactions, and photon for the electromagnetic. The scalar Higgs boson is the only SM... really independent and arbitrarily de ned in nature? Choice and structure of the gauge group: why do we have three independent symmetry groups? 6 How is the electroweak symmetry broken? Is the Higgs boson, which was put into the theory as a \\convenient...

  10. Search for vector-like quark production in the lepton+jets and dilepton+jets final states using 5.4 fb-1 of Run II data

    SciTech Connect (OSTI)

    Caughron, Seth; /Columbia U.

    2010-10-01

    The Standard Model of particle physics provides an excellent description of particle interactions at energies up to {approx}1 TeV, but it is expected to fail above that scale. Multiple models developed to describe phenomena above the TeV scale predict the existence of very massive, vector-like quarks. A search for single electroweak production of such particles in p{anti p} collisions at a center-of-mass energy of 1.96 TeV is performed in the W+jets and Z+jets channels. The data were collected by the D0 detector at the Fermilab Tevatron Collider and correspond to an integrated luminosity of 5.4 fb{sup -1}. Events consistent with a heavy object decaying to a vector boson and a jet are selected. We observe no significant excess in comparison to the background prediction and set 95% confidence level upper limits on production cross sections for vector-like quarks decaying to W+jet and Z+jet. Assuming a vector-like quark -- standard model quark coupling parameter {tilde {kappa}}{sub qQ} of unity, we exclude vector-like quarks with mass below 693 GeV for decays to W+jet and mass below 449 GeV for decays to Z+jet. These represent the most sensitive limits to date.

  11. Measurement of the WZ and ZZ production cross sections using leptonic final states in 8.6 fb?¹ of pp? collisions

    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.; Aoki, M.; et al

    2012-06-12

    We study the processes pp??WZ?l±?l?l? and pp??ZZ?l?l???¯, where l=e or ?. Using 8.6 fb?¹ of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron collider, we measure the WZ production cross section to be 4.50+0.63–0.66 pb which is consistent with, but slightly larger than, the prediction of the standard model. The ZZ cross section is measured to be 1.64±0.46 pb, in agreement with a prediction of the standard model. Combination with an earlier analysis of the ZZ?l?l?l?l? channel yields a ZZ cross section of 1.44+0.35–0.34 pb.

  12. Measurement of the top-quark pair-production cross section in events with two leptons and bottom-quark jets using the full CDF data set

    E-Print Network [OSTI]

    Gomez-Ceballos, Guillelmo

    We present a measurement of the top-quark pair production cross section in proton-antiproton collisions at ?s = 1.96??TeV. The data were collected at the Fermilab Tevatron by the CDF II detector and correspond to an ...

  13. Measurement of the ZZ production cross section and search for the standard model Higgs boson in the four lepton final state in pp-bar collisions

    E-Print Network [OSTI]

    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.; Agnew, J. P.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Askew, A.

    2013-08-15

    S. Malik,58 V. L. Malyshev,31 J. Mansour,20 J. Mart?´nez-Ortega,28 R. McCarthy,63 C. L. McGivern,40 M.M.Meijer,29,74 A. Melnitchouk,44 D. Menezes,46 P. G. Mercadante,3 M. Merkin,33 A. Meyer,18 J. Meyer,20,‡‡ F. Miconi,16 N.K. Mondal,25 M. Mulhearn,72... Leeuwen,75 N. Varelas,45 E.W. Varnes,41 I. A. Vasilyev,34 A. Y. Verkheev,31 L. S. Vertogradov,31 M. Verzocchi,44 M. Vesterinen,40 D. Vilanova,15 P. Vokac,7 H.D. Wahl,43 M.H. L. S. Wang,44 J. Warchol,50 G. Watts,73 M. Wayne,50 J. Weichert,21 L. Welty...

  14. Search for $W'\\rightarrow t\\bar{b}$ in the lepton plus jets final states with the ATLAS detector at the LHC

    E-Print Network [OSTI]

    Geoffrey Gilles

    2014-11-28

    This document presents a search for a $W'$ boson, decaying to a top quark and a $b$ quark in an effective coupling approach, using a multivariate method based on boosted decision trees. It reports exclusion limits on the $W'\\rightarrow tb$ cross-section times branching ratio and effective couplings as a function of the $W'$-boson mass. The search covers $W'$-boson masses between 0.5 and 3.0 TeV, for right-handed or left-handed $W'$-boson, with 20.3 fb$^{-1}$ of proton-proton collision data produced by the LHC in 2012, at a center-of-mass energy of 8 TeV and collected by the ATLAS detector.

  15. Search for Supersymmetry Using Final States with One Lepton, Jets, and Missing Transverse Momentum with the ATLAS Detector in ?s=7 TeV pp Collisions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aad, G.; Abbott, B.; Abdallah, J.; Abdelalim, A. A.; Abdesselam, A.; Abdinov, O.; Abi, B.; Abolins, M.; Abramowicz, H.; Abreu, H.; et al

    2011-03-28

    This Letter presents the first search for supersymmetry in final states containing one isolated electron or muon, jets, and missing transverse momentum from ?s=7 TeV proton-proton collisions at the LHC. The data were recorded by the ATLAS experiment during 2010 and correspond to a total integrated luminosity of 35 pb?¹. No excess above the standard model background expectation is observed. Limits are set on the parameters of the minimal supergravity framework, extending previous limits. Within this framework, for A0=0 GeV, tan??=3, and ?>0 and for equal squark and gluino masses, gluino masses below 700 GeV are excluded at 95% confidencemore »level.« less

  16. Neutrino Masses: Where Are We? Angelo Nucciotti

    E-Print Network [OSTI]

    · lepton number violation · neutrinoless double beta decay · rare processes (e.g. µ e) · vacuum neutrino

  17. A Neutrino Superbeam Physics Program as a First Stage of a Neutrino Factory

    E-Print Network [OSTI]

    McDonald, Kirk

    efficiency/rejection of lepton sign identification in a magnetized liquid argon detector. 5 #12;Detector

  18. MiniBooNE nu/nubar combined data set Release

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    energy (EnuQE), lepton visible energy (Evis), cosine of lepton-beam direction (costhe). neutrino data: MBnudatatables.csv, csv file with tables of events in EnuQE,...

  19. Nambu--Goldstone Dark Matter and Cosmic Ray Electron and Positron...

    Office of Scientific and Technical Information (OSTI)

    Language: English Subject: 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; BOSONS; ELECTRONS; LEPTONS; NONLUMINOUS MATTER; POSITRONS; RESONANCE; SUPERSYMMETRY...

  20. CDF Note 11045 Combined CDF Search for Single Top Quark s-channel Production in pp Collisions at

    E-Print Network [OSTI]

    Quigg, Chris

    algoritm in use. The sample is subidived according to the lepton category and the number of b-tagged jets

  1. Search for W' ? t[bar over b] in the lepton plus jets final state in proton-proton collisions at a centre-of-mass energy of ?s = 8 TeV with the ATLAS detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    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 ?s = 8 TeV, using a dataset corresponding to an integrated ...

  2. Fiducial and differential cross sections of Higgs boson production measured in the four-lepton decay channel in pp collisions at ?s = 8 TeV with the ATLAS detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    Measurements of fiducial and differential cross sections of Higgs boson production in the H?ZZ*?4? decay channel are presented. The cross sections are determined within a fiducial phase space and corrected for detection ...

  3. Search for light top squark pair production in final states with leptons and b-jets with the ATLAS detector in ?s = 7 TeV proton–proton collisions

    E-Print Network [OSTI]

    Taylor, Frank E.

    The results of a search for pair production of light top squarks are presented, using 4.7 fb[superscript ?1] ?s = 7 TeV proton–proton collisions collected with the ATLAS detector at the Large Hadron Collider. This search ...

  4. Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in ?s = 7 TeV pp collisions with the ATLAS detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb[superscript -1] of ?s = 7 TeV ...

  5. Measurements of Higgs boson production and couplings in the four-lepton channel in pp collisions at center-of-mass energies of 7 and 8 TeV with the ATLAS detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    The final ATLAS Run 1 measurements of Higgs boson production and couplings in the decay channel H?ZZ*??[superscript +]?[superscript?]?' [superscript +], ?' [superscript ?], where ?, ??=e or ?, are presented. These measurements ...

  6. Measurement of WZ production and searches for anomalous top quark decays and Higgs boson production using tri-lepton final states in ppbar collisions at ?s = 1.96 TeV

    E-Print Network [OSTI]

    McGivern, Carrie Lynne

    2012-05-31

    We present the results of three analyses; a WZ production cross section measurement, a search for new physics in anomalous top quark decays, and the search for the standard model Higgs boson, all with final states of three ...

  7. Measurement of the tt-bar cross section in pp-bar collisions at sqrt[s]=1.96 TeV using dilepton events with a lepton plus track selection

    E-Print Network [OSTI]

    Xie, Si

    This paper reports a measurement of the cross section for the pair production of top quarks in pp? collisions at ?s=1.96??TeV at the Fermilab Tevatron. The data were collected from the CDF run II detector in a set of runs ...

  8. Direct electron pair production in. pi. /sup -/p interactions at 16 GeV/c and a model for direct lepton and photon production at low P/sub T/

    SciTech Connect (OSTI)

    Blockus, D.; Dunwoodie, W.; Leith, D.W.G.S.

    1981-07-01

    The production of prompt electron-positron pairs in 16 GeV/c ..pi../sup -/p collisions has been measured using the LASS spectrometer at SLAC. An excess of events is observed above the estimated contributions of direct and Dalitz decay of known resonances in the kinematic range defined by 0.1 less than or equal to x less than or equal to 0.45, 0 less than or equal to P/sub T/ less than or equal to 0.8 GeV/c and 0.2 less than or equal to M(e/sup +/e/sup -/) less than or equal to 0.7 GeV/c/sup 2/. The excess signal decreases slowly with increasing M, but exhibits very steep x and P/sub T//sup 2/ dependence. The contribution of this signal to the e/sup +/e/sup -//..pi../sup +/..pi../sup -/ and ..gamma../..pi.. ratios is discussed. Detailed comparisons are made between e/sup +/e/sup -/ distributions and the corresponding low mass ..mu../sup +/..mu../sup -/ distributions, and a simple production mechanism is proposed which describes the 16 GeV/c data well. The implications for direct photon production are presented, and it is shown that the model provides simultaneously a good description of the experimental data on the (e/..pi..) and (..mu../..pi..) ratios for p/sub T/ < 1 GeV/c.

  9. Measurement of the Top-antitop Production Cross Section in pp Collisions at sqrt(s)=7 TeV using the Kinematic Properties of Events with Leptons and Jets

    SciTech Connect (OSTI)

    Chatrchyan, Serguei; et al.

    2011-09-01

    A measurement of the top-antitop production cross section in proton-proton collisions at a centre-of-mass energy of 7 TeV has been performed at the LHC with the CMS detector. The analysis uses a data sample corresponding to an integrated luminosity of 36 inverse picobarns and is based on the reconstruction of the final state with one isolated, high transverse-momentum electron or muon and three or more hadronic jets. The kinematic properties of the events are used to separate the top-antitop signal from W+jets and QCD multijet background events. The measured cross section is 173 + 39 - 32 (stat. + syst.) pb, consistent with standard model expectations.

  10. Search for Higgs Bosons Predicted in Two-Higgs-Doublet Models via Decays to Tau Lepton Pairs in 1.96 TeV pp[over-bar] Collisions

    E-Print Network [OSTI]

    Bauer, Gerry P.

    We present the results of a search for Higgs bosons predicted in two-Higgs-doublet models, in the case

  11. Search for the Standard Model Higgs Boson Decaying to W[superscript +]W[superscript -] in the Fully Leptonic Final State in pp Collisions at ?s = 7 TeV

    E-Print Network [OSTI]

    Alver, B.

    A search for the standard model Higgs boson decaying to W[superscript +]W[superscript ?] in pp collisions at ?s = 7 TeV is reported. The data are collected at the LHC with the CMS detector, and correspond to an integrated ...

  12. Associated production of the Higgs boson with a W boson in proton-proton collisions: an explorative analysis of the three-leptons final state with the ATLAS experiment

    E-Print Network [OSTI]

    AUTHOR|(SzGeCERN)720937

    This work concern the study of the properties of the recently discovered Higgs boson in proton-proton collisions at the Large Hadron Collider (LHC). The Higgs boson is the particle that, according to the Standard Model (SM) theory, is responsible for the mass of all the known elementary particles (fermions and bosons). Its existence was postulated during the '60s in the so-called Brout- Englert-Higgs mechanism (BEH), but to have the experimental evidence of this particle scientists had to wait for the first results of the ATLAS and CMS Collaborations at the LHC (2012). Studying the Higgs boson production and decay modes at LHC is one of the purposes of the ATLAS Collaboration. This thesis, in particular, focuses on the study of the Higgs boson production in association with a W boson in proton-proton collision at a centre-of-mass energy of 8 TeV. The channel studied, with the Higgs boson further decaying in two W bosons, allows to direct probe the Higgs boson coupling exclusively with W bosons. The analysis h...

  13. Search for Direct Top Squark Pair Production in Final States with One Isolated Lepton, Jets, and Missing Transverse Momentum in ?s=7??TeV pp Collisions Using 4.7??fb[superscript -1] of ATLAS Data

    E-Print Network [OSTI]

    Taylor, Frank E.

    A search is presented for direct top squark pair production in final states with one isolated electron or muon, jets, and missing transverse momentum in proton-proton collisions at ?s=7??TeV. The measurement is based on ...

  14. Search for the production of dark matter in association with top-quark pairs in the single-lepton final state in proton-proton collisions at ?s = 8 TeV

    E-Print Network [OSTI]

    Apyan, Aram

    A search is presented for particle dark matter produced in association with a pair of top quarks in pp collisions at a centre-of-mass energy of ?s = 8 TeV. The data were collected with the CMS detector at the LHC and ...

  15. Measurements of Higgs boson production and couplings in the four-lepton channel in $pp$ collisions at center-of-mass energies of 7 and 8 TeV with the ATLAS detector

    E-Print Network [OSTI]

    ATLAS Collaboration

    2015-02-11

    The final ATLAS Run 1 measurements of Higgs boson production and couplings in the decay channel $H\\to ZZ^{*}\\to\\ell^+\\ell^-\\ell^{'+}\\ell^{'-}$, where $\\ell,\\ell^{'}=e$ or $\\mu$, are presented. These measurements were performed using $pp$ collision data corresponding to integrated luminosities of 4.5 fb$^{-1}$ and 20.3 fb$^{-1}$ at center-of-mass energies of 7 TeV and 8 TeV, respectively, recorded with the ATLAS detector at the LHC. The $H\\to ZZ^{*}\\to 4\\ell$ signal is observed with a significance of 8.1 standard deviations, with an expectation of 6.2 standard deviations, at $m_{H}$ = 125.36 GeV, the combined ATLAS measurement of the Higgs boson mass from the $H\\to \\gamma\\gamma$ and $H\\to ZZ^{*}\\to 4\\ell$ channels. The production rate relative to the Standard Model expectation, the signal strength, is measured in four different production categories in the $H\\to ZZ^{*}\\to 4\\ell$ channel. The measured signal strength, at this mass, and with all categories combined, is 1.44 $^{+0.40}_{-0.33}$. The signal strength for Higgs boson production in gluon fusion or in association with $t\\bar{t}$ or $b\\bar{b}$ pairs is found to be 1.7 $^{+0.5}_{-0.4}$, while the signal strength for vector-boson fusion combined with $WH/ZH$ associated production is found to be 0.3 $^{+1.6}_{-0.9}$.

  16. Search for Pair Production of a Heavy Up-Type Quark Decaying to a W Boson and a b Quark in the lepton+jets Channel with the ATLAS Detector

    E-Print Network [OSTI]

    Taylor, Frank E.

    A search is presented for production of a heavy up-type quark (t?) together with its antiparticle, assuming subsequent decay to a W boson and a b quark, t?t? ?-->W[superscript+]bW[superscript -]b? . The search is based on ...

  17. Search for Maximal Flavor Violating Scalars in Same-Charge Lepton Pairs in p anti-p Collisions at s**(1/2) = 1.96-TeV

    SciTech Connect (OSTI)

    Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, Michael G.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, Dante E.; Anastassov, A.; Annovi, Alberto; Antos, J.; Aoki, M.; /Illinois U., Urbana /Fermilab

    2008-09-01

    Models of Maximal Flavor Violation (MxFV) in elementary particle physics may contain at least one new scalar SU(2) doublet field {Phi}{sub FV} = ({eta}{sup 0},{eta}{sup +}) that couples the first and third generation quarks (q{sub 1}; q{sub 3}) via a Lagrangian term L{sub FV} = {zeta}{sub 13}{Phi}{sub FV}q{sub 1}q{sub 3}. These models have a distinctive signature of same-charge top-quark pairs and evade flavor-changing limits from meson mixing measurements. Data corresponding to 2 fb{sup -1} collected by the CDF II detector in p{bar p} collisions at {radical}s = 1.96 TeV are analyzed for evidence of the MxFV signature. For a neutral scalar {eta}{sup 0} with m{sub {eta}{sup 0}} = 200 GeV/c{sup 2} and coupling {zeta}{sub 13} = 1, {approx} 11 signal events are expected over a background of 2.1 {+-} 1.8 events. Three events are observed in the data, consistent with background expectations, and limits are set on the coupling {zeta}{sub 13} for m{sub {eta}{sup 0}} = 180-300 GeV/c{sup 2}.

  18. Neutrino masses, dominant neutrinoless double beta decay, and observable lepton flavor violation in left-right models and SO(10) grand unification with low mass $\\bf W_R, Z_R$ bosons

    E-Print Network [OSTI]

    Ram Lal Awasthi; M. K. Parida; Sudhanwa Patra

    2013-08-07

    While the detection of $W_R$-boson at the Large Hadron Collider is likely to resolve the mystery of parity violation in weak interaction, observation of neutrinoless double beta decay ($0\

  19. Search for the Standard Model Higgs Boson Decaying to a bb? Pair in Events with No Charged Leptons and Large Missing Transverse Energy using the Full CDF Data Set

    E-Print Network [OSTI]

    Gomez-Ceballos, Guillelmo

    We report on a search for the standard model Higgs boson produced in association with a vector boson in the full data set of proton-antiproton collisions at ?s=1.96??TeV recorded by the CDF II detector at the Tevatron, ...

  20. Search for the standard model Higgs boson decaying to a bb pair in events with one charged lepton and large missing transverse energy using the full CDF data set

    E-Print Network [OSTI]

    The CDF Collaboration

    2012-08-09

    We present a search for the standard model Higgs boson produced in association with a W boson in sqrt(s) = 1.96 TeV p-pbar collision data collected with the CDF II detector at the Tevatron corresponding to an integrated luminosity of 9.45 fb-1. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the W boson to an electron or muon and a neutrino, we set 95% credibility level upper limits on the WH production cross section times the H->bb branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125 GeV/c2 we observe (expect) a limit of 4.9 (2.8) times the standard model value.