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1

Top Quark Mass Measurements  

Science Journals Connector (OSTI)

First observed in 1995 the top quark is one of a pair of third?generation quarks in the Standard Model of particle physics. It has charge +2/3e and a mass of 171.4 GeV about 40 times heavier than its partner the bottom quark. The CDF and DØ collaborations have identified several hundred events containing the decays of top?antitop pairs in the large dataset collected at the Tevatron proton?antiproton collider over the last four years. They have used these events to measure the top quark’s mass to nearly 1% precision and to study other top quark properties. The mass of the top quark is a fundamental parameter of the Standard Model and knowledge of its value with small uncertainty allows us to predict properties of the as?yet?unobserved Higgs boson. This paper presents the status of the measurements of the top quark mass. It is based on a talk I gave at the Conference on the Intersections of Particle and Nuclear Physics in Puerto Rico May 2006 which also included discussion of measurements of other top quark properties.

A. P. Heinson; CDF Collaboration; DØ Collaboration

2006-01-01T23:59:59.000Z

2

Top Quark Mass Measurements at the Tevatron  

SciTech Connect

We report the latest results on the top-quark mass and on the top-antitop mass difference from the CDF and D0 collaborations using data collected at the Fermilab Tevatron p{bar p} collider at {radical}s = 1.96 TeV. We discuss general issues in top-quark mass measurements and present new results from direct measurements and from top-pair production cross-section. We also report new results on the top-antitop mass difference.

Ye, Zhenyu; /Fermilab

2011-07-01T23:59:59.000Z

3

edited1_TopQuarkMass  

NLE Websites -- All DOE Office Websites (Extended Search)

CALCULATE THE TOP QUARK MASS CALCULATE THE TOP QUARK MASS TEACHER NOTES DESCRIPTION Students use momentum conservation, energy conservation and two-dimensional vector addition to calculate the mass of the heaviest of the six known quarks. They gather data from data plots from the DØ experiment at Fermilab. The events were chosen carefully; all of the decay products moved in a plane perpendicular to the beam. This makes the vector addition much simpler. STANDARDS National Science Education Standards (U.S. National Research Council) * Physical Science Content Standard B: As a result of this activity . . . students should develop an understanding of: o Conservation of energy and increase in disorder. o Interactions in energy and matter. LEARNING OBJECTIVES Students will know and be able to:

4

Top-quark mass measurements: Alternative techniques (LHC + Tevatron)  

E-Print Network (OSTI)

Measurements of the top-quark mass employing alternative techniques are presented, performed by the D0 and CDF collaborations at the Tevatron as well as the ATLAS and CMS experiments at the LHC. The alternative methods presented include measurements using the lifetime of $B$-hadrons, the transverse momentum of charged leptons and the endpoints of kinematic distributions in top quark anti-quark pair ($t\\bar{t}$) final states. The extraction of the top-quark pole mass from the $t\\bar{t}$ production cross-section and the normalized differential $t\\bar{t}$ + 1-jet cross-section are discussed as well as the top-quark mass extraction using fixed-order QCD predictions at detector level. Finally, a measurement of the top-quark mass using events enhanced in single top t-channel production is presented.

Adomeit, Stefanie

2014-01-01T23:59:59.000Z

5

Measurement of the Top Quark Mass With 2012 CMS Data  

E-Print Network (OSTI)

The mass of the top quark was an active topic of research at CMS using 2011 data, and remains so as the 2012 data analysis campaign proceeds. Here we discuss some of the earliest results on the top mass using 2012 sqrt(s) = 8 TeV CMS data, including measurements of the top mass from semileptonic t\\bar{t} decays and the lifetime of the B-hadron, as well as a measurement of the top-antitop mass difference.

Richard Nally

2014-09-01T23:59:59.000Z

6

Testing ETC Generation of the Top Quark Mass  

E-Print Network (OSTI)

We consider constraints on models in which a top quark mass is generated through unenhanced extended technicolor interactions. The deviation in the $\\rho$ parameter from unity and $B$--$\\overline{B}$ mixing could be large, but given the uncertainties in strong dynamics and variations in the parameters of models, no conclusive statement can be given. We conclude that the low technicolor scale which is required to generate the top quark mass is not ruled out.

L. Randall

1992-10-13T23:59:59.000Z

7

Top quark mass measurement using the template method at CDF  

We present a measurement of the top quark mass in the lepton+jets and dilepton channels of tt? decays using the template method. The data sample corresponds to an integrated luminosity of 5.6 fb-1 of pp? collisions at Tevatron with ?s = 1.96 TeV, collected with the CDF II detector. The measurement is performed by constructing templates of three kinematic variables in the lepton+jets and two kinematic variables in the dilepton channel. The variables are two reconstructed top quark masses from different jets-to-quarks combinations and the invariant mass of two jets from the W decay in the lepton+jets channel, and a reconstructed top quark mass and mT2, a variable related to the transverse mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the lepton+jets and dilepton channels to the data yields a measured top quark mass of Mtop = 172.1±1.1 (stat)±0.9 (syst) GeV/c2.

Aaltonen, T [Helsinki Inst. of Phys.; Alvarez Gonzalez, B [Oviedo U.; Cantabria Inst. of Phys.; Amerio, S [INFN, Padua; Amidei, D [Michigan U.; Anastassov, A [Northwestern U.; Annovi, A [Frascati; Antos, J [Comenius U.; Apollinari, G [Fermilab; Appel, J A [Fermilab; Apresyan, A [Purdue U.; Arisawa, T [Waseda U.; Dubna, JINR

2011-06-03T23:59:59.000Z

8

A Precision Measurement of the Mass of the Top Quark  

E-Print Network (OSTI)

The Standard Model of particle physics contains about two dozen parameters - such as particle masses - whose origins are still unknown and cannot be predicted, but whose values are constrained through their interactions. In particular, the masses of the top (t) quark (M_t) and W boson constrain the mass of the long-hypothesized, but thus far not observed, Higgs boson. A precise measurement of the top-quark mass can therefore point to where to look for the Higgs, and indeed whether the hypothesis of a SM Higgs is consistent with experimental data. Since top quarks are produced in pairs and decay in only ~10^-24 s into various final states, reconstructing their mass from their decay products is very challenging. Here we report a technique that extracts far more information from each top-quark event and yields a greatly improved precision on the top mass of 5.3 GeV/c^2, compared to previous measurements. When our new result is combined with our published measurement in a complementary decay mode and with the onl...

Abazov, V M; Abdesselam, A; Abolins, M; Abramov, V; Acharya, B S; Adams, D L; Adams, M; Ahmed, S N; Alexeev, G D; Alton, A; Alves, G A; Arnoud, Y; Avila, C; Babintsev, V V; Babukhadia, L; Bacon, Trevor C; Baden, A; Baffioni, S; Baldin, B Yu; Balm, P W; Banerjee, S; Barberis, E; Baringer, P; Barreto, J; Bartlett, J F; Bassler, U; Bauer, D; Bean, A; Beaudette, F; Begel, M; Belyaev, A; Beri, S B; Bernardi, G; Bertram, I; Besson, A; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Bhattacharjee, M; Blazey, G; Blekman, F; Blessing, S; Böhnlein, A; Bozhko, N; Bolton, T A; Borcherding, F; Bos, K; Bose, T; Brandt, A; Briskin, G; Brock, R; Brooijmans, G; Bross, A; Buchholz, D; Bühler, M; Büscher, V; Burtovoi, V S; Butler, J M; Canelli, F; Carvalho, W; Casey, D; Castilla-Valdez, H; Chakraborty, D; Chan, K M; Chekulaev, S V; Cho, D K; Choi, S; Chopra, S; Claes, D; Clark, A R; Connolly, B; Cooper, W E; Coppage, D; Crepe-Renaudin, S; Cummings, M A C; Cutts, D; Da Motta, H; Davis, G A; De, K; De Jong, S J; Demarteau, M; Demina, R; Demine, P; Denisov, D; Denisov, S P; Desai, S; Diehl, H T; Diesburg, M; Doulas, S; Dudko, L V; Duflot, L; Dugad, S R; Duperrin, A; Dyshkant, A; Edmunds, D; Ellison, J; Eltzroth, J T; Elvira, V D; Engelmann, R; Eno, S; Eppley, G; Ermolov, P; Eroshin, O V; Estrada, J; Evans, H; Evdokimov, V N; Ferbel, T; Filthaut, F; Fisk, H E; Fortner, M; Fox, H; Fu, S; Fuess, S; Gallas, E; Galjaev, A N; Gao, M; Gavrilov, V; Genik, R J; Genser, K; Gerber, C E; Gershtein, Yu; Ginther, G; Gómez, B; Goncharov, P I; Gounder, K; Goussiou, A; Grannis, P D; Greenlee, H; Greenwood, Z D; Grinstein, S; Groer, L; Grünendahl, S; Grünewald, M W; Gurzhev, S N; Gutíerrez, G; Gutíerrez, P; Hadley, N J; Haggerty, H; Hagopian, S; Hagopian, V; Hall, R E; Han, C; Hansen, S; Hauptman, J M; Hebert, C; Hedin, D; Heinmiller, J M; Heinson, A P; Heintz, U; Hildreth, M D; Hirosky, R; Hobbs, J D; Hoeneisen, B; Huang, J; Huang, Y; Iashvili, I; Illingworth, R; Ito, A S; Jaffré, M; Jain, S; Jesik, R; Johns, K; Johnson, M; Jonckheere, A; Jöstlein, H; Juste, A; Kahl, W; Kahn, S; Kajfasz, E; Kalinin, A M; Karmanov, D; Karmgard, D; Kehoe, R; Kesisoglou, S; Khanov, A; Kharchilava, A I; Klima, B; Kohli, J M; Kostritskii, A V; Kotcher, J; Kothari, B; Kozelov, A V; Kozlovskii, E A; Krane, J; Krishnaswamy, M R; Krivkova, P; Krzywdzinski, S; Kubantsev, M A; Kuleshov, S; Kulik, Y; Kunori, S; Kupco, A; Kuznetsov, V E; Landsberg, G L; Lee, W M; Leflat, A; Lehner, F; Leonidopoulos, C; Li, J; Li, Q Z; Lima, J G R; Lincoln, D; Linn, S L; Linnemann, J; Lipton, R; Lucotte, A; Lueking, L; Lundstedt, C; Luo, C; Maciel, A K A; Madaras, R J; Malyshev, V L; Manankov, V; Mao, H S; Marshall, T; Martin, M I; Mattingly, S E K; Mayorov, A A; McCarthy, R; McMahon, T; Melanson, H L; Melnitchouk, A S; Merkin, M; Merritt, K W; Miao, C; Miettinen, H; Mihalcea, D; Mokhov, N V; Mondal, N K; Montgomery, H E; Moore, R W; Mutaf, Y D; Nagy, E; Narain, M; Narasimham, V S; Naumann, N A; Neal, H A; Negret, J P; Nelson, S; Nomerotski, A; Nunnemann, T; O'Neil, D; Oguri, V; Oshima, N; Padley, P; Papageorgiou, K; Parashar, N; Partridge, R; Parua, N; Patwa, A; Peters, O; Petroff, P; Piegaia, R; Pope, B G; Prosper, H B; Protopopescu, S D; Przybycien, M B; Qian, J; Rajagopalan, S; Rapidis, P A; Reay, N W; Reucroft, S; Ridel, M; Rijssenbeek, M; Rizatdinova, F K; Rockwell, T; Royon, C; Rubinov, P; Ruchti, R; Sabirov, B M; Sajot, G; Santoro, A F S; Sawyer, L; Schamberger, R D; Schellman, H; Schwartzman, A; Shabalina, E; Shivpuri, R K; Shpakov, D; Shupe, M; Sidwell, R A; Simák, V; Sirotenko, V I; Slattery, P F; Smith, R P; Snow, G R; Snow, J; Snyder, S; Solomon, J; Song, Y; Sorin, V; Sosebee, M; Sotnikova, N; Soustruznik, K; Souza, M; Stanton, N R; Steinbruck, G; Stoker, D; Stolin, V; Stone, A; Stoyanova, D A; Strang, M A; Strauss, M; Strovink, M; Stutte, L; Sznajder, A; Talby, M; Taylor, W; Tentindo-Repond, S; Trippe, T G; Turcot, A S; Tuts, P M; Van Kooten, R; Vaniev, V; Varelas, N; Villeneuve-Séguier, F; Volkov, A A; Vorobev, A P; Wahl, H D; Wang, Z M; Warchol, J; Watts, G; Wayne, M; Weerts, H; White, A; Whiteson, D; Wijngaarden, D A; Willis, S; Wimpenny, S J; Womersley, J; Wood, D R; Xu, Q; Yamada, R; Yasuda, T; Yatsunenko, Y A; Yip, K; Yu, J; Zanabria, M; Zhang, X; Zhou, B; Zhou, Z; Zielinski, M; Zieminska, D; Zieminski, A; Zutshi, V; Zverev, E G; Zylberstejn, A

2004-01-01T23:59:59.000Z

9

Precision Top-Quark Mass Measurements at CDF  

SciTech Connect

We present a precision measurement of the top-quark mass using the full sample of Tevatron {radical}s = 1.96 TeV proton-antiproton collisions collected by the CDF II detector, corresponding to an integrated luminosity of 8.7 fb{sup -1}. Using a sample of t{bar t} candidate events decaying into the lepton+jets channel, we obtain distributions of the top-quark masses and the invariant mass of two jets from the W boson decays from data. We then compare these distributions to templates derived from signal and background samples to extract the top-quark mass and the energy scale of the calorimeter jets with in situ calibration. The likelihood fit of the templates from signal and background events to the data yields the single most-precise measurement of the top-quark mass, mtop = 172.85 {+-} 0.71 (stat) {+-} 0.85 (syst) GeV/c{sup 2}.

Aaltonen, T.; /Helsinki Inst. of Phys.; Alvarez Gonzalez, B.; /Oviedo U. /Cantabria Inst. of Phys.; Amerio, S.; /INFN, Padua; Amidei, D.; /Michigan U.; Anastassov, A.; /Northwestern U. /Fermilab; Annovi, A.; /Frascati; Antos, J.; /Comenius U.; Apollinari, G.; /Fermilab; Appel, J.A.; /Fermilab; Arisawa, T.; /Waseda U.; Artikov, A.; /Dubna, JINR /Texas A-M

2012-07-01T23:59:59.000Z

10

Top Quark Measurements  

E-Print Network (OSTI)

Ten years after its discovery at the Tevatron collider, we still know little about the top quark. Its large mass suggests it may play a key role in the mechanism of Electroweak Symmetry Breaking (EWSB), or open a window of sensitivity to new physics related to EWSB and preferentially coupled to it. To determine whether this is the case, precision measurements of top quark properties are necessary. The high statistics samples being collected by the Tevatron experiments during Run II start to incisively probe the top quark sector. This report summarizes the experimental status of the top quark, focusing in particular on the recent measurements from the Tevatron Run II.

A. Juste

2005-12-20T23:59:59.000Z

11

Precise measurement of the top quark mass in the lepton+jets topology at CDF II  

SciTech Connect

The authors present a measurement of the mass of the top quark from proton-antiproton collisions recorded at the CDF experiment in Run II of the Fermilab Tevatron. They analyze events from the single lepton plus jets final state (t{bar t} {yields} W{sup +}bW{sup -}{bar b} {yields} lvbq{bar q}{bar b}). The top quark mass is extracted using a direct calculation of the probability density that each event corresponds to the t{bar t} final state. The probability is a function of both the mass of the top quark and the energy scale of the calorimeter jets, which is constrained in situ by the hadronic W boson mass. Using 167 events observed in 955 pb{sup -1} of integrated luminosity, they achieve the single most precise measurement of the top quark mass, 170.8 {+-} 2.2(stat.) {+-} 1.4(syst.) GeV/c{sup 2}.

Abulencia, A.; /Illinois U., Urbana; Adelman, J.; /Chicago U.; Affolder, T.; /UC, Santa Barbara; Akimoto, T.; /Tsukuba U.; Albrow, M.G.; /Fermilab; Amerio, S.; /Padua U.; Amidei, D.; /Michigan U.; Anastassov, A.; /Rutgers U., Piscataway; Anikeev, K.; /Fermilab; Annovi, A.; /Frascati; Antos, J.; /Comenius U. /Tsukuba U.

2007-03-01T23:59:59.000Z

12

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

SciTech Connect

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.

Fedorko, Wojciech T.; /Chicago U.

2008-09-01T23:59:59.000Z

13

Top-quark mass predictions from W,Z masses and Z partial widths  

Science Journals Connector (OSTI)

We use recent measurements of the W- and Z-boson masses and the leptonic, hadronic, and total Z widths to constrain the top-quark mass in the standard model, including full radiative corrections. From a maximum-likelihood analysis we find the most likely value of mt to be 151 GeV and we obtain the bound mt?200 GeV at 95% C.L. based on the central measured value of the Z mass assuming a Higgs-boson mass of 100 GeV and ?s(MZ2)=0.12.

V. Barger; J. L. Hewett; T. G. Rizzo

1990-09-10T23:59:59.000Z

14

Top-quark mass measurement using events with missing transverse energy and jets at CDF  

SciTech Connect

We present a measurement of the top-quark mass with tt? events using a data sample corresponding to an integrated luminosity of 5.7 fb -1 of pp? collisions at the Fermilab Tevatron with ?s = 1.96 TeV and collected by the CDF II Detector. We select events having no identified charged leptons, large missing transverse energy, and four, five, or six jets with at least one jet containing a secondary vertex consistent with the decay of a b quark. This analysis considers events from the semileptonic tt? decay channel, including events that contain tau leptons, which are usually not included in the top-quark mass measurements. The measurement uses as kinematic variables the invariant mass of two jets consistent with the mass of the W boson, and the invariant masses of two different three-jet combinations. We fit the data to signal templates of varying top-quark masses and background templates, and measure a top-quark mass of Mtop = 172.3 ± 2.4 (stat) ± 1.0 (syst) GeV/c2.

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

2013-07-01T23:59:59.000Z

15

Precise measurement of the top-quark mass from lepton+jets events at D0  

SciTech Connect

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.

Abazov, Victor Mukhamedovich [Dubna, JINR; Abbott, Braden Keim [Oklahoma U.; Acharya, Bannanje Sripath [Tata Inst.; Adams, Mark Raymond [Illinois U., Chicago; Adams, Todd [Florida State U.; Alexeev, Guennadi D [Dubna, JINR; Alkhazov, Georgiy D [St. Petersburg, INP; Alton, Andrew K [Michigan U.; Augustana Coll., Sioux Falls; Alverson, George O [Northeastern U.; Alves, Gilvan Augusto [Rio de Janeiro, CBPF; Ancu, Lucian Stefan [Nijmegen U.; Fermilab

2011-08-09T23:59:59.000Z

16

Precise measurement of the top-quark mass from lepton+jets events at D0  

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.

Abazov, Victor Mukhamedovich [Dubna, JINR; Abbott, Braden Keim [Oklahoma U.; Acharya, Bannanje Sripath [Tata Inst.; Adams, Mark Raymond [Illinois U., Chicago; Adams, Todd [Florida State U.; Alexeev, Guennadi D [Dubna, JINR; Alkhazov, Georgiy D [St. Petersburg, INP; Alton, Andrew K [Michigan U.; Augustana Coll., Sioux Falls; Alverson, George O [Northeastern U.; Alves, Gilvan Augusto [Rio de Janeiro, CBPF; Ancu, Lucian Stefan [Nijmegen U.; Fermilab

2011-08-09T23:59:59.000Z

17

Measurement of the top quark mass in lepton+jets events with secondary vertex tagging  

SciTech Connect

A measurement of the top quark mass with the matrix element method in the lepton + jets final state in D0 Run II is presented. Events with single isolated energetic charged lepton (electron or muon), exactly four calorimeter jets, and significant missing transverse energy are selected. Probabilities used to discriminate between signal and background are assumed to be proportional to differential cross-sections, calculated using event kinematics and folding in object resolutions and parton distribution functions. The event likelihoods constructed using these probabilities are varied with the top quark mass, m{sub t}, and the jet energy scale, JES, to give the smallest possible combined statistical + JES uncertainty.

Harrington, Robert Duane; /Northeastern U.

2007-02-01T23:59:59.000Z

18

Top Quark Current Experimental Status  

E-Print Network (OSTI)

Ten years after its discovery at the Tevatron collider, we still know little about the top quark. Its large mass suggests it may play a key role in the mechanism of Electroweak Symmetry Breaking (EWSB), or open a window of sensitivity to new physics related to EWSB and preferentially coupled to it. To determine whether this is the case, precision measurements of top quark properties are necessary. The high statistics samples being collected by the Tevatron experiments during Run II start to incisively probe the top quark sector. This report summarizes the experimental status of the top quark, focusing in particular on the recent measurements from the Tevatron.

A. Juste

2006-03-04T23:59:59.000Z

19

Measurement of the Top Quark Mass in the All-Hadronic Mode at CDF  

SciTech Connect

A measurement of the top quark mass (M{sub top}) in the all-hadronic decay channel is presented. It uses 5.8 fb{sup -1} of p{bar p} data collected with the CDF II detector at the Fermilab Tevatron Collider. Events with six to eight jets are selected by a neural network algorithm and by the requirement that at least one of the jets is tagged as a b quark jet. The measurement is performed with a likelihood fit technique, which simultaneously determines M{sub top} and the jet energy scale (JES) calibration. The fit yields a value of M{sub top} = 172.5 {+-} 1.4 (stat) {+-} 1.0 (JES) {+-} 1.1 (syst) GeV/c{sup 2}.

Aaltonen, T.; /Helsinki Inst. of Phys.; Alvarez Gonzalez, B.; /Oviedo U. /Cantabria Inst. of Phys.; Amerio, S.; /INFN, Padua; Amidei, D.; /Michigan U.; Anastassov, A.; /Northwestern U. /Fermilab; Annovi, A.; /Frascati; Antos, J.; /Comenius U.; Apollinari, G.; /Fermilab; Appel, J.A.; /Fermilab; Arisawa, T.; /Waseda U.; Artikov, A.; /Dubna, JINR /Texas A-M

2011-12-01T23:59:59.000Z

20

A measurement of the top quark mass with a matrix element method  

SciTech Connect

The authors present a measurement of the mass of the top quark. The event sample is selected from proton-antiproton collisions, at 1.96 TeV center-of-mass energy, observed with the CDF detector at Fermilab's Tevatron. They consider a 318 pb{sup -1} dataset collected between March 2002 and August 2004. They select events that contain one energetic lepton, large missing transverse energy, exactly four energetic jets, and at least one displaced vertex b tag. The analysis uses leading-order t{bar t} and background matrix elements along with parameterized parton showering to construct event-by-event likelihoods as a function of top quark mass. From the 63 events observed with the 318 pb{sup -1} dataset they extract a top quark mass of 172.0 {+-} 2.6(stat) {+-} 3.3(syst) GeV/c{sup 2} from the joint likelihood. The mean expected statistical uncertainty is 3.2 GeV/c{sup 2} for m{sub t} = 178 GTeV/c{sup 2} and 3.1 GeV/c{sup 2} for m{sub t} = 172.5 GeV/c{sup 2}. The systematic error is dominated by the uncertainty of the jet energy scale.

Gibson, Adam Paul; /UC, Berkeley

2006-12-01T23:59:59.000Z

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21

Top quark studies at hadron colliders  

SciTech Connect

The techniques used to study top quarks at hadron colliders are presented. The analyses that discovered the top quark are described, with emphasis on the techniques used to tag b quark jets in candidate events. The most recent measurements of top quark properties by the CDF and DO Collaborations are reviewed, including the top quark cross section, mass, branching fractions, and production properties. Future top quark studies at hadron colliders are discussed, and predictions for event yields and uncertainties in the measurements of top quark properties are presented.

Sinervo, P.K. [Univ. of Toronto, Ontario (Canada)

1997-01-01T23:59:59.000Z

22

Precision Measurement of the Mass of the Top Quark in p anti-p Collisions  

SciTech Connect

We report a measurement of the mass of the top quark (m{sub top}) in p{bar p} collisions at a center of mass energy of 1.96 TeV. The analysis is based on p{bar p}{yields}t{bar t}{yields} lepton+jets data recorded with the D0 detector at the Fermilab Tevatron Collider. Events were preselected in the e+jets (913 events/pb of data) and in the {mu}+jets (871 events/pb of data) channels. These were analyzed through a comparison of the matrix element for the production and decay of the t{bar t} states with data, using a likelihood method and 'tagged' b quarks from the t {yields} Wb decays.

Garcia, Carlos A.; /Rochester U.; ,

2007-01-01T23:59:59.000Z

23

Measurement of the top quark mass in final states with two leptons  

Science Journals Connector (OSTI)

We present measurements of the top quark mass (mt) in tt¯ candidate events with two final state leptons using 1??fb-1 of data collected by the D0 experiment. Our data sample is selected by requiring two fully identified leptons or by relaxing one lepton requirement to an isolated track if at least one jet is tagged as a b jet. The top quark mass is extracted after reconstructing the event kinematics under the tt¯ hypothesis using two methods. In the first method, we integrate over expected neutrino rapidity distributions, and in the second we calculate a weight for the possible top quark masses based on the observed particle momenta and the known parton distribution functions. We analyze 83 candidate events in the data and obtain mt=176.2±4.8(stat)±2.1(sys)??GeV and mt=173.2±4.9(stat)±2.0(sys)??GeV for the two methods, respectively. Accounting for correlations between the two methods, we combine the measurements to obtain mt=174.7±4.4(stat)±2.0(sys)??GeV.

V. M. Abazov et al. (The D0 Collaboration)

2009-11-20T23:59:59.000Z

24

The Higgs boson and Top quark masses as tests of Electroweak Vacuum Stability  

E-Print Network (OSTI)

The measurements of the Higgs boson and top quark masses can be used to extrapolate the Standard Model Higgs potential at energies up to the Planck scale. Adopting a NNLO renormalization procedure, we: i) find that electroweak vacuum stability is at present allowed, discuss the associated theoretical and experimental errors and the prospects for its future tests; ii) determine the boundary conditions allowing for the existence of a shallow false minimum slightly below the Planck scale, which is a stable configuration that might have been relevant for primordial inflation; iii) derive a conservative upper bound on type I seesaw right-handed neutrino masses, following from the requirement of electroweak vacuum stability.

Masina, Isabella

2013-01-01T23:59:59.000Z

25

Higgs boson and Top quark masses as tests of Electroweak Vacuum Stability  

E-Print Network (OSTI)

The measurements of the Higgs boson and top quark masses can be used to extrapolate the Standard Model Higgs potential at energies up to the Planck scale. Adopting a NNLO renormalization procedure, we: i) find that electroweak vacuum stability is at present allowed, discuss the associated theoretical and experimental errors and the prospects for its future tests; ii) determine the boundary conditions allowing for the existence of a shallow false minimum slightly below the Planck scale, which is a stable configuration that might have been relevant for primordial inflation; iii) derive a conservative upper bound on type I seesaw right-handed neutrino masses, following from the requirement of electroweak vacuum stability.

Isabella Masina

2012-09-03T23:59:59.000Z

26

Independent measurement of the top quark mass and the light- and bottom-jet energy scales at hadron colliders  

E-Print Network (OSTI)

A method for the simultaneous determination of the energy scales for b-quark jets and light jets, the jet energy resolution, and the top quark mass at hadron colliders is presented. The method exploits the unique kinematics of events with top-antitop pair production, where one of the top quarks involves a leptonic and one a hadronic W boson decay. The paper shows a feasibility study of how this simultaneous measurement can be performed at the upcoming LHC experiments ATLAS and CMS.

Frank Fiedler

2007-06-12T23:59:59.000Z

27

Measurement of the Top-Quark Mass in the All-Hadronic Channel using the full CDF data set  

E-Print Network (OSTI)

The top-quark mass M_top is measured using top quark-antiquark pairs produced in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV and decaying into a fully hadronic final state. The full data set collected with the CDFII detector at the Fermilab Tevatron Collider, corresponding to an integrated luminosity of 9.3 fb-1, is used. Events are selected that have six to eight jets, at least one of which is identified as having originated from a b quark. In addition, a multivariate algorithm, containing multiple kinematic variables as inputs, is used to discriminate signal events from background events due to QCD multijet production. Templates for the reconstructed top-quark mass are combined in a likelihood fit to measure M_top with a simultaneous calibration of the jet-energy scale. A value of M_top = 175.07+- 1.19(stat)+1.55-1.58(syst) GeV/c^2 is obtained for the top-quark mass.

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

2014-10-08T23:59:59.000Z

28

CDF measurement of the top quark mass in the lepton + jets channel using the multivariate template method  

SciTech Connect

The authors measure the mass of the top quark using 162 pb{sup -1} of data collected by the CDF experiment at FNAL in Run II. The decay chain t{bar t} {yields} bq{bar q}{bar b}lv is studied using a novel technique called the Multivariate Template Method (MTM). Using this technique they obtain a result of M{sub top} = 179.6{sub -6.3}{sup +6.4} {+-} 6.8 GeV/c{sup 2} for the top quark.

Freeman, John; /Fermilab

2004-12-01T23:59:59.000Z

29

Top Mass and Properties  

E-Print Network (OSTI)

The top quark was discovered in 1995. The top quark mass is now well measured at the Tevatron, with uncertainty getting below 1% of the top mass. The world average from last year was 170.9 $\\pm$ 1.8 GeV/$c^2$. The new CDF measurement is 172 $\\pm$ 1.2 (stat) $\\pm$ 1.5 (sys) GeV/$c^2$, and D0 will soon present a new measurement. The top quark mass is an important parameter in the Standard Model, and should be measured as precisely as possible. To learn more about the top quark observed and study possible new physics, other properties also should be measured. At the Tevatron, the charge of the top quark can be measured directly. Examples of other properties studied and reported in this presentation are W helicity, top decay branching ratio to b ($R_b$), searches for $t \\to H b$ and for flavor changing neutral current (FCNC). The results are all consistent with the Standard Model within current statistics. With significantly more data being collected at the Tevatron, precision measurements of the top properties are just starting.

Yen-Chu Chen

2008-05-15T23:59:59.000Z

30

Theory of top quark production and decay  

SciTech Connect

Direct and indirect information on the top quark mass and its decay modes is reviewed. The theory of top production in hadron- and electron-positron-colliders is presented.

Kuehn, J.H. [Universitaet Karlsruhe (Germany)

1997-01-01T23:59:59.000Z

31

Measurement of the top quark mass and pp-bar -->tt-bar cross section in the all-hadronic mode with the CDF II detector  

E-Print Network (OSTI)

We present a measurement of the top quark mass and of the top-antitop (tt? ) pair production cross section using pp? data collected with the CDF II detector at the Tevatron Collider at the Fermi National Accelerator ...

Paus, Christoph M. E.

32

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

SciTech Connect

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}.

Aaltonen, T.; /Helsinki Inst. of Phys.; Adelman, J.; /Chicago U., EFI; Akimoto, T.; /Tsukuba U.; Alvarez Gonzalez, B.; /CSIC, Catalunya; Amerio, S.; /INFN, Padua; Amidei, D.; /Michigan U.; Anastassov, A.; /Northwestern U.; Annovi, A.; /Frascati; Antos, J.; /Comenius U.; Apollinari, G.; /Fermilab; Apresyan, A.; /Purdue U. /Waseda U.

2008-12-01T23:59:59.000Z

33

Top Quark Condensate Revisited  

Science Journals Connector (OSTI)

......hence a strong connection with the Higgs boson itself. Such a situation can be...the top quark condensate. The Higgs boson emerges as aft bound state and...at A~ 1019 GeV. (3 19) The Higgs boson was predicted as a ft bound state......

Koichi Yamawaki

1996-02-01T23:59:59.000Z

34

Measurement of the top quark mass in topologies enhanced with single top quarks produced in the $t$-channel at $\\sqrt{s}=8\\,\\mathrm{TeV}$ using the ATLAS experiment  

E-Print Network (OSTI)

This article presents a measurement of the top quark mass in topologies enhanced with single top quarks produced in the $t$-channel produced via weak interactions. The dataset was collected at a centre-of-mass energy of $\\sqrt{s}=8\\,\\mathrm{TeV}$ with the ATLAS detector at the LHC and corresponds to an integrated luminosity of $20.3\\,\\mathrm{fb^{-1}}$. To determine the top quark mass a template method is used based on the distribution of the invariant mass of the lepton and the $b$-tagged jet as estimator. The result of the measurement is $m_{\\mathrm{top}} = 172.2 \\pm 0.7 {\\mathrm{(stat.)}} \\pm 2.0 {\\mathrm{(syst.)}}\\,\\mathrm{GeV}$.

Esch, Hendrik; The ATLAS collaboration

2014-01-01T23:59:59.000Z

35

Measurement of the top quark mass in topologies enhanced with single top quarks produced in the $t$-channel at $\\sqrt{s}=8\\,\\mathrm{TeV}$ using the ATLAS experiment  

E-Print Network (OSTI)

A measurement of the top quark mass in topologies enhanced with single top quarks produced in the $t$-channel produced via weak interactions is presented. The dataset was collected at a centre-of-mass energy of $\\sqrt{s}=8\\,\\mathrm{TeV}$ with the ATLAS detector at the LHC and corresponds to an integrated luminosity of $20.3\\,\\mathrm{fb^{-1}}$. To determine the top quark mass a template method is used based on the distribution of the invariant mass of the lepton and the $b$-tagged jet as estimator. The result of the measurement is $m_{\\mathrm{top}} = 172.2 \\pm 0.7 {\\mathrm{(stat.)}} \\pm 2.0 {\\mathrm{(syst.)}}\\,\\mathrm{GeV}$.

Esch, Hendrik

2014-01-01T23:59:59.000Z

36

Observation of the Top Quark  

DOE R&D Accomplishments (OSTI)

Top quark production is observed in{bar p}p collisions at{radical}s= 1.8 TeV at the Fermilab Tevatron. The Collider Detector at Fermilab (CDF) and D{O} observe signals consistent with t{bar t} to WWb{bar b}, but inconsistent with the background prediction by 4.8{sigma} (CDF), 4.6a (D{O}). Additional evidence for the top quark Is provided by a peak in the reconstructed mass distribution. The kinematic properties of the excess events are consistent with the top quark decay. They measure the top quark mass to be 176{plus_minus}8(stat.){plus_minus}10(sys.) GeV/c{sup 2} (CDF), 199{sub -21}{sup+19}(stat.){plus_minus}22(sys.) GeV/c{sup 2} (D{O}), and the t{bar t} production cross section to be 6.8{sub -2.4}{sup+3.6}pb (CDF), 6.4{plus_minus}2.2 pb (D{O}).

Kim, S. B.

1995-08-00T23:59:59.000Z

37

Virtual corrections to Higgs boson pair production in the large top quark mass limit  

Science Journals Connector (OSTI)

Abstract We calculate the three-loop matching coefficient C H H , required for a consistent description of Higgs boson pair production in gluon fusion through next-to-next-to-leading order QCD in the heavy top quark approximation. We also compute the g g ? H H amplitude in m t ? ? approximation in the full theory and show its consistency with an earlier computation in heavy-top effective theory.

Jonathan Grigo; Kirill Melnikov; Matthias Steinhauser

2014-01-01T23:59:59.000Z

38

Top Quark Production at the Tevatron  

SciTech Connect

The top quark is the most recently discovered of the standard model quarks, and because of its very large mass, studies of the top quark and its interactions are important both as tests of the standard model and searches for new phenomena. In this document, recent results of analyses of top quark production, via both the electroweak and strong interactions, from the CDF and D0 experiments are presented. The results included here utilize a dataset corresponding to up to 6 fb{sup -1} of integrated luminosity, slightly more than half of the dataset recorded by each experiment before the Tevatron was shutdown in September 2011.

Mietlicki, David J.

2011-12-01T23:59:59.000Z

39

Measurement of the top quark mass and top-antitop production cross section from dilepton events at the Collider Detector at Fermilab  

E-Print Network (OSTI)

We present an analysis of dilepton events originating from top-antitop production in proton-antiproton collisions at sqrt{s}=1.8 TeV at the Fermilab Tevatron Collider. The sample corresponds to an integrated luminosity of 109+-7 pb^{-1}. We observe 9 candidate events, with an estimated background of 2.4+-0.5 events. We determine the mass of the top quark to be M_top = 161+-17(stat.)+-10(syst.) GeV/c^2. In addition we measure a top-antitop production cross section of 8.2+4.4-3.4 pb (where M_top = 175 GeV/c^2 has been assumed for the acceptance estimate).

CDF collaboration

1998-02-18T23:59:59.000Z

40

Review of Top Quark Physics Results  

SciTech Connect

As the heaviest known fundamental particle, the top quark has taken a central role in the study of fundamental interactions. Production of top quarks in pairs provides an important probe of strong interactions. The top quark mass is a key fundamental parameter which places a valuable constraint on the Higgs boson mass and electroweak symmetry breaking. Observations of the relative rates and kinematics of top quark final states constrain potential new physics. In many cases, the tests available with study of the top quark are both critical and unique. Large increases in data samples from the Fermilab Tevatron have been coupled with major improvements in experimental techniques to produce many new precision measurements of the top quark. The first direct evidence for electroweak production of top quarks has been obtained, with a resulting direct determination of V{sub tb}. Several of the properties of the top quark have been measured. Progress has also been made in obtaining improved limits on potential anomalous production and decay mechanisms. This review presents an overview of recent theoretical and experimental developments in this field. We also provide a brief discussion of the implications for further efforts.

Kehoe, R.; Narain, M.; Kumar, A.; ,

2007-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "top quark mass" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Top quark physics at CDF  

SciTech Connect

We present the recent results of top-quark physics using up to 6 fb{sup -1} of p{bar p} collisions analyzed by the CDF collaboration. The large number of top quark events analyzed, of the order of several thousands, allows stringent checks of the standard model predictions. Also, the top quark is widely believed to be a window to new physics. We present the latest measurements of top quark intrinsic properties as well as direct searches for new physics in the top sector.

Potamianos, Karolos

2011-12-01T23:59:59.000Z

42

The Top Quark, QCD, And New Physics.  

DOE R&D Accomplishments (OSTI)

The role of the top quark in completing the Standard Model quark sector is reviewed, along with a discussion of production, decay, and theoretical restrictions on the top quark properties. Particular attention is paid to the top quark as a laboratory for perturbative QCD. As examples of the relevance of QCD corrections in the top quark sector, the calculation of e{sup+}e{sup -}+ t{bar t} at next-to-leading-order QCD using the phase space slicing algorithm and the implications of a precision measurement of the top quark mass are discussed in detail. The associated production of a t{bar t} pair and a Higgs boson in either e{sup+}e{sup -} or hadronic collisions is presented at next-to-leading-order QCD and its importance for a measurement of the top quark Yulrawa coupling emphasized. Implications of the heavy top quark mass for model builders are briefly examined, with the minimal supersymmetric Standard Model and topcolor discussed as specific examples.

Dawson, S.

2002-06-00T23:59:59.000Z

43

Production and decay of heavy top quarks  

SciTech Connect

Experimental evidence indicates that the top quark exists and has a mass between 50 and 200 GeV/c{sup 2}. The decays of a top quark with a mass in this range are studied with emphasis placed on the mass region near the threshold for production of real W bosons. Topics discussed are: (1) possible enhancement of strange quark production when M{sub W} + m{sub s} < m{sub t} < M{sub W} + m{sub b}; (2) exclusive decays of T mesons to B and B{asterisk} mesons using the non-relativistic quark model; (3) polarization of intermediate W's in top quark decay as a source of information on the top quark mass. The production of heavy top quarks in an e{sup +}e{sup {minus}} collider with a center-of-mass energy of 2 TeV is studied. The effective-boson approximation for photons, Z{sup 0}'s and W's is reviewed and an analogous approximation for interfaces between photons and Z{sup 0}'s is developed. The cross sections for top quark pair production from photon-photon, photon-Z{sup 0}, Z{sup 0}Z{sup 0}, and W{sup +}W{sup {minus}} fusion are calculated using the effective-boson approximation. Production of top quarks along with anti-bottom quarks via {gamma}W{sup +} and Z{sup 0}W{sup +} fusion is studied. An exact calculation of {gamma}e{sup +} {yields} {bar {nu}}t{bar b} is made and compared with the effective-W approximation. 31 refs., 46 figs.

Kauffman, R.P.

1989-08-01T23:59:59.000Z

44

Measurements of top quark properties at the Tevatron collider  

SciTech Connect

The discovery of the top quark in 1995 opened a whole new sector of investigation of the Standard Model; today top quark physics remains a key priority of the Tevatron program. Some of the measurements of top quark properties, for example its mass, will be a long-standing legacy. The recent evidence of an anomalously large charge asymmetry in top quark events suggests that new physics could couple preferably with top quarks. I will summarize this long chapter of particle physics history and discuss the road the top quark is highlighting for the LHC program.

Margaroli, Fabrizio

2011-05-01T23:59:59.000Z

45

Review of recent top-quark LHC combinations  

E-Print Network (OSTI)

A review of recent combinations of top-quark measurements performed at the LHC, by the ATLAS and CMS collaborations, is provided. The typical uncertainty categorisations, and their assumed correlation patterns are presented, together with the results of the combinations of the top-quark pair and single top-quark production cross sections, the top-quark mass, as well as of the $W$ boson polarisation and the charge asymmetry in $t\\bar t$ events.

Cortiana, Giorgio

2014-01-01T23:59:59.000Z

46

Top-Quark Mass Data and the Sum of Quasi-Degenerate Neutrino Masses (One small electroweak-bound e-parameter organizes elementary particle 3-flavor phenomenology)  

E-Print Network (OSTI)

The absolute neutrino masses and type of neutrino mass hierarchy are among the main problems in neutrino physics. Top-quark mass is another topical problem in particle physics. These problems extend the old puzzle of electron-muon mass ratio close to the fine structure constant, which is still not solved by known theory. Here I continue the search for a general flavor pattern that may incorporate these problems. Relations between neutrino/electron and electron/top-quark pole mass ratios are obtained from supposition that realistic elementary particle dimensionless bare flavor quantities are small deviated (measured by universal parameter e) from the values of a stated flavor pattern (at e=0) and experimental data hints. With the world average t-quark mass data the sum of QD-neutrino masses is estimated (0.50 +- 0.003)eV in agreement with cosmological constraints and known QD-neutrino mass estimations from experimental data on neutrino oscillation mass-squared differences.

E. M. Lipmanov

2008-10-01T23:59:59.000Z

47

Top quark properties at ATLAS  

E-Print Network (OSTI)

The ATLAS potential for the study of the top quark properties and physics beyond the Standard Model in the top quark sector, is described. The measurements of the top quark charge, the spin and spin correlations, the Standard Model decay (t-> bW), rare top quark decays associated to flavour changing neutral currents (t-> qX with X = gluon, Z, photon) and ttbar resonances are discussed. The sensitivity of the ATLAS experiment is estimated for an expected luminosity of 1fb-1 at the LHC. The full simulation of the ATLAS detector is used. For the Standard Model measurements the expected precision is presented. For the tests of physics beyond the Standard Model, the 5 sigma discovery potential (in the presence of a signal) and the 95% Confidence Level (CL) limit (in the absence of a signal) are given.

Dilip Jana; for the ATLAS Collaboration

2008-10-20T23:59:59.000Z

48

Top quark charge asymmetry measurements with ATLAS detector  

E-Print Network (OSTI)

The top quark charge asymmetry measurements performed with ATLAS detector at a centre-of-mass energy of 7 TeV are presented.

U. De Sanctis; for the ATLAS Collaboration

2014-11-13T23:59:59.000Z

49

Top quark charge asymmetry measurements with ATLAS detector  

E-Print Network (OSTI)

The top quark charge asymmetry measurements performed with ATLAS detector at a centre-of-mass energy of 7 TeV are presented.

De Sanctis, Umberto; The ATLAS collaboration

2014-01-01T23:59:59.000Z

50

Top quark production at ATLAS and CMS  

E-Print Network (OSTI)

A review of the main recent results on top quark production from the ATLAS and CMS experiments is presented. Results on both electroweak single top quark production and strong top pair production are presented.

Luca Lista; on behalf of the ATLAS; CMS collaborations

2014-05-20T23:59:59.000Z

51

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

SciTech Connect

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.

Aaltonen, T [Helsinki Inst. of Phys.; Alvarez Gonzalez, B [Oviedo U., Cantabria Inst. of Phys.; Amerio, S [INFN, Padua; Amidei, D [Michigan U.; Anastassov, A [Northwestern U.; Annovi, A [Frascati

2011-10-14T23:59:59.000Z

52

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

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.

Aaltonen, T [Helsinki Inst. of Phys.; Alvarez Gonzalez, B [Oviedo U., Cantabria Inst. of Phys.; Amerio, S [INFN, Padua; Amidei, D [Michigan U.; Anastassov, A [Northwestern U.; Annovi, A [Frascati

2011-10-14T23:59:59.000Z

53

Top quark jets at the LHC  

Science Journals Connector (OSTI)

We investigate the reconstruction of high pT hadronically decaying top quarks at the Large Hadron Collider. One of the main challenges in identifying energetic top quarks is that the decay products become increasingly collimated. This reduces the efficacy of conventional reconstruction methods that exploit the topology of the top quark decay chain. We focus on the cases where the decay products of the top quark are reconstructed as a single jet, a “top jet.” The most basic “top-tagging” method based on jet mass measurement is considered in detail. To analyze the feasibility of the top-tagging method, both theoretical and experimental aspects of the large QCD jet background contribution are examined. Based on a factorization approach, we derive a simple analytic approximation for the shape of the QCD jet mass spectrum. We observe very good agreement with the Monte Carlo simulation. We consider high-pT tt¯ production in the standard model as an example, and show that our theoretical QCD jet mass distributions can efficiently characterize the background via sideband analyses. We show that with 25??fb-1 of data, our approach allows us to resolve top jets with pT?1??TeV, from the QCD background, and about 1.5 TeV top jets with 100??fb-1, without relying on b-tagging. To further improve the significance we consider jet shapes (recently analyzed in 10), which resolve the substructure of energy flow inside cone jets. A method of measuring the top quark polarization by using the transverse momentum of the bottom quark is also presented. The main advantages of our approach are (i) the mass distributions are driven by first principle calculations, instead of relying solely on Monte Carlo simulation; (ii) for high pT jets (pT?1??TeV), IR-safe jet shape variables are robust against detector resolution effects. Our analysis can be applied to other boosted massive particles such as the electroweak gauge bosons and the Higgs.

Leandro G. Almeida; Seung J. Lee; Gilad Perez; Ilmo Sung; Joseph Virzi

2009-04-16T23:59:59.000Z

54

Measurement of the Top Quark Mass and ppbar -> ttbar Cross Section in the All-Hadronic Mode with the CDFII Detector  

SciTech Connect

We present a measurement of the top quark mass and of the top-antitop pair production cross section using p{bar p} data collected with the CDF II detector at the Tevatron Collider at the Fermi National Accelerator Laboratory and corresponding to an integrated luminosity of 2.9 fb{sup -1}. We select events with six or more jets satisfying a number of kinematical requirements imposed by means of a neural network algorithm. At least one of these jets must originate from a b quark, as identified by the reconstruction of a secondary vertex inside the jet. The mass measurement is based on a likelihood fit incorporating reconstructed mass distributions representative of signal and background, where the absolute jet energy scale (JES) is measured simultaneously with the top quark mass. The measurement yields a value of 174.8 {+-} 2.4(stat+JES){sub -1.0}{sup +1.2}(syst)GeV/c{sup 2}, where the uncertainty from the absolute jet energy scale is evaluated together with the statistical uncertainty. The procedure measures also the amount of signal from which we derive a cross section, {sigma}{sub t{bar t}} = 7.2 {+-} 0.5(stat) {+-} 1.0(syst) {+-} 0.4(lum) pb, for the measured values of top quark mass and JES.

Aaltonen, T.; /Helsinki Inst. of Phys.; Adelman, J.; /Chicago U., EFI; Alvarez Gonzalez, B.; /Cantabria Inst. of Phys.; Amerio, S.; /INFN, Padua; Amidei, D.; /Michigan U.; Anastassov, A.; /Northwestern U.; Annovi, A.; /Frascati; Antos, J.; /Comenius U.; Apollinari, G.; /Fermilab; Appel, J.; /Fermilab; Apresyan, A.; /Purdue U. /Waseda U.

2010-02-01T23:59:59.000Z

55

Measurement of the Top Quark Mass using Dilepton Events and a Neutrino Weighting Algorithm with the D0 Experiment at the Tevatron (Run II)  

SciTech Connect

Elementary particle physics raises questions that are several thousand years old. What are the fundamental components of matter and how do they interact? These questions are linked to the question of what happened in the very first moments after the creation of the universe. Modern physics systematically tests nature to find answers to these and other fundamental questions. Precise theories are developed that describe various phenomena and at the same time are reduced to a few basic principals of nature. Simplification and reduction have always been guiding concepts of physics. The interplay between experimental data and theoretical descriptions led to the Standard Model of elementary particle physics. It summarizes the laws of nature and is one of most precise descriptions of nature achieved by mankind. Despite the great success of the Standard Model it is not the ultimate theory of everything. Models beyond the Standard Model try to unify all interactions in one grand unified theory. The number of free parameters is attempted to be reduced. Gravity is attempted to be incorporated. Extensions to the Standard Model like supersymmetry address the so-called hierarchy problem. Precision measurements are the key for searches of new particles and new physics. A powerful tool of experimental particle physics are particle accelerators. They provide tests of the Standard Model at smallest scales. New particles are produced and their properties are investigated. In 1995 the heaviest known elementary particle, called top quark, has been discovered at Fermilab. It differs from all other lighter quarks due to the high mass and very short lifetime. This makes the top quark special and an interesting object to be studied. A rich program of top physics at Fermilab investigates whether the top quark is really the particle as described by the Standard Model. The top quark mass is a free parameter of the theory that has been measured precisely. This thesis presents a precise measurement of the top quark mass by the D0 experiment at Fermilab in the dilepton final states. The comparison of the measured top quark masses in different final states allows an important consistency check of the Standard Model. Inconsistent results would be a clear hint of a misinterpretation of the analyzed data set. With the exception of the Higgs boson, all particles predicted by the Standard Model have been found. The search for the Higgs boson is one of the main focuses in high energy physics. The theory section will discuss the close relationship between the physics of the Higgs boson and the top quark.

Meyer, Joerg; /Bonn U.

2007-01-01T23:59:59.000Z

56

A Measurement of the mass of the Top Quark in the di-lepton channels using the D0 Detector at Fermilab  

SciTech Connect

This dissertation describes a measurement of the mass of the top quark using events consistent with the hypothesis t{bar t} {yields} bW{sup +} {bar b}W{sup -} {yields} bl{sup +}{nu}{bar b}l{sup -}{bar {nu}}, where (l=e,{mu}). The events are obtained from nearly 230 pb{sup -1} of p{bar p} collision data collected by the D0 experiment between 2002 and 2004 during Run II. In this decay channel two neutrinos remain undetected. Extraction of the mass of the top quark by kinematic reconstruction is not possible because the event is under-constrained. Therefore, a dynamical likelihood method is developed to obtain the mass of the top quark. The mass of top quark obtained from the candidate events selected in the di-electron channel and the e{mu} channel is: 154.1 {sup +14.2}{sub -12.8}(stat.) {+-}6.6 (syst.) GeV.

Fatakia, Sarosh Noshir; /Boston U.; ,

2005-01-01T23:59:59.000Z

57

Top Quark Production at the LHC  

E-Print Network (OSTI)

Top quark production in proton proton collisions at the Large Hadron Collider (LHC) is reviewed using data collected by the ATLAS and CMS detectors. Most recent results on searches for new physics related to top quark production mechanism are included.

Francesco Spanò; for the ATLAS; CMS collaborations

2011-12-16T23:59:59.000Z

58

Top quark physics at the LHC  

E-Print Network (OSTI)

The physics perspectives of the production and decay of single top quarks and top quark pairs at the CERN Large Hadron Collider (LHC) are reviewed from a phenomenological point of view.

Werner Bernreuther

2008-05-09T23:59:59.000Z

59

Evidence for a Mass Dependent Forward-Backward Asymmetry in Top Quark Pair Production  

SciTech Connect

We present a new measurement of the inclusive forward-backward t{bar t} production asymmetry and its rapidity and mass dependence. The measurements are performed with data corresponding to an integrated luminosity of 5.3 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV, recorded with the CDF II Detector at the Fermilab Tevatron. Significant inclusive asymmetries are observed in both the laboratory frame and the t{bar t} rest frame, and in both cases are found to be consistent with CP conservation under interchange of t and {bar t}. In the t{bar t} rest frame, the asymmetry is observed to increase with the t{bar t} rapidity difference, {Delta}y, and with the invariant mass M{sub t{bar t}} of the t{bar t} system. Fully corrected parton-level asymmetries are derived in two regions of each variable, and the asymmetry is found to be most significant at large {Delta}y and M{sub t{bar t}}. For M{sub t{bar t}} {ge} 450 GeV/c{sup 2}, the parton-level asymmetry in the t{bar t} rest frame is A{sup t{bar t}} = 0.475 {+-} 0.114 compared to a next-to-leading order QCD prediction of 0.088 {+-} 0.013.

Aaltonen, T.; /Helsinki Inst. of Phys.; Alvarez Gonzalez, B.; /Cantabria Inst. of Phys.; Amerio, S.; /INFN, Padua; Amidei, D.; /Michigan U.; Anastassov, A.; /Northwestern U.; Annovi, A.; /Frascati; Antos, J.; /Comenius U.; Apollinari, G.; /Fermilab; Appel, J.A.; /Fermilab; Apresyan, A.; /Purdue U.; Arisawa, T.; /Waseda U. /Dubna, JINR

2011-01-01T23:59:59.000Z

60

Top quark physics expectations at the LHC  

E-Print Network (OSTI)

The top quark will be produced copiously at the LHC. This will make both detailed physics studies and the use of top quark decays for detector calibration possible. This talk reviews plans and prospects for top physics activities in the ATLAS and CMS experiments.

Andrei Gaponenko; for the ATLAS Collaboration; for the CMS Collaboration

2008-10-22T23:59:59.000Z

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to obtain the most current and comprehensive results.


61

Measurement of the Top Quark Mass at D0 Run II with the Matrix Element Method in the Lepton+Jets Final State  

SciTech Connect

The mass of the top quark is a fundamental parameter of the Standard Model. Its precise knowledge yields valuable insights into unresolved phenomena in and beyond the Standard Model. A measurement of the top quark mass with the matrix element method in the lepton+jets final state in D0 Run II is presented. Events are selected requiring an isolated energetic charged lepton (electron or muon), significant missing transverse energy, and exactly four calorimeter jets. For each event, the probabilities to originate from the signal and background processes are calculated based on the measured kinematics, the object resolutions and the respective matrix elements. The jet energy scale is known to be the dominant source of systematic uncertainty. The reference scale for the mass measurement is derived from Monte Carlo events. The matrix element likelihood is defined as a function of both, m{sub top} and jet energy scale JES, where the latter represents a scale factor with respect to the reference scale. The top mass is obtained from a two-dimensional correlated fit, and the likelihood yields both the statistical and jet energy scale uncertainty. Using a dataset of 320 pb{sup -1} of D0 Run II data, the mass of the top quark is measured to be: m{sub top}{sup {ell}+jets} = 169.5 {+-} 4.4(stat. + JES){sub -1.6}{sup +1.7}(syst.) GeV; m{sub top}{sup e+jets} = 168.8 {+-} 6.0(stat. + JES){sub -1.9}{sup +1.9}(syst.) GeV; m{sub top}{sup {mu}+jets} = 172.3 {+-} 9.6(stat.+JES){sub -3.3}{sup +3.4}(syst.) GeV. The jet energy scale measurement in the {ell}+jets sample yields JES = 1.034 {+-} 0.034, suggesting good consistency of the data with the simulation. The measurement forecasts significant improvements to the total top mass uncertainty during Run II before the startup of the LHC, as the data sample will grow by a factor of ten and D0's tracking capabilities will be employed in jet energy reconstruction and flavor identification.

Schieferdecker, Philipp; /Munich U.; ,

2005-08-01T23:59:59.000Z

62

Gluon Radiation and Energy Losses in Top Quark Production  

E-Print Network (OSTI)

The emission of energetic gluons in $\\tt$ production in $\\ee$ annihilation can have important experimental consequences, in particular on top quark mass measurements. We present compact, analytical expressions for the gluon energy distribution and its average value at first order in QCD perturbation theory. Our results are valid for arbitrary masses, collision energies and production currents. We pay particular attention to top quark production near threshold, and show that in certain cases the soft gluon approximation is insufficient to describe the radiation spectrum.

Yu. L. Dokshitzer; V. A. Khoze; W. J. Stirling

1994-05-06T23:59:59.000Z

63

Measurement of the Top Quark Mass with the Dynamical Likelihood Method using Lepton plus Jets Events with b-tags in ppbar Collisions at s**(1/2) = 1.96 TeV  

E-Print Network (OSTI)

This report describes a measurement of the top quark mass, M_{top}, with the dynamical likelihood method (DLM) using the CDF II detector at the Fermilab Tevatron. The Tevatron produces top/anti-top pairs in protons and anti-protons collisions at a center-of-mass energy of 1.96 TeV. The data sample used in this analysis was accumulated from March 2002 through August 2004, which corresponds to an integrated luminosity of 318 pb^{-1}. We use the top/anti-top candidates in the ``lepton+jets'' decay channel, requiring at least one jet identified as a b quark by finding a displaced secondary vertex. The DLM defines a likelihood for each event based on the differential cross section as a function of M_{top} per unit phase space volume of the final partons, multiplied by the transfer functions from jet to parton energies. The method takes into account all possible jet combinations in an event, and the likelihood is multiplied event by event to derive the top quark mass by the maximum likelihood method. Using 63 top quark candidates observed in the data, with 9.2 events expected from background, we measure the top quark mass to be 173.2 +2.6/-2.4 (stat.) +/- 3.2 (syst.) GeV/c^2, or 173.2 +4.1/-4.0 GeV/c^2.

CDF Collaboration

2005-12-05T23:59:59.000Z

64

CP violation in top-quark physics  

E-Print Network (OSTI)

In this talk I review how to search for CP violation in top-quark pair production and decay using T-odd correlations. I discuss two examples which illustrate many of the relevant features: CP violation in a heavy neutral Higgs boson; and CP violating anomalous top-quark couplings. I present some numerical results for the LHC and some for the Tevatron.

German Valencia

2010-07-27T23:59:59.000Z

65

Observation of $t$-channel electroweak top quark production  

SciTech Connect

The top quark is the heaviest known fundamental particle, with a mass of 172.0{sub -1.3}{sup +0.9}GeV. This is nearly twice the mass of the second heaviest known particle, the Z boson, and roughly the mass of a gold atom. Because of its unusually large mass, studying the top quark may provide insight into the Higgs mechanism and other beyond the standard model physics. Only two accelerators in the world are powerful enough to produce top quarks. The Tevatron, which first accelerated protons in 1983, has produced almost 400,000 top quarks, roughly half at each of its two detectors: DO and CDF. The LHC is a much newer accelerator which currently has accumulated about 0.5% as much data as the Tevatron. However, when running at full luminosity, the LHC is capable of producing a top quark about once every second and will quickly surpass the Tevatron as the leading producer of top quarks. This analysis uses data from the D0 detector at the Tevatron, which are described in chapter 3. Top quarks are produced most often in pairs of top and anti-top quarks through an interaction of the strong force. This production mode was first observed in 1995 at the Tevatron. However, top quarks can also be produced though an electroweak interaction, which produces just one top quark. This production mode was first observed at the Tevatron in 2008. Single top quark production can occur in different channels. In this analysis, a measurement of the cross section of the t-channel production mode is performed. This measurement uses 5.4 fb{sup -1} of data and uses the technique of boosted decision trees in order to separate signal from background events. The t-channel cross section is measured to be: {sigma}(p{bar p} {yields} tqb + X) = 3.03{sub -0.66}{sup +0.78}pb (0.0.1). Additional cross section measurements were also performed for the s-channel as well as the s + t-channel. The measurement of each one of these three cross sections was repeated three times using different techniques, and all three methods were combined into a 'super-method' which achieves the best performance. The details of these additional measurements are shown in appendix A.

Triplett, Nathan; /Iowa State U.

2011-04-01T23:59:59.000Z

66

Measurement of the front back asymmetry in top-antitop quark pairs produced in proton-antiproton collisions at center of mass energy = 1.96 TeV  

SciTech Connect

Quarks, along with leptons and force carrying particles, are predicted by the Standard Model to be the fundamental constituents of nature. In distinction from the leptons, the quarks interact strongly through the chromodynamic force and are bound together within the hadrons. The familiar proton and neutron are bound states of the light ''up'' and ''down'' quarks. The most massive quark by far, the ''top'' quark, was discovered by the CDF and D0 experiments in March, 1995. The new quark was observed in p{bar p} collisions at 1.8 TeV at the Fermilab Tevatron. The mass of the top quark was measured to be 176 {+-} 13 GeV/c{sup 2} and the cross section 6.8{sub -2.4}{sup +3.6} pb. It is the Q = 2/3, T{sub 3} = +1/2 member of the third generation weak-isospin doublet along with the bottom quark. The top quark is the final Standard Model quark to be discovered. Along with whatever is responsible for electroweak symmetry breaking, top quark physics is considered one of the least understood sectors of the Standard Model and represents a front line of our understanding of particle physics. Currently, the only direct measurements of top quark properties come from the CDF and D0 experiments observing p{bar p} collisions at the Tevatron. Top quark production at the Tevatron is almost exclusively by quark-antiquark annihilation, q{bar q} {yields} t{bar t} (85%), and gluon fusion, gg {yields} t{bar t} (15%), mediated by the strong force. The theoretical cross-section for this process is {sigma}{sub t{bar t}} = 6.7 {+-} 0.8 pb for m{sub t} = 175 GeV/c{sup 2}. Top quarks can also be produced at the Tevatron via q{bar b}{prime} {yields} tb and qg {yields} q{prime}tb through the weak interaction. The cross section for these processes is lower (3pb) and the signal is much more difficult to isolate as backgrounds are much higher. The top quark is predicted to decay almost exclusively into a W-boson and a bottom quark (t {yields} Wb). The total decay width t {yields} Wb is {Lambda} = 1.50 GeV. This corresponds to an incredibly short lifetime of 0.5 x 10{sup -24} seconds. This happens so quickly that hadronization and bound states do not take place, which leads to the interesting consequence that the top quark spin information is passed to the decay products.

Schwarz, Thomas A.; /Michigan U.

2006-01-01T23:59:59.000Z

67

Top Quark Properties from Top Pair Events and Decays  

SciTech Connect

Over a decade since the discovery of the top quark we are still trying to unravel mysteries of the heaviest observed particle and learn more about its nature. The continuously accumulating statistics of CDF and DO data provide the means for measuring top quark properties with ever greater precision and the opportunity to search for signs of new physics that could be manifested through subtle deviations from the standard model in the production and decays of top quarks. In the following we present a slice of the rich program in top quark physics at the Fermilab Tevatron: measurements of the properties of top quark decays and searches for unusual phenomena in events with pair produced tops. In particular, we discuss the most recent and precise CDF and DO measurements of the transverse polarization of W bosons from top decays, branching ratios and searches for flavor-changing neutral current decays, decays into charged Higgs and invisible decays. These analyses correspond to integrated luminosities ranging from 0.9 to 2.7 fb{sup -1}.

Ivanov, A.; /UC, Davis

2008-11-01T23:59:59.000Z

68

Press Pass - Press Release - Single top quark  

NLE Websites -- All DOE Office Websites (Extended Search)

9-04 9-04 March 9, 2009 For immediate release Media Contacts: Judy Jackson, Fermilab, +1-630-840-3351, jjackson@fnal.gov Kurt Riesselmann, Fermilab, +1-630-840-3351, kurtr@fnal.gov Graphics and photos are available at: http://www.fnal.gov/pub/presspass/images/Single-Top-Quark-2009.html Fermilab collider experiments discover rare single top quark Batavia, Ill.-Scientists of the CDF and DZero collaborations at the Department of Energy's Fermi National Accelerator Laboratory have observed particle collisions that produce single top quarks. The discovery of the single top confirms important parameters of particle physics, including the total number of quarks, and has significance for the ongoing search for the Higgs particle at Fermilab's Tevatron, currently the world's most powerful operating particle accelerator.

69

Observation of the top quark with the DO detector  

SciTech Connect

The DO Collaboration reports on the observation of the top quark in p{bar p} collisions at {radical}s = 1.8 TeV at the Fermilab Tevatron. We measure the top quark mass to be 199{sub -21}{sup -19}(stat){sub -21}{sup +14}(syst.) GeV/c{sup 2} and its production cross section to be 6.4 {+-}2.2 pb. Our result is based on approximately 50 pb{sup -1} of data. We observe 17 events with an expected background of 3.8 {+-} 0.6 events. The probability of an upward fluctuation of the background to produce the observed signal is 2 x 10{sup -6} (equivalent to 4.6 standard deviations). The kinematic properties of the events are consistent with top quark decay, and the distribution of events across the seven decay channels is consistent with the Standard Model top quark branching fractions. We describe the analysis that led to the observation of the top quark as well as the properties of the top quark events.

Hadley, N.J. [Univ. of Maryland, College Park, MD (United States)

1997-01-01T23:59:59.000Z

70

Evidence for production of single top quarks  

Science Journals Connector (OSTI)

We present first evidence for the production of single top quarks in the D0 detector at the Fermilab Tevatron pp¯ collider. The standard model predicts that the electroweak interaction can produce a top quark together with an antibottom quark or light quark, without the antiparticle top-quark partner that is always produced from strong-coupling processes. Top quarks were first observed in pair production in 1995, and since then, single top-quark production has been searched for in ever larger data sets. In this analysis, we select events from a 0.9??fb-1 data set that have an electron or muon and missing transverse energy from the decay of a W boson from the top-quark decay, and two, three, or four jets, with one or two of the jets identified as originating from a b hadron decay. The selected events are mostly backgrounds such as W+jets and tt¯ events, which we separate from the expected signals using three multivariate analysis techniques: boosted decision trees, Bayesian neural networks, and matrix-element calculations. A binned likelihood fit of the signal cross section plus background to the data from the combination of the results from the three analysis methods gives a cross section for single top-quark production of ?(pp¯?tb+X,tqb+X)=4.7±1.3??pb. The probability to measure a cross section at this value or higher in the absence of signal is 0.014%, corresponding to a 3.6 standard deviation significance. The measured cross section value is compatible at the 10% level with the standard model prediction for electroweak top-quark production. We use the cross section measurement to directly determine the Cabibbo-Kobayashi-Maskawa quark mixing matrix element that describes the Wtb coupling and find |Vtbf1L|=1.31-0.21+0.25, where f1L is a generic vector coupling. This model-independent measurement translates into 0.68<|Vtb|?1 at the 95% C.L. in the standard model.

V. M. Abazov et al. (The D0 Collaboration)

2008-07-14T23:59:59.000Z

71

Uncovering the single top: observation of electroweak top quark production  

SciTech Connect

The top quark is generally produced in quark and anti-quark pairs. However, the Standard Model also predicts the production of only one top quark which is mediated by the electroweak interaction, known as 'Single Top'. Single Top quark production is important because it provides a unique and direct way to measure the CKM matrix element V{sub tb}, and can be used to explore physics possibilities beyond the Standard Model predictions. This dissertation presents the results of the observation of Single Top using 2.3 fb{sup -1} of Data collected with the D0 detector at the Fermilab Tevatron collider. The analysis includes the Single Top muon+jets and electron+jets final states and employs Boosted Decision Tress as a method to separate the signal from the background. The resulting Single Top cross section measurement is: (1) {sigma}(p{bar p} {yields} tb + X, tqb + X) = 3.74{sub -0.74}{sup +0.95} pb, where the errors include both statistical and systematic uncertainties. The probability to measure a cross section at this value or higher in the absence of signal is p = 1.9 x 10{sup -6}. This corresponds to a standard deviation Gaussian equivalence of 4.6. When combining this result with two other analysis methods, the resulting cross section measurement is: (2) {sigma}(p{bar p} {yields} tb + X, tqb + X) = 3.94 {+-} 0.88 pb, and the corresponding measurement significance is 5.0 standard deviations.

Benitez, Jorge Armando; /Michigan State U.

2009-08-01T23:59:59.000Z

72

Top Quark Physics at the LHC  

E-Print Network (OSTI)

An overview of the prospects of top quark physics at the LHC is presented. The ATLAS and the CMS detectors are about to produce a large amount of data with high top quark contents from the LHC proton-proton collisions. A wide variet y of physics analyses is planned in both experiments, and a number of useful insights have already been obtained regarding their detector performance and physics potential. This summary is based on the talk presented at the Hadron C ollider Physics Symposium 2008, Galena, Illinois, May 27-31, 2008.

Akira Shibata

2008-07-31T23:59:59.000Z

73

Measurement of the top quark mass with the dynamical likelihood method using lepton plus jets events with b-tags in pp¯ collisions at s=1.96??TeV  

Science Journals Connector (OSTI)

This paper describes a measurement of the top quark mass, Mtop, with the dynamical likelihood method (DLM) using the CDF II detector at the Fermilab Tevatron. The Tevatron produces top/antitop (tt¯) pairs in pp¯ collisions at a center-of-mass energy of 1.96 TeV. The data sample used in this analysis was accumulated from March 2002 through August 2004, which corresponds to an integrated luminosity of 318??pb-1. We use the tt¯ candidates in the “lepton+jets” decay channel, requiring at least one jet identified as a b quark by finding a displaced secondary vertex. The DLM defines a likelihood for each event based on the differential cross section as a function of Mtop per unit phase space volume of the final partons, multiplied by the transfer functions from jet to parton energies. The method takes into account all possible jet combinations in an event, and the likelihood is multiplied event by event to derive the top quark mass by the maximum likelihood method. Using 63 tt¯ candidates observed in the data, with 9.2 events expected from background, we measure the top quark mass to be 173.2+2.6-2.4(stat.)±3.2(syst.)??GeV/c2, or 173.2+4.1-4.0??GeV/c2.

A. Abulencia et al. (CDF Collaboration)

2006-05-10T23:59:59.000Z

74

Top quark pair cross section prospects in ATLAS  

E-Print Network (OSTI)

The observation of the top quark will be an important milestone in ATLAS. This talk reviews methods that ATLAS plans to use to observe the top quark pair production process and measure its cross section.

Andrei Gaponenko; for the ATLAS Collaboration

2009-10-20T23:59:59.000Z

75

Calculation of the cross section for top quark production  

SciTech Connect

The authors summarize calculations of the cross section for top quark production at hadron colliders within the context of perturbative quantum chromodynamics, including resummation of the effects of initial-state soft gluon radiation to all orders in the strong coupling strength. In their approach they resume the universal leading-logarithm contributions, and they restrict the calculation to the region of phase space that is demonstrably perturbative. They compare the approach with other methods. They present predictions of the physical cross section as a function of the top quark mass in proton-antiproton reactions at center-of-mass energies of 1.8 and 2.0 TeV, and they discuss estimated uncertainties.

Berger, E.L.; Contopanagos, H. [Argonne National Lab., IL (United States). High Energy Physics Div.

1996-06-21T23:59:59.000Z

76

Determination of the top-quark pole mass and strong coupling constant from the t t-bar production cross section in pp collisions at sqrt(s) = 7 TeV  

E-Print Network (OSTI)

The inclusive cross section for top-quark pair production measured by the CMS experiment in proton-proton collisions at a center-of-mass energy of 7 TeV is compared to the QCD prediction at next-to-next-to-leading order with various parton distribution functions to determine the top-quark pole mass, mtpole, or the strong coupling constant, alphaS. With the parton distribution function set NNPDF2.3, a pole mass of 176.7 +3.0 -2.8 GeV is obtained when constraining alphaS at the scale of the Z boson mass, mZ, to the current world average. Alternatively, by constraining mtpole to the latest average from direct mass measurements, a value of alphaS(mZ) = 0.1151 +0.0028 -0.0027 is extracted. This is the first determination of alphaS using events from top-quark production.

CMS Collaboration

2014-08-20T23:59:59.000Z

77

Supersymmetric electroweak corrections to top quark production at the Fermilab Tevatron  

Science Journals Connector (OSTI)

We calculate the genuine supersymmetric electroweak corrections of order ?mt2/mW2, which arise from loops of the chargino, neutralino, and squark, to top quark production at the Fermilab Tevatron in the minimal supersymmetric model. The observable hadronic cross section can be enhanced by 20% for a top quark mass of 170 GeV and squark mass of 100 GeV. When the squark mass gets larger, the corrections decrease rapidly.

Jin Min Yang and Chong Sheng Li

1995-08-01T23:59:59.000Z

78

Top Quark Studies with the first CMS Data  

E-Print Network (OSTI)

Studies are presented of the selection of events consistent with top quark pair production in data recorded by the CMS detector at the LHC, corresponding to an integrated luminosity of 0.84+/-0.09 1/pb and at center-of-mass energy sqrt{s}=7 TeV. Results are presented for the lepton+jets as well as dilepton channels. Event yields in data are compared to those in simulation, and several background processes are estimated using data-driven techniques. The observed yields of top-antitop candidate events are roughly consistent with the Standard Model.

Frank-Peter Schilling

2010-10-12T23:59:59.000Z

79

Search for Single Top Quark Production at HERA  

E-Print Network (OSTI)

A search for single top quark production is performed in the full ep data sample collected by the H1 experiment at HERA, corresponding to an integrated luminosity of 474 pb^-1. Decays of top quarks into a b quark and a W boson with subsequent leptonic or hadronic decay of the W are investigated. A multivariate analysis is performed to discriminate top quark production from Standard Model background processes. An upper limit on the top quark production cross section via flavour changing neutral current processes sigma (ep -> etX) < 0.25 pb is established at 95% CL. Limits on the anomalous coupling kappa_{tu gamma} are derived.

Aaron, F D; Alexa, C; Alimujiang, K; Andreev, V; Antunovic, B; Asmone, A; Backovic, S; Baghdasaryan, A; Barrelet, E; Bartel, W; Begzsuren, K; Belousov, A; Bizot, J C; Boudry, V; Bozovic-Jelisavcic, I; Bracinik, J; Brandt, G; Brinkmann, M; Brisson, V; Bruncko, D; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Cantun Avila, K B; Cassol-Brunner, F; Cerny, K; Cerny, V; Chekelian, V; Cholewa, A; Contreras, J G; Coughlan, J A; Cozzika, G; Cvach, J; Dainton, J B; Daum, K; Deak, M; de Boer, Y; Delcourt, B; Del Degan, M; Delvax, J; De Roeck, A; De Wolf, E A; Diaconu, C; Dodonov, V; Dossanov, A; Dubak, A; Eckerlin, G; Efremenko, V; Egli, S; Eliseev, A; Elsen, E; Falkiewicz, A; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Fischer, D J; Fleischer, M; Fomenko, A; Gabathuler, E; Gayler, J; Ghazaryan, S; Glazov, A; Glushkov, I; Goerlich, L; Gogitidze, N; Gouzevitch, M; Grab, C; Greenshaw, T; Grell, B R; Grindhammer, G; Habib, S; Haidt, D; Helebrant, C; Henderson, R C W; Hennekemper, E; Henschel, H; Herbst, M; Herrera, G; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R; Hreus, T; Jacquet, M; Janssen, M E; Janssen, X; Jonsson, L; Jung, Andreas Werner; Jung, H; Kapichine, M; Katzy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Kluge, T; Knutsson, A; Kogler, R; Kostka, P; Kraemer, M; Krastev, K; Kretzschmar, J; Kropivnitskaya, A; Kruger, K; Kutak, K; Landon, M P J; Lange, W; Lastovicka-Medin, G; Laycock, P; Lebedev, A; Leibenguth, G; Lendermann, V; Levonian, S; Li, G; Lipka, K; Liptaj, A; List, B; List, J; Loktionova, N; Lopez-Fernandez, R; Lubimov, V; Lytkin, L; Makankine, A; Malinovski, E; Marage, P; Marti, Ll; Martyn, H U.; Maxfield, S J; Mehta, A; Meyer, A B; Meyer, H; Meyer, H; Meyer, J; Michels, V; Mikocki, S; Milcewicz-Mika, I; Moreau, F; Morozov, A; Morris, J V; Mozer, Matthias Ulrich; Mudrinic, M; Muller, K; Murin, P; Naumann, Th; Newman, P R; Niebuhr, C; Nikiforov, A; Nowak, G; Nowak, K; Nozicka, M; Olivier, B; Olsson, J E; Osman, S; Ozerov, D; Palichik, V; Panagoulias, I; Pandurovic, M; Papadopoulou, Th; Pascaud, C; Patel, G D; Pejchal, O; Perez, E; Petrukhin, A; Picuric, I; Piec, S; Pitzl, D; Placakyte, R; Pokorny, B; Polifka, R; Povh, B; Preda, T; Radescu, V; Rahmat, A J; Raicevic, N; Raspiareza, A; Ravdandorj, T; Reimer, P; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rotaru, M; Ruiz Tabasco, J E; Rurikova, Z; Rusakov, S; Salek, D; Sankey, D P C; Sauter, M; Sauvan, E; Schmitt, S; Schmitz, C; Schoeffel, L; Schoning, A; Schultz-Coulon, H C; Sefkow, F; Shaw-West, R N; Shtarkov, L N; Shushkevich, S; Sloan, T; Smiljanic, Ivan; Soloviev, Y; Sopicki, P; South, D; Spaskov, V; Specka, Arnd E; Staykova, Z; Steder, M; Stella, B; Stoicea, G; Straumann, U.; Sunar, D; Sykora, T; Tchoulakov, V; Thompson, G; Thompson, P D; Toll, T; Tomasz, F; Tran, T H; Traynor, D; Trinh, T N; Truol, P; Tsakov, I; Tseepeldorj, B; Turnau, J; Urban, K; Valkarova, A; Vallee, C; Van Mechelen, P; Vargas Trevino, A; Vazdik, Y; Vinokurova, S; Volchinski, V; von den Driesch, M; Wegener, D; Wissing, Ch; Wunsch, E; Zacek, J; Zalesak, J; Zhang, Z; Zhokin, A; Zimmermann, T; Zohrabyan, H; Zomer, F; Zus, R; 10.1016/j.physletb.2009.06.057

2009-01-01T23:59:59.000Z

80

Search for electroweak single top quark production with CDF  

SciTech Connect

We report on a search for Standard Model t-channel and s-channel single top quark production in p{bar p} collisions at a center of mass energy of 1.96 TeV. We use a data sample corresponding to 162 pb{sup -1} recorded by the upgraded Collider Detector at Fermilab. We find no significant evidence for electroweak top quark production and set upper limits at the 95% confidence level on the production cross section, consistent with the Standard Model: 10.1 pb for the t-channel, 13.6 pb for the s-channel and 17.8 pb for the combined cross section of t- and s-channel.

Kemp, Y.; /Karlsruhe U.

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "top quark mass" from the National Library of EnergyBeta (NLEBeta).
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We encourage you to perform a real-time search of NLEBeta
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81

The Top Quark, Its Discovery, and Subsequent Research  

Office of Scientific and Technical Information (OSTI)

The Top Quark, Its Discovery, and Subsequent Research The Top Quark, Its Discovery, and Subsequent Research Resources with Additional Information 'Ever since the existence of the bottom (or b) quark was inferred from the discovery of the Upsilon family of resonances at Fermilab in 1977, particle physicists have been on the lookout for its partner, called top (or t). The long search, which occupied experimenters at laboratories around the world, came to a successful conclusion in February 1995 with the announcement that the top quark had been observed in two experiments at the Tevatron proton-antiproton collider at Fermilab. ... Top Quark Courtesy Fermilab Top is the last of the fundamental constituents of subnuclear matter that theories of the strong, weak, and electromagnetic interactions and a wealth of experimental information had led particle physicists to expect. Theoretically, top's existence was required to make the electroweak theory internally consistent.'1

82

Dynamical electroweak symmetry breaking and the top quark  

SciTech Connect

In this talk, I discuss theories of dynamical electroweak symmetry breaking, with emphasis on the implications of a heavy top quark on the weak interaction {rho} parameter.

Chivukula, R.S. [Boston Univ., MA (United States)

1997-01-01T23:59:59.000Z

83

Top-mass measurements from D0  

SciTech Connect

We present three recent analyses (Abstracts 169, 170 and 174) of the mass of the top quark (M{sub t}) using top-antitop candidate events collected by the D0 experiment at the Fermilab Tevatron Collider: (i) a 3.6 events/fb sample of data in the lepton+jets channel analyzed to extract a precision value of M{sub t} using the 'Matrix-Element' (ME) method, wherein each event probability is calculated from the differential production cross section as a function of M{sub t} and the overall jet energy scale, with the latter constrained by the two jets from W decay into q{prime}{bar q}, (ii) a first measurement of the mass difference between top and antitop quarks as a check of CPT invariance in the quark sector, also based on the ME method in lepton+jets channels, and corresponding to a 1 event/fb data sample, and (iii) measurements of M{sub t} in dilepton final states (updated to 3.6 events/fb), based on 'matrix' weighting, 'neutrino' weighting and the ME method, which rely, respectively, on the likelihood of observing the events in data for a range of assumed M{sub t} values, distributions generated from event weights that compare calculated and reconstructed missing transverse energies, and event probabilities based on the leading-order differential cross section as a function of assumed M{sub t}. In addition, we provide a combination of recent top-mass measurements from D0.

Ferbel, T.; /Rochester U. /Maryland U.

2009-01-01T23:59:59.000Z

84

Associated production of a top quark and a charged Higgs boson  

Science Journals Connector (OSTI)

We compute the inclusive and differential cross sections for the associated production of a top quark along with a charged Higgs boson at hadron colliders to next-to-leading order (NLO) in perturbative quantum chromodynamics (QCD) and in supersymmetric QCD. For small Higgs boson masses we include top-quark pair production diagrams with subsequent top-quark decay into a bottom quark and a charged Higgs boson. We compare the NLO differential cross sections obtained in the bottom parton picture with those for the gluon-initiated production process and find good agreement. The effects of supersymmetric loop contributions are explored. Only the corrections to the Yukawa coupling are sizable in the potential discovery region at the CERN Large Hadron Collider (LHC). All expressions and numerical results are fully differential, permitting selections on the momenta of both the top quark and the charged Higgs boson.

Edmond L Berger; Tao Han; Jing Jiang; Tilman Plehn

2005-06-28T23:59:59.000Z

85

Search for baryon number violation in top-quark decays  

E-Print Network (OSTI)

A search for baryon number violation (BNV) in top-quark decays is performed using pp collisions produced by the LHC at [sqrt s]=8 TeV. The top-quark decay considered in this search results in one light lepton (muon or ...

CMS Collaboration

86

Search for New Particles Decaying to Dijets, Bottom Quarks, and Top Quarks at CDF  

E-Print Network (OSTI)

We present three searches for new particles at CDF. First, using 70 pb^-1 of data we search the dijet mass spectrum for resonances. There is an upward fluctuation near 550 GeV (2.6 sigma) with an angular distribution that is adequately described by either QCD alone or QCD plus 5% signal. There is insufficient evidence to claim a signal, but we set the most stringent mass limits on the hadronic decays of axigluons, excited quarks, technirhos, W', Z', and E6 diquarks. Second, using 19 pb^-1 of data we search the b-tagged dijet mass spectrum for b anti-b resonances. Again, an upward fluctuation near 600 GeV (2 sigma) is not significant enough to claim a signal, so we set the first mass limits on topcolor bosons. Finally, using 67 pb^-1 of data we search the top quark sample for t anti-t resonances like a topcolor Z'. Other than an insignificant shoulder of 6 events on a background of 2.4 in the mass region 475-550 GeV, there is no evidence for new particle production. Mass limits, currently in progress, should be sensitive to a topcolor Z' near 600 GeV. In all three searches there is insufficient evidence to claim new particle production, yet there is an exciting possibility that the upward fluctuations are the first signs of new physics beyond the standard model.

Robert M. Harris

1995-06-15T23:59:59.000Z

87

Study on the top quark pair production mechanism in 1.96 TeV proton-antiproton collisions  

SciTech Connect

The study of the top quark pair production mechanism in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV is described. The main subjects are the measurements of the top quark pair production cross section, the top quark mass and a search for a new particle decaying to the top quark pair. The analyses are based on 1.9 fb{sup -1} of data collected by the Collider Detector at Fermilab (CDF) Run II experiment between March 2002 and May 2007, using the lepton+jets events. The measured top quark pair production cross section is 8.2 {+-} 0.5 (stat.) {+-} 0.8 (syst.) {+-} 0.5 (lum.) pb, which is slightly higher than the standard model prediction at the top mass of 175 GeV/c{sup 2}. The top quark mass is an important parameter in the standard model, and also in the experimental studies. The measured top quark mass if 171.6 {+-} 2.0 (stat.) {+-} 1.3(syst.) GeV/c{sup 2}. Finally, they report on a search for a new gauge boson decaying to t{bar t}, which interferes with the standard model gluon in the q{bar q} {yields} t{bar t} production process. They call such a hypothetical particle a 'Massive Gluon'. The observed t{bar t} invariant mass distribution is consistent with the standard model expectations, and also the measured massive gluon coupling strength with quarks is consistent within a statistical fluctuation of the standard model expectation in the wide range of the massive gluon masses and widths. They set the upper and lower limits on the coupling strength of the massive gluon.

Naganoma, Junji; /Waseda U.

2008-03-01T23:59:59.000Z

88

Observation of s-Channel Production of Single Top Quarks at the Tevatron  

E-Print Network (OSTI)

We report the first observation of single-top-quark production in the s channel through the combination of the CDF and D0 measurements of the cross section in proton-antiproton collisions at a center-of-mass energy of ...

Aaltonen, T.

89

Ultraviolet photodissociation enhances top?down mass...  

NLE Websites -- All DOE Office Websites (Extended Search)

Ultraviolet photodissociation enhances top-down mass spectrometry as demonstrated on green fluorescent protein variants Xibei Dang 1,2 and Nicolas L. Young 1 1 Ion Cyclotron...

90

Measurement of the top-antitop quark pair differential cross section with respect to the invariant mass of the pair in proton-antiproton collisions at a center of mass energy of 1.96 TeV  

SciTech Connect

I present a measurement of the t{bar t} differential cross section, d{sigma}/dM{sub t{bar t}}, in p{bar p} collisions at {radical}s = 1.96 TeV using 2.7 fb{sup -1} of CDF II data. I find that d{sigma}/dM{sub t{bar t}} is consistent with the Standard Model expectation, as modeled by PYTHIA with CTEQ5L parton distribution functions. I set limits on the ratio {kappa}/M{sub Pl} in the Randall-Sundrum model by looking for Kaluza Klein gravitons which decay to top quarks. I find {kappa}/M{sub Pl} > 0.16 at the 95% confidence level.

Bridgeman, Alice; /Illinois U., Urbana

2008-10-01T23:59:59.000Z

91

Reconstruction of stop quark mass at the LHC  

Science Journals Connector (OSTI)

The cascade mass reconstruction approach was applied to simulated production of the lightest stop quark at the LHC in the cascade decay g˜?t˜1t??˜20tt??˜R?tt??˜10??tt with top quarks decaying into hadrons. The stop quark mass was reconstructed assuming that the masses of gluino, slepton, and the two lightest neutralinos were reconstructed in advance. A data sample set for the SU3 model point containing 400 k supersymmetry events was generated which corresponded to an integrated luminosity of about 20??fb-1 at 14 TeV. These events were passed through the AcerDET detector simulator, which parametrized the response of a generic LHC detector. The mass of the t˜1 was reconstructed with a precision of about 10%.

Diego Casadei; Rostislav Konoplich; Rashid Djilkibaev

2010-10-15T23:59:59.000Z

92

Top quarks as a probe for heavy new physics  

E-Print Network (OSTI)

The heaviest fermion is expected to couple strongly to new physics and appears therefore as a natural probe in many BSM scenarios. Moreover, top physics has now entered in a precision era thanks to the huge amount of top quarks produced at hadron colliders, advanced experimental methods and accurate theoretical predictions. In this talk, we will used effective field theory to search for heavy new physics in a model independent way. This method can also be used to quantify the room left for new physics if no deviation from the SM is found.

Celine Degrande

2014-07-11T23:59:59.000Z

93

Forward-backward asymmetry in top quark-antiquark production  

SciTech Connect

We present a measurement of forward-backward asymmetry in top quark-antiquark production in proton-antiproton collisions in the final state containing a lepton and at least four jets. Using a dataset corresponding to an integrated luminosity of 5.4 fb-1, collected by the D0 experiment at the Fermilab Tevatron Collider, we measure the t{bar t} forward-backward asymmetry to be (9.2 ± 3.7)% at the reconstruction level. When corrected for detector acceptance and resolution, the asymmetry is found to be (19.6 ± 6.5)%. We also measure a corrected asymmetry based on the lepton from a top quark decay, found to be (15.2 ± 4.0)%. The results are compared to predictions based on the next-to-leading-order QCD generator mc@nlo. The sensitivity of the measured and predicted asymmetries to the modeling of gluon radiation is discussed.

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; Aoki, Masato [Fermilab; Louisiana Tech. U.

2011-12-12T23:59:59.000Z

94

QCD and Top Quark Physics at the LHC  

E-Print Network (OSTI)

The expected performance of the ATLAS and CMS detectors at the Large Hadron Collider (LHC) in QCD and top quark measurements is discussed, with a focus on the early data taking phase. Such processes are amongst the primary backgrounds in the searches for new physics, and thus must be understood very well before discoveries can be made. In addition, they serve as useful detector calibration candles.

Frank-Peter Schilling

2009-01-30T23:59:59.000Z

95

Diphoton decay of the Higgs boson and new bound states of top and anti-top quarks  

E-Print Network (OSTI)

We consider the constraints, provided by the LHC results on Higgs boson decay into 2 photons and its production via gluon fusion, on the previously proposed Standard Model (SM) strongly bound state $S$ of 6 top quarks and 6 anti-top quarks. A correlation is predicted between the ratios $\\kappa_{\\gamma}$ and $\\kappa_g$ of the Higgs diphoton decay and gluon production amplitudes respectively to their SM values. We estimate the contribution to these amplitudes from one loop diagrams involving the 12 quark bound state $S$ and related excited states using an atomic physics based model. We find two regions of parameter space consistent with the ATLAS and CMS data on ($\\kappa_{\\gamma}$, $\\kappa_g$) at the 3 sigma level: a region close to the SM values ($\\kappa_{\\gamma}=1$, $\\kappa_g =1$) with the mass of the bound state $m_S > 400$ GeV and a region with ($\\kappa_{\\gamma} \\sim 3/2$, $\\kappa_g \\sim -3/4$) corresponding to a bound state mass of $m_S \\sim 220$ GeV.

Froggatt, C D; Laperashvili, L V; Nielsen, H B

2015-01-01T23:59:59.000Z

96

Using jet mass to discover vector quarks at the CERN LHC  

Science Journals Connector (OSTI)

We illustrate the utility of jet-mass distributions as probes of new physics at the LHC, focusing on a heavy vector-quark doublet that mixes with the top as a concrete example. For 1 TeV vector-quark masses, we find that signals with greater than 5? significance can be achieved after 100??fb-1. More generally, jet-mass distributions have the potential to provide signals for heavy states that produce highly boosted weak gauge bosons and/or top quarks.

Witold Skiba and David Tucker-Smith

2007-06-14T23:59:59.000Z

97

Exclusion of exotic top-like quarks with -4/3 electric charge using jet-charge tagging in single-lepton ttbar events at CDF  

E-Print Network (OSTI)

We report on a measurement of the top-quark electric charge in ttbar events in which one W boson originating from the top-quark pair decays into leptons and the other into hadrons. The event sample was collected by the CDF II detector in sqrt(s)=1.96 TeV proton-antiproton collisions and corresponds to 5.6 fb^(-1). We find the data to be consistent with the standard model and exclude the existence of an exotic quark with -4/3 electric charge and mass of the conventional top quark at the 99% confidence level.

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

2014-10-09T23:59:59.000Z

98

Collider Detector at Fermilab (CDF): Data from the Top Group's Top Quark Research  

DOE Data Explorer (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 Top group studies the properties of the top quark, the heaviest known fundamental particle. Their public web page makes data and numerous figures available from both CDF Runs I and II.

99

Top mass measurements at the Tevatron run II  

SciTech Connect

The latest top quark mass measurements by the CDF and D0 experiments are presented here. The mass has been determined in the dilepton (t{bar t} {yields} e{mu}, ee, {mu}{mu} + jets + E{sub T}) and lepton plus jets (t{bar t} {yields} e or {mu} + jets + E{sub T}) final states. The most accurate single result from lepton plus jets channel is 173.5{sub -3.6}{sup +3.7}(stat. + Jet Energy Scale Systematic) {+-} 1.3(syst.) GeV/c{sup 2}, which is better than the combined CDF and D0 Run I average. A preliminary and unofficial average of the best experimental Run II results gives M{sub top} = 172.7 {+-} 3.5 GeV/c{sup 2}.

Velev, Gueorgui V.; /Fermilab

2005-10-01T23:59:59.000Z

100

Z?bb¯ excess and top quark decay  

Science Journals Connector (OSTI)

The apparent excess of Z?bb¯ events at CERN LEP may be an indication of new physics beyond the standard model. However, in either the two-Higgs-doublet model or the minimal supersymmetric standard model any explanation would lead to an important new decay mode of the top quark and suppresses the t?Wb branching fraction, which goes against what has been observed at the Fermilab Tevatron. In the two-Higgs-doublet model, the branching fraction of Z?bb¯+a light boson which decays predominantly into bb¯ would be at least of order 10-4. © 1995 The American Physical Society.

Ernest Ma and Daniel Ng

1996-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "top quark mass" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Constraints on Top Couplings in Models with Exotic Quarks  

Science Journals Connector (OSTI)

The extension of the standard model with exotic quark singlets and doublets introduces large flavor changing neutral couplings between ordinary fermions. We derive inequalities which translate the precise determination of the diagonal Z couplings, in particular, at LEP, into stringent bounds on the off-diagonal ones. The resulting limits can be saturated in minimal extensions with one vector doublet or singlet. In this case, 23 and 6 single top events, respectively, are predicted at LEP2 for an integrated luminosity of 500 pb-1 per experiment.

F. del Aguila; J. A. Aguilar-Saavedra; R. Miquel

1999-02-22T23:59:59.000Z

102

A Search for the Standard Model Higgs Boson Produced in Association with Top Quarks.  

E-Print Network (OSTI)

??We have performed a search for the Standard Model Higgs boson produced in association with top quarks in the lepton plus jets channel. We impose… (more)

Wilson, Jonathan S.

2012-01-01T23:59:59.000Z

103

Probing the flavor violating scalar top quark signal at the LHC  

Science Journals Connector (OSTI)

The Large Hadron Collider (LHC) has completed its run at 8 TeV with the experiments ATLAS and CMS having collected about 25??fb?1 of data each. Discovery of a light Higgs boson coupled with lack of evidence for supersymmetry at the LHC so far, has motivated studies of supersymmetry in the context of naturalness with the principal focus being the third generation squarks. In this work, we analyze the prospects of the flavor violating decay mode t˜1?c?10 at 8 and 13 TeV center-of-mass energy at the LHC. This channel is also relevant in the dark matter context for the stop-coannihilation scenario, where the relic density depends on the mass difference between the lighter stop quark (t˜1) and the lightest neutralino (?10) states. This channel is extremely challenging to probe, especially for situations when the mass difference between the lighter stop quark and the lightest neutralino is small. Using certain kinematical properties of signal events we find that the level of backgrounds can be reduced substantially. We find that the prospect for this channel is limited due to the low production cross section for top squarks and limited luminosity at 8 TeV, but at the 13 TeV LHC with 100??fb?1 luminosity, it is possible to probe top squarks with masses up to ?450??GeV. We also discuss how the sensitivity could be significantly improved by tagging charm jets.

Genevieve Belanger; Diptimoy Ghosh; Rohini Godbole; Monoranjan Guchait; Dipan Sengupta

2014-01-06T23:59:59.000Z

104

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

E-Print Network (OSTI)

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 ...

Apyan, Aram

105

Search for Pair Production of Supersymmetric Top Quarks in Dilepton Events at the Tevatron  

SciTech Connect

We search for pair production of the supersymmetric partner of the top quark, the stop quark {tilde t}{sub 1}, decaying to a b-quark and a chargino {tilde {chi}}{sub 1}{sup {+-}} with a subsequent decay into a neutralino {tilde {chi}}{sub 1}{sup 0}, lepton {ell}, and neutrino {nu}. Using 2.7 fb{sup -1} of {radical}s = 1.96 TeV p{bar p} collision data collected by the CDF II experiment, we reconstruct the mass of candidate stop events and fit the observed mass spectrum to a combination of standard model processes and stop signal. No evidence of {tilde t}{sub 1}{tilde {bar 1}}{sub 1} production is found, therefore we set 95% C.L. limits on the masses of the stop and the neutralino for several values of the chargino mass and the branching ratio {Beta} ({tilde {chi}}{sub 1}{sup {+-}} {yields} {tilde {chi}}{sub 1}{sup 0}{ell}{sup {+-}}{nu}).

Johnson, William Casey; /UC, Davis

2010-05-01T23:59:59.000Z

106

Heavy quark masses from Fermilab Fermions  

E-Print Network (OSTI)

Using automated perturbation theory techniques, we have computed the one-loop mass of Fermilab fermions, with an improved gluon action. We will present the results of these calculations, and the resulting predictions for the charm and bottom quark masses in the MSbar scheme. We report mc(mc) = 1:22(9) GeV and mb(mb) = 4:7(4) GeV. In addition we present results for the one-loop coeffcients of the Fermilab action.

Matthew Nobes; Howard Trottier

2005-09-26T23:59:59.000Z

107

Domain wall QCD with physical quark masses  

E-Print Network (OSTI)

We present results for several light hadronic quantities ($f_\\pi$, $f_K$, $B_K$, $m_{ud}$, $m_s$, $t_0^{1/2}$, $w_0$) obtained from simulations of 2+1 flavor domain wall lattice QCD with large physical volumes and nearly-physical pion masses at two lattice spacings. We perform a short, O(3)%, extrapolation in pion mass to the physical values by combining our new data in a simultaneous chiral/continuum `global fit' with a number of other ensembles with heavier pion masses. We use the physical values of $m_\\pi$, $m_K$ and $m_\\Omega$ to determine the two quark masses and the scale - all other quantities are outputs from our simulations. We obtain results with sub-percent statistical errors and negligible chiral and finite-volume systematics for these light hadronic quantities, including: $f_\\pi$ = 130.2(9) MeV; $f_K$ = 155.5(8) MeV; the average up/down quark mass and strange quark mass in the $\\overline {\\rm MS}$ scheme at 3 GeV, 2.997(49) and 81.64(1.17) MeV respectively; and the neutral kaon mixing parameter, $B_K$, in the RGI scheme, 0.750(15) and the $\\overline{\\rm MS}$ scheme at 3 GeV, 0.530(11).

RBC; UKQCD collaborations; :; T. Blum; P. A. Boyle; N. H. Christ; J. Frison; N. Garron; R. J. Hudspith; T. Izubuchi; T. Janowski; C. Jung; A. Juettner; C. Kelly; R. D. Kenway; C. Lehner; M. Marinkovic; R. D. Mawhinney; G. McGlynn; D. J. Murphy; S. Ohta; A. Portelli; C. T. Sachrajda; A. Soni

2014-11-25T23:59:59.000Z

108

Measurement of the Single Top Quark Production Cross Section and |Vtb| in Events with One Charged Lepton, Large Missing Transverse Energy, and Jets at CDF  

E-Print Network (OSTI)

We report a measurement of single top quark production in proton-antiproton collisions at a center-of-mass energy of \\sqrt{s} = 1.96 TeV using a data set corresponding to 7.5 fb-1 of integrated luminosity collected by the Collider Detector at Fermilab. We select events consistent with the single top quark decay process t \\to Wb \\to l{\

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

2014-07-15T23:59:59.000Z

109

Measurement of the Single Top Quark Production Cross Section and |Vtb| in Events with One Charged Lepton, Large Missing Transverse Energy, and Jets at CDF  

E-Print Network (OSTI)

We report a measurement of single top quark production in proton-antiproton collisions at a center-of-mass energy of \\sqrt{s} = 1.96 TeV using a data set corresponding to 7.5 fb-1 of integrated luminosity collected by the Collider Detector at Fermilab. We select events consistent with the single top quark decay process t \\to Wb \\to l{\

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

2015-01-25T23:59:59.000Z

110

Finding the charge of the top quark in the dilepton channel  

SciTech Connect

There is a question about the identity of the top quark. Is it the top quark of the Standard Model (SM) with electric charge 2/3 or is it an exotic quark with charge -4/3? An exotic quark has been proposed by D. Chang et al. [1]. This analysis will use the standard CDF run II dilepton sample. The key ingredients of this analysis are the correct pairing of the lepton and b-jet, the determination of the charge of the b-jet. The analysis proceeds by using a binomial distribution and is formulated so that rejecting one hypothesis means support for the other hypothesis.

Beretvas, A.; Antos, J.; Chen, Y.C.; Gunay, Z.; Sorin, V.; Tollefson, K.; Bednar, P.; Tokar, S.; Boisvert, V.; Hopkins, W.; McFarland, K.; /Fermilab /Kosice, IEF /Taiwan,

2006-08-01T23:59:59.000Z

111

Search for the associated production of the Higgs boson with a top-quark pair  

E-Print Network (OSTI)

A search for the standard model Higgs boson produced in association with a top-quark pair (t tbar H) is presented, using data samples corresponding to integrated luminosities of up to 5.1 inverse femtobarns and 19.7 inverse femtobarns collected in pp collisions at center-of-mass energies of 7 TeV and 8 TeV respectively. The search is based on the following signatures of the Higgs boson decay: H to hadrons, H to photons, and H to leptons. The results are characterized by an observed t tbar H signal strength relative to the standard model cross section, mu = sigma/sigma[SM], under the assumption that the Higgs boson decays as expected in the standard model. The best fit value is mu = 2.8 +/- 1.0 for a Higgs boson mass of 125.6 GeV.

CMS Collaboration

2014-09-18T23:59:59.000Z

112

TC corrections to the single-top-quark production at the Fermilab Tevatron  

E-Print Network (OSTI)

We calculate one-loop corrections to the single-top-quark production via $q\\overline{q}' \\to t\\overline b$ at the Fermilab Tevatron from the Pseudo-Goldstone bosons ( PGBs ) in the framework of one generation technicolor model. The maximum correction to the total cross section for the single-top-quark production is found to reach -2.4% relative to the tree-level cross section, which may be observable at a high-luminosity Tevatron.

Gongru Lu; Yigang Cao; Jinshu Huang; Junde Zhang; Zhenjun Xiao

1997-01-29T23:59:59.000Z

113

Invisible Higgs in weak bosons associative production with heavy quarks at LHC: probing mass and width  

E-Print Network (OSTI)

New physics coupled to the Higgs boson may hide it in the standard decay channels to be investigated at LHC. We consider the models where new invisible dominant decay modes of the Higgs boson are responsible for this hiding. We propose to study at LHC the weak boson production associated with heavy quarks: our analysis revealed that boson pair invariant mass distribution is sensitive to both mass and width of the invisible Higgs boson, if it is not too far from the weak boson pair threshold. We present tree-level results for the most relevant cases of top quarks and of bottom quarks in Standard Model extensions with large $b$-quark Yukawa coupling. We argue that QCD corrections do not spoil these results allowing for unambiguous extraction of the Higgs boson mass and width from the analysis of large enough amount of data.

E. E. Boos; S. V. Demidov; D. S. Gorbunov

2010-10-26T23:59:59.000Z

114

Measurement of the Electric Charge of the Top Quark in $\\boldsymbol{t\\bar{t}}$ Events  

E-Print Network (OSTI)

We present a measurement of the electric charge of top quarks using $t\\bar{t}$ events produced in $p\\bar{p}$ collisions at the Tevatron. The analysis is based on fully reconstructed $t\\bar{t}$ pairs in lepton+jets final states. Using data corresponding to 5.3 $\\rm fb^{-1}$ of integrated luminosity, we exclude the hypothesis that the top quark has a charge of $Q=-4/3\\,e$ at a significance greater than 5 standard deviations. We also place an upper limit of 0.46 on the fraction of such quarks that can be present in an admixture with the standard model top quarks ($Q=+2/3\\,e$) at a 95\\% confidence level.

D0 Collaboration

2014-09-25T23:59:59.000Z

115

QCD Thermodynamics with an almost realistic quark mass spectrum  

E-Print Network (OSTI)

We will report on the status of a new large scale calculation of thermodynamic quantities in QCD with light up and down quarks corresponding to an almost physical light quark mass value and a heavier strange quark mass. These calculations are currently being performed on the QCDOC Teraflops computers at BNL. We will present new lattice calculations of the transition temperature and various susceptibilities reflecting properties of the chiral transition. All these quantities are of immediate interest for heavy ion phenomenology.

C. Schmidt

2006-01-25T23:59:59.000Z

116

Congeniality bounds on quark masses from nucleosynthesis  

Science Journals Connector (OSTI)

The work of Jaffe, Jenkins and Kimchi [Phys. Rev. D 79, 065014 (2009)] is revisited to see if indeed the region of congeniality found in their analysis survives further restrictions from nucleosynthesis. It is observed that much of their congenial region disappears when imposing conditions required to produce the correct and required abundances of the primordial elements as well as ensure that stars can continue to burn hydrogen nuclei to form helium as the first step in forming heavier elements in stellar nucleosynthesis. The remaining region is a very narrow slit reduced in width from around 29 MeV found by Jaffe et al. to only about 2.2 MeV in the difference of the nucleon/quark masses. Further bounds on ?mq/mq seem to reduce even this narrow slit to the physical point itself.

M. Hossain Ali; M. Jakir Hossain; Abdullah Shams Bin Tariq

2013-08-02T23:59:59.000Z

117

Finding the Charge of the top quark in the Dilepton Channel  

E-Print Network (OSTI)

There is a question about the identity of the top quark. Is it the top quark of the Standard Model (SM) with electric charge 2/3 or is it an exotic quark with charge -4/3? An exotic quark has been proposed by D. Chang et al.\\cite{hep-ph/9810531, hep-ph/9805273}. This analysis will use the standard CDF run II dilepton sample. The key ingredients of this analysis are the correct pairing of the lepton and b-jet, the determination of the charge of the b-jet. The analysis proceeds by using a binomial distribution and is formulated so that rejecting one hypothesis means support for the other hypothesis.

Beretvas, A; Chen, Y C; Gunay, Z; Sorin, V; Tollefson, K; Bednar, P; Tokar, S; Boisvert, V; Hopkins, W; McFarland, K

2007-01-01T23:59:59.000Z

118

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)

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 ...

Aaltonen, T.

119

Top Physics at ATLAS  

E-Print Network (OSTI)

The Large Hadron Collider LHC is a top quark factory: due to its high design luminosity, LHC will produce about 200 millions of top quarks per year of operation. The large amount of data will allow to study with great precision the properties of the top quark, most notably cross-section, mass and spin. The Top Physics Working Group has been set up at the ATLAS experiment, to evaluate the precision reach of physics measurements in the top sector, and to study the systematic effects of the ATLAS detector on such measurements. This reports give an overview of the main activities of the ATLAS Top Physics Working Group in 2004.

Marcello Barisonzi

2005-08-02T23:59:59.000Z

120

Higgs boson production in association with top quarks in the POWHEG BOX  

E-Print Network (OSTI)

We present results from the analytic calculation of top+antitop+Higgs hadronic production at Next-to-Leading Order in QCD interfaced with parton-shower Monte Carlo event generators in the POWHEG BOX framework. We consider kinematic distributions of the top quark and Higgs boson at the 8 TeV Large Hadron Collider and study the theoretical uncertainties due to specific choices of renormalization/factorization scales and parton-showering algorithms, namely PYTHIA and HERWIG. The importance of spin-correlations in the production and decay stages of a top/antitop quark is discussed on the example of kinematic distributions of leptons originating from the top/antitop decays. The corresponding code is now part of the public release of the POWHEG BOX.

Hartanto, Heribertus B; Reina, Laura; Wackeroth, Doreen

2015-01-01T23:59:59.000Z

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121

Weak interaction corrections to hadronic top quark pair production: contributions from quark-gluon and $b \\bar b$ induced reactions  

E-Print Network (OSTI)

As an addendum to our previous evaluation of the weak-interaction corrections to hadronic top-quark pair production we determine the leading weak-interaction contributions due to the subprocesses $b {\\bar b} \\to t {\\bar t}$ and $g q ({\\bar q}) \\to t {\\bar t} q ({\\bar q})$. For several distributions in $t {\\bar t}$ production at the LHC we find that these contributions are non-negligible as compared to the weak corrections from the other partonic subprocesses.

Werner Bernreuther; Michael Fuecker; Zong-Guo Si

2008-04-08T23:59:59.000Z

122

Measurement of the Top Quark Pair Production Cross Section in pp Collisions at a Center-of-Mass Energy of 7 TeV with the CMS Experiment at the LHC  

E-Print Network (OSTI)

its position in the ECAL bore in the experimental cavern aton top of a HCAL wedge in the experimental cavern atHCAL wedges in the experimental cavern as shown in Fig. C.1.

Jeng, Geng-yuan

2011-01-01T23:59:59.000Z

123

Search for V+A current in top quark decay in p anti-p collisions at s**(1/2) = 1.96-TeV  

SciTech Connect

The authors report an upper limit on the fraction of V + A current, f{sub V+A}, in top quark decays, using approximately 700 pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV acquired by the upgraded Collider Detector at Fermilab. For the decay t {yields} wb {yields} {ell}vb (where {ell} = e or {mu}), the invariant mass of the charged lepton and the bottom quark jet is sensitive to the polarization of the W boson. They determine f{sub V+A} = -0.06 {+-} 0.25 given a top quark mass of 175 GeV/c{sup 2}. They set an upper limit on f{sub V+A} of 0.29 at the 95% confidence level, which represents an improvement by a factor of two on the previous best direct limit.

Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D.; Amerio, S.; Amidei, D.; Anastassov, A.; Anikeev, K.; Annovi, A.; /Taiwan, Inst. Phys.

2006-08-01T23:59:59.000Z

124

Search for V + A current in top quark decay in p anti-p collisions at s**(1/2) = 1.96 TeV  

SciTech Connect

The authors report an upper limit on the fraction of V + A current, f{sub V+A}, in top quark decays, using approximately 700 pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV acquired by the upgraded Collider Detector at Fermilab. For the decay t {yields} Wb {yields} {ell}{nu}b (where {ell} = e or {mu}), the invariant mass of the charged lepton and the bottom quark jet is sensitive to the polarization of the W boson. They determine f{sub V+A} = -0.06 {+-} 0.25 given a top quark mass of 175 GeV/c{sup 2}. They set an upper limit on f{sub V+A} of 0.29 at the 95% confidence level, which represents an improvement by a factor of two on the previous best direct limit.

Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D.; Amerio, S.; Amidei, D.; Anastassov, A.; Anikeev, K.; Annovi, A.; Antos, J.; Aoki, M.; Apollinari, G.; Arguin, J.-F.; Arisawa, T.; Artikov, A.; Ashmanskas, W.; Attal, A.; Azfar, F.; Azzi-Bacchetta, P.

2006-09-01T23:59:59.000Z

125

Observation of single top quark production and measurement of |Vtb| with CDF  

E-Print Network (OSTI)

We report the observation of electroweak single top quark production in 3.2??fb-1 [fb superscript -1] of pp? collision data collected by the Collider Detector at Fermilab at ?s=1.96??TeV [square root of s=1.96 TeV]. Candidate ...

Bauer, Gerry P.

126

Simona Rolli, Fermilab W&C Recent results on top quark,  

E-Print Network (OSTI)

4/27/04 Simona Rolli, Fermilab W&C seminar 1 Recent results on top quark, electroweak and new;4/27/04 Simona Rolli, Fermilab W&C seminar 2 Introduction Exciting time now at CDF ! frenzy activity in physics datasets Common identification/reconstruction cuts #12;4/27/04 Simona Rolli, Fermilab W&C seminar 3 Outline

Fermilab

127

Search for the associated production of the Higgs boson with a top-quark pair  

E-Print Network (OSTI)

A search for the standard model Higgs boson produced in association with a top-quark pair (tt¯H) is presented, using data samples corresponding to integrated luminosities of up to 5.1 fb?1 and 19.7 fb?1 collected in pp ...

CMS Collaboration

128

Search for single top quark production in pbar p collisions at sqrt{s}=1.96 TeV in the missing transverse energy plus jets topology  

SciTech Connect

We report a search for single top quark production with the CDF II detector using 2.1 fb{sup -1} of integrated luminosity of p{bar p} collisions at {radical}s = 1.96 TeV. The data selected consist of events characterized by large energy imbalance in the transverse plane and hadronic jets, and no identified electrons and muons, so the sample is enriched in W {yields} {tau}{nu} decays. In order to suppress backgrounds, additional kinematic and topological requirements are imposed through a neural network, and at least one of the jets must be identified as a b quark jet. We measure an excess of signal-like events in agreement with the standard model prediction, but inconsistent with a model without single top quark production by 2.1 standard deviations ({sigma}), with a median expected sensitivity of 1.4 {sigma}. Assuming a top quark mass of 175 GeV/c{sup 2} and ascribing the excess to single top quark production, the cross section is measured to be 4.9{sub -2.2}{sup +2.5} (stat+syst) pb, consistent with measurements performed in independent datasets and with the standard model prediction.

Aaltonen, T.; /Helsinki Inst. of Phys.; Adelman, J.; /Chicago U., EFI; Alvarez Gonzalez, B.; /Cantabria Inst. of Phys.; Amerio, S.; /INFN, Padua; Amidei, D.; /Michigan U.; Anastassov, A.; /Northwestern U.; Annovi, A.; /Frascati; Antos, J.; /Comenius U.; Apollinari, G.; /Fermilab; Appel, J.; /Fermilab; Apresyan, A.; /Purdue U. /Waseda U.

2010-01-01T23:59:59.000Z

129

Search for a Heavy Top-Like Quark in $p\\bar{p}$ Collisions at ${\\surd}s = 1.96$~TeV  

SciTech Connect

We present the results of a search for pair production of a heavy top-like (t') quark decaying to W q final states using data corresponding to an integrated luminosity of 5.6 fb{sup -1} collected by the CDF II detector in p{anti p} collisions at {radical}{ovr s} = 1.96 TeV. We perform parallel searches for t' {yields} W b and t' {yields} W q (where q is a generic down-type quark) in events containing a lepton and four or more jets. By performing a fit to the two-dimensional distribution of total transverse energy versus reconstructed t' quark mass, we set upper limits on the t'{anti t}' production cross section and exclude a standard model fourth-generation t' quark decaying to W b (W q) with mass below 358 (340) GeV/c{sup 2} at 95% CL.

Aaltonen, T.; /Helsinki Inst. of Phys.; Alvarez Gonzalez, B.; /Oviedo U. /Cantabria Inst. of Phys.; Amerio, S.; /INFN, Padua; Amidei, D.; /Michigan U.; Anastassov, A.; /Northwestern U.; Annovi, A.; /Frascati; Antos, J.; /Comenius U.; Apollinari, G.; /Fermilab; Appel, J.A.; /Fermilab; Apresyan, A.; /Purdue U.; Arisawa, T.; /Waseda U. /Dubna, JINR

2011-07-01T23:59:59.000Z

130

Early physics with top quarks at the LHC  

E-Print Network (OSTI)

The ATLAS and CMS experiments are now in their final installation phase and will be soon ready to study the physics of proton-proton collisions at the Large Hadron Collider. The LHC, by producing 2 $t\\bar{t}$ events per second, will provide more than 8 million top events a year at start-up. In this paper, particular emphasis is given to the $t\\bar{t}$ physics studies that can be performed at the beginning of the LHC running, with a limited amount of integrated luminosity ($\\le$10 fb$^{-1}$).

Pamela Ferrari

2007-05-21T23:59:59.000Z

131

Search for charged Higgs bosons in decays of top quarks in p anti-p collisions at s**(1/2) = 1.96 TeV  

SciTech Connect

We report on the first direct search for charged Higgs bosons in decays of top quarks in p{bar p} collisions at {radical}s = 1.96 TeV. The search uses a data sample corresponding to an integrated luminosity of 2.2 fb{sup -1} collected by the CDF II detector at Fermilab, and looks for a resonance in the invariant mass distribution of two jets in the lepton+jets sample of t{bar t} candidates. We observe no evidence of charged Higgs bosons in top quark decays. Hence, 95% upper limits on the top quark decay branching ratio are placed at {Beta}(t {yields} H{sup +}b) < 0.1 to 0.3 for charged Higgs boson masses of 60 to 150 GeV/c{sup 2}, assuming {Beta}(H{sup +} {yields} c{bar s}) = 1.0. The upper limits on {Beta}(t {yields} H{sup +}b) can also be used as model-independent limits on the decay branching ratio of top quarks to generic scalar charged bosons beyond the standard model.

Aaltonen, T.; /Helsinki U. /Helsinki Inst. of Phys.; Adelman, J.; /Chicago U., EFI; Akimoto, T.; /Tsukuba U.; Alvarez Gonzalez, B.; /Cantabria Inst. of Phys.; Amerio, S.; /Padua U. /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.

2009-07-01T23:59:59.000Z

132

ATLAS sensitivity to Wtb anomalous couplings in top quark decays  

E-Print Network (OSTI)

We study the sensitivity of the ATLAS experiment to Wtb anomalous couplings in top pair production with semileptonic decay, pp -> t tbar -> W+ b W- bbar, with one of the W bosons decaying leptonically and the other hadronically. Several observables are examined, including the W helicity fractions and new quantities recently introduced, such as the ratios of helicity fractions and some angular asymmetries defined in the W rest frame. The dependence on anomalous couplings of all these observables has been previously obtained. In this work we show that some of the new observables also have smaller systematic uncertainties than the helicity fractions, with a dependence on anomalous couplings similar or stronger than for helicity fractions. Consequently, their measurement can significantly improve the limits on anomalous couplings. Moreover, the most sensitive measurements can be combined. In this case, the precision achieved in the determination of Wtb anomalous couplings can be of a few percent in the semileptonic channel alone.

J. A. Aguilar-Saavedra; J. Carvalho; N. Castro; A. Onofre; F. Veloso

2007-12-17T23:59:59.000Z

133

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

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.

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

2008-05-01T23:59:59.000Z

134

Top quark pair production cross section using the ATLAS detector at the LHC  

E-Print Network (OSTI)

Measurements of the inclusive top quark pair production cross sections in proton-proton collisions with the ATLAS detector at the Large Hadron Collider are presented. The measurements are performed requiring one or two electrons or muons in the final state. Various experimental techniques are compared. The most accurate result in obtained requiring opposite sign electrons and muons, achieves a precision of a few percent, and is in good agreement with a recent NNLO+NNLL QCD calculation. In addition, a di erential measurement of the top transverse momentum and kinematic properties of the top pair system are presented. This measurement requires one electron or muon in the final state and probes our understanding of top pair production in the TeV regime and is compared to recent Monte Carlo generators and theory calculations.

Theveneaux-Pelzer, Timothee; The ATLAS collaboration

2014-01-01T23:59:59.000Z

135

Search for H ? ?? produced in association with top quarks and constraints on the Yukawa coupling between the top quark and the Higgs boson using data taken at 7 TeV and 8 TeV with the ATLAS detector  

E-Print Network (OSTI)

A search is performed for Higgs bosons produced in association with top quarks using the diphoton decay mode of the Higgs boson. Selection requirements are optimized separately for leptonic and fully hadronic final states ...

Taylor, Frank E.

136

Evidence for $s$-channel Single-Top-Quark Production in Events with one Charged Lepton and two Jets at CDF  

E-Print Network (OSTI)

We report evidence for $s$-channel single-top-quark production in proton-antiproton collisions at center-of-mass energy $\\sqrt{s}= 1.96 \\mathrm{TeV}$ using a data set that corresponds to an integrated luminosity of $9.4 \\mathrm{fb}^{-1}$ collected by the Collider Detector at Fermilab. We select events consistent with the $s$-channel process including two jets and one leptonically decaying $W$ boson. The observed significance is $3.8$ standard deviations with respect to the background-only prediction. Assuming a top-quark mass of $172.5 \\mathrm{GeV}/c^2$, we measure the $s$-channel cross section to be $1.41^{+0.44}_{-0.42} \\mathrm{pb}$.

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

2014-04-21T23:59:59.000Z

137

Search for invisible particles produced in association with single-top-quarks in proton-proton collisions at $\\sqrt{s}$ = 8 TeV with the ATLAS detector  

E-Print Network (OSTI)

A search for the production of single-top-quarks in association with missing energy is performed in proton--proton collisions at a centre-of-mass energy of $\\sqrt{s}$ = 8 TeV with the ATLAS experiment at the Large Hadron Collider using data collected in 2012, corresponding to an integrated luminosity of 20.3 fb$^{-1}$. In this search, the $W$ boson from the top quark is required to decay into an electron or a muon and a neutrino. No deviation from the Standard Model prediction is observed, and upper limits are set on the production cross-section for resonant and non-resonant production of an invisible exotic state in association with a right-handed top quark. In the case of resonant production, for a spin-$0$ resonance with a mass of 500 GeV, an effective coupling strength above 0.15 is excluded at 95% confidence level for the top quark and an invisible spin-$1/2$ state with mass between 0 GeV and 100 GeV. In the case of non-resonant production, an effective coupling strength above 0.2 is excluded at 95% confidence level for the top quark and an invisible spin-$1$ state with mass between 0 GeV and 657 GeV.

ATLAS Collaboration

2014-10-20T23:59:59.000Z

138

Perspectives on top quark physics after Run I of the LHC: sqrt(s)=13 TeV and beyond  

E-Print Network (OSTI)

A summary of the on-going preparations from the ATLAS and CMS collaborations to perform top quark physics in Run II of the LHC and at the HL-LHC is given. To maintain the current level of precision and profit from the high-luminosity scenario expected in the next runs of the LHC, several new reconstruction techniques and detector upgrades are foreseen. The prospects for precise measurements and possible discovery stories for new physics with top quarks are summarized.

Pedro Silva

2014-11-25T23:59:59.000Z

139

Top Physics at CDF  

SciTech Connect

We present the recent results of top-quark physics using up to 6 fb{sup -1} of p{bar p} collisions at a center of mass energy of {radical}s = 1.96 TeV analyzed by the CDF collaboration. Thanks to this large data sample, precision top quark measurements are now a reality at the Tevatron. Further, several new physics signals could appear in this large dataset. We will present the latest measurements of top quark intrinsic properties as well as direct searches for new physics in the top sector.

Moon, Chang-Seong

2011-06-01T23:59:59.000Z

140

Measurement of the W-boson helicity in top-quark decays from tt-bar production in lepton+jets events in pp collisions at s?=7 TeV  

E-Print Network (OSTI)

as the combined secondary-vertex (CSV) algorithm [26], is used to separate jets originating from light quarks (or gluons) and heavy quarks, i.e. charm or bottom quarks. Jets are first divided into cat- egories according to the probability of reconstructing a... measured value from the CSV tagger discriminant (see section 4). Since the top-quark and W-boson reconstructed masses are dominated by experimental resolu- tion effects, the parameters ?mt,t and ?M lep, hadW in eq. (5.1) are approximated as Gaussian widths...

Baringer, Philip S.; Bean, Alice; Benelli, Gabriele; Kenny, R. P. III; Murray, Michael J.; Noonan, Danny; Sanders, Stephen J.; Stringer, Robert W.; Wood, Jeffrey Scott; Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.

2013-10-24T23:59:59.000Z

Note: This page contains sample records for the topic "top quark mass" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Search for a heavy particle decaying to a top quark and a light quark in $p\\bar{p}$ collisions at $\\sqrt{s}=1.96$ TeV  

SciTech Connect

We present a search for a new heavy particle M produced in association with a top quark, p{bar p} {yields} t(M {yields} {bar t}q) or p{bar p} {yields} {bar t}({bar M} {yields} t{bar q}), where q stands for up quarks and down quarks. Such a particle may explain the recent anomalous measurements of top-quark forward-backward asymmetry. If the light-flavor quark (q) is reconstructed as a jet (j), this gives a {bar t}+j or t+j resonance in t{bar t}+jet events, a previously unexplored experimental signature. In a sample of events with exactly one lepton, missing transverse momentum and at least five jets, corresponding to an integrated luminosity of 8.7 fb{sup -1} collected by the CDF II detector, we find the data to be consistent with the standard model. We set cross-section upper limits on the production (p{bar p} {yields} Mt or {bar M} {bar t}) at 95% confidence level from 0.61 pb to 0.02 pb for M masses ranging from 200 GeV/c{sup 2} to 800 GeV/c{sup 2}, respectively.

Aaltonen, T.; /Helsinki Inst. of Phys.; Adelman, J.; /Yale U.; Alvarez Gonzalez, B.; /Oviedo U. /Cantabria Inst. of Phys.; Amerio, S.; /INFN, Padua; Amidei, D.; /Michigan U.; Anastassov, A.; /Northwestern U. /Fermilab; Annovi, A.; /Frascati; Antos, J.; /Comenius U.; Apollinari, G.; /Fermilab; Appel, J.A.; /Fermilab; Arisawa, T.; /Waseda U. /Dubna, JINR

2012-03-01T23:59:59.000Z

142

Renormalization group-induced phenomena of top pairs from four-quark effective operators  

E-Print Network (OSTI)

We study the renormalization group(RG) evolution of four-quark operators that contribute to the top pair production. In particular, we focus on the cases in which certain observables are \\emph{first} induced from the one-loop RG while being absent at tree-level. From the operator mixing pattern, we classify all such RG-induced phenomena and underlying models that can induce them. We then calculate the full one-loop QCD RG evolution as the leading estimator of the effects and address the question of which RG-induced phenomena have largest and observable effects. The answer is related to the color structure of QCD. The studied topics include the RG-induction of top asymmetries, polarizations and polarization mixings as well as issues arising at this order. The RG-induction of top asymmetries is further compared with the generation of asymmetries from QCD and QED at one-loop order. We finally discuss the validity of using the RG as the proxy of one-loop effects on the top pair production. As an aside, we clarify the often-studied relations between top pair observables.

Sunghoon Jung; P. Ko; Yeo Woong Yoon; Chaehyun Yu

2014-06-18T23:59:59.000Z

143

Search for charged Higgs bosons in decays of top quarks in proton - antiproton collisions at s**(1/2) = 1.96 TeV  

SciTech Connect

In this dissertation we report on the first direct search for charged Higgs bosons in decays of top quarks in p{bar p} collisions at {radical}s = 1.96 TeV. The search uses a data sample with an integrated luminosity of 2.2 fb{sup -1} collected by the CDF II detector at Fermilab and looks for a resonance in the invariant mass distribution of two jets in the lepton+jets sample of t{bar t} candidates. We observe no evidence of charged Higgs bosons in top quark decays; hence 95% C.L. upper limits on the branching ratio are placed at {Beta}(t {yields} H{sup +}b) < 0.1 to 0.3 for charged Higgs boson masses of 60 to 150 GeV/c{sup 2} assuming {Beta}(H{sup +} {yields} c{bar s}) = 1.0 and {Beta}(t {yields} Wb)+{Beta}(t {yields} H{sup +}b) = 1.0. The upper limits on {Beta}(t {yields} H{sup +}b) are also used as model independent limits on the decay branching ratio of top quarks to any charged scalar bosons beyond the standard model.

Yu, Geum Bong; /Rochester U.

2009-08-01T23:59:59.000Z

144

Studies of high-transverse momentum jet substructure and top quarks produced in 1.96 TeV proton-antiproton collisions  

E-Print Network (OSTI)

Results of a study of the substructure of the highest transverse momentum (pT) jets observed by the CDF collaboration are presented. Events containing at least one jet with pT > 400 GeV/c in a sample corresponding to an integrated luminosity of 5.95 inverse fb, collected in 1.96 TeV proton-antiproton collisions at the Fermilab Tevatron collider, are selected. A study of the jet mass, angularity, and planar-flow distributions is presented, and the measurements are compared with predictions of perturbative quantum chromodynamics. A search for boosted top-quark production is also described, leading to a 95% confidence level upper limit of 38 fb on the production cross section of top quarks with pT > 400 GeV/c.

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

2014-07-13T23:59:59.000Z

145

Supersymmetric Electroweak Corrections to Single Top Quark Production at the Fermilab Tevatron  

E-Print Network (OSTI)

We have calculated the $O(\\alpha_{ew} M_t^2/M_W^2)$ supersymmetric electroweak corrections to single top quark production via $q\\bar q' \\to t\\bar b$ at the Fermilab Tevatron in the minimal supersymmetric model. The supersymmetric electroweak corrections to the cross section are a few percent for $tan \\beta> 1$, and can exceed 10% for $tan\\beta<1$. The combined effects of SUSY electroweak corrections and the Yukawa corrections can exceed 10% for favorable parameter values, which might be observable at a high-luminosity Tevatron.

Chong Sheng Li; Robert J. Oakes; Jin Min Yang

1996-11-27T23:59:59.000Z

146

DZero (D0) Experiment Results for Top Quark Physics from the Fermilab Tevatron  

DOE Data Explorer (OSTI)

The D0 (DZero) Experiment is a worldwide collaboration of scientists conducting research on the fundamental nature of matter. The experiment is located at the Tevatron Collider, Fermilab. The research is focused on precise studies of interactions of protons and antiprotons and involves an intense search for subatomic clues that reveal the character of the building blocks of the universe. This web page provides access to Run II research results of the Top Quark Physics group, including preliminary, submitted, and published results. Figures and data plots are found in the directories with their respective papers.

147

Discovery Mass Reach for Excited Quarks at Hadron Colliders  

E-Print Network (OSTI)

If quarks are composite particles then excited states are expected. We estimate the discovery mass reach as a function of integrated luminosity for excited quarks decaying to dijets at the Tevatron, LHC, and a Very Large Hadron Collider (VLHC). At the Tevatron the mass reach is 0.94 TeV for Run II (2 fb^-1) and 1.1 TeV for TeV33 (30 fb^-1). At the LHC the mass reach is 6.3 TeV for 100 fb^-1. At a VLHC with a center of mass energy, sqrt(s), of 50 TeV (200 TeV) the mass reach is 25 TeV (78 TeV) for an integrated luminosity of 10^4 fb^-1. However, an excited quark with a mass of 25 TeV would be discovered at a hadron collider with sqrt(s)=100 TeV and an integrated luminosity of 13 fb^-1, illustrating a physics example where a factor of 2 in machine energy is worth a factor of 1000 in luminosity.

Robert M. Harris

1996-09-11T23:59:59.000Z

148

Searching the Inclusive Lepton + Photon + Missing E(T) + b-quark Signature for Radiative Top Quark Decay and Non-Standard-Model Processes  

SciTech Connect

In a search for new phenomena in a signature suppressed in the standard model of elementary particles (SM), we compare the inclusive production of events containing a lepton ({ell}), a photon ({gamma}), significant transverse momentum imbalance (E{sub T}), and a jet identified as containing a b-quark, to SM predictions. The search uses data produced in proton-antiproton collisions at {radical}s = 1.96 TeV corresponding to 1.9 fb{sup -1} of integrated luminosity taken with the CDF detector at the Fermilab Tevatron. We find 28 {ell}{gamma}bE{sub T} events versus an expectation of 31.0{sub -3.5}{sup +4.1} events. If we further require events to contain at least three jets and large total transverse energy, simulations predict that the largest SM source is top-quark pair production with an additional radiated photon, t{bar t} + {gamma}. In the data we observe 16 t{bar t}{gamma} candidate events versus an expectation from non-top-quark SM sources of 11.2{sub -2.1}{sup +2.3}. Assuming the difference between the observed number and the predicted non-top-quark total is due to SM top quark production, we estimate the t{bar t} cross section to be 0.15 {+-} 0.08 pb.

Aaltonen, T.; /Helsinki Inst. of Phys.; Adelman, Jahred A.; /Chicago U., EFI; Akimoto, T.; /Tsukuba U.; Alvarez Gonzalez, B.; /Cantabria Inst. of Phys.; Amerio, S.; /INFN, Padua; Amidei, Dante E.; /Michigan U.; Anastassov, A.; /Northwestern U.; Annovi, Alberto; /Frascati; Antos, Jaroslav; /Comenius U.; Apollinari, G.; /Fermilab; Apresyan, A.; /Purdue U. /Waseda U.

2009-06-01T23:59:59.000Z

149

Renormalization group-induced phenomena of top pairs from four-quark effective operators  

E-Print Network (OSTI)

We study the renormalization group(RG) evolution of four-quark operators that contribute to the top pair production. In particular, we focus on the cases in which certain observables are first induced from the one-loop RG while being absent at tree-level. From the operator mixing pattern, we classify all such RG-induced phenomena and underlying models that can induce them. We then calculate the full one-loop QCD RG evolution as the leading estimator of the effects and address the question of which RG-induced phenomena have largest and observable effects. The answer is related to the color structure of QCD. The studied topics include the RG-induction of top asymmetries, polarizations and polarization mixings as well as issues arising at this order. The RG-induction of top asymmetries is further compared with the generation of asymmetries from QCD and QED at one-loop order. We finally discuss the validity of using the RG as the proxy of one-loop effects on the top pair production. As an aside, we clarify the of...

Jung, Sunghoon; Yoon, Yeo Woong; Yu, Chaehyun

2014-01-01T23:59:59.000Z

150

Top Production  

NLE Websites -- All DOE Office Websites (Extended Search)

Top Principal ESTOY PERDIDO!!! Top Principal ESTOY PERDIDO!!! Protón + Antiprotón --> Top + Antitop Un quark (perteneciente a un protón) y un antiquark (perteneciente a un antiprotón), colisionando a alta energía, pueden aniquilarse para producir un quark top y un antiquark top, los cuales decaen luego hacia otras partículas. Cuadro 1: un quark de un protón y un antiquark de un antiprotón se precipitan uno al encuentro del otro. Cuadro 2: los quarks colisionan y se aniquilan.... Cuadro 3: ...en gluones virtuales. Cuadro 4: de la nube de gluones emergen un quark top y un antiquark top. Cuadro 5: los quarks comienzan separarse, estirando el campo de fuerza de color (campo de gluones) entre ambos. Cuadro 6: antes de que el quark top y el antiquark top se hayan separado mucho, ambos decaen hacia un quark bottom y un antiquark bottom

151

Search for s-channel single top-quark production in proton-proton collisions at $\\sqrt{s}$=8 TeV with the ATLAS detector  

E-Print Network (OSTI)

This Letter presents a search at the LHC for s-channel single top-quark production in proton-proton collisions at a centre-of-mass energy of 8 TeV. The analyzed data set was recorded by the ATLAS detector and corresponds to an integrated luminosity of 20.3 fb$^{-1}$. Selected events contain one charged lepton, large missing transverse momentum and exactly two b-tagged jets. A multivariate event classifier based on boosted decision trees is developed to discriminate s-channel single top-quark events from the main background contributions. The signal extraction is based on a binned maximum-likelihood fit of the output classifier distribution. The analysis leads to an upper limit on the s-channel single top-quark production cross-section of 14.6 pb at the 95% confidence level. The fit gives a cross-section of $\\sigma_s$=5.0$\\pm$4.3 pb, consistent with the Standard Model expectation.

ATLAS Collaboration

2015-02-12T23:59:59.000Z

152

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)

I present the results of a search for pair production of scalar top quarks (~t1) in an R-parity violating supersymmetric scenario using 322 pb_1 of pp collisions at ps = 1.96 TeV collected by the upgraded Collider Detector at Fermilab. I assume each...

Khotilovich, Vadim Gennadyevich

2009-05-15T23:59:59.000Z

153

Spectral probabilities of top-down tandem mass spectra  

SciTech Connect

In mass spectrometry (MS)-based proteomics, accurate estimation of statistical signicance of peptide and protein identications is desired for determining whether they are actually correct. Probabilistic models, such as the generating function method, have been successfully applied to compute statistical signicance of peptide-spectrum matches (PSMs) in bottom-up MS, but it is limited to PSMs of short peptides without post-translational modications (PTMs). Recently, top-down MS has be- come available in many laboratories, which often identies intact proteins with PTMs. In this paper, we propose an extended generating function (EGF) method for accurately computing statistical signicance of protein- spectrum matches (PrSMs) with PTMs.

Liu, Xiaowen; Segar, Matthew W.; Li, Shuai Cheng; Kim, Sangtae

2014-01-24T23:59:59.000Z

154

CP nonconservation in supersymmetry with radiative quark masses  

Science Journals Connector (OSTI)

In supersymmetric extensions of the standard model, the neutron-electric-dipole moment is typically two or three orders of magnitude above its experimental upper bound unless the relevant CP-nonconserving phase is suppressed. This situation is highly undesirable, especially in models of radiative masses, in general, where the absence of small parameters at tree level is their raison d’être. In this paper we identify the various sources of CP nonconservation in such models and present a possible solution which also gives the observed pattern of quark masses and mixing angles.

Ernest Ma and Daniel Ng

1990-11-12T23:59:59.000Z

155

CP violation in seesaw models of quark masses  

Science Journals Connector (OSTI)

CP phenomenology in ‘‘seesaw’’ models of quark masses is shown to parallel that of the usual left-right-symmetric models with the additional advantage that it provides a natural solution to the strong CP problem. For the case where the third-generation mixing parameter Vub is extremely small, the neutral-Higgs-boson interactions lead to ?’/??10-3 and the electric dipole moment of the neutron dn?10-25 e cm. Smallness of the neutrino masses is understood as a two-loop effect.

K. S. Babu and Rabindra N. Mohapatra

1989-03-06T23:59:59.000Z

156

Search for scalar top quark production in p[bar over p] collisions at ?s = 1.96 TeV  

E-Print Network (OSTI)

We report on a search for the supersymmetric partner of the top quark (scalar top) decaying into a charm quark and a neutralino in p[¯ over p] collisions at ?s = 1.96 TeV. The data sample, collected by the CDF II detector ...

Gomez-Ceballos, Guillelmo

157

Production of single top-quark final states at the LHC from supersymmetric FCNC interactions  

E-Print Network (OSTI)

We discuss the production of single top-quark final states by direct supersymmetric flavor-changing interactions at the LHC. The total cross section pp(gg)->t\\bar{c}+\\bar{t}c is computed at the 1-loop order within the unconstrained MSSM. We prove that SUSY-QCD effects may furnish sizeable production rates amounting up to barely 10^5 t\\bar{c}(c\\bar{t}) events per 100 fb^{-1} of integrated luminosity, in full compliance with the stringent low-energy constraints from b->s gamma. Furthermore, we show that the cooperative SUSY-EW effects can be sizeable on their own, regardless of the SUSY-QCD contribution, with maximum production rates of the order of 10^3 events per 100 fb^{-1}. Owing to the fact that FCNC production of electrically neutral heavy-quark pairs is virtually absent within the SM, we conclude that the observation of such pp(gg)->t\\bar{c}+\\bar{t}c processes at the LHC could lead to evidence of new physics - of likely supersymmetric nature.

David Lopez-Val; Jaume Guasch; Joan Sola

2008-01-16T23:59:59.000Z

158

Kinematic evidence for top quark pair production in W+multijet events in pp¯ collisions at ?s =1.8 TeV  

Science Journals Connector (OSTI)

We present a study of W+multijet events that compares the kinematics of the observed events with expectations from direct QCD W+jet production and from production and decay of top quark pairs. The data were collected in the 1992–93 run with the Collider Detector at Fermilab (CDF) from 19.3 pb-1 of proton-antiproton collisions at ?s =1.8 TeV. A W+?2 jet sample and a W+?3 jet sample are selected with the requirement that at least the two or three jets have energy transverse with respect to the beam axis in excess of 20 GeV. The jet energy distributions for the W+?2 jet sample agree well with the predictions of direct QCD W production. From the W+?3 jet events, a ‘‘signal sample’’ with an improved ratio of tt¯ to QCD produced W events is selected by requiring each jet to be emitted centrally in the event center of mass frame. This sample contains 14 events with unusually hard jet ET distributions not well described by expectations for jets from direct QCD W production and other background processes. Using expected jet ET distributions, a relative likelihood is defined and used to determine if an event is more consistent with the decay of tt¯ pairs, with Mtop=170 GeV/c2, than with direct QCD W production. Eight of the 14 signal sample events are found to be more consistent with top-quark than direct QCD W production, while only 1.7 such top-quark–like events are expected in the absence of tt¯.The probability that the observation is due to an upward fluctuation of the number of background events is found to be 0.8%. The robustness of the result was tested by varying the cuts defining the signal sample, and the largest probability for such a fluctuation found was 1.9%. Good agreement in the jet spectra is obtained if jet production from tt¯ pair decays is included. For those events kinematically more consistent with tt¯ we find evidence for a b-quark content in their jets to the extent expected from top quark decay, and larger than expected for background processes. For events with four or more jets, the discrepancy with the predicted jet distributions from direct QCD W production, and the associated excess of b-quark content, is more pronounced.

F. Abe et al.

1995-05-01T23:59:59.000Z

159

Observation of Top Quark Production in [¯ over p]p Collisions with the Collider Detector at Fermilab  

E-Print Network (OSTI)

We establish the existence of the top quark using a 67pb[superscript ?1] data sample of [¯ over p]p collisions at ?s = 1.8TeV collected with the Collider Detector at Fermilab (CDF). Employing techniques similar to those ...

Bauer, Gerry P.

160

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

SciTech Connect

We measure the inclusive forward-backward asymmetry of the charged-lepton pseudorapidities from top-quark pairs produced in proton-antiproton collisions, and decaying to final states that contain two charged leptons (electrons or muons), using data collected with the Collider Detector at Fermilab.

Aaltonen, Timo Antero; et al.,

2014-07-23T23:59:59.000Z

Note: This page contains sample records for the topic "top quark mass" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Heavy flavour physics from top to bottom  

SciTech Connect

We review the status of heavy flavour physics at the Fermilab Tevatron collider by summarizing recent top quark and B physics results from CDF and D0. In particular we discuss the measurement of the top quark mass and top production cross section as well as B meson lifetimes and time dependent B{bar B} mixing results. An outlook of perspectives for top and B physics in Run II starting in 1999 is also given. 38 refs., 23 figs., 8 tabs.

Paulini, M. [Lawrence Berkeley National Lab., CA (United States); CDF and D0 Collaborations

1997-01-01T23:59:59.000Z

162

TOP AND HIGGS PHYSICS AT THE HADRON COLLIDERS  

SciTech Connect

This review summarizes the recent results for top quark and Higgs boson measurements from experiments at Tevatron, a proton–antiproton collider at a center-of-mass energy of ? s =1 . 96 TeV, and the Large Hadron Collider, a proton–proton collider at a center- of-mass energy of ? s = 7 TeV. These results include the discovery of a Higgs-like boson and measurement of its various properties, and measurements in the top quark sector, e.g. top quark mass, spin, charge asymmetry and production of single top quark.

Jabeen, Shabnam

2013-10-20T23:59:59.000Z

163

Quarkonium mass splittings with Fermilab heavy quarks and 2+1 flavors of improved staggered sea quarks  

E-Print Network (OSTI)

We present results from an ongoing lattice study of the lowest lying charmonium and bottomonium level splittings using the Fermilab heavy quark formalism. Our objective is to test the performance of this action on MILC-collaboration ensembles of (2+1) flavors of light improved staggered (asqtad) quarks. Measurements are done on 16 ensembles with degenerate up and down quarks of various masses, thus permitting a chiral extrapolation, and over lattice spacings ranging from 0.09 fm to 0.18 fm, thus permitting study of lattice-spacing dependence. We examine combinations of the mass splittings that are sensitive to components of the effective quarkonium potential.

T. Burch; C. E. DeTar; M. Di Pierro; A. X. El-Khadra; Steven Gottlieb; A. S. Kronfeld; L. Levkova; P. B. Mackenzie; J. Simone

2009-11-02T23:59:59.000Z

164

E-Print Network 3.0 - arbitrary quark mass Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

Group, Brookhaven National Laboratory Collection: Physics 2 SpontaneousViolation of CP Symmetry in the Strong Interactions Michael Creutz Summary: of quark mass parameters for...

165

Model-independent measurement of $\\boldsymbol{t}$-channel single top quark production in $\\boldsymbol{p\\bar{p}}$ collisions at $\\boldsymbol{\\sqrt{s}=1.96}$ TeV  

SciTech Connect

We present a model-independent measurement of t-channel electroweak production of single top quarks in p{bar p} collisions at {radical}s = 1.96 TeV. Using 5.4 fb{sup -1} of integrated luminosity collected by the D0 detector at the Fermilab Tevatron Collider, and selecting events containing an isolated electron or muon, missing transverse energy and one or two jets originating from the fragmentation of b quarks, we measure a cross section {sigma}(p{bar p} {yields} tqb + X) = 2.90 {+-} 0.59 (stat + syst) pb for a top quark mass of 172.5 GeV. The probability of the background to fluctuate and produce a signal as large as the one observed is 1.6 x 10{sup -8}, corresponding to a significance of 5.5 standard deviations.

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

2011-05-01T23:59:59.000Z

166

Quark and lepton masses and mixing in the landscape  

E-Print Network (OSTI)

Even if quark and lepton masses are not uniquely predicted by the fundamental theory, as may be the case in the string theory landscape, nevertheless their pattern may reveal features of the underlying theory. We use statistical techniques to show that the observed masses appear to be representative of a scale invariant distribution, rho(m) ~ 1/m. If we extend this distribution to include all the Yukawa couplings, we show that the resulting CKM matrix elements typically show a hierarchical pattern similar to observations. The Jarlskog invariant measuring the amount of CP violation is also well reproduced in magnitude. We also apply this framework to neutrinos using the seesaw mechanism. The neutrino results are ambiguous, with the observed pattern being statistically allowed even though the framework does not provide a natural explanation for the observed two large mixing angles. Our framework highly favors a normal hierarchy of neutrino masses. We also are able to make statistical predictions in the neutrino sector when we specialize to situations consistent with the known mass differences and two large mixing angles. Within our framework, we show that with 95% confidence the presently unmeasured MNS mixing angle sin theta_{13} is larger than 0.04 and typically of order 0.1. The leptonic Jarlskog invariant is found to be typically of order 10^{-2} and the magnitude of the effective Majorana mass m_{ee} is typically of order 0.001 eV.

John F. Donoghue; Koushik Dutta; Andreas Ross

2006-01-27T23:59:59.000Z

167

QCD Corrections to Flavor Changing Neutral Coupling Mediated Rare Top Quark Decays  

E-Print Network (OSTI)

Recently we have presented an analysis of flavor changing neutral coupling mediated radiative top quark decays at next-to-leading order in QCD. In the present paper we provide the details of the calculation of QCD corrections to t-> q gamma and t-> q Z decays within the effective theory approach including operator mixing. In particular, we calculate virtual matrix element corrections and the corresponding bremsstrahlung contributions. In the case of t-> q gamma we study the effects of kinematic cuts on the extracted branching ratios. Analytical formulae are given at all stages of the calculation. We find that the t-> q gamma decay can be used to probe also the effective operators mediating t-> q g processes, since these can naturally contribute 10% or more to the radiative decay, given typical experimental cuts on the decay kinematics at hadron colliders. Conversely, we argue that any positive experimental signal of the t-> q g process would indicate a natural lower bound on t-> q gamma decay rate.

Jure Drobnak; Svjetlana Fajfer; Jernej F. Kamenik

2010-07-15T23:59:59.000Z

168

Combination of CDF and D0 measurements of the $W$ boson helicity in top quark decays  

SciTech Connect

We report the combination of recent measurements of the helicity of the W boson from top quark decay by the CDF and D0 collaborations, based on data samples corresponding to integrated luminosities of 2.7-5.4 fb{sup -1} of p{bar p} collisions collected during Run II of the Fermilab Tevatron Collider. Combining measurements that simultaneously determine the fractions of W bosons with longitudinal (f{sub 0}) and right-handed (f{sub +}) helicities, we find f{sub 0} = 0.722 {+-} 0.081 [{+-} 0.062 (stat.) {+-} 0.052 (syst.)] and f{sub +} = -0.033 {+-} 0.046 [{+-} 0.034 (stat.) {+-} 0.031 (syst.)]. Combining measurements where one of the helicity fractions is fixed to the value expected in the standard model, we find f{sub 0} = 0.682 {+-} 0.057 [{+-} 0.035 (stat.) {+-} 0.046 (syst.)] and f{sub +} = ?0.015 {+-} 0.035 [{+-} 0.018 (stat.) {+-} 0.030 (syst.)]. The results are consistent with standard model expectations.

Aaltonen, T.; /Helsinki Inst. of Phys.; Abazov, V.M.; /Dubna, JINR; Abbott, B.; /Oklahoma U.; Acharya, B.S.; /Tata Inst.; Adams, M.; /Illinois U., Chicago; Adams, T.; /Florida State U.; Alexeev, G.D.; /Dubna, JINR; Alkhazov, G.; /St. Petersburg, INP; Alton, A.; /Augustana Coll., Sioux Falls /Michigan U.; Alvarez Gonzalez, B.; /Oviedo U. /Cantabria Inst. of Phys.; Alverson, G.; /Northeastern U. /INFN, Padua

2012-02-01T23:59:59.000Z

169

CDF Top Physics  

DOE R&D Accomplishments (OSTI)

The authors present the latest results about top physics obtained by the CDF experiment at the Fermilab Tevatron collider. The data sample used for these analysis (about 110 pb{sup{minus}1}) represents almost the entire statistics collected by CDF during four years (1992--95) of data taking. This large data size has allowed detailed studies of top production and decay properties. The results discussed here include the determination of the top quark mass, the measurement of the production cross section, the study of the kinematics of the top events and a look at top decays.

Tartarelli, G. F.; CDF Collaboration

1996-05-00T23:59:59.000Z

170

The role of quark mass in cold and dense perturbative QCD  

E-Print Network (OSTI)

We consider the equation of state of QCD at high density and zero temperature in perturbation theory to first order in the coupling constant $\\alpha_s$. We compute the thermodynamic potential including the effect of a non-vanishing mass for the strange quark and show that corrections are sizable. Renormalization group running of the coupling and the strange quark mass plays a crucial role. The structure of quark stars is dramatically modified.

Eduardo S. Fraga; Paul Romatschke

2005-05-27T23:59:59.000Z

171

Search for top-quark production via flavor-changing neutral currents in W+1 jet events at CDF  

SciTech Connect

We report on the first search for top-quark production via flavor-changing neutral-current (FCNC) interactions in the non-standard-model process u(c)+g {yields} t using p{bar p} collision data collected by the CDF II detector. The data set corresponds to an integrated luminosity of 2.2 fb{sup -1}. The candidate events feature the signature of semileptonic top-quark decays and are classified as signal-like or background-like by an artificial neural network trained on simulated events. The observed discriminant distribution is in good agreement with the one predicted by the standard model and provides no evidence for FCNC top-quark production, resulting in a Bayesian upper limit on the production cross section {sigma}(u(c)+g {yields} t) < 1.8 pb at the 95% confidence level. Using theoretical predictions we convert the cross-section limit to upper limits on FCNC branching ratios: {Beta}(t {yields} u + g) < 3.9 x 10{sup -4} and {Beta}(t {yields} c + g) < 5.7 x 10{sup -3}.

Aaltonen, T.; /Helsinki Inst. of Phys.; Adelman, J.; /Chicago U., EFI; Akimoto, T.; /Tsukuba U.; Alvarez Gonzalez, B.; /CSIC, Catalunya; Amerio, S.; /INFN, Padua; Amidei, D.; /Michigan U.; Anastassov, A.; /Northwestern U.; Annovi, A.; /Frascati; Antos, J.; /Comenius U.; Apollinari, G.; /Fermilab; Apresyan, A.; /Purdue U. /Waseda U.

2008-12-01T23:59:59.000Z

172

Unified Explanation of Quark and Lepton Masses and Mixings in the Supersymmetric SO(10) Model  

E-Print Network (OSTI)

We discussed neutrino masses and mixings in SUSY SO(10) model where quarks and leptons have Yukawa couplings to at least two 10 and one $\\bar{126}$ Higgs scalars. In this model, the Dirac and the right-handed Majorana mass terms are expressed by linear combinations of quark and charged lepton mass matrices, which then determine the neutrino mass matrix by the see-saw mechanism. We show that there are various solutions to reproduce a large mixing angle for $\

Kin-ya Oda; Eiichi Takasugi; Minoru Tanaka; Masaki Yoshimura

1998-08-06T23:59:59.000Z

173

Mesure de la section efficace de production de paires de quarks top dans l'etat final di-electron avec les donnees collectees par l'experience D0 au RunIIa  

SciTech Connect

The top quark has been discovered in 1995 by CDF and D0 collaborations in proton-antiproton collisions at the Tevatron. The amount of data recorded by both experiments makes it possible to accurately measure the properties of this very massive quark. This thesis is devoted to the measurement of the top pair production cross-section via the strong interaction, in a final state composed of two electrons, two particle jets and missing transverse energy. It is based on a 1 fb{sup -1} data set collected by the D0 experiment between 2002 and 2006. The reconstruction and identification of electrons and jets is of major importance in this analysis, and have been studied in events where a Z boson is produced together with one or more jets. The Z+jets process is indeed the dominant physics background to top pair production in the dielectron final state. The primary goal of this cross-section measurement is to verify Standard Model predictions. In this document, this result is also interpreted to indirectly extract the top quark mass. Moreover, the cross-section measurement is sensitive to new physics such as the existence of a charged Higgs boson. The selection established for the cross-section analysis has been used to search for a H{sup +} boson lighter than the top quark, where the latter can decay into a W{sup +} or H{sup +} boson and a b quark. The model that has been studied makes the assumption that the H{sup +} boson can only decay into a tau lepton and a neutrino.

Martin Dit Latour, Bertrand; /LPSC, Grenoble

2008-09-01T23:59:59.000Z

174

Top-quark production in proton-nucleus and nucleus-nucleus collisions at LHC energies and beyond  

E-Print Network (OSTI)

Single and pair top-quark production in proton-lead (p-Pb) and lead-lead (Pb-Pb) collisions at the CERN Large Hadron Collider (LHC) and future circular collider (FCC) energies, are studied with next-to-leading-order perturbative QCD calculations including nuclear parton distribution functions. At the LHC, the pair-production cross sections amount to sigma(t-tbar) = 3.4 mub in Pb-Pb at sqrt(s) = 5.5 TeV, and sigma(t-tbar) = 60 nb in p-Pb at sqrt(s) = 8.8 TeV. At the FCC energies of sqrt(s) = 39 and 63 TeV, the same cross sections are factors of 90 and 55 times larger respectively. In the leptonic final-state t-tbar --> W+b W-bbar --> b bbar l+l- nu+nu-, after typical acceptance and efficiency cuts, one expects about 90 and 300 top-quarks per nominal LHC-year and 4.7 10^4 and 10^5 per FCC-year in Pb-Pb and p-Pb collisions respectively. The total t-tbar cross sections, dominated by gluon fusion processes, are enhanced by 3--8% in nuclear compared to p-p collisions due to an overall net gluon antishadowing, although different regions of their differential distributions are depleted due to shadowing or EMC-effect corrections. The rapidity distributions of the decay leptons in t-tbar processes can be used to reduce the uncertainty on the Pb gluon density at high virtualities by up to 30% at the LHC (full heavy-ion programme), and by 70% per FCC-year. The cross sections for single-top production in electroweak processes are also computed, yielding about a factor of 30 smaller number of measurable top-quarks after cuts, per system and per year.

David d'Enterria; Krisztian Krajczar; Hannu Paukkunen

2015-01-23T23:59:59.000Z

175

Search for Scalar Top Quark Pair-Production in Scenario with Violated R-parity in ppbar Collisions at sqrt(s)=1.96 TeV  

SciTech Connect

A search for the pair production of supersymmetric partner of the top quark in scenario with R-parity violation is presented. The quantum number called R-parity distinguishes particles in standard model from supersymmetric particles. A scalar top quark (stop) is assumed to decay only via R{sub p}-violating supersymmetric coupling into tau lepton and b-quark. To collect events with multiple taus, a new special tau trigger (the lepton plus track trigger) is installed in Run II experiment of the Collider Detector at Fermilab (CDF). The goal of the lepton plus track trigger is to collect generic dilepton ({ell}{ell}, {ell}{tau}, {tau}{tau}) events with lower p{sub T} threshold (8 GeV/c) and without prescale even at high luminosity. The Z {yields} {tau}{tau} event, where one {tau}-lepton decays leptonically and the other hadronically, is a good benchmark to calibrate the lepton plus track trigger and {tau} identification. The data sample of 72 pb{sup -1}, collected using the electron plus track trigger, contains clear a {tau} signal from Z {yields} {tau}{tau} events. The data used in stop search correspond to 200 pb{sup -1}. The lower stop mass bound of 134 GeV/c{sup 2} at a 95% confidence level is obtained. This limit is also directly applicable to the case of the third generation scalar leptoquark (LQ{sub 3}) assuming a 100% branching for the LQ{sub 3} {yields} {tau}b decay mode.

Ogawa, Takashi; /Waseda U.

2005-01-01T23:59:59.000Z

176

Finite top-mass effects in gluon-induced Higgs production with a jet-veto at NNLO  

E-Print Network (OSTI)

Effects from a finite top quark mass on the H+n-jet cross section through gluon fusion are studied for $n=0/n\\ge 1$ at NNLO/NLO QCD. For this purpose, sub-leading terms in $1/m_t$ are calculated. We show that the asymptotic expansion of the jet-vetoed cross section at NNLO is very well behaved and that the heavy-top approximation is valid at the five permille level up to jet-veto cuts of 300 GeV. For the inclusive Higgs+jet rate, we introduce a matching procedure that allows for a reliable prediction of the top-mass effects using the expansion in $1/m_t$. The quality of the effective field theory to evaluate differential K-factors for the distribution of the hardest jet is found to be better than 1-2% as long as the transverse momentum of the jet is integrated out or remains below about 150 GeV.

Neumann, Tobias

2014-01-01T23:59:59.000Z

177

Search for a Very Light CP-Odd Higgs Boson in Top Quark Decays from pp? Collisions at ?s = 1.96 TeV  

We present the results of a search for a very light CP-odd Higgs boson a10 originating from top quark decays t?H±b ? W±(*)a10b, and subsequently decaying into ?+?-. Using a data sample corresponding to an integrated luminosity of 2.7 fb-1 collected by the CDF II detector in pp? collisions at 1.96 TeV, we perform a search for events containing a lepton, three or more jets, and an additional isolated track with transverse momentum in the range 3 to 20 GeV/c. Observed events are consistent with background sources, and 95% C.L. limits are set on the branching ratio of t?H±b for various masses of H± and a10.

Aaltonen, T [Helsinki Inst. of Phys.; Gonzalez, B Alvarez [Oviedo U.; Cantabria Inst. of Phys.; Amerio, S [INFN, Padua; Amidei, D [Michigan U.; Anastassov, A [Northwestern U.; Annovi, A [Frascati; Antos, J [Comenius U.; Apollinari, G [Fermilab; Appel, J A [Fermilab; Apresyan, A [Purdue U.; Arisawa, T [Waseda U.; Dubna, JINR

2011-07-11T23:59:59.000Z

178

Constraining a fourth generation of quarks: non-perturbative Higgs boson mass bounds  

E-Print Network (OSTI)

We present a non-perturbative determination of the upper and lower Higgs boson mass bounds with a heavy fourth generation of quarks from numerical lattice computations in a chirally symmetric Higgs-Yukawa model. We find that the upper bound only moderately rises with the quark mass while the lower bound increases significantly, providing additional constraints on the existence of a straight-forward fourth quark generation. We examine the stability of the lower bound under the addition of a higher dimensional operator to the scalar field potential using perturbation theory, demonstrating that it is not significantly altered for small values of the coupling of this operator. For a Higgs boson mass of $\\sim125\\mathrm{GeV}$ we find that the maximum value of the fourth generation quark mass is $\\sim300\\mathrm{GeV}$, which is already in conflict with bounds from direct searches.

John Bulava; Karl Jansen; Attila Nagy

2013-01-15T23:59:59.000Z

179

Top-quark production in proton-nucleus and nucleus-nucleus collisions at LHC energies and beyond  

E-Print Network (OSTI)

Single and pair top-quark production in proton-lead (p-Pb) and lead-lead (Pb-Pb) collisions at the CERN Large Hadron Collider (LHC) and future circular collider (FCC) energies, are studied with next-to-leading-order perturbative QCD calculations including nuclear parton distribution functions. At the LHC, the pair-production cross sections amount to sigma(t-tbar) = 3.4 mub in Pb-Pb at sqrt(s) = 5.5 TeV, and sigma(t-tbar) = 60 nb in p-Pb at sqrt(s) = 8.8 TeV. At the FCC energies of sqrt(s) = 39 and 63 TeV, the same cross sections are factors of 90 and 55 times larger respectively. In the leptonic final-state t-tbar --> W+b W-bbar --> b bbar l+l- nu+nu-, after typical acceptance and efficiency cuts, one expects about 90 and 300 top-quarks per nominal LHC-year and 4.7 10^4 and 10^5 per FCC-year in Pb-Pb and p-Pb collisions respectively. The total t-tbar cross sections, dominated by gluon fusion processes, are enhanced by 3--8% in nuclear compared to p-p collisions due to an overall net gluon antishadowing, altho...

d'Enterria, David; Paukkunen, Hannu

2015-01-01T23:59:59.000Z

180

Updated Measurement of the Single Top Quark Production Cross Section and $V{tb}$ in the Missing Transverse Energy Plus Jets Topology in $p\\bar{p}$ Collisions at $\\sqrt{s} = 1.96$ TeV  

E-Print Network (OSTI)

An updated measurement of the single top quark production cross section is presented using the full data set collected by the Collider Detector at Fermilab (CDF) and corresponding to 9.5 fb${}^{-1}$ of integrated luminosity from proton-antiproton collisions at 1.96 TeV center-of-mass energy. The events selected contain an imbalance in the total transverse energy, jets identified as originating from $b$ quarks, and no identified leptons. The sum of the $s$- and $t$-channel single top quark cross sections is measured to be $3.53_{-1.16}^{+1.25}$ pb and a lower limit on $V_{tb}$ of 0.63 is obtained at the 95% credibility level. These measurements are combined with previously reported CDF results obtained from events with an imbalance in total transverse energy, jets identified as originating from $b$ quarks, and exactly one identified lepton. The combined cross section is measured to be $3.02_{-0.48}^{+0.49}$ pb and a lower limit on $V{tb}$ of 0.84 is obtained at the 95% credibility level.

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

2014-10-21T23:59:59.000Z

Note: This page contains sample records for the topic "top quark mass" from the National Library of EnergyBeta (NLEBeta).
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181

Top condensation as a motivated explanation of the top forward-backward asymmetry  

E-Print Network (OSTI)

Models of top condensation can provide both a compelling solution to the hierarchy problem as well as an explanation of why the top-quark mass is large. The spectrum of such models, in particular topcolor-assisted technicolor, includes top-pions, top-rhos and the top-Higgs, all of which can easily have large top-charm or top-up couplings. Large top-up couplings in particular would lead to a top forward-backward asymmetry through $t$-channel exchange, easily consistent with the Tevatron measurements. Intriguingly, there is destructive interference between the top-mesons and the standard model which conspire to make the overall top pair production rate consistent with the standard model. The rate for same-sign top production is also small due to destructive interference between the neutral top-pion and the top-Higgs. Flavor physics is under control because new physics is mostly confined to the top quark. In this way, top condensation can explain the asymmetry and be consistent with all experimental bounds. There are many additional signatures of topcolor with large tu mixing, such as top(s)+jet(s) events, in which a top and a jet reconstruct a resonance mass, which make these models easily testable at the LHC.

Yanou Cui; Zhenyu Han; Matthew D. Schwartz

2011-06-15T23:59:59.000Z

182

Radiative Generation of Quark Masses and Mixing Angles in the Two Higgs Doublet Model  

E-Print Network (OSTI)

We present a framework to generate the quark mass hierarchies and mixing angles by extending the Standard Model with one extra Higgs doublet. The charm and strange quark masses are generated by small quantum effects, thus explaining the hierarchy between the second and third generation quark masses. All the mixing angles are also generated by small quantum effects: the Cabibbo angle is generated at zero-th order in perturbation theory, while the remaining off-diagonal entries of the Cabibbo-Kobayashi-Maskawa matrix are generated at first order, hence explaining the observed hierarchy $|V_{ub}|,|V_{cb}|\\ll |V_{us}|$. The values of the radiatively generated parameters depend only logarithmically on the heavy Higgs mass, therefore this framework can be reconciled with the stringent limits on flavor violation by postulating a sufficiently large new physics scale.

Alejandro Ibarra; Ana Solaguren-Beascoa

2014-07-04T23:59:59.000Z

183

Grand Unified Yukawa Matrix Ansatz: The Standard Model Fermion Mass, Quark Mixing and CP Violation Parameters  

E-Print Network (OSTI)

We propose a new mass matrix ansatz: At the grand unified (GU) scale, the standard model (SM) Yukawa coupling matrix elements are integer powers of the square root of the GU gauge coupling constant \\varepsilon \\equiv \\sqrt{\\alpha_{\\text{GU}}}, multiplied by order unity random complex numbers. It relates the hierarchy of the SM ermion masses and quark mixings to the gauge coupling constants, greatly reducing the SM parameters, and can give good fitting results of the SM fermion mass, quark mixing and CP violation parameters. This is a neat but very effective ansatz.

Yong-Chao Zhang; De-Hai Zhang

2009-10-20T23:59:59.000Z

184

Search for Top-Quark Production via Flavor-Changing Neutral Currents in W+1 Jet Events at CDF  

SciTech Connect

We report on a search for the non-standard-model process u(c)+g{yields}t using pp collision data collected by the Collider Detector at Fermilab II detector corresponding to 2.2 fb{sup -1}. The candidate events are classified as signal-like or backgroundlike by an artificial neural network. The observed discriminant distribution yields no evidence for flavor-changing neutral current top-quark production, resulting in an upper limit on the production cross section {sigma}(u(c)+g{yields}t)<1.8 pb at the 95% C.L. Using theoretical predictions we convert the cross section limit to upper limits on flavor-changing neutral current branching ratios: B(t{yields}u+g)<3.9x10{sup -4} and B(t{yields}c+g)<5.7x10{sup -3}.

Aaltonen, T.; Maki, T.; Mehtala, P.; Orava, R.; Osterberg, K.; Saarikko, H.; Remortel, N. van [Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki (Finland); Adelman, J.; Brubaker, E.; Fedorko, W. T.; Grosso-Pilcher, C.; Kim, Y. K.; Krop, D.; Kwang, S.; Lee, H. S.; Paramonov, A. A.; Schmidt, M. A.; Shiraishi, S.; Shochet, M.; Wilbur, S. [Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637 (United States)] (and others)

2009-04-17T23:59:59.000Z

185

Measurement of the W boson helicity in top quark decays using 5.4??fb-1 of pp¯ collision data  

Science Journals Connector (OSTI)

We present a measurement of the helicity of the W boson produced in top quark decays using tt¯ decays in the ?+jets and dilepton final states selected from a sample of 5.4??fb-1 of collisions recorded using the D0 detector at the Fermilab Tevatron pp¯ collider. We measure the fractions of longitudinal and right-handed W bosons to be f0=0.669±0.102[±0.078(stat.)±0.065(syst.)] and f+=0.023±0.053[±0.041(stat.)±0.034(syst.)], respectively. This result is consistent at the 98% level with the standard model. A measurement with f0 fixed to the value from the standard model yields f+=0.010±0.037[±0.022(stat.)±0.030(syst.).].

V. M. Abazov et al. (D0 Collaboration)

2011-02-18T23:59:59.000Z

186

Multivariate methods and the search for single top-quark production in association with a $W$ boson in ATLAS  

E-Print Network (OSTI)

This thesis describes three machine learning algorithms that can be used for physics analyses. The first is a density estimator that was derived from the Green’s function identity of the Laplace operator and is capable of tagging data samples according to the signal purity. This latter task can also be performed with regression methods, and such an algorithm was implemented based on fast multi-dimensional polynomial regression. The accuracy was improved with a decision tree using smooth boundaries. Both methods apply rigorous checks against overtraining to make sure the results are drawn from statistically significant features. These two methods were applied in the search for the single top-quark production with a $W$ boson. Their separation power differ highly in favour for the regression method, mainly because it can exploit the extra information available during training. The third method is an unsupervised learning algorithm that offers finding an optimal coordinate system for a sample in the sense of m...

Kovesarki, Peter; Dingfelder, Jochen

187

Resummed corrections to the ?parameter due to a finite width of the top quark  

E-Print Network (OSTI)

We perform an all-order calculation of the \\rho parameter in a simplified framework, where the top propagator can be calculated exactly. Special emphasis is placed on the question of gauge invariance and the treatment of non-perturbative cut-off effects.

D. Bettinelli; J. J. van der Bij

2010-09-27T23:59:59.000Z

188

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)

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 ...

CMS Collaboration

189

The Two-Loop Scale Dependence of the Static QCD Potential including Quark Masses  

SciTech Connect

The interaction potential V(Q{sup 2}) between static test charges can be used to define an effective charge {alpha}{sub V}(Q{sup 2}) and a physically-based renormalization scheme for quantum chromodynamics and other gauge theories. In this paper we use recent results for the finite-mass fermionic corrections to the heavy-quark potential at two-loops to derive the next-to-leading order term for the Gell Mann-Low function of the V-scheme. The resulting effective number of flavors N{sub F}(Q{sup 2}/m{sup 2}) in the {alpha}{sub V} scheme is determined as a gauge-independent and analytic function of the ratio of the momentum transfer to the quark pole mass. The results give automatic decoupling of heavy quarks and are independent of the renormalization procedure. Commensurate scale relations then provide the next-to-leading order connection between all perturbatively calculable observables to the analytic and gauge-invariant {alpha}{sub V} scheme without any scale ambiguity and a well defined number of active flavors. The inclusion of the finite quark mass effects in the running of the coupling is compared with the standard treatment of finite quark mass effects in the {ovr MS} scheme.

Brodsky, Stanley J.

1999-06-14T23:59:59.000Z

190

Magnetized strange quark matter in a mass-density-dependent model  

E-Print Network (OSTI)

We investigate the properties of strange quark matter in a strong magnetic field with quark confinement by the density dependence of quark mass considering the total baryon number conservation, charge neutrality and chemical equilibrium. The strength of the magnetic field considered in this article is $10^{16} \\sim 10^{20}$ G. It is found that an additional term should appear in the pressure expression to maintain thermodynamic consistency. At fixed density, the energy density of magnetized strange quark matter varies with the magnetic field strength. The exists a minimum with increasing the field strength, depending on the density. It is about $6\\times10^{19}$ Gauss at two times the normal nuclear saturation density.

J. X. Hou; G. X. Peng; C. J. Xia; J. F. Xu

2014-03-05T23:59:59.000Z

191

Evidence for electroweak top quark production in proton-antiproton collisions at s**(1/2) = 1.96 TeV  

SciTech Connect

We present the first evidence for electroweak single top quark production using nearly 1 fb{sup -1} of Tevatron Run II data at {radical}s = 1.96 TeV. We select single-top-like data events in the lepton+jets decay channel and separate them from backgrounds using the matrix element analysis method. This technique uses leading order matrix elements to compute an event probability for both signal and background hypotheses. Using the expected signal acceptance, background, and observed data we measure the single top quark cross section: {sigma}(p{bar p} {yields} tb + tqb + X) = 4.6{sub -1.5}{sup +}1.8 pb. The probability for the background to have fluctuated up to give at least the cross section measured in this analysis is 0.21%, which corresponds to a Gaussian equivalent significance of 2.9{sigma}.

Gadfort, Thomas; /Washington U., Seattle

2007-04-01T23:59:59.000Z

192

Higgs boson mass bounds in the presence of a heavy fourth quark family  

E-Print Network (OSTI)

We present Higgs boson mass bounds in a lattice regularization allowing thus for non-perturbative investigations. In particular, we employ a lattice modified chiral invariant Higgs-Yukawa model using the overlap operator. We show results for the upper and lower Higgs boson mass bounds in the presence of a heavy mass-degenerate quark doublet with masses ranging up to 700 GeV. We perform infinite volume extrapolations in most cases, and examine several values of the lattice cutoff. Furthermore, we argue that the lower Higgs boson mass bound is stable with respect to the addition of higher dimensional operators to the scalar field potential. Our results have severe consequences for the phenomenology of a fourth generation of quarks if a light Higgs boson is discovered at the LHC.

John Bulava; Philipp Gerhold; Karl Jansen; Jim Kallarackal; Attila Nagy

2013-01-16T23:59:59.000Z

193

Single top-quark production by strong and electroweak supersymmetric flavor-changing interactions at the LHC  

E-Print Network (OSTI)

(Abridged) We report on a complete study of the single top-quark production by direct supersymmetric flavor-changing neutral-current (FCNC) processes at the LHC. The total cross section for pp(gg)->t\\bar{c}+\\bar{t}c is computed at the 1-loop order within the unconstrained Minimal Supersymmetric Standard Model (MSSM). The present study extends the results of the supersymmetric strong effects (SUSY-QCD), which were advanced by some of us in a previous work, and includes the computation of the full supersymmetric electroweak corrections (SUSY-EW). Our analysis of pp(gg)->t\\bar{c}+\\bar{t}c in the MSSM has been performed in correspondence with the stringent low-energy constraints from b->s gamma. In the most favorable scenarios, the SUSY-QCD contribution can give rise to production rates of around 10^5 events per 100 fb^{-1} of integrated luminosity. Furthermore, we show that there exist regions of the MSSM parameter space where the SUSY-EW correction becomes sizeable. In the SUSY-EW favored regions, one obtains lower, but still appreciable, event production rates that can reach the 10^3 level for the same range of integrated luminosity. We study also the possible reduction in the maximum event rate obtained from the full MSSM contribution if we additionally include the constraints from B^0_s-\\bar{B}^0_s. In view of the fact that the FCNC production of heavy quark pairs of different flavors is extremely suppressed in the SM, the detection of a significant number of these events could lead to evidence of new physics -- of likely supersymmetric origin.

David Lopez-Val; Jaume Guasch; Joan Sola

2007-12-10T23:59:59.000Z

194

Search for a Very Light CP-Odd Higgs Boson in Top Quark Decays from pp? Collisions at ?s = 1.96 TeV  

SciTech Connect

We present the results of a search for a very light CP-odd Higgs boson a10 originating from top quark decays t?H±b ? W±(*)a10b, and subsequently decaying into ?+?-. Using a data sample corresponding to an integrated luminosity of 2.7 fb-1 collected by the CDF II detector in pp? collisions at 1.96 TeV, we perform a search for events containing a lepton, three or more jets, and an additional isolated track with transverse momentum in the range 3 to 20 GeV/c. Observed events are consistent with background sources, and 95% C.L. limits are set on the branching ratio of t?H±b for various masses of H± and a10.

Aaltonen, T [Helsinki Inst. of Phys.; Gonzalez, B Alvarez [Oviedo U.; Cantabria Inst. of Phys.; Amerio, S [INFN, Padua; Amidei, D [Michigan U.; Anastassov, A [Northwestern U.; Annovi, A [Frascati; Antos, J [Comenius U.; Apollinari, G [Fermilab; Appel, J A [Fermilab; Apresyan, A [Purdue U.; Arisawa, T [Waseda U.; Dubna, JINR

2011-07-11T23:59:59.000Z

195

Search for the Standard Model Higgs boson produced in association with top quarks in pp collisions at ?s=8 TeV with the ATLAS detector  

E-Print Network (OSTI)

A search for the Standard Model Higgs boson produced in association with a pair of top quarks, t\\overline{t}H, is presented. The analysis uses 20.3 fb^{-1} of pp collision data at \\sqrt{s} = 8 TeV, collected with the ATLAS detector at the Large Hadron Collider during 2012. The search is designed for the H\\to~b\\overline{b} decay mode and uses events containing one or two leptons (electrons or/and muons). The Higgs boson is assumed to have a mass of 125 GeV. In order to improve the sensitivity of the search, events are categorised according to their jet and b-tagged jet multiplicities. A multivariate technique is used to discriminate between signal and background events, which are dominated by t\\overline{t}+jets production. No significant excess of events above the background expectation is found and an observed (expected) 95% confidence-level limit of 4.1 (2.6) times the Standard Model cross section is obtained.

Moreno Llácer, M; The ATLAS collaboration

2014-01-01T23:59:59.000Z

196

Invariant mass distributions for heavy quark-antiquark pairs in deep inelastic electroproduction  

E-Print Network (OSTI)

We have completed the ${\\cal O}(\\alpha_s)$ QCD corrections to exclusive heavy quark-antiquark distributions in deep inelastic electroproduction and present here the differential distributions in the masses of charm-anticharm and bottom-antibottom pairs at the electron-proton collider HERA.

B. W. Harris; J. Smith

1995-02-15T23:59:59.000Z

197

Measurement of the inclusive leptonic asymmetry in top-quark pairs that decay to two charged leptons at CDF  

E-Print Network (OSTI)

We measure the inclusive forward-backward asymmetry of the charged-lepton pseudorapidities from top-quark pairs produced in proton-antiproton collisions, and decaying to final states that contain two charged leptons (electrons or muons), using data collected with the Collider Detector at Fermilab. With an integrated luminosity of 9.1 $\\rm{fb}^{-1}$, the leptonic forward-backward asymmetry, $A_{\\text{FB}}^{\\ell}$, is measured to be $0.072 \\pm 0.060$ and the leptonic pair forward-backward asymmetry, $A_{\\text{FB}}^{\\ell\\ell}$, is measured to be $0.076 \\pm 0.082$, compared with the standard model predictions of $A_{\\text{FB}}^{\\ell} = 0.038 \\pm 0.003$ and $A_{\\text{FB}}^{\\ell\\ell} = 0.048 \\pm 0.004$, respectively. Additionally, we combine the $A_{\\text{FB}}^{\\ell}$ result with a previous determination from a final state with a single lepton and hadronic jets and obtain $A_{\\text{FB}}^{\\ell} = 0.090^{+0.028}_{-0.026}$.

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

2014-04-14T23:59:59.000Z

198

QCD thermodynamics with $N_f=2+1$ near the continuum limit at realistic quark masses  

E-Print Network (OSTI)

We report on our study of QCD thermodynamics with 2+1 flavors of dynamical quarks. In this proceeding we present several thermodynamic quantities and our recent calculation of the critical temperature. In order to investigate the thermodynamic properties of QCD near the continuum limit we adopt improved staggered (p4) quarks coupled with tree-level Symanzik improved glue on $N_t=4$ and 6 lattices. The simulations are performed with a physical value of the strange quark mass and light quark masses which are in the range of $m_q/m_s=0.05-0.4$. The lightest quark mass corresponds to a pion mass of about 150 MeV.

Takashi Umeda

2006-10-03T23:59:59.000Z

199

Top Physics at LHC  

E-Print Network (OSTI)

The Large Hadron Collider (LHC) will provide a huge amount of top-antitop events, making the LHC a top quark factory, producing 1 tt pair per second at a luminosity of 10^33cm-2s-1. A large top quark sample will be available from the start of LHC and will play an important role in commissioning the CMS and ATLAS detectors. An overview of the top quark measurements during the first data-taking period is given.

M. Vander Donckt; for the CMS; ATLAS Collaborations

2008-05-21T23:59:59.000Z

200

Measurement of the t-Channel Single Top Quark Production Cross Section in pp Collisions at sqrt[s]=7??TeV  

SciTech Connect

Electroweak production of the top quark is measured in pp collisions at sqrt(s) = 7 TeV, using a dataset collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 36 inverse picobarns. With an event selection optimized for t-channel production, two complementary analyses are performed. The first one exploits the special angular properties of the signal, together with background estimates from data. The second approach uses a multivariate analysis technique to probe the compatibility with signal topology expected from electroweak top quark production. The combined measurement of the cross section is 83.6 +/- 29.8 (stat.+syst.) +/- 3.3 (lumi.) pb, consistent with the standard model expectation.

Chatrchyan, Serguei; et al.

2011-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "top quark mass" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

arXiv:0802.2965v1[hep-ex]21Feb2008 Single Top Quark Production at the Fermilab Tevatron Collider  

E-Print Network (OSTI)

arXiv:0802.2965v1[hep-ex]21Feb2008 Single Top Quark Production at the Fermilab Tevatron Collider at the Fermilab Tevatron Collider are s-channel, which involve the exchange of a time-like W boson, and t be created in association with an an on-shell W boson, but this process is negligible at the Fermilab

California at Santa Cruz, University of

202

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

E-Print Network (OSTI)

) u(k1)(?iFV )?? (VV l ?AV l?5) v(k2) , (2.15) 4 where mV and ?V are the mass and the width of the vector boson respectively, and Mµ is the amplitude for the process a(P1) + b(P2) ?? V (q) +X(x) , (2.16) µ being the Lorentz index associated with V... to thank the CERN TH division for hospitality during the completion of this work. We also would like to thank Fabio Maltoni for his collaboration during early stages of this work, and Chris White for useful discussions. The work of E.L. and P...

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

203

Quark-gluon vertex dressing and meson masses beyond ladder-rainbow truncation  

SciTech Connect

We include a generalized infinite class of quark-gluon vertex dressing diagrams in a study of how dynamics beyond the ladder-rainbow truncation influences the Bethe-Salpeter description of light quark pseudoscalar and vector mesons. The diagrammatic specification of the vertex is mapped into a corresponding specification of the Bethe-Salpeter kernel, which preserves chiral symmetry. This study adopts the algebraic format afforded by the simple interaction kernel used in previous work on this topic. The new feature of the present work is that in every diagram summed for the vertex and the corresponding Bethe-Salpeter kernel, each quark-gluon vertex is required to be the self-consistent vertex solution. We also adopt from previous work the effective accounting for the role of the explicitly non-Abelian three gluon coupling in a global manner through one parameter determined from recent lattice-QCD data for the vertex. With the more consistent vertex used here, the error in ladder-rainbow truncation for vector mesons is never more than 10% as the current quark mass is varied from the u/d region to the b region.

Hrayr Matevosyan; Anthony Thomas; Peter Tandy

2007-04-01T23:59:59.000Z

204

Quark-antiquark potential with retardation and radiative contributions and the heavy quarkonium mass spectra  

Science Journals Connector (OSTI)

The charmonium and bottomonium mass spectra are calculated with the systematic account of all relativistic corrections of order v2/c2 and the one-loop radiative corrections. Special attention is paid to the contribution of the retardation effects to the spin-independent part of the quark-antiquark potential, and a general approach to accounting for retardation effects in the long-range (confining) part of the potential is presented. A good fit to available experimental data on the mass spectra is obtained.

D. Ebert, R. N. Faustov, and V. O. Galkin

2000-07-12T23:59:59.000Z

205

Top Physics at the LHC  

E-Print Network (OSTI)

The LHC will be a top quark factory. In this note, the central role of the top quark for LHC physics will be discussed, and an overview will be given of the studies of top quark properties in preparation, with an emphasis on the systematic uncertainties that will dominate most measurements.

P. de Jong

2009-02-27T23:59:59.000Z

206

Gluon condensates and c, b quark masses from quarkonia ratios of moments  

E-Print Network (OSTI)

We extract (for the first time) the ratio of the gluon condensate / expressed in terms of the liquid instanton radius rho_c from charmonium moments sum rules by examining the effects of in the determinations of both rho_c and the running MS mass m_c(m_c). Using a global analysis of selected ratios of moments at different Q^2=0, 4m_c^2 and 8m_c^2 and taking from 0.06 GeV^4, where the estimate of rho_c is almost independent of , we deduce: rho_c=0.98(21) GeV^{-1} which corresponds to = (31+- 13) GeV^2 . The value of m_c(m_c) is less affected (within the errors) by the variation of , where a common solution from different moments are reached for greater than 0.02 GeV^4. Using the values of =0.06(2) GeV^4 from some other channels and the previous value of , we deduce: m_c(m_c)=1260(18) MeV and m_b(m_b)=4173(10) MeV, where an estimate of the 4-loops contribution has been included. Our analysis indicates that the errors in the determinations of the charm quark mass without taking into account the ones of the gluon condensates have been underestimated. To that accuracy, one can deduce the running light and heavy quark masses and their ratios evaluated at M_Z, where it is remarkable to notice the approximate equalities: m_s/m_u= m_b/m_s= m_t/m_b= 51(4), which might reveal some eventual underlying novel symmetry of the quark mass matrix in some Grand Unified Theories.

Stephan Narison

2011-10-13T23:59:59.000Z

207

CP violating anomalous top-quark coupling in p$\\bar{p}$ collision at $\\sqrt{s}=1.96$ TeV  

SciTech Connect

We conduct the first study of the T-odd correlations in tt events produced in p{bar p} collision at the Fermilab Tevatron collider that can be used to search for CP violation. We select events which have lepton+jets final states to identify t{bar t} events and measure counting asymmetries of several physics observables. Based on the result, we search the top quark anomalous couplings at the production vertex at the Tevatron. In addition, Geant4 development, photon identification, the discrimination of a single photon and a photon doublet from {pi}{sup 0} decay are discussed in this thesis.

Lee, Sehwook; /Iowa State U.

2011-04-01T23:59:59.000Z

208

Measurement of the top quark mass in the lepton+jets channel using the ideogram method  

E-Print Network (OSTI)

in the overall likelihood fit. This paper is organized as follows: Sections II and III describe the D0 Run II detector and the event reconstruc- tion, respectively. Sections IV, V, and VI describe the data and simulation samples used and outline the event selec... in Sec. IX and the systematic uncertainties are discussed in Sec. X. Section XI presents a cross-check of the JES calibration, followed by the con- clusion in Sec. XII. II. THE D0 DETECTOR Run II of the Fermilab Tevatron collider started in 2001 after...

Baringer, Philip S.; Bean, Alice; Hensel, Carsten; Moulik, Tania; Wilson, Graham Wallace; Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.

2007-05-11T23:59:59.000Z

209

Quark mass dependence of the vacuum electric conductivity induced by the magnetic field in SU(2) lattice gluodynamics  

SciTech Connect

We study the electric conductivity induced by the magnetic field B in quenched SU(2) lattice gauge theory at a finite temperature below the deconfinement phase transition as a function of the bare quark mass m{sub q} in the range m{sub q}=55 MeV...540 MeV. At fixed quark mass, the conductivity grows linearly with the magnetic field strength |B|. The proportionality coefficient in this dependence increases towards smaller quark masses and seems to saturate at some finite value in the zero-mass limit. The nonanalytic dependence on the field strength might result from the mixing between vector mesons and pions in an external magnetic field. We discuss the implications of our results for dilepton angular distributions in heavy-ion collisions.

Buividovich, P. V. [ITEP, 117218 Russia, Moscow, B. Cheremushkinskaya str. 25 (Russian Federation); JINR, 141980 Russia, Moscow Region, Dubna, Joliot-Curie str. 6 (Russian Federation); Polikarpov, M. I. [ITEP, 117218 Russia, Moscow, B. Cheremushkinskaya str. 25 (Russian Federation)

2011-05-01T23:59:59.000Z

210

Quark Matter  

NLE Websites -- All DOE Office Websites (Extended Search)

Quark Quark Matter in Neutron Stars Prashanth Jaikumar Argonne National Laboratory, (PHY) September 7th, 2006 . - p.1/29 Outline * Neutron stars: observations by a theorist . - p.2/29 Outline * Neutron stars: observations by a theorist * Mass-Radius constraints on Equation of State (EoS) . - p.2/29 Outline * Neutron stars: observations by a theorist * Mass-Radius constraints on Equation of State (EoS) * Is quark matter inside neutron stars ruled out? . - p.2/29 Outline * Neutron stars: observations by a theorist * Mass-Radius constraints on Equation of State (EoS) * Is quark matter inside neutron stars ruled out? ------------------------ * Strange Quark stars: Features and "Findings" . - p.2/29 Outline * Neutron stars: observations by a theorist * Mass-Radius constraints on Equation of State (EoS) * Is quark matter inside neutron stars ruled out? ------------------------

211

Search for the Standard Model Higgs boson production in association with top quarks in pp collisions at 8 TeV with the ATLAS detector  

E-Print Network (OSTI)

The search for the production of the Higgs boson associated with a pair of top quarks in the ATLAS experiment is presented. It focuses on Higgs bosons decaying to $b\\bar{b}$ and events containing two leptons (electrons and/or muons). It uses 20.3 fb$^{-1}$ of $pp$ collision data at $\\sqrt{s}$ = 8 TeV collected with the ATLAS detector at the LHC in 2012. No significant excess of events is found and the 95% CL observed (expected) limit is 7.0xSM (4.3xSM). After combining with the single lepton final state an observed (expected) limit of 4.1xSM (2.6xSM) with a best fit of $\\mu=1.7\\pm1.4$ is obtained.

Moreno Llacer, Maria

2014-01-01T23:59:59.000Z

212

Top Physics at the LHC  

E-Print Network (OSTI)

Top quark physics will be a prominent topic in Standard Model physics at the LHC. The enormous amount of top quarks expected to be produced will allow to perform a wide range of precision measurements. An overview of the planned top physics programme of the ATLAS and CMS experiments at the LHC is given.

Christian Weiser

2005-06-10T23:59:59.000Z

213

Search for single top quark production in pp[over-bar] collisions at [sqrt]s=1.96??TeV in the missing transverse energy plus jets topology  

E-Print Network (OSTI)

We report a search for single top quark production with the CDF II detector using 2.1??fb[superscript -1] of integrated luminosity of p[over-bar p] collisions at [sqrt]s=1.96??TeV. The data selected consist of events ...

Paus, Christoph M. E.

214

SciTech Connect: Quark mass variation constraints from Big Bang...  

Office of Scientific and Technical Information (OSTI)

NUCLEAR PHYSICS; NUCLEOSYNTHESIS; QUANTUM CHROMODYNAMICS; QUARKS; REACTION KINETICS Word Cloud More Like This Full Text preview image File size NAView Full Text View Full Text...

215

Next-to-leading order QCD corrections to the top quark associated with $?$ production via model-independent flavor-changing neutral-current couplings at hadron colliders  

E-Print Network (OSTI)

We present the complete next-to-leading order (NLO) QCD corrections to the top quark associated with $\\gamma$ production induced by model-independent $tq\\gamma$ and $tqg$ flavor-changing neutral-current (FCNC) couplings at hadron colliders, respectively. We also consider the mixing effects between the $tq\\gamma$ and $tqg$ FCNC couplings for this process. Our results show that, for the $tq\\gamma$ couplings, the NLO QCD corrections can enhance the total cross sections by about 50% and 40% at the Tevatron and LHC, respectively. Including the contributions from the $tq\\gamma$, $tqg$ FCNC couplings and their mixing effects, the NLO QCD corrections can enhance the total cross sections by about 50% for the $tu\\gamma$ and $tug$ FCNC couplings, and by about the 80% for the $tc\\gamma$ and $tcg$ FCNC couplings at the LHC, respectively. Moreover, the NLO corrections reduce the dependence of the total cross section on the renormalization and factorization scale significantly. We also evaluate the NLO corrections for several important kinematic distributions.

Yue Zhang; Bo Hua Li; Chong Sheng Li; Jun Gao; Hua Xing Zhu

2011-01-27T23:59:59.000Z

216

Measurement of associated production of vector bosons and top quark-antiquark pairs in pp collisions at ?s=7??TeV  

The first measurement of vector-boson production associated with a top quark-antiquark pair in proton-proton collisions at ?s=7??TeV is presented. The results are based on a data set corresponding to an integrated luminosity of 5.0??fb?1 , recorded by the CMS detector at the LHC in 2011. The measurement is performed in two independent channels through a trilepton analysis of tt¯Z events and a same-sign dilepton analysis of tt¯V (V=W or Z ) events. In the trilepton channel a direct measurement of the tt¯Z cross section ?tt¯Z =0.28+0.14?0.11 ?(stat)+0.06?0.03 ?(syst)??pb is obtained. In the dilepton channel a measurement of the tt¯V cross section yields ?tt¯V =0.43+0.17?0.15 ?(stat)+0.09?0.07 ?(syst)??pb . These measurements have a significance, respectively, of 3.3 and 3.0 standard deviations from the background hypotheses and are compatible, within uncertainties, with the corresponding next-to-leading order predictions of 0.137+0.012?0.016 and 0.306+0.031?0.053??pb .

Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Aguilo, E.; Bergauer, T.; Dragicevic, M.; Erö, J.; Fabjan, C.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knünz, V.; Krammer, M.; Krätschmer, I.; Liko, D.; Mikulec, I.; Pernicka, M.; Rabady, D.; Rahbaran, B.; Rohringer, C.; Rohringer, H.; Schöfbeck, R.; Strauss, J.; Taurok, A.; 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.; Luyckx, S.; Mucibello, L.; Ochesanu, S.; Roland, B.; Rougny, R.; Selvaggi, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Blekman, F.; Blyweert, S.; D’Hondt, J.; Gonzalez Suarez, R.; Kalogeropoulos, A.; Maes, M.; Olbrechts, A.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Villella, I.; Clerbaux, B.; De Lentdecker, G.; Dero, V.; Gay, A. P. R.; Hreus, T.; Léonard, A.; Marage, P. E.; Mohammadi, A.; Reis, T.; Thomas, L.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Adler, V.; Beernaert, K.; Cimmino, A.; Costantini, S.; Garcia, G.; Grunewald, M.; Klein, B.; Lellouch, J.; Marinov, A.; Mccartin, J.; Ocampo Rios, A. A.; Ryckbosch, D.; Sigamani, M.; Strobbe, N.; Thyssen, F.; Tytgat, M.; Walsh, S.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Bruno, G.; Castello, R.; Ceard, L.; Delaere, C.; du Pree, T.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Lemaitre, V.; Liao, J.; Militaru, O.; Nuttens, C.; Pagano, D.; Pin, A.; Piotrzkowski, K.; Vizan Garcia, J. M.; Beliy, N.; Caebergs, T.; Daubie, E.; Hammad, G. H.; Alves, G. A.; Correa Martins Junior, M.; Martins, T.; Pol, M. E.; Souza, M. H. G.; Aldá Júnior, W. L.; 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.; Santoro, A.; Soares Jorge, L.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Anjos, T. S.; Bernardes, C. A.; Dias, F. A.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Lagana, C.; Marinho, F.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Genchev, V.; Iaydjiev, P.; Piperov, S.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Tcholakov, V.; Trayanov, R.; Vutova, M.; Dimitrov, A.; Hadjiiska, R.; Kozhuharov, V.; Litov, L.; Pavlov, B.; Petkov, P.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Jiang, C. H.; Liang, D.; Liang, S.; Meng, X.; Tao, J.; Wang, J.; Wang, X.; Wang, Z.; Xiao, H.; Xu, M.; Zang, J.; Zhang, 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.; Carrillo Montoya, C. A.; Gomez, J. P.; Gomez Moreno, B.; Osorio Oliveros, A. F.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Plestina, R.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Duric, S.; Kadija, K.; Luetic, J.; Mekterovic, D.; Morovic, S.; Tikvica, L.; Attikis, A.; Galanti, M.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Finger, M.; Finger, M.; Assran, Y.; Elgammal, S.; Ellithi Kamel, A.; Kuotb Awad, A. M.; Mahmoud, M. A.; Radi, A.; Kadastik, M.; Müntel, M.; Murumaa, M.; Raidal, M.; Rebane, L.; Tiko, A.; Eerola, P.; Fedi, G.; Voutilainen, M.; Härkönen, J.; Heikkinen, A.; 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.; Ungaro, D.; Wendland, L.; Korpela, A.; Tuuva, T.; Besancon, M.; Choudhury, S.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Malcles, J.; Millischer, L.; Nayak, A.; Rander, J.; Rosowsky, A.; Titov, M.; Baffioni, S.; Beaudette, F.; Benhabib, L.; Bianchini, L.; Bluj, M.; Busson, P.; Charlot, C.; Daci, N.; Dahms, T.; Dalchenko, M.; Dobrzynski, L.; Florent, A.; Granier de Cassagnac, R.; Haguenauer, M.; Miné, P.; Mironov, C.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Paganini, P.; Sabes, D.; Salerno, R.; Sirois, Y.; Veelken, C.; Zabi, A.; Agram, J.-L.; Andrea, J.; Bloch, D.; Bodin, D.; Brom, J.-M.; Cardaci, M.; Chabert, E. C.; Collard, C.; Conte, E.; Drouhin, F.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Juillot, P.; Le Bihan, A.-C.; Van Hove, P.; Beauceron, S.; Beaupere, N.; Bondu, O.; Boudoul, G.; Brochet, S.; Chasserat, J.; Chierici, R.; Contardo, D.; Depasse, P.; El Mamouni, H.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Kurca, T.; Lethuillier, M.; Mirabito, L.; Perries, S.; Sgandurra, L.; Sordini, V.; Tschudi, Y.; Verdier, P.; Viret, S.; Tsamalaidze, Z.; Autermann, C.

2013-04-01T23:59:59.000Z

217

Deconfinement phase transition in hybrid neutron stars from the Brueckner theory with three-body forces and a quark model with chiral mass scaling  

E-Print Network (OSTI)

We study the properties of strange quark matter in equilibrium with normal nuclear matter. Instead of using the conventional bag model in quark sector, we achieve the confinement by a density-dependent quark mass derived from in-medium chiral condensates. In nuclear matter, we adopt the equation of state from the Brueckner-Bethe-Goldstone approach with three-body forces. It is found that the mixed phase can occur, for a reasonable confinement parameter, near the normal nuclear saturation density, and goes over into pure quark matter at about 5 times the saturation. The onset of mixed and quark phases is compatible with the observed class of low-mass neutron stars, but it hinders the occurrence of kaon condensation.

G. X. Peng; A. Li; U. Lombardo

2008-07-01T23:59:59.000Z

218

Measurement of \\boldmath $R = {\\mathcal{B}\\left(t \\rightarrow Wb \\right)/\\mathcal{B}\\left(t \\rightarrow Wq \\right)} $ in Top--Quark--Pair Decays using Dilepton Events and the Full CDF Run II Data Set  

E-Print Network (OSTI)

We present a measurement of the ratio of the top-quark branching fractions $R=\\mathcal{B}(t\\rightarrow Wb)/\\mathcal{B}(t\\rightarrow $ $q$ represents quarks of flavors $b$, $s$, or $d$, in the final state, in events with two charged leptons, missing transverse energy and at least two jets. The measurement uses $\\sqrt{s}$ = 1.96 TeV proton--antiproton collision data corresponding to an integrated luminosity of 8.7 fb$^{-1}$ and collected with the Collider Detector at Fermilab during Run II of the Tevatron. We measure $R=0.87 \\pm 0.07$ (stat+syst), and extract the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element, $\\left|V_{tb}\\right| = 0.93 \\pm 0.04$ (stat+syst) assuming three generations of quarks. Under these assumptions, a lower limit of $|V_{tb}|>0.85$ at 95% credibility level is set.

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

2014-04-13T23:59:59.000Z

219

Measurement of beauty and charm production in deep inelastic scattering at HERA and measurement of the beauty-quark mass  

E-Print Network (OSTI)

The production of beauty and charm quarks in ep interactions has been studied with the ZEUS detector at HERA for exchanged four-momentum squared 5 energy and pseudorapidity were measured and compared with next-to-leading-order QCD calculations. The beauty and charm contributions to the proton structure functions were extracted from the double-differential cross section as a function of x and Q^2. The running beauty-quark mass, m_b at the scale m_b, was determined from a QCD fit at next-to-leading order to HERA data for the first time and found to be 4.07 \\pm 0.14 (fit} ^{+0.01}_{-0.07} (mod.) ^{+0.05}_{-0.00} (param.) ^{+0.08}_{-0.05} (theo) GeV.

ZEUS collaboration; H. Abramowicz; I. Abt; L. Adamczyk; M. Adamus; R. Aggarwal; S. Antonelli; O. Arslan; V. Aushev; Y. Aushev; O. Bachynska; A. N. Barakbaev; N. Bartosik; O. Behnke; J. Behr; U. Behrens; A. Bertolin; S. Bhadra; I. Bloch; V. Bokhonov; E. G. Boos; K. Borras; I. Brock; R. Brugnera; A. Bruni; B. Brzozowska; P. J. Bussey; A. Caldwell; M. Capua; C. D. Catterall; J. Chwastowski; J. Ciborowski; R. Ciesielski; A. M. Cooper-Sarkar; M. Corradi; F. Corriveau; G. D'Agostini; R. K. Dementiev; R. C. E. Devenish; G. Dolinska; V. Drugakov; S. Dusini; J. Ferrando; J. Figiel; B. Foster; G. Gach; A. Garfagnini; A. Geiser; A. Gizhko; L. K. Gladilin; O. Gogota; Yu. A. Golubkov; J. Grebenyuk; I. Gregor; G. Grzelak; O. Gueta; M. Guzik; W. Hain; G. Hartner; D. Hochman; R. Hori; Z. A. Ibrahim; Y. Iga; M. Ishitsuka; A. Iudin; F. Januschek; I. Kadenko; S. Kananov; T. Kanno; U. Karshon; M. Kaur; P. Kaur; L. A. Khein; D. Kisielewska; R. Klanner; U. Klein; N. Kondrashova; O. Kononenko; Ie. Korol; I. A. Korzhavina; A. Kota?ski; U. Kötz; N. Kovalchuk; H. Kowalski; O. Kuprash; M. Kuze; B. B. Levchenko; A. Levy; V. Libov; S. Limentani; M. Lisovyi; E. Lobodzinska; W. Lohmann; B. Löhr; E. Lohrmann; A. Longhin; D. Lontkovskyi; O. Yu. Lukina; J. Maeda; I. Makarenko; J. Malka; J. F. Martin; S. Mergelmeyer; F. Mohamad Idris; K. Mujkic; V. Myronenko; K. Nagano; A. Nigro; T. Nobe; D. Notz; R. J. Nowak; K. Olkiewicz; Yu. Onishchuk; E. Paul; W. Perla?ski; H. Perrey; N. S. Pokrovskiy; A. S. Proskuryakov; M. Przybycie?; A. Raval; P. Roloff; I. Rubinsky; M. Ruspa; V. Samojlov; D. H. Saxon; M. Schioppa; W. B. Schmidke; U. Schneekloth; T. Schörner-Sadenius; J. Schwartz; L. M. Shcheglova; R. Shehzadi; R. Shevchenko; O. Shkola; I. Singh; I. O. Skillicorn; W. S?omi?ski; V. Sola; A. Solano; A. Spiridonov; L. Stanco; N. Stefaniuk; A. Stern; T. P. Stewart; P. Stopa; J. Sztuk-Dambietz; D. Szuba; J. Szuba; E. Tassi; T. Temiraliev; K. Tokushuku; J. Tomaszewska; A. Trofymov; V. Trusov; T. Tsurugai; M. Turcato; O. Turkot; T. Tymieniecka; A. Verbytskyi; O. Viazlo; R. Walczak; W. A. T. Wan Abdullah; K. Wichmann; M. Wing; G. Wolf; S. Yamada; Y. Yamazaki; N. Zakharchuk; A. F. ?arnecki; L. Zawiejski; O. Zenaiev; B. O. Zhautykov; N. Zhmak; D. S. Zotkin

2014-10-21T23:59:59.000Z

220

Model-Independent Production of a Top-Philic Resonance at the LHC  

E-Print Network (OSTI)

We investigate the collider phenomenology of a color-singlet vector resonance, which couples to the heaviest quarks, the top quarks, but very weakly to the rest of the fermions in the Standard Model. We find that the dominant production of such a resonance does not appear at the tree level -- it rather occurs at the one-loop level in association with an extra jet. Signatures like t anti-t plus jets readily emerge as a result of the subsequent decay of the resonance into a pair of top quarks. Without the additional jet, the resonance can still be produced off-shell, which gives a sizeable contribution at low masses. The lower top quark multiplicity of the loop induced resonance production facilitates its reconstruction as compared to the tree level production that gives rise to more exotic signatures involving three or even four top quarks in the final state. For all these cases, we discuss the constraints on the resonance production stemming from recent experimental measurements in the top quark sector. We find that the top-philic vector resonance remains largely unconstrained for the majority of the parameter space, although this will be scrutinized closely in the Run 2 phase of the LHC.

Nicolas Greiner; Kyoungchul Kong; Jong-Chul Park; Seong Chan Park; Jan-Christopher Winter

2014-10-22T23:59:59.000Z

Note: This page contains sample records for the topic "top quark mass" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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221

A Measurement of the production cross section of top-antitop pairs in proton-antiproton collisions at a center of mass of 1.96 TeV using secondary vertex b-tagging.  

SciTech Connect

A measurement of the t{bar t} pair production cross section is presented using 162 pb{sup -1} of data collected by the CDF experiment during Run II at the Tevatron. t{bar t} events in the lepton+jets channel are isolated by identifying electrons and muons, reconstructing jets and transverse missing energy, and identifying b jets with a secondary vertex tagging algorithm. The efficiency of the algorithm is measured in a control sample using a novel technique that is less dependent on the simulation. For a top quark mass of 175 GeV/c{sup 2}, a cross section of {sigma}{sub t{bar t}} = 5.6{sub -1.1}{sup +1.2}(stat.){sub -0.6}{sup +0.9}(syst.)pb is measured.

Bachacou, Henri; /UC, Berkeley; ,

2004-12-01T23:59:59.000Z

222

Consecutive Ion Activation for Top Down Mass Spectrometry:? Improved Protein Sequencing by Nozzle?Skimmer Dissociation  

Science Journals Connector (OSTI)

Mass spectra produced by nozzle?skimmer dissociation (NSD) have been little used in the past for structural characterization. NSD cannot be used on mass-separated ions (MS/MS), and for electrosprayed protein ions, previous NSD spectra showed backbone ...

Huili Zhai; Xuemei Han; Kathrin Breuker; Fred W. McLafferty

2005-08-20T23:59:59.000Z

223

Search for pair production of third-generation scalar leptoquarks and top squarks in proton-proton collisions at sqrt(s) = 8 TeV  

E-Print Network (OSTI)

A search for pair production of third-generation scalar leptoquarks and supersymmetric top quark partners, top squarks, in final states involving tau leptons and bottom quarks is presented. The search uses events from a data sample of proton-proton collisions corresponding to an integrated luminosity of 19.7 inverse femtobarns, collected with the CMS detector at the LHC with sqrt(s) = 8 TeV. The number of observed events is found to be in agreement with the expected standard model background. Third-generation scalar leptoquarks with masses below 740 GeV are excluded at 95% confidence level, assuming a 100% branching fraction for the leptoquark decay to a tau lepton and a bottom quark. In addition, this mass limit applies directly to top squarks decaying via an R-parity violating coupling lambda'[333]. The search also considers a similar signature from top squarks undergoing a chargino-mediated decay involving the R-parity violating coupling lambda'[3jk]. Each top squark decays to a tau lepton, a bottom quark, and two light quarks. Top squarks in this model with masses below 580 GeV are excluded at 95% confidence level. The constraint on the leptoquark mass is the most stringent to date, and this is the first search for top squarks decaying via lambda'[3jk].

CMS Collaboration

2014-08-04T23:59:59.000Z

224

Search for the standard model Higgs boson produced in association with a top-quark pair in pp collisions at the LHC  

E-Print Network (OSTI)

a pseudorapidity in the range |?| CSV) algorithm [42]. This algorithm combines information about the impact parameter of tracks and reconstructed secondary... vertices within the jets in a multivariate algorithm designed to separate jets containing the decay products of bottom-flavored hadrons from jets originating from charm quarks, light quarks, or gluons. The CSV algorithm provides a continuous output...

Baringer, Philip S.; Bean, Alice; Benelli, Gabriele; Kenny, R. P. III; Murray, Michael J.; Noonan, Danny; Sanders, Stephen J.; Stringer, Robert W.; Wood, Jeffrey Scott; Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö , J.; Fabjan, C.

2013-05-28T23:59:59.000Z

225

Measurement of beauty and charm production in deep inelastic scattering at HERA and measurement of the beauty-quark mass  

E-Print Network (OSTI)

The production of beauty and charm quarks in ep interactions has been studied with the ZEUS detector at HERA for exchanged four-momentum squared 5 content in events with at least one jet have been extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of Q^2, Bjorken x, jet transverse energy and pseudorapidity were measured and compared with next-to-leading-order QCD calculations. The beauty and charm contributions to the proton structure functions were extracted from the double-differential cross section as a function of x and Q^2. The running beauty-quark mass, m_b at the scale m_b, was determined from a QCD fit at next-to-leading order to HERA data for the first time and found to be 4.07 \\pm 0.14 (fit} ^{+0.01}_{-0.07} (mod.) ^{+0.05}_{-0.00} (param.) ^{+0.08}_{-0.05} (theo) GeV.

Abramowicz, H; Adamczyk, L; Adamus, M; Aggarwal, R; Antonelli, S; Arslan, O; Aushev, V; Aushev, Y; Bachynska, O; Barakbaev, A N; Bartosik, N; Behnke, O; Behr, J; Behrens, U; Bertolin, A; Bhadra, S; Bloch, I; Bokhonov, V; Boos, E G; Borras, K; Brock, I; Brugnera, R; Bruni, A; Brzozowska, B; Bussey, P J; Caldwell, A; Capua, M; Catterall, C D; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cooper-Sarkar, A M; Corradi, M; Corriveau, F; D'Agostini, G; Dementiev, R K; Devenish, R C E; Dolinska, G; Drugakov, V; Dusini, S; Ferrando, J; Figiel, J; Foster, B; Gach, G; Garfagnini, A; Geiser, A; Gizhko, A; Gladilin, L K; Gogota, O; Golubkov, Yu A; Grebenyuk, J; Gregor, I; Grzelak, G; Gueta, O; Guzik, M; Hain, W; Hartner, G; Hochman, D; Hori, R; Ibrahim, Z A; Iga, Y; Ishitsuka, M; Iudin, A; Januschek, F; Kadenko, I; Kananov, S; Kanno, T; Karshon, U; Kaur, M; Kaur, P; Khein, L A; Kisielewska, D; Klanner, R; Klein, U; Kondrashova, N; Kononenko, O; Korol, Ie; Korzhavina, I A; Kota?ski, A; Kötz, U; Kovalchuk, N; Kowalski, H; Kuprash, O; Kuze, M; Levchenko, B B; Levy, A; Libov, V; Limentani, S; Lisovyi, M; Lobodzinska, E; Lohmann, W; Löhr, B; Lohrmann, E; Longhin, A; Lontkovskyi, D; Lukina, O Yu; Maeda, J; Makarenko, I; Malka, J; Martin, J F; Mergelmeyer, S; Idris, F Mohamad; Mujkic, K; Myronenko, V; Nagano, K; Nigro, A; Nobe, T; Notz, D; Nowak, R J; Olkiewicz, K; Onishchuk, Yu; Paul, E; Perla?ski, W; Perrey, H; Pokrovskiy, N S; Proskuryakov, A S; Przybycie?, M; Raval, A; Roloff, P; Rubinsky, I; Ruspa, M; Samojlov, V; Saxon, D H; Schioppa, M; Schmidke, W B; Schneekloth, U; Schörner-Sadenius, T; Schwartz, J; Shcheglova, L M; Shehzadi, R; Shevchenko, R; Shkola, O; Singh, I; Skillicorn, I O; S?omi?ski, W; Sola, V; Solano, A; Spiridonov, A; Stanco, L; Stefaniuk, N; Stern, A; Stewart, T P; Stopa, P; Sztuk-Dambietz, J; Szuba, D; Szuba, J; Tassi, E; Temiraliev, T; Tokushuku, K; Tomaszewska, J; Trofymov, A; Trusov, V; Tsurugai, T; Turcato, M; Turkot, O; Tymieniecka, T; Verbytskyi, A; Viazlo, O; Walczak, R; Abdullah, W A T Wan; Wichmann, K; Wing, M; Wolf, G; Yamada, S; Yamazaki, Y; Zakharchuk, N; ?arnecki, A F; Zawiejski, L; Zenaiev, O; Zhautykov, B O; Zhmak, N; Zotkin, D S

2014-01-01T23:59:59.000Z

226

Top partner probes of extended Higgs sectors  

E-Print Network (OSTI)

Natural theories of the weak scale often include fermionic partners of the top quark. If the electroweak symmetry breaking sector contains scalars beyond a single Higgs doublet, then top partners can have sizable branching ...

Kearney, John

227

Magnetic susceptibility and equation of state of N_f = 2+1 QCD with physical quark masses  

E-Print Network (OSTI)

We determine the free energy of strongly interacting matter as a function of an applied constant and uniform magnetic field. We consider N_f = 2+1 QCD with physical quark masses, discretized on a lattice by stout improved staggered fermions and a tree level improved Symanzik pure gauge action, and explore three different lattice spacings. For magnetic fields of the order of those produced in non-central heavy ion collisions (eB ~ 0.1 GeV^2) strongly interacting matter behaves like a medium with a linear response, and is paramagnetic both above and below the deconfinement transition, with a susceptibility which steeply rises in the deconfined phase. We compute the equation of state, showing that the relative increase in the pressure due to the magnetic field gets larger around the transition, and of the order of 10 % for eB ~ 0.1 GeV^2.

Claudio Bonati; Massimo D'Elia; Marco Mariti; Francesco Negro; Francesco Sanfilippo

2014-05-13T23:59:59.000Z

228

Search for Production of Heavy Particles Decaying to Top Quarks and Invisible Particles in $p\\bar{p}$ collisions at $\\sqrt{s}=1.96$ TeV  

SciTech Connect

We present a search for a new particle T{prime} decaying to a top-quark via T{prime} {yields} t + X, where X is an invisible particle. In a data sample with 4.8 fb{sup -1} of integrated luminosity collected by the CDF II detector at Fermilab in p{bar p} collisions with {radical}s = 1.96 TeV, we search for pair production of T0 in the lepton+jets channel, p{bar p} {yields} t{bar t} + XX {yields} {ell}{nu}bqq{prime}b + XX. We interpret our results primarily in terms of a model where T{prime} are exotic fourth generation quarks and X are dark matter particles. The data are consistent with standard model expectations, and we set 95% confidence level limits on the generic production of T{prime}{bar T}{prime} {yields} t{bar t} + XX. We apply these limits to the dark matter model and exclude the fourth generation exotic quarks T{prime} at 95% confidence level up to m{sub T{prime}} = 360 GeV/c{sup 2} for m{sub x} {<=} 100 GeV/c{sup 2}.

Aaltonen, T.; /Helsinki Inst. of Phys.; Alvarez Gonzalez, B.; /Oviedo U. /Cantabria Inst. of Phys.; Amerio, S.; /INFN, Padua; Amidei, D.; /Michigan U.; Anastassov, A.; /Northwestern U.; Annovi, A.; /Frascati; Antos, J.; /Comenius U.; Apollinari, G.; /Fermilab; Appel, J.A.; /Fermilab; Apresyan, A.; /Purdue U.; Arisawa, T.; /Waseda U. /Dubna, JINR

2011-03-01T23:59:59.000Z

229

Cold quark matter in compact stars  

SciTech Connect

We used an equation of state for the cold quark matter to the study of properties of quark stars. We also discuss the absolute stability of quark matter and compute the mass-radius relation for self-bound stars.

Franzon, B.; Fogaca, D. A.; Navarra, F. S. [Instituto de Fisica, Universidade de Sao Paulo Rua do Matao, Travessa R, 187, 05508-090 Sao Paulo, SP (Brazil); Horvath, J. E. [Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao, 1226, 05508-090, Sao Paulo, SP (Brazil)

2013-03-25T23:59:59.000Z

230

Single Top production at LHC  

E-Print Network (OSTI)

The Production of single top quarks at LHC provides an ideal framework to investigate the properties of electroweak interaction, in particular of the {\\it tWb} coupling. Moreover, single top is a powerful mean to identify physics beyond the standard model. All three different production mechanisms of single top are expected to be observed at LHC. Recent studies from ATLAS and CMS are presented.

M. Mohammadi Najafabadi

2006-05-12T23:59:59.000Z

231

Reduction of Quark Mass Scheme Dependence in B bar -> Xs gamma at the NNLL Level  

SciTech Connect

The uncertainty of the theoretical prediction of the B {yields} X{sub s}{gamma} branching ratio at NLL level is dominated by the charm mass renormalization scheme ambiguity. In this paper we calculate those NNLL terms which are related to the renormalization of m{sub c}, in order to get an estimate of the corresponding uncertainty at the NNLL level. We find that these terms significantly reduce (by typically a factor of two) the error on BR(B {yields} X{sub s}{gamma}) induced by the definition of m{sub c}. Taking into account the experimental accuracy of around 10% and the future prospects of the B factories, we conclude that a NNLL calculation would increase the sensitivity of the observable B {yields} X{sub s}{gamma} to possible new degrees of freedom beyond the SM significantly.

Asatrian, H.M.; /Yerevan Phys. Inst.; Greub, C.; /Bern U.; Hovhannisyan, A.; /Yerevan Phys. Inst.; Hurth, T.; /CERN /SLAC; Poghosyan, V.; /Yerevan Phys. Inst.

2005-06-20T23:59:59.000Z

232

Limits on the temporal variation of the fine structure constant, quark masses and strong interaction from quasar absorption spectra and atomic clock experiments  

E-Print Network (OSTI)

We perform calculations of the dependence of nuclear magnetic moments on quark masses and obtain limits on the variation of $(m_q/\\Lambda_{QCD})$ from recent measurements of hydrogen hyperfine (21 cm) and molecular rotational transitions in quasar absorption systems, atomic clock experiments with hyperfine transitions in H, Rb, Cs, Yb$^+$, Hg$^+$ and optical transition in Hg$^+$. Experiments with Cd$^+$, deuterium/hydrogen, molecular SF$_6$ and Zeeman transitions in $^3$He/Xe are also discussed.

V. V. Flambaum; D. B. Leinweber; A. W. Thomas; R. D. Young

2004-02-10T23:59:59.000Z

233

Quark-mass effects for jet production in e+e? collisions at the next-to-leading order: results and applications  

Science Journals Connector (OSTI)

We present a detailed description of our calculation of next-to-leading order QCD corrections to heavy quark production in e+e? collisions including mass effects. In particular, we study the observables \\{R3bl\\} and \\{D2bl\\} in the E, EM, JADE and DURHAM jet-clustering algorithms and show how one can use these observables to obtain mb(mz) from data at the Z peak.

Germán Rodrigo; Mikhail Bilenky; Arcadi Santamaria

1999-01-01T23:59:59.000Z

234

Implications of the measurement of pulsars with two solar masses for quark matter in compact stars and HIC. A NJL model case study  

E-Print Network (OSTI)

The precise measurement of the high masses of the pulsars PSR J1614-2230 (M_{1614}=1.97 +- 0.04 solar masses) and PSR J0348-0432 (M_{0348}=2.01 +- 0.04 solar masses) provides an important constraint for the equation of state of cold, dense matter and is suited to give interesting insights regarding the nature and existence of the possible phase transition to deconfined quark matter in the cores of neutron stars. We analyze the stability and composition of compact star sequences for a class of hybrid nuclear - quark-matter equations of state. The quark matter phase is described in the framework of a standard color superconducting 3-flavor Nambu-Jona-Lasinio model and the hadronic phase is given by the Dirac-Brueckner-Hartree-Fock equation of state for the Bonn-A potential. The phase transition is obtained by a Maxwell construction. Within this model setup we aim to constrain otherwise not strictly fixed parameters of the NJL model, namely the coupling strengths in the vector meson and diquark interaction chann...

Klahn, T; ?astowiecki, R

2013-01-01T23:59:59.000Z

235

Quark Condensates: Flavour Dependence  

E-Print Network (OSTI)

We determine the q-bar q condensate for quark masses from zero up to that of the strange quark within a phenomenologically successful modelling of continuum QCD by solving the quark Schwinger-Dyson equation. The existence of multiple solutions to this equation is the key to an accurate and reliable extraction of this condensate using the operator product expansion. We explain why alternative definitions fail to give the physical condensate.

R. Williams; C. S. Fischer; M. R. Pennington

2007-03-23T23:59:59.000Z

236

Searches for new physics in top decays at the LHC  

E-Print Network (OSTI)

The search for new physics in top quark decays at the LHC is reviewed in this paper. Results from ATLAS and CMS experiments on top quark decays within the Standard Model are presented together with the measurements of the W boson polarizations and the study of the structure of the Wtb vertex. As a natural step forward, the experimental status on measurements sensitive to top quark couplings to gauge bosons (\\gamma, Z, W and H) is reviewed as well as possible top quark decays Beyond the Standard Model (MSSM and FCNC).

A. Onofre

2012-12-31T23:59:59.000Z

237

Anatomy of Coannihilation with a Scalar Top Partner  

E-Print Network (OSTI)

We investigate a simplified model of dark matter where a Majorana fermion $\\chi$ coannihilates with a colored scalar top partner $\\tilde{t}$. We explore the cosmological history, with particular emphasis on the most relevant low-energy parameters: the mass splitting between the dark matter and the coannihilator, and the Yukawa coupling $y_\\chi$ that connects these fields to the Standard Model top quarks. We also allow a free quartic coupling $\\lambda_h$ between a pair of Higgs bosons and $\\tilde{t}$ pairs. We pay special attention to the case where the values take on those expected where $\\tilde{t}$ corresponds to the superpartner of the right-handed top, and $\\chi$ is a bino. Direct detection, indirect detection, and colliders are complementary probes of this simple model.

Ibarra, A; Shah, N R; Vogl, S

2015-01-01T23:59:59.000Z

238

Searches for new physics in top events at the Tevatron  

SciTech Connect

During the past years the CDF and D0 detectors have collected large amounts of data obtaining a relatively pure sample of pair-produced top quarks and a well understood sample containing singly-produced top quarks. These samples have been used for the precise measurement of the top quark properties, and have set stringent limits on new physics in the top sample. This reports presents the latest results from the CDF and D0 collaborations on the search for new physics within the top sample using an integrated data sample of up to 3.6 fb{sup -1}.

Eusebi, Ricardo; collaboration, CDF; collaboration, D0

2009-05-01T23:59:59.000Z

239

Determination of $|V_{us}|$ from a lattice-QCD calculation of the $K\\to?\\ell?$ semileptonic form factor with physical quark masses  

E-Print Network (OSTI)

We calculate the kaon semileptonic form factor $f_+(0)$ from lattice QCD, working, for the first time, at the physical light-quark masses. We use gauge configurations generated by the MILC collaboration with $N_f=2+1+1$ flavors of sea quarks, which incorporate the effects of dynamical charm quarks as well as those of up, down, and strange. We employ data at three lattice spacings to extrapolate to the continuum limit. Our result, $f_+(0) = 0.9704(32)$, where the error is the total statistical plus systematic uncertainty added in quadrature, is the most precise determination to date. Combining our result with the latest experimental measurements of $K$ semileptonic decays, one obtains the Cabibbo-Kobayashi-Maskawa matrix element $|V_{us}|=0.22290(74)(52)$, where the first error is from $f_+(0)$ and the second one is from experiment. In the first-row test of Cabibbo-Kobayashi-Maskawa unitarity, the error stemming from $|V_{us}|$ is now comparable to that from $|V_{ud}|$.

A. Bazavov; C. Bernard; C. Bouchard; C. DeTar; D. Du; A. X. El-Khadra; J. Foley; E. D. Freeland; E. Gámiz; Steven Gottlieb; U. M. Heller; J. Kim; A. S. Kronfeld; J. Laiho; L. Levkova; P. B. Mackenzie; E. T. Neil; M. B. Oktay; Si-Wei Qiu; J. N. Simone; R. Sugar; D. Toussaint; R. S. Van de Water; Ran Zhou

2013-12-04T23:59:59.000Z

240

quarks-web.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

and and 2013 update for the 2014 edition (URL: http://pdg.lbl.gov) December 18, 2013 12:00 - 2- the introduction of a dimensionful scale parameter µ. The mass parameters in the QCD Lagrangian Eq. (1) depend on the renor- malization scheme used to define the theory, and also on the scale parameter µ. The most commonly used renormalization scheme for QCD perturbation theory is the MS scheme. The QCD Lagrangian has a chiral symmetry in the limit that the quark masses vanish. This symmetry is spontaneously broken by dynamical chiral symmetry breaking, and explicitly broken by the quark masses. The nonperturbative scale of dynamical chiral symmetry breaking, Λ χ , is around 1 GeV [2]. It is conventional to call quarks heavy if m > Λ χ , so that explicit chiral symmetry breaking dominates (c, b, and t quarks are heavy), and light if m < Λ χ , so that spontaneous chiral symmetry breaking

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241

Techniques for the Top Squark Search at the Fermilab Tevatron  

E-Print Network (OSTI)

This dissertation addresses the question of how to detect light top squarks at the upgraded Fermilab Tevatron collider. After a brief introduction to supersymmetry, the basic phenomenology of the light stop is reviewed and the current experimental situation is surveyed. The analysis presented here is based on collider event simulations. The main decay modes accessible to the Tevatron are studied, feasible discovery channels are identified, and recipes for experimental analysis are proposed. It is found that stops with masses up to the top quark mass are liable to detection under these schemes with the data from a few years' running at the upgraded Tevatron. With such an extended run, significant portions of parameter space may be probed.

John Sender

2000-10-04T23:59:59.000Z

242

String Junction Model, Cluster Hypothesis, Penta-Quark Baryon and Tetra-Quark Meson  

Science Journals Connector (OSTI)

......and mB 1 GeV is the ordinary light baryon mass. In this paper...non-strange quarks. Mass of such light penta-quark baryons with NJ...O(10) MeV. While mass of light tetra-quark meson with NJ...junction was first written in the Christmas greeting card of Y. Nambu around......

Masahiro Imachi; Shoichiro Otsuki; Fumihiko Toyoda

2008-10-01T23:59:59.000Z

243

W Transverse Mass  

NLE Websites -- All DOE Office Websites (Extended Search)

Some Data Analysis Some Data Analysis The Tevatron produces millions of collisions each second in CDF and DZero. The detectors have hardware triggers to decide if a collision is "interesting," that is it contains a candidate event for any one of a number studies. Our dataset contains 48,844 candidate events for a W mass study. There are other datasets to study Z mass, top and b quarks, QCD, etc. Why don't all the W decays give exactly the same mass? Are all these candidates really Ws? What if we chose only some of these data. How would our choice effect the value of the transverse mass? Work with your classmates. Test the data to see what you can learn. Help with data analysis. Record the best estimate of the W transverse mass from your data analysis. Explain which data you used and why. Check with your classmates and explain any differences between your estimate and theirs.

244

Identifying the top of the tropical tropopause layer from vertical mass flux analysis and CALIPSO lidar cloud observations  

E-Print Network (OSTI)

defined as the level of zero net radiative heating, which occurs near 14.5­15 km [e.g., Folkins et al layer (TTL) by analyzing the vertical mass flux profile based on radiative transfer calculations will rise into the stratosphere. Thus convection has to transport air at least to the zero radiative heating

Hochberg, Michael

245

Top physics at CDF  

SciTech Connect

We report on top physics results using a 100 pb{sup -1} data sample of p{bar p} collisions at {radical}s = 1.8 TeV collected with the Collider Detector at Fermilab (CDF). We have identified top signals in a variety of decay channels, and used these channels to extract a measurement of the top mass and production cross section. A subset of the data (67 pb{sup -1}) is used to determine M{sub top} = 176 {+-} 8(stat) {+-} 10(syst) and {sigma}(tt) = 7.6 {sub -2.0}{sup +2.4} pb. We present studies of the kinematics of t{bar t} events and extract the first direct measurement of V{sub tb}. Finally, we indicate prospects for future study of top physics at the Tevatron.

Hughes, R.E. [Univ. of Rochester, NY (United States)

1997-01-01T23:59:59.000Z

246

Quark Interactions  

NLE Websites -- All DOE Office Websites (Extended Search)

Interacciones del quark Interacciones del quark Volver Principal ESTOY PERDIDO!!! Los quarks tienen carga eléctrica, por lo que sufren interacciones electromagnéticas. Los quarks tienen carga de color, de modo que sufren las interacciones fuertes. Las interacciones fuertes causan que los quarks se combinen formando hadrones. Las interacciones fuertes residuales mantienen a los hadrones juntos, para formar núcleos. Los diferentes tipos de quark (u, d, c, ...) se denominan sabores. El sabor sólo se altera por medio de interacciones debiles cargadas. Por ejemplo: Todos los quarks del lado izquierdo también aparecen del lado derecho . Sin embargo, cuando un quark emite un bosón ( virtual) W+ o W-, debe cambiar su carga eléctrica y, por lo tanto, su sabor. El proceso débil predominante es el que involucra transiciones entre quarks de la misma

247

Heavy quarks in the jet calculus  

Science Journals Connector (OSTI)

In this paper we explore a method for treating heavy quarks such as c and b quarks within the jet calculus. These quarks are differentiated from the more common u, d, and s quarks by the requirement that the gluons never branch into heavy-quark pairs during the jet development. We compute and discuss the charmed-quark "propagators"; the x distribution of colorless clusters containing a charmed quark, a noncharmed antiquark, and gluons; and the mass distribution of the parent partons giving rise to these colorless clusters.

L. M. Jones

1983-07-01T23:59:59.000Z

248

Electroweak Corrections to the Top Quark Decay  

E-Print Network (OSTI)

We have calculated the one-loop electroweak corrections to the decay t-> bW+, including the counterterm for the CKM matrix elements V(tb). Previous calculations used an incorrect delta V(tb) that led to a gauge dependent amplitude. However, since the contribution stemming from delta V(tb) is small, those calculations only underestimate the width by roughly one part in 10^5.

S. M. Oliveira; L. Bruecher; R. Santos; A. Barroso

2001-01-18T23:59:59.000Z

249

Top quark physics expectations at the LHC  

E-Print Network (OSTI)

physics expectations at the LHC Andrei Gaponenko, on behalfbe produced copiously at the LHC. This will make possiblepurpose detectors at the LHC, which will provide proton-

Gaponenko, Andrei; ATLAS Collaboration; CMS Collaboration

2008-01-01T23:59:59.000Z

250

Funny Quarks  

NLE Websites -- All DOE Office Websites (Extended Search)

graciosos quarks graciosos quarks Volver Principal ESTOY PERDIDO!!! Un poco de la historia del quark: En 1964 Murray Gell-Mann y George Zweig sugirieron que cientos de las partículas conocidas hasta el momento, podrían ser explicadas como una combinación de sólo 3 partículas fundamentales. Gell-Mann eligió el nombre caprichoso de "quarks" para estos constituyentes. Esta palabra aparece en la frase "three quarks for Muster Mark" en la novela de James Joyce, Finnegan's Wake. La parte revolucionaria de la idea era que ellos debieron asignarle a los quarks cargas eléctricas de 2/3 y -1/3 (en unidades de la carga del protón): nunca habían sido observadas cargas como esas. Primero los quarks fueron considerados como un truco matemático, pero los experimentos

251

Probing top-Z dipole moments at the LHC and ILC  

E-Print Network (OSTI)

We investigate the weak electric and magnetic dipole moments of top quark-Z boson interactions at the Large Hadron Collider (LHC) and the International Linear Collider (ILC). Their vanishingly small magnitude in the Standard Model makes these couplings ideal for probing New Physics interactions and for exploring the role of top quarks in electroweak symmetry breaking. In our analysis, we consider the production of two top quarks in association with a Z boson at the LHC, and top quark pairs mediated by neutral gauge bosons at the ILC. These processes yield direct sensitivity to top quark-Z boson interactions and complement indirect constraints from electroweak precision data. Our computation is accurate to next-to-leading order in QCD, we include the full decay chain of top quarks and the Z boson, and account for theoretical uncertainties in our constraints. We find that LHC experiments will soon be able to probe weak dipole moments for the first time.

Raoul Röntsch; Markus Schulze

2015-01-23T23:59:59.000Z

252

Probing top-Z dipole moments at the LHC and ILC  

E-Print Network (OSTI)

We investigate the weak electric and magnetic dipole moments of top quark-Z boson interactions at the Large Hadron Collider (LHC) and the International Linear Collider (ILC). Their vanishingly small magnitude in the Standard Model makes these couplings ideal for probing New Physics interactions and for exploring the role of top quarks in electroweak symmetry breaking. In our analysis, we consider the production of two top quarks in association with a Z boson at the LHC, and top quark pairs mediated by neutral gauge bosons at the ILC. These processes yield direct sensitivity to top quark-Z boson interactions and complement indirect constraints from electroweak precision data. Our computation is accurate to next-to-leading order in QCD, we include the full decay chain of top quarks and the Z boson, and account for theoretical uncertainties in our constraints. We find that LHC experiments will soon be able to probe weak dipole moments for the first time.

Röntsch, Raoul

2015-01-01T23:59:59.000Z

253

A Measurement of the Top Quark Mass in 1.96 TeV Proton-Antiproton Collisions Using a Novel Matrix Element Method  

E-Print Network (OSTI)

antiprotons i n a circular synchroton, it is lJ-Wl Here, /whereupon they enter a synchroton whose diameter is roughly

Henderson, Anytra S; CDF Collaboration

2007-01-01T23:59:59.000Z

254

Search for a Vectorlike Quark with Charge 2/3 in t+Z Events from pp Collisions at sqrt[s]=7??TeV  

SciTech Connect

A search for pair-produced heavy vector-like charge-2/3 quarks, T, in pp collisions at a center-of-mass energy of 7 TeV, is performed with the CMS detector at the LHC. Events consistent with the flavor-changing-neutral-current decay of a T quark to a top quark and a Z boson are selected by requiring two leptons from the Z-boson decay, as well as an additional isolated charged lepton. In a data sample corresponding to an integrated luminosity of 1.14 inverse femtobarns, the number of observed events is found to be consistent with the standard model background prediction. Assuming a branching fraction of 100% for the decay T to tZ, a T quark with a mass less than 475 GeV/c^2 is excluded at the 95% confidence level.

Chatrchyan, Serguei; et al.

2011-12-01T23:59:59.000Z

255

Origin of masses in the Early Universe  

E-Print Network (OSTI)

New model is suggested, where the Casimir mechanism is the source of masses and conformal symmetry breaking at the Planck epoch in the beginning of the Universe. The mechanism is the Casimir energy and associated condensate, which are resulted from the vacuum postulate and normal ordering of the conformal invariant Hamiltonian with respect to the quantum elementary field operators. It is shown that the Casimir top-quark condensate specifies the value of the Higgs particle mass without involving the Higgs tachyon mass, which is put equal to zero. The Casimir mechanism yields another value of the coupling constant for the self-interaction of scalar field than the standard model does.

Pervushin, Victor N; Cherny, Alexander Yu; Shilin, Vadim I; Nazmitdinov, Rashid G; Pavlov, Alexander E; Pichugin, Konstantin N; Zakharov, Alexander F

2015-01-01T23:59:59.000Z

256

Measurement of the high-mass Drell-Yan cross section and limits on quark-electron compositeness scales  

E-Print Network (OSTI)

We present a measurement of the Drell-Yan cross section at high dielectron invariant mass using 120 pb(-1) of data collected in p (p) over bar, collisions at root s = 1.8TeV by the D0 Collaboration during 1992-1996. No ...

Baringer, Philip S.

1999-06-01T23:59:59.000Z

257

Quark condensate for various heavy flavors  

E-Print Network (OSTI)

The quark condensate is calculated within the world-line effective-action formalism, by using for the Wilson loop an ansatz provided by the stochastic vacuum model. Starting with the relation between the quark and the gluon condensates in the heavy-quark limit, we diminish the current quark mass down to the value of the inverse vacuum correlation length, finding in this way a 64%-decrease in the absolute value of the quark condensate. In particular, we find that the conventional formula for the heavy-quark condensate cannot be applied to the c-quark, and that the corrections to this formula can reach 23% even in the case of the b-quark. We also demonstrate that, for an exponential parametrization of the two-point correlation function of gluonic field strengths, the quark condensate does not depend on the non-confining non-perturbative interactions of the stochastic background Yang-Mills fields.

Dmitri Antonov; Jose Emilio F. T. Ribeiro

2012-10-04T23:59:59.000Z

258

Search for Pair Production of Third-Generation Leptoquarks and Top Squarks in pp Collisions at ?s=7??TeV  

Results are presented from a search for the pair production of third-generation scalar and vector leptoquarks, as well as for top squarks in R -parity-violating supersymmetric models. In either scenario, the new, heavy particle decays into a ? lepton and a b quark. The search is based on a data sample of pp collisions at ?s =7??TeV , which is collected by the CMS detector at the LHC and corresponds to an integrated luminosity of 4.8??fb?1. The number of observed events is found to be in agreement with the standard model prediction, and exclusion limits on mass parameters are obtained at the 95% confidence level. Vector leptoquarks with masses below 760 GeV are excluded and, if the branching fraction of the scalar leptoquark decay to a ? lepton and a b quark is assumed to be unity, third-generation scalar leptoquarks with masses below 525 GeV are ruled out. Top squarks with masses below 453 GeV are excluded for a typical benchmark scenario, and limits on the coupling between the top squark, ? lepton, and b quark, ? ?333 are obtained. These results are the most stringent for these scenarios to date.

Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Aguilo, E.; Bergauer, T.; Dragicevic, M.; Erö, J.; Fabjan, C.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hammer, J.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knünz, V.; Krammer, M.; Krätschmer, I.; Liko, D.; Mikulec, I.; Pernicka, M.; Rahbaran, B.; Rohringer, C.; Rohringer, H.; Schöfbeck, R.; Strauss, J.; Taurok, A.; Waltenberger, W.; Walzel, G.; Widl, E.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Bansal, M.; Bansal, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Luyckx, S.; Mucibello, L.; Ochesanu, S.; Roland, B.; Rougny, R.; Selvaggi, M.; Staykova, Z.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Blekman, F.; Blyweert, S.; D’Hondt, J.; Gonzalez Suarez, R.; Kalogeropoulos, A.; Maes, M.; Olbrechts, A.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Villella, I.; Clerbaux, B.; De Lentdecker, G.; Dero, V.; Gay, A. P. R.; Hreus, T.; Léonard, A.; Marage, P. E.; Mohammadi, A.; Reis, T.; Thomas, L.; Vander Marcken, G.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Adler, V.; Beernaert, K.; Cimmino, A.; Costantini, S.; Garcia, G.; Grunewald, M.; Klein, B.; Lellouch, J.; Marinov, A.; Mccartin, J.; Ocampo Rios, A. A.; Ryckbosch, D.; Strobbe, N.; Thyssen, F.; Tytgat, M.; Verwilligen, P.; Walsh, S.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Bruno, G.; Castello, R.; Ceard, L.; Delaere, C.; du Pree, T.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Lemaitre, V.; Liao, J.; Militaru, O.; Nuttens, C.; Pagano, D.; Pin, A.; Piotrzkowski, K.; Schul, N.; Vizan Garcia, J. M.; Beliy, N.; Caebergs, T.; Daubie, E.; Hammad, G. H.; Alves, G. A.; Correa Martins Junior, M.; De Jesus Damiao, D.; Martins, T.; Pol, M. E.; Souza, M. H. G.; Aldá Júnior, W. L.; Carvalho, W.; Custódio, A.; Da Costa, E. M.; De Oliveira Martins, C.; Fonseca De Souza, S.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Oguri, V.; Prado Da Silva, W. L.; Santoro, A.; Soares Jorge, L.; Sznajder, A.; Anjos, T. S.; Bernardes, C. A.; Dias, F. A.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Lagana, C.; Marinho, F.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Genchev, V.; Iaydjiev, P.; Piperov, S.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Tcholakov, V.; Trayanov, R.; Vutova, M.; Dimitrov, A.; Hadjiiska, R.; Kozhuharov, V.; Litov, L.; Pavlov, B.; Petkov, P.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Jiang, C. H.; Liang, D.; Liang, S.; Meng, X.; Tao, J.; Wang, J.; Wang, X.; Wang, Z.; Xiao, H.; Xu, M.; Zang, J.; Zhang, Z.; Asawatangtrakuldee, C.; Ban, Y.; Guo, Y.; Li, W.; Liu, S.; Mao, Y.; Qian, S. J.; Teng, H.; Wang, D.; Zhang, L.; Zou, W.; Avila, C.; Gomez, J. P.; Gomez Moreno, B.; Osorio Oliveros, A. F.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Plestina, R.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Duric, S.; Kadija, K.; Luetic, J.; Morovic, S.; Attikis, A.; Galanti, M.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Finger, M.; Finger, M.; Assran, Y.; Elgammal, S.; Ellithi Kamel, A.; Mahmoud, M. A.; Radi, A.; Kadastik, M.; Müntel, M.; Raidal, M.; Rebane, L.; Tiko, A.; Eerola, P.; Fedi, G.; Voutilainen, M.; Härkönen, J.; Heikkinen, A.; 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.; Ungaro, D.; Wendland, L.; Banzuzi, K.; Karjalainen, A.; Korpela, A.; Tuuva, T.; Besancon, M.; Choudhury, S.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Malcles, J.; Millischer, L.; Nayak, A.; Rander, J.; Rosowsky, A.; Shreyber, I.; Titov, M.; Baffioni, S.; Beaudette, F.; Benhabib, L.; Bianchini, L.; Bluj, M.; Broutin, C.; Busson, P.; Charlot, C.; Daci, N.; Dahms, T.; Dobrzynski, L.; Granier de Cassagnac, R.; Haguenauer, M.; Miné, P.; Mironov, C.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Paganini, P.; Sabes, D.; Salerno, R.; Sirois, Y.; Veelken, C.; Zabi, A.; Agram, J.-L.; Andrea, J.; Bloch, D.; Bodin, D.; Brom, J.-M.; Cardaci, M.; Chabert, E. C.; Collard, C.; Conte, E.; Drouhin, F.; Ferro, C.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Juillot, P.; Le Bihan, A.-C.; Van Hove, P.; Fassi, F.; Mercier, D.; Beauceron, S.; Beaupere, N.; Bondu, O.; Boudoul, G.; Chasserat, J.; Chierici, R.; Contardo, D.; Depasse, P.; El Mamouni, H.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Kurca, T.; Lethuillier, M.; Mirabito, L.; Perries, S.; Sgandurra, L.; Sordini, V.; Tschudi, Y.; Verdier, P.; Viret, S.; Tsamalaidze, Z.; Anagnostou, G.; Autermann, C.; Beranek, S.; Edelhoff, M.; Feld, L.; Heracleous, N.; Hindrichs, O.; Jussen, R.

2013-02-01T23:59:59.000Z

259

Detecting heavy quarks  

SciTech Connect

In this exercise we examine the performance of a detector specifically configured to tag heavy quark (HQ) jets through direct observations of D-meson decays with a high resolution vertex detector. To optimize the performance of such a detector, we assume the small diamond beam crossing configuration as described in the 1978 ISABELLE proposal, giving a luminosity of 10/sup 32/ cm/sup -2/ sec/sup -1/. Because of the very large backgrounds from light quark (LQ) jets, most triggering schemes at this luminosity require high P/sub perpendicular to/ leptons and inevitably give missing neutrinos. If alternative triggering schemes could be found, then one can hope to find and calculate the mass of objects decaying to heavy quarks. A scheme using the high resolution detector will also be discussed in detail. The study was carried out with events generated by the ISAJET Monte Carlo and a computer simulation of the described detector system. (WHK)

Benenson, G.; Chau, L.L.; Ludlam, T.; Paige, F.E.; Platner, E.D.; Protopopescu, S.D.; Rehak, P.

1983-01-01T23:59:59.000Z

260

Discovery Mass Reach for Topgluons Decaying to t anti-t at the Tevatron  

E-Print Network (OSTI)

In topcolor assisted technicolor, topgluons are massive gluons which couple mainly to top and bottom quarks. We estimate the mass reach for topgluons decaying to t anti-t at the Tevatron as a function of integrated luminosity. The mass reach for topgluons decreases with increasing topgluon width, and is 1.0 - 1.1 TeV for Run II (2 fb^-1) and 1.3-1.4 TeV for TeV33 (30 fb^-1).

Robert M. Harris

1996-09-11T23:59:59.000Z

Note: This page contains sample records for the topic "top quark mass" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Discovery Mass Reach for Topgluons Decaying to b anti-b at the Tevatron  

E-Print Network (OSTI)

In topcolor assisted technicolor, topgluons are massive gluons which couple mainly to top and bottom quarks. We estimate the mass reach for topgluons decaying to b anti-b at the Tevatron as a function of integrated luminosity. The mass reach for topgluons decreases with increasing topgluon width, and is 0.77 - 0.95 TeV for Run II (2 fb^-1) and 1.0-1.2 TeV for TeV33 (30 fb^-1).

Robert M. Harris

1996-09-11T23:59:59.000Z

262

Shear Viscosity of Quark Matter  

E-Print Network (OSTI)

We consider the shear viscosity of a system of quarks and its ratio to the entropy density above the critical temperature for deconfinement. Both quantities are derived and computed for different modeling of the quark self-energy, also allowing for a temperature dependence of the effective mass and width. The behaviour of the viscosity and the entropy density is argued in terms of the strength of the coupling and of the main characteristics of the quark self-energy. A comparison with existing results is also discussed.

W. M. Alberico; S. Chiacchiera; H. Hansen; A. Molinari; M. Nardi

2007-07-30T23:59:59.000Z

263

Phenomenological applications of non-perturbative heavy quark effective theory  

E-Print Network (OSTI)

We briefly review the strategy to perform non-perturbative heavy quark effective theory computations and we specialize to the case of the b quark mass which has recently been computed including the 1/m term.

Mauro Papinutto

2007-10-11T23:59:59.000Z

264

Remarks on quark-quark and quark-antiquark potentials  

Science Journals Connector (OSTI)

The quark-quark potential in antisymmetrical color states and the quark-antiquark potential in color-singlet states are given to the fourth order in perturbative quantum chromodynamics. We have also corrected an error involving the charge conjugation of color matrices in our recent derivation of the quark-antiquark potential for arbitrary color states.

Suraj N. Gupta and Stanley F. Radford

1982-06-15T23:59:59.000Z

265

Current trends in non-accelerator particle physics: 1, Neutrino mass and oscillation. 2, High energy neutrino astrophysics. 3, Detection of dark matter. 4, Search for strange quark matter. 5, Magnetic monopole searches  

SciTech Connect

This report is a compilation of papers reflecting current trends in non-accelerator particle physics, corresponding to talks that its author was invited to present at the Workshop on Tibet Cosmic Ray Experiment and Related Physics Topics held in Beijing, China, April 4--13, 1995. The papers are entitled `Neutrino Mass and Oscillation`, `High Energy Neutrino Astrophysics`, `Detection of Dark Matter`, `Search for Strange Quark Matter`, and `Magnetic Monopole Searches`. The report is introduced by a survey of the field and a brief description of each of the author`s papers.

He, Yudong [California Univ., Berkeley, CA (United States)]|[Lawrence Berkeley Lab., CA (United States)

1995-07-01T23:59:59.000Z

266

QuarkNet  

NLE Websites -- All DOE Office Websites (Extended Search)

QuarkNet: The science connection you've been waiting for! QuarkNet: The science connection you've been waiting for! The Opportunity: "Your program rejuvenates my soul. It connects me with a cadre of intelligent and excited educators. It reinvigorates my teaching and provides me avenues to extend and enliven the projects that I can offer my students. Without the Quarknet program I am sure that I would have left teaching years ago." The Players: High school students, teachers and physicsts working together on physics research projects exploring the hidden nature of matter, energy, space and time. The Questions: What are the origins of mass? Can the basic forces of nature be unified? How did the universe begin? How will it evolve? LHC & Fermilab Links For Teachers For Students CERN Homepage ATLAS Experiment

267

Excited quark production at the CERN LHC  

Science Journals Connector (OSTI)

We study the production of excited quarks q? of spin-1/2 predicted by composite models. Production rates, signatures, and backgrounds are discussed for the CERN LHC. We estimate the discovery mass reach for the excited quarks decaying to jet+photon.

O. Çak?r and R. Mehdiyev

1999-06-22T23:59:59.000Z

268

Discovering strong top dynamics at the LHC  

Science Journals Connector (OSTI)

We analyze the phenomenology of the top-pion and top-Higgs states in models with strong top dynamics, and translate the present LHC searches for the Standard Model Higgs into bounds on these scalar states. We explore the possibility that the new state at a mass of approximately 125 GeV observed at the LHC is consistent with a neutral pseudoscalar top-pion state. We demonstrate that a neutral pseudoscalar top pion can generate the diphoton signal at the observed rate. However, the region of model parameter space where this is the case does not correspond to classic top-color-assisted technicolor scenarios with degenerate charged and neutral top pions and a top-Higgs mass of order 2mt; rather, additional isospin violation would need to be present and the top dynamics would be more akin to that in top seesaw models. Moreover, the interpretation of the new state as a top pion can be sustained only if the ZZ (four-lepton) and WW (two-lepton plus missing energy) signatures initially observed at the 3? level decline in significance as additional data are accrued.

R. Sekhar Chivukula; Pawin Ittisamai; Elizabeth H. Simmons; Baradhwaj Coleppa; Heather E. Logan; Adam Martin; Jing Ren

2012-11-16T23:59:59.000Z

269

Building a Better Boosted Top Tagger  

E-Print Network (OSTI)

Distinguishing hadronically decaying boosted top quarks from massive QCD jets is an important challenge at the Large Hadron Collider. In this paper we use the power counting method to study jet substructure observables designed for top tagging, and gain insight into their performance. We introduce a powerful new family of discriminants formed from the energy correlation functions which outperform the widely used N-subjettiness. These observables take a highly non-trivial form, demonstrating the importance of a systematic approach to their construction.

Andrew J. Larkoski; Ian Moult; Duff Neill

2014-11-03T23:59:59.000Z

270

Cosmological Constraints on the Higgs Boson Mass  

Science Journals Connector (OSTI)

For a robust interpretation of upcoming observations from PLANCK and Large Hadron Collider experiments it is imperative to understand how the inflationary dynamics of a non-minimally coupled Higgs scalar field with gravity may affect the determination of the inflationary observables. We make a full proper analysis of the Wilkinson Microwave Anisotropy Probe, Type Ia supernova distance-redshift relation, and the baryon acoustic oscillations data sets in a context of the non-minimally coupled Higgs inflation field with gravity. For the central value of the top quark pole mass mT = 171.3 GeV, the fit of the inflation model with a non-minimally coupled Higgs scalar field leads to a Higgs boson mass in the range 143.7 GeV ? mH ? 167 GeV (95% CL). We show that the inflation driven by a non-minimally coupled scalar field to the Einstein gravity leads to significant constraints on the scalar spectral index nS and the tensor-to-scalar ratio R when compared with a tensor with similar constraints to form the standard inflation with a minimally coupled scalar field. We also show that an accurate reconstruction of the Higgs potential in terms of inflationary observables requires an improved accuracy of other parameters of the standard model of particle physics such as the top quark mass and the effective QCD coupling constant.

L. A. Popa; A. Caramete

2010-01-01T23:59:59.000Z

271

Quark confinement mechanism for baryons  

E-Print Network (OSTI)

The confinement mechanism proposed earlier and then successfully applied to meson spectroscopy by the author is extended over baryons. For this aim the wave functions of baryons are built as tensorial products of those corresponding to the 2-body problem underlying the confinement mechanism of two quarks. This allows one to obtain the Hamiltonian of the quark interactions in a baryon and, accordingly, the possible energy spectrum of the latter. Also one may construct the electric and magnetic form factors of baryon in a natural way which entails the expressions for the root-mean-square radius and anomalous magnetic moment. To ullustrate the formalism in the given Chapter for the sake of simplicity only symmetrical baryons (i.e., composed from three quarks of the same flavours) $\\Delta^{++}$, $\\Delta^{-}$, $\\Omega^-$ are considered. For them the masses, the root-mean-square radii and anomalous magnetic moments are expressed in an explicit analytical form through the parameters of the confining SU(3)-gluonic field among quarks and that enables one to get a number of numerical estimates for the mentioned parameters from experimental data. We also discuss chiral limit for the baryons under consideration and estimate the purely gluonic contribution to their masses. Further the problem of masses in particle physics is shortly discussed within the framework of the given approach. Finally, a few remarks are made about the so-called Yang-Mills Millennium problem and a possible way for proving it is outlined.

Yu. P. Goncharov

2013-12-14T23:59:59.000Z

272

Color screening in cold quark matter  

E-Print Network (OSTI)

We compute color screening at finite quark chemical potentials cold quark matter at the one-loop level, comparing the normal, BCS paired U(1)_em, or Higgs, and a singlet phase with color-singlet condensate near the Fermi surface. The latter phase is computed in the example of two-color QCD with a color singlet diquark condensate. In contrast to the normal and Higgs phases, neither electric nor magnetic screening masses appear in the singlet phase. The absence of a magnetic mass, within a perturbative framework, is a consequence of proper treatment of gauge invariance. While at large momenta the gluon self-energies approach those in the normal phase, the medium contributions to the infrared region below a scale of the mass gap are substantially suppressed. Infrared gluons at low quark density in the singlet phase appear protected from medium effects, unless the quark-gluon vertices are significantly enhanced in the infrared.

Kojo, Toru

2014-01-01T23:59:59.000Z

273

Dijet mass spectrum and a search for quark compositeness in (p)over-bar-p collisions at root s=1.8TeV  

E-Print Network (OSTI)

Using the D0 detector at the 1.8 TeV (p)over-bar-p Fermilab Tevatron collider, we have measured the inclusive dijet mass spectrum in the central pseudorapidity region [eta(jet)] less-than 1.0 for dijet masses greater-than ...

Baringer, Philip S.

1999-03-01T23:59:59.000Z

274

Single top measurements and the $|V_{\\rm tb}|$ extraction at the LHC  

E-Print Network (OSTI)

The CMS and ATLAS experiments have performed detailed studies on the electroweakly produced top quarks at the LHC. These studies range from accurate measurements of the cross section and $|V_{\\rm tb}|$ in different production modes to search for new interactions in the $\\rm tWb$ vertex. Moreover, different properties of the top quark are precisely measured in this context. All measurements are consistent with the standard model and no sign of new physics is observed.

Jafari, Abideh

2014-01-01T23:59:59.000Z

275

Playing Tag with ANN: Boosted Top Identification with Pattern Recognition  

E-Print Network (OSTI)

Many searches for physics beyond the Standard Model at the Large Hadron Collider (LHC) rely on top tagging algorithms, which discriminate between boosted hadronic top quarks and the much more common jets initiated by light quarks and gluons. We note that the hadronic calorimeter (HCAL) effectively takes a "digital image" of each jet, with pixel intensities given by energy deposits in individual HCAL cells. Viewed in this way, top tagging becomes a canonical pattern recognition problem. With this motivation, we present a novel top tagging algorithm based on an Artificial Neural Network (ANN), one of the most popular approaches to pattern recognition. The ANN is trained on a large sample of boosted tops and light quark/gluon jets, and is then applied to independent test samples. The ANN tagger demonstrated excellent performance in a Monte Carlo study: for example, for jets with p_T in the 1100-1200 GeV range, 60% top-tag efficiency can be achieved with a 4% mis-tag rate. We discuss the physical features of the ...

Almeida, Leandro G; Cliche, Mathieu; Lee, Seung J; Perelstein, Maxim

2015-01-01T23:59:59.000Z

276

Searches for heavy scalar and pseudoscalar Higgs bosons and for flavor-violating decays of the top quark into a Higgs boson in $\\mathrm{p}\\mathrm{p}$ collisions at $\\sqrt{s}$ = 8 TeV  

E-Print Network (OSTI)

Searches are presented for heavy scalar ($\\mathrm{H}$) and pseudoscalar ($\\mathrm{A}$) Higgs bosons posited in the two doublet model (2HDM) extensions of the standard model (SM). These searches are based on a data sample of $\\mathrm{p}\\mathrm{p}$ collisions collected with the CMS experiment at the LHC at a center-of-mass energy of $\\sqrt{s} = 8~\\mathrm{TeV}$ and corresponding to an integrated luminosity of $19.5~\\mathrm{fb}^{-1}$. The decays $\\mathrm{H} \\rightarrow \\mathrm{h} \\mathrm{h}$ and $\\mathrm{A} \\rightarrow \\mathrm{Z} \\mathrm{h}$, where $\\mathrm{h}$ denotes an SM-like Higgs boson, lead to events with three or more isolated charged leptons or with a photon pair accompanied by one or more isolated leptons. The search results are presented in terms of the $\\mathrm{H}$ and $\\mathrm{A}$ production cross sections times branching fractions and are further interpreted in terms of 2HDM parameters. We place 95% CL cross section upper limits of approximately $7~\\mathrm{pb}$ on $\\sigma \\mathcal{B}$ for $\\mathrm{H...

Khachatryan, Vardan; Tumasyan, Armen; Adam, Wolfgang; Bergauer, Thomas; Dragicevic, Marko; Erö, Janos; Fabjan, Christian; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hartl, Christian; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kiesenhofer, Wolfgang; Knünz, Valentin; Krammer, Manfred; Krätschmer, Ilse; Liko, Dietrich; Mikulec, Ivan; Rabady, Dinyar; Rahbaran, Babak; Rohringer, Herbert; Schöfbeck, Robert; Strauss, Josef; Taurok, Anton; Treberer-Treberspurg, Wolfgang; Waltenberger, Wolfgang; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Alderweireldt, Sara; Bansal, Monika; Bansal, Sunil; Cornelis, Tom; De Wolf, Eddi A; Janssen, Xavier; Knutsson, Albert; Luyckx, Sten; Ochesanu, Silvia; Roland, Benoit; Rougny, Romain; Van De Klundert, Merijn; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Van Spilbeeck, Alex; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Daci, Nadir; Heracleous, Natalie; Keaveney, James; Lowette, Steven; Maes, Michael; Olbrechts, Annik; Python, Quentin; Strom, Derek; Tavernier, Stefaan; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Caillol, Cécile; Clerbaux, Barbara; De Lentdecker, Gilles; Dobur, Didar; Favart, Laurent; Gay, Arnaud; Grebenyuk, Anastasia; Léonard, Alexandre; Mohammadi, Abdollah; Perniè, Luca; Reis, Thomas; Seva, Tomislav; Thomas, Laurent; Vander Velde, Catherine; Vanlaer, Pascal; Wang, Jian; Adler, Volker; Beernaert, Kelly; Benucci, Leonardo; Cimmino, Anna; Costantini, Silvia; Crucy, Shannon; Dildick, Sven; Fagot, Alexis; Garcia, Guillaume; Mccartin, Joseph; Ocampo Rios, Alberto Andres; Ryckbosch, Dirk; Salva Diblen, Sinem; Sigamani, Michael; Strobbe, Nadja; Thyssen, Filip; Tytgat, Michael; Yazgan, Efe; Zaganidis, Nicolas; Basegmez, Suzan; Beluffi, Camille; Bruno, Giacomo; Castello, Roberto; Caudron, Adrien; Ceard, Ludivine; Da Silveira, Gustavo Gil; Delaere, Christophe; Du Pree, Tristan; Favart, Denis; Forthomme, Laurent; Giammanco, Andrea; Hollar, Jonathan; Jez, Pavel; Komm, Matthias; Lemaitre, Vincent; Nuttens, Claude; Pagano, Davide; Perrini, Lucia; Pin, Arnaud; Piotrzkowski, Krzysztof; Popov, Andrey; Quertenmont, Loic; Selvaggi, Michele; Vidal Marono, Miguel; Vizan Garcia, Jesus Manuel; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Hammad, Gregory Habib; Aldá Júnior, Walter Luiz; Alves, Gilvan; Brito, Lucas; Correa Martins Junior, Marcos; Dos Reis Martins, Thiago; Mora Herrera, Clemencia; Pol, Maria Elena; Carvalho, Wagner; Chinellato, Jose; Custódio, Analu; Da Costa, Eliza Melo; De Jesus Damiao, Dilson; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Malbouisson, Helena; Matos Figueiredo, Diego; Mundim, Luiz; Nogima, Helio; Prado Da Silva, Wanda Lucia; Santaolalla, Javier; Santoro, Alberto; Sznajder, Andre; Tonelli Manganote, Edmilson José; Vilela Pereira, Antonio; Bernardes, Cesar Augusto; Dogra, Sunil; Tomei, Thiago; De Moraes Gregores, Eduardo; Mercadante, Pedro G; Novaes, Sergio F; Padula, Sandra; Aleksandrov, Aleksandar; Genchev, Vladimir; Iaydjiev, Plamen; Marinov, Andrey; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Tcholakov, Vanio; Vutova, Mariana; Dimitrov, Anton; Glushkov, Ivan; Hadjiiska, Roumyana; Kozhuharov, Venelin; Litov, Leander; Pavlov, Borislav; Petkov, Peicho; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Chen, Mingshui; Du, Ran; Jiang, Chun-Hua; Liang, Song; Plestina, Roko; Tao, Junquan; Wang, Xianyou; Wang, Zheng; Asawatangtrakuldee, Chayanit; Ban, Yong; Guo, Yifei; Li, Qiang; Li, Wenbo; Liu, Shuai; Mao, Yajun; Qian, Si-Jin; Wang, Dayong; Zhang, Linlin; Zou, Wei; Avila, Carlos; Chaparro Sierra, Luisa Fernanda; Florez, Carlos; Gomez, Juan Pablo; Gomez Moreno, Bernardo; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Kovac, Marko; Brigljevic, Vuko; Kadija, Kreso; Luetic, Jelena; Mekterovic, Darko; Sudic, Lucija; Attikis, Alexandros; Mavromanolakis, Georgios; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Bodlak, Martin; Finger, Miroslav; Finger Jr, Michael; Assran, Yasser; Ellithi Kamel, Ali; Mahmoud, Mohammed; Radi, Amr; Kadastik, Mario; Murumaa, Marion; Raidal, Martti; Tiko, Andres; Eerola, Paula; Fedi, Giacomo; Voutilainen, Mikko; Härkönen, Jaakko; Karimäki, Veikko; Kinnunen, Ritva; Kortelainen, Matti J; Lampén, Tapio; Lassila-Perini, Kati; Lehti, Sami; Lindén, Tomas; Luukka, Panja-Riina; Mäenpää, Teppo; Peltola, Timo; Tuominen, Eija; Tuominiemi, Jorma; Tuovinen, Esa; Wendland, Lauri; Tuuva, Tuure

2014-01-01T23:59:59.000Z

277

Five-quark components in baryons  

E-Print Network (OSTI)

Evidence has been accumulating for the existence of significant intrinsic non-perturbative five-quark components in various baryons. The inclusion of the five-quark components gives a natural explanation of the excess of $\\bar d$ over $\\bar u$, significant quark orbital angular momentum in the proton, the problematic mass and decay pattern of the lowest $1/2^-$ baryon nonet, etc.. A breathing mode of $qqq\\leftrightarrow qqqq\\bar q$ is suggested for the lowest $1/2^-$ baryon octet. Evidence of a predicted member of the new scheme, $\\Sigma^*(1/2^-)$ around 1380 MeV, is introduced.

B. S. Zou

2010-01-07T23:59:59.000Z

278

The Onset of Quark-Hadron Duality in Pion Electroproduction  

E-Print Network (OSTI)

A large data set of charged-pion electroproduction from both hydrogen and deuterium targets has been obtained spanning the low-energy residual-mass region. These data conclusively show the onset of the quark-hadron duality phenomenon, as predicted for high-energy hadron electroproduction. We construct several ratios from these data to exhibit the relation of this phenomenon to the high-energy factorization ansatz of electron-quark scattering and subsequent quark-to- pion production mechanisms.

T. Navasardyan

2006-08-18T23:59:59.000Z

279

The Onset of Quark-Hadron Duality in Pion Electroproduction  

SciTech Connect

A large data set of charged-pion electroproduction from both hydrogen and deuterium targets has been obtained spanning the low-energy residual-mass region. These data conclusively show the onset of the quark-hadron duality phenomenon, as predicted for high-energy hadron electroproduction. We construct several ratios from these data to exhibit the relation of this phenomenon to the high-energy factorization ansatz of electron-quark scattering and subsequent quark-to- pion production mechanisms.

Tigran Navasardyan; Gary Adams; Abdellah Ahmidouch; Tatiana Angelescu; John Arrington; Razmik Asaturyan; O. Baker; Nawal Benmouna; Crystal Bertoncini; Henk Blok; Werner Boeglin; Peter Bosted; Herbert Breuer; Michael Christy; Simon Connell; Yonggang Cui; Mark Dalton; Samuel Danagoulian; Donal Day; T. Dodario; James Dunne; Dipangkar Dutta; Najib Elkhayari; Rolf Ent; Howard Fenker; Valera Frolov; Liping Gan; David Gaskell; Kawtar Hafidi; Wendy Hinton; Roy Holt; Tanja Horn; Garth Huber; Ed Hungerford; Xiaodong Jiang; Mark Jones; Kyungseon Joo; Narbe Kalantarians; James Kelly; Cynthia Keppel; Edward Kinney; V. Kubarovski; Ya Li; Yongguang Liang; Simona Malace; Pete Markowitz; Erin McGrath; Daniella Mckee; David Meekins; Hamlet Mkrtchyan; Brian Moziak; Gabriel Niculescu; Maria-Ioana Niculescu; Allena Opper; Tanya Ostapenko; Paul Reimer; Joerg Reinhold; Julie Roche; Stephen Rock; Elaine Schulte; Edwin Segbefia; C. Smith; G.R. Smith; Paul Stoler; Vardan Tadevosyan; Liguang Tang; Maurizio Ungaro; Alicia Uzzle; Sandra Vidakovic; Anthony Villano; William Vulcan; Miao Wang; Glen Warren; Frank Wesselmann; Bogdan Wojtsekhowski; Stephen Wood; Chuncheng Xu; Lulin Yuan; Xiaochao Zheng; Hong Guo Zhu

2006-08-29T23:59:59.000Z

280

Covariant nonlocal chiral quark models with separable interactions  

SciTech Connect

We present a comparative analysis of chiral quark models which include nonlocal covariant four-fermion couplings. We consider two alternative ways of introducing the nonlocality, as well as various shapes for the momentum-dependent form factors governing the effective interactions. In all cases we study the behavior of model parameters and analyze numerical results for constituent quark masses and quark propagator poles. Advantages of these covariant nonlocal schemes over instantaneous nonlocal schemes and the standard NJL model are pointed out.

Dumm, D. Gomez [IFLP - Dpto. de Fisica, Universidad Nacional de La Plata, C.C. 67, 1900 La Plata (Argentina); CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Grunfeld, A. G. [Physics Department, Comision Nacional de Energia Atomica, Av. Libertador 8250, 1429 Buenos Aires (Argentina); Scoccola, N. N. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Physics Department, Comision Nacional de Energia Atomica, Av. Libertador 8250, 1429 Buenos Aires (Argentina); Universidad Favaloro, Solis 453, 1078 Buenos Aires (Argentina)

2006-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "top quark mass" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Report of the Quark Flavor Physics Working Group  

E-Print Network (OSTI)

This report represents the response of the Intensity Frontier Quark Flavor Physics Working Group to the Snowmass charge. We summarize the current status of quark flavor physics and identify many exciting future opportunities for studying the properties of strange, charm, and bottom quarks. The ability of these studies to reveal the effects of new physics at high mass scales make them an essential ingredient in a well-balanced experimental particle physics program.

Butler, J N; Ritchie, J L; Cirigliano, V; Kettell, S; Briere, R; Petrov, A A; Schwartz, A; Skwarnicki, T; Zupan, J; Christ, N; Sharpe, S R; Van de Water, R S; Altmannshofer, W; Arkani-Hamed, N; Artuso, M; Asner, D M; Bernard, C; Bevan, A J; Blanke, M; Bonvicini, G; Browder, T E; Bryman, D A; Campana, P; Cenci, R; Cline, D; Comfort, J; Cronin-Hennessy, D; Datta, A; Dobbs, S; Duraisamy, M; El-Khadra, A X; Fast, J E; Forty, R; Flood, K T; Gershon, T; Grossman, Y; Hamilton, B; Hill, C T; Hill, R J; Hitlin, D G; Jaffe, D E; Jawahery, A; Jessop, C P; Kagan, A L; Kaplan, D M; Kohl, M; Krizan, P; Kronfeld, A S; Lee, K; Littenberg, L S; MacFarlane, D B; Mackenzie, P B; Meadows, B T; Olsen, J; Papucci, M; Parsa, Z; Paz, G; Perez, G; Piilonen, L E; Pitts, K; Purohit, M V; Quinn, B; Ratcliff, B N; Roberts, D A; Rosner, J L; Rubin, P; Seeman, J; Seth, K K; Schmidt, B; Schopper, A; Sokoloff, M D; Soni, A; Stenson, K; Stone, S; Sundrum, R; Tschirhart, R; Vainshtein, A; Wah, Y W; Wilkinson, G; Wise, M B; Worcester, E; Xu, J; Yamanaka, T

2013-01-01T23:59:59.000Z

282

Top Science of 2013  

NLE Websites -- All DOE Office Websites (Extended Search)

RAPTOR telescope witnesses black hole birth science-innovationassetsimagesicon-science.jpg Top Science of 2013 Our strong interdisciplinary teaming and unique research...

283

Top Science of 2013  

NLE Websites -- All DOE Office Websites (Extended Search)

firsts pave way for greener, faster supercomputing science-innovationassetsimagesicon-science.jpg Top Science of 2013 Our strong interdisciplinary teaming and unique...

284

Effects of R-parity violating supersymmetry in top pair production at linear colliders with polarized beams  

E-Print Network (OSTI)

In the minimal supersymmetric standard model with R-parity violation, the lepton number violating top quark interactions can contribute to the top pair production at a linear collider via tree-level u-channel squark exchange diagrams. We calculate such contributions and find that in the allowed range of these R-violating couplings, the top pair production rate as well as the top quark polarization and the forward-backward asymmetry can be significantly altered. By comparing the unpolarized beams with the polarized beams, we find that the polarized beams are more powerful in probing such new physics.

Xuelei Wang; Jitao Li; Suzhen Liu

2006-11-06T23:59:59.000Z

285

Combined search for the quarks of a sequential fourth generation  

Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5??fb?1 recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about ±20??GeV . These results significantly reduce the allowed parameter space for a fourth generation of fermions.

Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Aguilo, E.; Bergauer, T.; Dragicevic, M.; Erö, J.; Fabjan, C.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hammer, J.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knünz, V.; Krammer, M.; Krätschmer, I.; Liko, D.; Mikulec, I.; Pernicka, M.; Rahbaran, B.; Rohringer, C.; Rohringer, H.; Schöfbeck, R.; Strauss, J.; Taurok, A.; Waltenberger, W.; Walzel, G.; Widl, E.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Bansal, M.; Bansal, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Luyckx, S.; Mucibello, L.; Ochesanu, S.; Roland, B.; Rougny, R.; Selvaggi, M.; Staykova, Z.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Blekman, F.; Blyweert, S.; D’Hondt, J.; Gonzalez Suarez, R.; Kalogeropoulos, A.; Maes, M.; Olbrechts, A.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Villella, I.; Clerbaux, B.; De Lentdecker, G.; Dero, V.; Gay, A. P. R.; Hreus, T.; Léonard, A.; Marage, P. E.; Mohammadi, A.; Reis, T.; Thomas, L.; Vander Marcken, G.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Adler, V.; Beernaert, K.; Cimmino, A.; Costantini, S.; Garcia, G.; Grunewald, M.; Klein, B.; Lellouch, J.; Marinov, A.; Mccartin, J.; Ocampo Rios, A. A.; Ryckbosch, D.; Strobbe, N.; Thyssen, F.; Tytgat, M.; Verwilligen, P.; Walsh, S.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Bruno, G.; Castello, R.; Ceard, L.; Delaere, C.; du Pree, T.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Lemaitre, V.; Liao, J.; Militaru, O.; Nuttens, C.; Pagano, D.; Pin, A.; Piotrzkowski, K.; Schul, N.; Vizan Garcia, J. M.; Beliy, N.; Caebergs, T.; Daubie, E.; Hammad, G. H.; Alves, G. A.; Correa Martins Junior, M.; De Jesus Damiao, D.; Martins, T.; Pol, M. E.; Souza, M. H. G.; Aldá Júnior, W. L.; Carvalho, W.; Custódio, A.; Da Costa, E. M.; De Oliveira Martins, C.; Fonseca De Souza, S.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Oguri, V.; Prado Da Silva, W. L.; Santoro, A.; Soares Jorge, L.; Sznajder, A.; Anjos, T. S.; Bernardes, C. A.; Dias, F. A.; Tomei, T.R. Fernandez Perez; Gregores, E. M.; Lagana, C.; Marinho, F.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Genchev, V.; Iaydjiev, P.; Piperov, S.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Tcholakov, V.; Trayanov, R.; Vutova, M.; Dimitrov, A.; Hadjiiska, R.; Kozhuharov, V.; Litov, L.; Pavlov, B.; Petkov, P.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Jiang, C. H.; Liang, D.; Liang, S.; Meng, X.; Tao, J.; Wang, J.; Wang, X.; Wang, Z.; Xiao, H.; Xu, M.; Zang, J.; Zhang, Z.; Asawatangtrakuldee, C.; Ban, Y.; Guo, S.; Guo, Y.; Li, W.; Liu, S.; Mao, Y.; Qian, S. J.; Teng, H.; Wang, D.; Zhang, L.; Zhu, B.; Zou, W.; Avila, C.; Gomez, J. P.; Gomez Moreno, B.; Osorio Oliveros, A. F.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Plestina, R.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Duric, S.; Kadija, K.; Luetic, J.; Morovic, S.; Attikis, A.; Galanti, M.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Finger, M.; Finger, M.; Assran, Y.; Elgammal, S.; Ellithi Kamel, A.; Khalil, S.; Mahmoud, M. A.; Radi, A.; Kadastik, M.; Müntel, M.; Raidal, M.; Rebane, L.; Tiko, A.; Eerola, P.; Fedi, G.; Voutilainen, M.; Härkönen, J.; Heikkinen, A.; 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.; Ungaro, D.; Wendland, L.; Banzuzi, K.; Karjalainen, A.; Korpela, A.; Tuuva, T.; Besancon, M.; Choudhury, S.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Malcles, J.; Millischer, L.; Nayak, A.; Rander, J.; Rosowsky, A.; Shreyber, I.; Titov, M.; Baffioni, S.; Beaudette, F.; Benhabib, L.; Bianchini, L.; Bluj, M.; Broutin, C.; Busson, P.; Charlot, C.; Daci, N.; Dahms, T.; Dobrzynski, L.; Granier de Cassagnac, R.; Haguenauer, M.; Miné, P.; Mironov, C.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Paganini, P.; Sabes, D.; Salerno, R.; Sirois, Y.; Veelken, C.; Zabi, A.; Agram, J.-L.; Andrea, J.; Bloch, D.; Bodin, D.; Brom, J.-M.; Cardaci, M.; Chabert, E. C.; Collard, C.; Conte, E.; Drouhin, F.; Ferro, C.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Juillot, P.; Le Bihan, A.-C.; Van Hove, P.; Fassi, F.; Mercier, D.; Beauceron, S.; Beaupere, N.; Bondu, O.; Boudoul, G.; Chasserat, J.; Chierici, R.; Contardo, D.; Depasse, P.; El Mamouni, H.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Kurca, T.; Lethuillier, M.; Mirabito, L.; Perries, S.; Sordini, V.; Tschudi, Y.; Verdier, P.; Viret, S.; Tsamalaidze, Z.; Anagnostou, G.; Beranek, S.; Edelhoff, M.; Feld, L.; Heracleous, N.; Hindrichs, O.; Jussen, R.; Klein, K.

2012-12-01T23:59:59.000Z

286

Combined search for the quarks of a sequential fourth generation  

E-Print Network (OSTI)

Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up- and down-type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant CKM matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. This result significantly reduces the allowed parameter space for a fourt...

Chatrchyan, Serguei; Sirunyan, Albert M; Tumasyan, Armen; Adam, Wolfgang; Aguilo, Ernest; Bergauer, Thomas; Dragicevic, Marko; Erö, Janos; Fabjan, Christian; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hammer, Josef; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kiesenhofer, Wolfgang; Knünz, Valentin; Krammer, Manfred; Krätschmer, Ilse; Liko, Dietrich; Mikulec, Ivan; Pernicka, Manfred; Rahbaran, Babak; Rohringer, Christine; Rohringer, Herbert; Schöfbeck, Robert; Strauss, Josef; Taurok, Anton; Waltenberger, Wolfgang; Walzel, Gerhard; Widl, Edmund; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Bansal, Monika; Bansal, Sunil; Cornelis, Tom; De Wolf, Eddi A; Janssen, Xavier; Luyckx, Sten; Mucibello, Luca; Ochesanu, Silvia; Roland, Benoit; Rougny, Romain; Selvaggi, Michele; Staykova, Zlatka; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Van Spilbeeck, Alex; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Gonzalez Suarez, Rebeca; Kalogeropoulos, Alexis; Maes, Michael; Olbrechts, Annik; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Clerbaux, Barbara; De Lentdecker, Gilles; Dero, Vincent; Gay, Arnaud; Hreus, Tomas; Léonard, Alexandre; Marage, Pierre Edouard; Mohammadi, Abdollah; Reis, Thomas; Thomas, Laurent; Vander Marcken, Gil; Vander Velde, Catherine; Vanlaer, Pascal; Wang, Jian; Adler, Volker; Beernaert, Kelly; Cimmino, Anna; Costantini, Silvia; Garcia, Guillaume; Grunewald, Martin; Klein, Benjamin; Lellouch, Jérémie; Marinov, Andrey; Mccartin, Joseph; Ocampo Rios, Alberto Andres; Ryckbosch, Dirk; Strobbe, Nadja; Thyssen, Filip; Tytgat, Michael; Verwilligen, Piet; Walsh, Sinead; Yazgan, Efe; Zaganidis, Nicolas; Basegmez, Suzan; Bruno, Giacomo; Castello, Roberto; Ceard, Ludivine; Delaere, Christophe; Du Pree, Tristan; Favart, Denis; Forthomme, Laurent; Giammanco, Andrea; Hollar, Jonathan; Lemaitre, Vincent; Liao, Junhui; Militaru, Otilia; Nuttens, Claude; Pagano, Davide; Pin, Arnaud; Piotrzkowski, Krzysztof; Schul, Nicolas; Vizan Garcia, Jesus Manuel; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Hammad, Gregory Habib; Alves, Gilvan; Correa Martins Junior, Marcos; De Jesus Damiao, Dilson; Martins, Thiago; Pol, Maria Elena; Henrique Gomes E Souza, Moacyr; Aldá Júnior, Walter Luiz; Carvalho, Wagner; Custódio, Analu; Da Costa, Eliza Melo; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Matos Figueiredo, Diego; Mundim, Luiz; Nogima, Helio; Oguri, Vitor; Prado Da Silva, Wanda Lucia; Santoro, Alberto; Soares Jorge, Luana; Sznajder, Andre; Souza Dos Anjos, Tiago; Bernardes, Cesar Augusto; De Almeida Dias, Flavia; Tomei, Thiago; De Moraes Gregores, Eduardo; Lagana, Caio; Da Cunha Marinho, Franciole; Mercadante, Pedro G; Novaes, Sergio F; Padula, Sandra; Genchev, Vladimir; Iaydjiev, Plamen; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Tcholakov, Vanio; Trayanov, Rumen; Vutova, Mariana; Dimitrov, Anton; Hadjiiska, Roumyana; Kozhuharov, Venelin; Litov, Leander; Pavlov, Borislav; Petkov, Peicho; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Jiang, Chun-Hua; Liang, Dong; Liang, Song; Meng, Xiangwei; Tao, Junquan; Wang, Jian; Wang, Xianyou; Wang, Zheng; Xiao, Hong; Xu, Ming; Zang, Jingjing; Zhang, Zhen; Asawatangtrakuldee, Chayanit; Ban, Yong; Guo, Shuang; Guo, Yifei; Li, Wenbo; Liu, Shuai; Mao, Yajun; Qian, Si-Jin; Teng, Haiyun; Wang, Dayong; Zhang, Linlin; Zhu, Bo; Zou, Wei; Avila, Carlos; Gomez, Juan Pablo; Gomez Moreno, Bernardo; Osorio Oliveros, Andres Felipe; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Plestina, Roko; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Kovac, Marko; Brigljevic, Vuko; Duric, Senka; Kadija, Kreso; Luetic, Jelena; Morovic, Srecko; Attikis, Alexandros; Galanti, Mario; Mavromanolakis, Georgios; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Finger, Miroslav; Finger Jr, Michael; Assran, Yasser; Elgammal, Sherif; Ellithi Kamel, Ali; Khalil, Shaaban; Mahmoud, Mohammed; Radi, Amr; Kadastik, Mario; Müntel, Mait; Raidal, Martti; Rebane, Liis; Tiko, Andres; Eerola, Paula; Fedi, Giacomo; Voutilainen, Mikko; Härkönen, Jaakko; Heikkinen, Mika Aatos; Karimäki, Veikko; Kinnunen, Ritva; Kortelainen, Matti J; Lampén, Tapio; Lassila-Perini, Kati; Lehti, Sami; Lindén, Tomas; Luukka, Panja-Riina; Mäenpää, Teppo; Peltola, Timo; Tuominen, Eija; Tuominiemi, Jorma; Tuovinen, Esa; Ungaro, Donatella; Wendland, Lauri; Banzuzi, Kukka; Karjalainen, Ahti; Korpela, Arja; Tuuva, Tuure; Besancon, Marc; Choudhury, Somnath

2012-01-01T23:59:59.000Z

287

Quark matter and meson properties in a Nonlocal SU(3) chiral quark model at finite temperature  

SciTech Connect

We study the finite temperature behavior of light scalar and pseudoscalar meson properties in the context of a three-flavor nonlocal chiral quark model. The model includes mixing with active strangeness degrees of freedom, and takes care of the effect of gauge interactions by coupling the quarks with a background color field. We analyze the chiral restoration and deconfinement transitions, as well as the temperature dependence of meson masses, mixing angles, and decay constants.

Gomez Dumm, D., E-mail: dumm@fisica.unlp.edu.ar [UNLP, IFLP, Departamento de Fisica (Argentina); Contrera, G. A., E-mail: contrera@tandar.cnea.gov.ar [CONICET (Argentina)

2012-06-15T23:59:59.000Z

288

Search for Excited Quarks in ep Collisions at HERA  

E-Print Network (OSTI)

A search for excited quarks is performed using the full ep data sample collected by the H1 experiment at HERA, corresponding to a total integrated luminosity of 475 pb^-1. The electroweak decays of excited quarks q* -> q gamma, q* -> q Z and q* -> q W with subsequent hadronic or leptonic decays of the W and Z bosons are considered. No evidence for first generation excited quark production is found. Mass dependent exclusion limits on q* production cross sections and on the ratio f/Lambda of the coupling to the compositeness scale are derived within gauge mediated models. These limits extend the excluded region compared to previous excited quark searches.

Aaron, F D; Alimujiang, K; Andreev, V; Antunovic, B; Asmone, A; Backovic, S; Baghdasaryan, A; Barrelet, E; Bartel, W; Begzsuren, K; Belousov, A; Bizot, J C; Boudry, V; Bozovic-Jelisavcic, I; Bracinik, J; Brandt, G; Brinkmann, M; Brisson, V; Bruncko, D; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Cantun Avila, K B; Cassol-Brunner, F; Cerny, K; Cerny, V; Chekelian, V; Cholewa, A; Contreras, J G; Coughlan, J A; Cozzika, G; Cvach, J; Dainton, J B; Daum, K; Deak, M; de Boer, Y; Delcourt, B; Del Degan, M; Delvax, J; De Roeck, A; De Wolf, E A; Diaconu, C; Dodonov, V; Dossanov, A; Dubak, A; Eckerlin, G; Efremenko, V; Egli, S; Eliseev, A; Elsen, E; Falkiewicz, A; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Fischer, D J; Fleischer, M; Fomenko, A; Gabathuler, E; Gayler, J; Ghazaryan, S; Glazov, A; Glushkov, I; Goerlich, L; Gogitidze, N; Gouzevitch, M; Grab, C; Greenshaw, T; Grell, B R; Grindhammer, G; Habib, S; Haidt, D; Helebrant, C; Henderson, R C W; Hennekemper, E; Henschel, H; Herbst, M; Herrera, G; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R; Hreus, T; Jacquet, M; Janssen, M E; Janssen, X; Jemanov, V; Jonsson, L; Jung, Andreas Werner; Jung, H; Kapichine, M; Katzy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Kluge, T; Knutsson, A; Kogler, R; Korbel, V; Kostka, P; Kraemer, M; Krastev, K; Kretzschmar, J; Kropivnitskaya, A; Kruger, K; Kutak, K; Landon, M P J; Lange, W; Lastovicka-Medin, G; Laycock, P; Lebedev, A; Leibenguth, G; Lendermann, V; Levonian, S; Li, G; Lipka, K; Liptaj, A; List, B; List, J; Loktionova, N; Lopez-Fernandez, R; Lubimov, V; Lytkin, L; Makankine, A; Malinovski, E; Marage, P; Marti, Ll; Martyn, H U; Maxfield, S J; Mehta, A; Meyer, A B; Meyer, H; Meyer, H; Meyer, J; Michels, V; Mikocki, S; Milcewicz-Mika, I; Moreau, F; Morozov, A; Morris, J V; Mozer, Matthias Ulrich; Mudrinic, M; Muller, K; Murin, P; Naroska, B; Naumann, Th; Newman, P R; Niebuhr, C; Nikiforov, A; Nowak, G; Nowak, K; Nozicka, M; Olivier, B; Olsson, J E; Osman, S; Ozerov, D; Palichik, V; Panagoulias, I; Pandurovic, M; Papadopoulou, Th; Pascaud, C; Patel, G D; Pejchal, O; Perez, E; Petrukhin, A; Picuric, I; Piec, S; Pitzl, D; Placakyte, R; Pokorny, B; Polifka, R; Povh, B; Preda, T; Radescu, V; Rahmat, A J; Raicevic, N; Raspiareza, A; Ravdandorj, T; Reimer, P; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rotaru, M; Ruiz Tabasco, J E; Rurikova, Z; Rusakov, S; Salek, D; Sankey, D P C; Sauter, M; Sauvan, E; Schmitt, S; Schmitz, C; Schoeffel, L; Schoning, A; Schultz-Coulon, H C; Sefkow, F; Shaw-West, R N; Sheviakov, I; Shtarkov, L N; Shushkevich, S; Sloan, T; Smiljanic, Ivan; Soloviev, Y; Sopicki, P; South, D; Spaskov, V; Specka, Arnd E; Staykova, Z; Steder, M; Stella, B; Stoicea, G; Straumann, U; Sunar, D; Sykora, T; Tchoulakov, V; Thompson, G; Thompson, P D; Toll, T; Tomasz, F; Tran, T H; Traynor, D; Trinh, T N; Truol, P; Tsakov, I; Tseepeldorj, B; Turnau, J; Urban, K; Valkarova, A; Vallee, C; Van Mechelen, P; Vargas Trevino, A; Vazdik, Y; Vinokurova, S; Volchinski, V; von den Driesch, M; Wegener, D; Wissing, Ch; Wunsch, E; Zacek, J; Zalesak, J; Zhang, Z; Zhokin, A; Zimmermann, T; Zohrabyan, H; Zomer, F; Zus, R; 10.1016/j.physletb.2009.06.044

2009-01-01T23:59:59.000Z

289

Charm quark and D^* cross sections in deeply inelastic scattering at DESY HERA  

E-Print Network (OSTI)

A next-to-leading order Monte Carlo program for the calculation of heavy quark cross sections in deeply inelastic scattering is described. Concentrating on charm quark and D^*(2010) production at HERA, several distributions are presented and their variation with respect to charm quark mass, parton distribution set, and renormalization-factorization scale is studied.

B. W. Harris; J. Smith

1997-06-11T23:59:59.000Z

290

Meson properties in a nonlocal SU(3) chiral quark model at finite temperature  

SciTech Connect

Finite temperature meson properties are studied in the context of a nonlocal SU(3) quark model which includes flavor mixing and the coupling of quarks to the Polyakov loop (PL). We analyze the behavior of scalar and pseudoscalar meson masses and mixing angles, as well as quark-meson couplings and pseudoscalar meson decay constants.

Contrera, G. A. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Physics Department, Centro Atomico Constituyentes, Buenos Aires (Argentina); Gomez Dumm, D. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); IFLP, Dpto. de Fisica, Universidad Nacional de La Plata, C.C. 67, (1900) La Plata (Argentina); Scoccola, N. N. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Universidad Favaloro, Solis 453, 1078 Buenos Aires (Argentina)

2010-11-12T23:59:59.000Z

291

Essence of the Vacuum Quark Condensate  

SciTech Connect

We show that the chiral-limit vacuum quark condensate is qualitatively equivalent to the pseudoscalar meson leptonic decay constant in the sense that they are both obtained as the chiral-limit value of well-defined gauge-invariant hadron-to-vacuum transition amplitudes that possess a spectral representation in terms of the current-quark mass. Thus, whereas it might sometimes be convenient to imagine otherwise, neither is essentially a constant mass-scale that fills all spacetime. This means, in particular, that the quark condensate can be understood as a property of hadrons themselves, which is expressed, for example, in their Bethe-Salpeter or light-front wavefunctions.

Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; Roberts, Craig D.; /Argonne, PHY /Peking U.; Shrock, Robert; /YITP, Stony Brook; Tandy, Peter C.; /Kent State U.

2010-08-25T23:59:59.000Z

292

Proceeding for LHCP2014 Poster: Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at $\\sqrt{s}=8$ TeV with the ATLAS detector  

E-Print Network (OSTI)

The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of $20.1 \\rm{fb}^{-1}$ of proton-proton collision data at $\\sqrt{s}=8$ TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via $\\tilde{t} \\rightarrow t \\tilde{\\chi}_{1}^{0}$ or $\\tilde{t}\\rightarrow b\\tilde{\\chi}_{1}^{\\pm} \\rightarrow b W^{\\left(\\ast\\right)} \\tilde{\\chi}_{1}^{0}$, where $\\tilde{\\chi}_{1}^{0}$ ($\\tilde{\\chi}_{1}^{\\pm}$) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of $\\tilde{t} \\rightarrow t \\tilde{\\chi}_{1}^{0}$. For a branching fraction of 100%, top squark masses in the range 270-645 GeV are excluded for $\\tilde{\\chi}_{1}^{0}$ masses below 30 GeV. For a branching fraction of 50% to either $\\tilde{t} \\rightarrow t \\tilde{\\chi}_{1}^{0}$ or $\\tilde{t}\\rightarrow b\\tilde{\\chi}_{1}^{\\pm}$, and assuming the $\\tilde{\\chi}_{1}^{\\pm}$ mass to be twice the $\\tilde{\\chi}_{1}^{0}$ mass, top squark masses in the range 250-550 GeV are excluded for $\\tilde{\\chi}_{1}^{0}$ masses below 60 GeV.

Chaowaroj Wanotayaroj; for the ATLAS Collaboration

2014-08-29T23:59:59.000Z

293

E-Print Network 3.0 - all-to-all quark propagators Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

using light quark masses equal... with fractional error less than 0.3. Because of the oscillating components in ... Source: Bernard, Claude - Department of Physics, Washington...

294

Relating quarks and leptons with the T7 flavour group  

E-Print Network (OSTI)

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.

Cesar Bonilla; Stefano Morisi; Eduardo Peinado; Jose W. F. Valle

2014-11-18T23:59:59.000Z

295

Relating quarks and leptons with the T7 flavour group  

E-Print Network (OSTI)

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.

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

2014-01-01T23:59:59.000Z

296

quark-web.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

FREE FREE QUARK SEARCHES The basis for much of the theory of particle scattering and hadron spectroscopy is the construction of the hadrons from a set of fractionally charged constituents (quarks). A central but unproven hypothesis of this theory, Quantum Chromodynamics, is that quarks cannot be observed as free particles but are confined to mesons and baryons. Experiments show that it is at best difficult to "unglue" quarks. Accelerator searches at increasing energies have pro- duced no evidence for free quarks, while only a few cosmic-ray and matter searches have produced uncorroborated events. This compilation is only a guide to the literature, since the quoted experimental limits are often only indicative. Reviews can be found in Refs. 1-4. References 1. M.L. Perl, E.R. Lee, and D. Lomba, Mod. Phys. Lett. A19, 2595 (2004). 2. P.F. Smith, Ann. Rev. Nucl. and Part. Sci. 39,

297

Down Type Isosinglet Quarks in ATLAS  

E-Print Network (OSTI)

We evaluate the discovery reach of the ATLAS experiment for down type isosinglet quarks, $D$, using both their neutral and charged decay channels, namely the process $pp\\to D\\bar{D}+X$ with subsequent decays resulting in $2\\ell+2j+E^{miss}_{T}$, $3\\ell+2j+E^{miss}_{T}$ and $2\\ell+4j$ final states. The integrated luminosity required for observation of a heavy quark is estimated for a mass range between 600 and 1000 GeV using the combination of results from different search channels.

R. Mehdiyev; A. Siodmok; S. Sultansoy; G. Unel

2007-11-07T23:59:59.000Z

298

Dark matter-motivated searches for exotic fourth-generation mirror quarks in Tevatron and early LHC data  

SciTech Connect

We determine the prospects for finding dark matter at the Tevatron and LHC through the production of exotic fourth-generation mirror quarks T{sup '} that decay through T{sup '{yields}}tX, where X is dark matter. The resulting signal of tt+Ee{sub T} has not previously been considered in searches for fourth-generation quarks, but there are both general and specific dark matter motivations for this signal, and with slight modifications, this analysis applies to any scenario where invisible particles are produced in association with top quarks. Current direct and indirect bounds on such exotic quarks restrict their masses to be between 300 and 600 GeV, and the dark matter's mass may be anywhere below m{sub T}{sup '}. We simulate the signal and main backgrounds with MadGraph/MadEvent-Pythia-PGS4. For the Tevatron, we find that an integrated luminosity of 20 fb{sup -1} will allow 3{sigma} discovery up to m{sub T}{sup '}=400 GeV and 95% exclusion up to m{sub T}{sup '}=455 GeV. For the 10 TeV LHC with 300 pb{sup -1}, the discovery and exclusion sensitivities rise to 490 GeV and 600 GeV. These scenarios are therefore among the most promising for dark matter at colliders. Perhaps most interestingly, we find that dark matter models that can explain results from the DAMA, CDMS, and CoGeNT collaborations can be tested with high statistical significance using data already collected at the Tevatron and have extraordinarily promising implications for early runs of the LHC.

Alwall, Johan [Department of Physics and National Center for Theoretical Sciences, National Taiwan University, Taipei 10617, Taiwan (China); Feng, Jonathan L. [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Kumar, Jason [Department of Physics and Astronomy, University of Hawaii, Honolulu, Hawaii 96822 (United States); Su Shufang [Department of Physics, University of Arizona, Tucson, Arizona 85721 (United States)

2010-06-01T23:59:59.000Z

299

Experimental results on $t\\bar{t}+W/Z/\\gamma$ and SM top couplings from the Tevatron and the LHC  

E-Print Network (OSTI)

(Proceedings of TOP2014 Conference) Experimental results from the CDF and D0 Collaborations at the Tevatron and the ATLAS and CMS Collaborations at the LHC on the processes related to probing top quark couplings are presented. Evidence of both $t\\bar{t}Z$ and $t\\bar{t}W$ processes is reported. All measurements are in agreement with the SM expectations.

Vazquez Schroeder, Tamara; The ATLAS collaboration

2014-01-01T23:59:59.000Z

300

Color screening in cold quark matter  

E-Print Network (OSTI)

We compute---at finite quark chemical potentials---the color screening of cold quark matter at the one-loop level, comparing the normal, BCS-paired U(1)em (or Higgs) phase and a singlet phase with color-singlet condensate near the Fermi surface. The latter phase is computed using the example of two-color QCD with a color-singlet diquark condensate. In contrast to the normal and Higgs phases, neither electric nor magnetic screening masses appear in the singlet phase. The absence of a magnetic mass, within a perturbative framework, is a consequence of the proper treatment of gauge invariance. While at large momenta the gluon self-energies approach those in the normal phase, the medium contributions to the infrared region below a scale of the mass gap are substantially suppressed. Infrared gluons at low quark density in the singlet phase appear protected from medium effects, unless the quark-gluon vertices are significantly enhanced in the infrared.

Toru Kojo; Gordon Baym

2014-04-04T23:59:59.000Z

Note: This page contains sample records for the topic "top quark mass" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

A measurement of the top pair production cross-section in the dilepton channel using lepton plus track selection  

SciTech Connect

Using 1.1 fb{sup -1} of data collected by the Collider Detector at Fermilab (CDF) from Run II of the Fermilab Tevatron, they measure the t{bar t} production cross section in events with two leptons, significant missing transverse energy, and {ge} 2 jets. As the Run II dataset grows, more stringent tests of Standard Model predictions for the top quark sector are becoming possible. The dilepton channel, where both top quarks decay t {yields} Wb {yields} {ell}{nu}b, is of particular interest due to its high purity even in the absence of a b jet 'tagging' requirement. Use of an isolated track as the second lepton significant increases the dilepton acceptance, at the price of some increase in background, particular from W + jets events where one of the jets is identified as a lepton. With the amount of data available, it has been possible to improve the estimate of the contribution from that background, reflected in a reduced systematic uncertainty. Assuming a branching ratio of BR(W {yields} {ell}{nu}) = 10.8% and a top mass of m{sub t} = 175 GeV/c{sup 2}, the measured cross-section is {sigma}(p{bar p} {yields} t{bar t}) = 8.3 {+-} 1.3(stat.) {+-} 0.7(syst.) {+-} 0.5(lumi.) pb. The result is consistent with the Standard Model prediction of 6.7{sub -0.9}{sup +0.7} pb and represents a significant improvement in precision over previous results using this selection.

Mills, Corrinne Elaine; /UC, Santa Barbara

2007-06-01T23:59:59.000Z

302

Questions and Answers - What kinds of quarks are protons and neutrons made  

NLE Websites -- All DOE Office Websites (Extended Search)

How many quarks are inprotons and neutrons? How many quarks are in<br>protons and neutrons? Previous Question (How many quarks are in protons and neutrons?) Questions and Answers Main Index Next Question (What is the charge of an up quark and of down quark?) What is the charge of an up quarkand of down quark? What kinds of quarks are protons and neutrons made of? What was the old name for the Top and Bottom quark? Protons are made of two Up and one Down quark. The neutron is made of two Down and one Up quark. The Up quarks have a 2/3 positive charge and the Down has a 1/3 negative charge. Fractional charges are a pretty funny concept, but remember we (humans) made up the unit of charge that a proton has, so its very possible that there could be a smaller division of charge. If you add those charges you will see that sum is positive one for the

303

Top Ten Lists  

NLE Websites -- All DOE Office Websites (Extended Search)

Fueleconomy Top Ten Fueleconomy Top Ten EPA Rated - 2014 EPA Rated - All Years Shared Estimates - All Years Misconceptions Fueleconomy.gov's Top Ten EPA-Rated Fuel Sippers (2014) Include all-electric and plug-in hybrid vehicles? Yes No Vehicles are ranked by their combined rating (weighted by 55% city and 45% highway). In the event of a tie, multiple vehicles may share the same ranking. Electric vehicles are measured in Miles Per Gallon equivalent (MPGe) where 33.7 kW-hrs = 1 gallon of gasoline. 1. 2014 Chevrolet Spark EV 2014 Chevrolet Spark EV Combined 119 City 128/Highway 109 All-electric, Auto (A1) 2. 2014 Honda Fit EV 2014 Honda Fit EV Combined 118 City 132/Highway 105 All-electric, Auto (A1) 3. 2014 Fiat 500e 2014 Fiat 500e Combined 116 City 122/Highway 108 All-electric, Auto (A1)

304

The NJL Model for Quark Fragmentation Functions  

SciTech Connect

A description of fragmentation functions which satisfy the momentum and isospin sum rules is presented in an effective quark theory. Concentrating on the pion fragmentation function, we first explain the reason why the elementary (lowest order) fragmentation process q ? q? is completely inadequate to describe the empirical data, although the “crossed” process ? ? qq describes the quark distribution functions in the pion reasonably well. Then, taking into account cascade-like processes in a modified jet-model approach, we show that the momentum and isospin sum rules can be satisfied naturally without introducing any ad-hoc parameters. We present numerical results for the Nambu-Jona-Lasinio model in the invariant mass regularization scheme, and compare the results with the empirical parametrizations. We argue that this NJL-jet model provides a very useful framework to calculate the fragmentation functions in an effective chiral quark theory.

T. Ito, W. Bentz, I. Cloet, A W Thomas, K. Yazaki

2009-10-01T23:59:59.000Z

305

Multiple Rankine topping cycles  

SciTech Connect

The efficiency of a Rankine cycle is primarily determined by the temperatures of heat addition and rejection. However, no working fluid has been identified which will operate in a Rankine cycle over an extremely wide temperature range. Multiple Rankine topping cycles offer a technique for achieving high thermal efficiencies in power plants by allowing the use of several working fluids. This paper gives a history of Rankine topping cycles, presents an analysis for the calculation of the overall efficiency of a three-module multiple Rankine cycle, and presents results from a case study for a sodium-mercury-water cycle.

McWhirter, J.D. [Argonne National Lab., Idaho Falls, ID (United States). Engineering Div.]|[Idaho State Univ., Pocatello, ID (United States). Coll. of Engineering

1995-07-01T23:59:59.000Z

306

Masses of Fundamental Particles  

E-Print Network (OSTI)

In the original paper entitled, "Masses of Fundamental Particles"(arXiv:1109.3705v5, 10 Feb 2012), not only the masses of fundamental particles including the weak bosons, Higgs boson, quarks, and leptons, but also the mixing angles of quarks and those of neutrinos are all explained and/or predicted in the unified composite models of quarks and leptons successfully. In this addendum entitled, "Higgs Boson Mass in the Minimal Unified Subquark Model", it is emphasized that the Higgs boson mass is predicted to be about 130Gev in the minimal unified subquark model, which agrees well with the experimental values of 125-126GeV recently found by the ATLAS and CMS Collaborations at the LHC.

Hidezumi Terazawa

2014-06-11T23:59:59.000Z

307

Heavy quark production in the black hole evaporation at LHC  

SciTech Connect

The understanding of Quantum Chromodynamics (QCD) and Quantum Gravity are currently two of the main open questions in Physics. In order to understand these problems some authors proposed the existence of extra dimensions in the Nature. These extra dimensions would be compacted and not visible on the macroscopic world, but the effects would be manifest in ultrarelativistic colision process. In particular, black holes (BH) could be produced in proton-proton colisions in the Large Hadron Collider (LHC) and in future colliders. The BH is an object characterized by its mass and temperature wich also characterizes the evaporation process. All kind of particle should be produced in this process. Our goal in this contribution is to study the BH production in proton - proton collisions at LHC and its evaporation rate in heavy quarks. We present our estimate considering two scenarios (with and without trapped energy corrections) and compare our predictions with those obtained using perturbative QCD. Our results demonstrate that in both scenarios the charm and bottom production in the BH evaporation are smaller than the QCD prediction at LHC. In contrast, the top production is similar or larger than the QCD prediction, if the trapped energy corrections are disregarded.

Thiel, M.; Goncalves, V. P.; Sauter, W. K. [Instituto de Fisica e Matematica, Universidade Federal de Pelotas (Brazil)

2013-03-25T23:59:59.000Z

308

Category:Top level | Open Energy Information  

Open Energy Info (EERE)

View form View form View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Category Facebook icon Twitter icon » Category:Top level Jump to: navigation, search This page has been deleted. The deletion and move log for the page are provided below for reference. 16:11, 16 August 2012 Rmckeel (Talk | contribs) deleted page Category:Top level (Mass removal of pages added by Fceeh) There is currently no text in this page. You can search for this page title in other pages, or search the related logs, but you do not have permission to create this page. Subcategories This category has only the following subcategory. H [×] Help‎ 68 pages Retrieved from "http://en.openei.org/wiki/Category:Top_level"

309

The Nambu sum rule and the relation between the masses of composite Higgs bosons  

E-Print Network (OSTI)

We review the known results on the bosonic spectrum in various NJL models both in the condensed matter physics and in relativistic quantum field theory including $^3$He-B, $^3$He-A, the thin films of superfluid He-3, and QCD (Hadronic phase and the Color Flavor Locking phase). Next, we calculate bosonic spectrum in the relativistic model of top quark condensation suggested in \\cite{Miransky}. In all considered cases the sum rule appears that relates the masses (energy gaps) $M_{boson}$ of the bosonic excitations in each channel with the mass (energy gap) of the condensed fermion $M_f$ as $\\sum M_{boson}^2 = 4 M_f^2$. Previously this relation was established by Nambu in \\cite{Nambu} for $^3$He-B and for the s - wave superconductor. We generalize this relation to the wider class of models and call it the Nambu sum rule. We discuss the possibility to apply this sum rule to various models of top quark condensation. In some cases this rule allows to calculate the masses of extra Higgs bosons that are the Nambu partners of the 125 GeV Higgs.

G. E. Volovik; M. A. Zubkov

2013-03-24T23:59:59.000Z

310

Proceeding for LHCP2014 Poster: Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at $\\sqrt{s}=8$ TeV with the ATLAS detector  

E-Print Network (OSTI)

The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of $20.1 \\rm{fb}^{-1}$ of proton-proton collision data at $\\sqrt{s}=8$ TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via $\\tilde{t} \\rightarrow t \\tilde{\\chi}_{1}^{0}$ or $\\tilde{t}\\rightarrow b\\tilde{\\chi}_{1}^{\\pm} \\rightarrow b W^{\\left(\\ast\\right)} \\tilde{\\chi}_{1}^{0}$, where $\\tilde{\\chi}_{1}^{0}$ ($\\tilde{\\chi}_{1}^{\\pm}$) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of $\\tilde{t} \\rightarrow t \\tilde{\\chi}_{1}^{0}$. For a branching fraction of 100%, top squark masses in the range 270-645...

Wanotayaroj, Chaowaroj

2014-01-01T23:59:59.000Z

311

Proceeding for LHCP2014 Poster: Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at ?s = 8 TeV with the ATLAS detector  

E-Print Network (OSTI)

The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of $20.1 \\rm{fb}^{-1}$ of proton-proton collision data at $\\sqrt{s}=8$ TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via $\\tilde{t} \\rightarrow t \\tilde{\\chi}_{1}^{0}$ or $\\tilde{t}\\rightarrow b\\tilde{\\chi}_{1}^{\\pm} \\rightarrow b W^{\\left(\\ast\\right)} \\tilde{\\chi}_{1}^{0}$, where $\\tilde{\\chi}_{1}^{0}$ ($\\tilde{\\chi}_{1}^{\\pm}$) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of $\\tilde{t} \\rightarrow t \\tilde{\\chi}_{1}^{0}$. For a branching fraction of 100%, top squark masses in the range 270-645...

Wanotayaroj, C; The ATLAS collaboration

2014-01-01T23:59:59.000Z

312

Secondary Production of Massive Quarks in Thrust  

E-Print Network (OSTI)

We present a factorization framework that takes into account the production of heavy quarks through gluon splitting in the thrust distribution for e+ e- --> hadrons. The explicit factorization theorems and some numerical results are displayed in the dijet region where the kinematic scales are widely separated, which can be extended systematically to the whole spectrum. We account for the necessary two-loop matrix elements, threshold corrections, and include resummation up to N3LL order. We include nonperturbative power corrections through a field theoretical shape function, and remove the O(Lambda_QCD) renormalon in the partonic soft function by appropriate mass-dependent subtractions. Our results hold for any value of the quark mass, from an infinitesimally small (merging to the known massless result) to an infinitely large one (achieving the decoupling limit). This is the first example of an application of a variable flavor number scheme to final state jets.

Andre H. Hoang; Vicent Mateu; Piotr Pietrulewicz

2014-12-22T23:59:59.000Z

313

Top Jets at the LHC  

E-Print Network (OSTI)

Physics Signatures at the LHC,” talk presented at the 2007Top Jets at the LHC Leandro G. Almeida, Seung J. Lee, GiladSEPT-DPP Top Jets at the LHC Leandro G. Almeida a , Seung J.

Almeida, L.G.

2009-01-01T23:59:59.000Z

314

Building America 2013 Top Innovations  

Energy.gov (U.S. Department of Energy (DOE))

This page provides a listing of and links to 2013 Top Innovations coming out of the Building America program.

315

Quark-gluon plasma paradox  

E-Print Network (OSTI)

Based on simple physics arguments it is shown that the concept of quark-gluon plasma, a state of matter consisting of uncorrelated quarks, antiquarks, and gluons, has a fundamental problem.

Dariusz Miskowiec

2007-07-06T23:59:59.000Z

316

Computing Z_top  

E-Print Network (OSTI)

This is the text of my habilitation thesis defended at the \\'Ecole Normale Sup\\'erieure. The topological string presents an arena in which many features of string theory proper, such as the interplay between worldsheet and target space descriptions or open-closed duality, can be distilled into computational techniques which yield results beyond perturbation theory. In this thesis, I will summarize my research activity in this area. The presentation is organized around computations of the topological string partition function Z_top based on various perspectives on the topological string.

Amir-Kian Kashani-Poor

2014-08-06T23:59:59.000Z

317

A handbook of vector-like quarks: mixing and single production  

E-Print Network (OSTI)

We obtain constraints on the mixing of vector-like quarks coupling predominantly to the third generation. We consider all (seven) possible types of vector-like quarks, individually. The constraints are derived from oblique corrections and Z -> b bbar measurements at LEP and SLC. We investigate the implications of these constraints on LHC phenomenology, concerning the decays of the heavy quarks and their single production. We also explore indirect effects of heavy quark mixing in top and bottom couplings. The most remarkable of these effects is the possibility of explaining the anomalous forward-backward asymmetry in Z -> b bbar at LEP, with a hypercharge -5/6 doublet. We also study the impact of the new quarks on single Higgs production at the LHC and Higgs decay.

Aguilar-Saavedra, J A; Heinemeyer, S; Perez-Victoria, M

2013-01-01T23:59:59.000Z

318

A handbook of vector-like quarks: mixing and single production  

E-Print Network (OSTI)

We obtain constraints on the mixing of vector-like quarks coupling predominantly to the third generation. We consider all (seven) relevant types of vector-like quarks, individually. The constraints are derived from oblique corrections and Z -> b bbar measurements at LEP and SLC. We investigate the implications of these constraints on LHC phenomenology, concerning the decays of the heavy quarks and their single production. We also explore indirect effects of heavy quark mixing in top and bottom couplings. A remarkable effect is the possibility of explaining the anomalous forward-backward asymmetry in Z -> b bbar at LEP, with a hypercharge -5/6 doublet. We also study the impact of the new quarks on single Higgs production at the LHC and Higgs decay.

J. A. Aguilar-Saavedra; R. Benbrik; S. Heinemeyer; M. Perez-Victoria

2013-06-03T23:59:59.000Z

319

Dilepton emission at temperature dependent baryonic quark-gluon plasma  

E-Print Network (OSTI)

A fireball of QGP is evoluted at temperature dependent chemical potential by a statistical model in the pionic medium. We study the dilepton emission rate at temperature dependent chemical potential (TDCP) from such a fireball of QGP. In this model, we take the dynamical quark mass as a finite value dependence on temparature and parametrization factor of the QGP evolution. The temperature and factor in quark mass enhance in the growth of the droplets as well as in the dilepton emission rates. The emission rate from the plasma shows dilepton spectrum in the intermediate mass region (IMR) of (1.0-4.0) GeV and its rate is observed to be a strong increasing function of the temperature dependent chemical potential for quark and antiquark annihilation.

S. Somorendro Singh; Yogesh Kumar

2012-08-04T23:59:59.000Z

320

The phase diagram of three-flavor quark matter under compact star constraints  

E-Print Network (OSTI)

The phase diagram of three-flavor quark matter is investigated within a Nambu--Jona-Lasinio model under the condition that compact star constraints of beta-equilibrium and neutrality with respect to color and electric charges be fulfilled locally. In the plane of temperature and quark chemical potential the dynamically generated quark masses and diquark pairing gaps are determined selfconsistently as absolute minima of the thermodynamic potential with respect to a variation of these order parameters.

Blaschke, D; Grigorian, H; Sandin, F

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "top quark mass" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Effective chiral meson-baryon Lagrangian from quark-diquark flavor dynamics  

Science Journals Connector (OSTI)

The approach of path integral hadronization is applied to an SU(2) model of quark-diquark flavor dynamics. Within such a scheme we derive an effective chiral meson-baryon Lagrangian, where the Goldberger-Treiman relation, found earlier at the quark-meson level, is now reestablished at the composite hadron level. Masses and coupling constants of composite hadrons are then calculable by the parameters of the underlying microscopic quark-diquark picture.

D. Ebert and Th. Jurke

1998-06-16T23:59:59.000Z

322

Induced Light-Quark Yukawa Couplings as a probe of Low-Energy Dynamics in QCD  

E-Print Network (OSTI)

We examine the heavy-quark-induced Yukawa interaction between light quarks and a light Higgs field, which is facilitated in the chiral limit by the dynamical mass of light quarks anticipated from the chiral-noninvariance of the QCD vacuum. A low-energy estimate of the strong coupling near unity can be obtained from a comparison of the explicit perturbative calculation of the induced Yukawa interaction at zero momentum to a Higgs-low-energy theorem prediction for the same interaction.

M. R. Ahmady; V. Elias; A. H. Fariborz; R. R. Mendel

1996-04-02T23:59:59.000Z

323

CP violation in the six-quark model  

Science Journals Connector (OSTI)

We construct a Weinberg-Salam-type gauge theory of a weak interaction with CP violation based on the six-quark model. Under the assumption of the validity of the Zweig-Iizuka rule and (quark mass W-meson mass )2?1 this leads to the superweak theory of CP violation for both uncharmed and charmed hadrons. We also propose a new assignment for the J and other ? particles, which predicts the existence of a 3.5-GeV 0- meson using the 2.85-GeV 0- state as input.

Sandip Pakvasa and Hirotaka Sugawara

1976-07-01T23:59:59.000Z

324

Eight-quark interactions as a chiral thermometer  

E-Print Network (OSTI)

A NJL Lagrangian extended to six and eight quark interactions is applied to study temperature effects (SU(3) flavor limit, massless case), and (realistic massive case). The transition temperature can be considerably reduced as compared to the standard approach, in accordance with recent lattice calculations. The mesonic spectra built on the spontaneously broken vacuum induced by the 't Hooft interaction strength, as opposed to the commonly considered case driven by the four-quark coupling, undergoes a rapid crossover to the unbroken phase, with a slope and at a temperature which is regulated by the strength of the OZI violating eight-quark interactions. This strength can be adjusted in consonance with the four-quark coupling and leaves the spectra unchanged, except for the sigma meson mass, which decreases. A first order transition behavior is also a possible solution within the present approach.

J. Moreira; A. A. Osipov; B. Hiller; A. H. Blin; J. Providencia

2008-06-02T23:59:59.000Z

325

Top Science of 2013  

NLE Websites -- All DOE Office Websites (Extended Search)

Space probes predict hazards to protect spacecraft Space probes predict hazards to protect spacecraft /science-innovation/_assets/images/icon-science.jpg Top Science of 2013 Our strong interdisciplinary teaming and unique research facilities allow us to develop solutions to complex problems, and to support partners and collaborators, all with the goal of strengthening national security and making a safer world. Space probes predict hazards to protect spacecraft placeholder Researchers think they've solved a 50-year-old space mystery about how electrons within the Van Allen radiation belts that surround our planet can become energetic enough to cripple orbiting satellites. With data collected by space-probe instruments, they discovered how electromagnetic radio waves cause electrons in these belts to greatly

326

Top Science of 2013  

NLE Websites -- All DOE Office Websites (Extended Search)

RAPTOR telescope witnesses black hole birth RAPTOR telescope witnesses black hole birth /science-innovation/_assets/images/icon-science.jpg Top Science of 2013 Our strong interdisciplinary teaming and unique research facilities allow us to develop solutions to complex problems, and to support partners and collaborators, all with the goal of strengthening national security and making a safer world. RAPTOR telescope witnesses black hole birth placeholder The first "thinking telescope" RAPTOR found the birth of big black holes, possibly the most powerful events since the big bang. This robotic array screens 100 million objects and runs real-time analysis-autonomously alerting us when there's a discovery or a threat. In 2006, RAPTOR was the first of its kind to make a discovery: the birth of

327

Aspects of the strongly interacting matter phase diagram within non-local quark models  

SciTech Connect

We study a nonlocal extension of the so-called Polyakov Nambu-Jona-Lasinio model at finite temperature and chemical potential, considering the impact of the presence of dynamical quarks on the scale parameter appearing in the Polyakov potential. Both real and imaginary chemical potentials are considered. The effect of varying the current quark mass is also investigated.

Pagura, V. [Department of Theoretical Physics, GIyA, CNEA, Libertador 8250, 1429 Buenos Aires (Argentina) and CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Dumm, D. G. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina) and IFLP, CONICET - Dpto. de Fisica, Univ. Nac. de La Plata, C.C. 67, 1900 La Plata (Argentina); Scoccola, N. N. [Department of Theoretical Physics, GIyA, CNEA, Libertador 8250, 1429 Buenos Aires (Argentina) and Universidad Favaloro, Solis 453, 1078 Buenos Aires (Argentina)

2013-03-25T23:59:59.000Z

328

Light hadron spectroscopy using domain wall valence quarks on an asqtad sea  

E-Print Network (OSTI)

We calculate the light hadron spectrum in full QCD using two plus one flavor asqtad sea quarks and domain wall valence quarks. Meson and baryon masses are calculated on a lattice of spatial size L?2.5??fm, and a lattice ...

Walker-Loud, A.

329

Method for establishing a combustion zone in an in situ oil shale retort having a pocket at the top  

DOE Patents (OSTI)

An in situ oil shale retort having a top boundary of unfragmented formation and containing a fragmented permeable mass has a pocket at the top, that is, an open space between a portion of the top of the fragmented mass and the top boundary of unfragmented formation. To establish a combustion zone across the fragmented mass, a combustion zone is established in a portion of the fragmented mass which is proximate to the top boundary. A retort inlet mixture comprising oxygen is introduced to the fragmented mass to propagate the combustion zone across an upper portion of the fragmented mass. Simultaneously, cool fluid is introduced to the pocket to prevent overheating and thermal sloughing of formation from the top boundary into the pocket.

Cha, Chang Y. (1904 Glenmont Dr., Bakersfield, CA 93309)

1980-01-01T23:59:59.000Z

330

Holographic Accelerated Heavy Quark-Anti-Quark Pair  

E-Print Network (OSTI)

The problem of a heavy quark-anti-quark pair which have constant eternal acceleration in opposite directions in the vacuum of deconfined maximally supersymmetric Yang-Mills theory is studied both in perturbation theory and at strong coupling using AdS/CFT. Perturbation theory is summed to obtain what is conjectured to be an exact result. It is shown to agree with a particular prescription for computing the disc amplitude in the string theory dual and it yields a value $s=\\sqrt{\\lambda}$ for the entanglement entropy of the quark and anti-quark.

Veronika E. Hubeny; Gordon W. Semenoff

2014-10-05T23:59:59.000Z

331

Exploiting Third Generation Quarks for New Physics Discoveries at the Energy Frontier  

SciTech Connect

The K-State group's effort is top quark physics and searches for beyond-standard-model physics in t{anti #22;}t final states. The KSU team performed the most precise measurement of the t#22;{anti t} cross section in the lepton + jets channel, and for the first time excluded the fourth generation of the standard model in the perturbative regime.

Ivanov, Andrew G. [KSU] (ORCID:0000000292705643)

2013-10-15T23:59:59.000Z

332

Octet Baryon Electromagnetic Form Factors in a Relativistic Quark Model  

SciTech Connect

We study the octet baryon electromagnetic properties by applying the covariant spectator quark model, and provide covariant parametrization that can be used to study baryon electromagnetic reactions. While we use the lattice QCD data in the large pion mass regime (small pion cloud effects) to determine the parameters of the model in the valence quark sector, we use the nucleon physical and octet baryon magnetic moment data to parameterize the pion cloud contributions. The valence quark contributions for the octet baryon electromagnetic form factors are estimated by extrapolating the lattice parametrization in the large pion mass regime to the physical regime. As for the pion cloud contributions, we parameterize them in a covariant, phenomenological manner, combined with SU(3) symmetry. We also discuss the impact of the pion cloud effects on the octet baryon electromagnetic form factors and their radii.

Gilberto Ramalho, Kazuo Tsushima

2011-09-01T23:59:59.000Z

333

Revisting the boiling of quark nuggets at nonzero chemical potential  

E-Print Network (OSTI)

The boiling of possible quark nuggets during the quark-hadron phase transition of the Universe at nonzero chemical potential is revisited within the microscopic Brueckner-Hartree-Fock approach employed for the hadron phase, using two kinds of baryon interactions as fundamental inputs. To describe the deconfined phase of quark matter, we use a recently developed quark mass density-dependent model with a fully self-consistent thermodynamic treatment of confinement. We study the baryon number limit $A_{\\rm boil}$ (above which boiling may be important) with three typical values for the confinement parameter $D$. It is firstly found that the baryon interaction with a softer equation of state for the hadron phase would only lead to a small increase of $A_{\\rm boil}$. However, results depend sensitively on the confinement parameter in the quark model. Specifically, boiling might be important during the Universe cooling for a limited parameter range around $D^{1/2} = 170$ MeV, a value satisfying recent lattice QCD calculations of the vacuum chiral condensate, while for other choices of this parameter, boiling might not happen and cosmological quark nuggets of $10^2 < A < 10^{50}$ could survive.

Ang Li; Tong Liu; Philipp Gubler; Ren-Xin Xu

2013-12-13T23:59:59.000Z

334

Phase transitions in quark matter under strong magnetic fields  

SciTech Connect

In this work we use de SU(2) Nambu-Jona-Lasinio model to study the chiral transition at finite temperature, chemical potential and magnetic field. We show how the magnetic field affects the location of the critical end-point in the phase diagram, the constituent quark masses and the spinodal lines concerning the first order transition.

Garcia, Andre F.; Pinto, Marcus B. [Physics Department, Universidade Federal de Santa Catarina (Brazil)

2013-03-25T23:59:59.000Z

335

Heavy quarks and long-lived hadrons  

Science Journals Connector (OSTI)

In a recent Letter we reported on some work which led us to suggest the possibility of narrow spikes in the e+e- annihilation cross section into hadrons. In this paper, we discuss the theoretical infrastructure of this work more thoroughly, and improve and extend the calculations and experimental predictions. We examine a colored quark-gluon model of hadronic matter, with color an exact SU(3) gauge symmetry. In addition to the light quarks that make up ordinary hadrons, a heavy quark, such as the charmed c, is included. The narrow resonances recently discovered by the MIT-BNL and SLAC-LBL groups are interpreted as cc¯ bound states (orthocharmonium). In this energy range, the effective coupling has become small according to asymptotic freedom, and many aspects of the bound-state structure can be calculated. The existence of 0- (paracharmonium) states is predicted, and decay widths and mass splittings are estimated. The total e+e- cross section into hadrons is predicted to scale asymptotically, with an approach to scaling from above that can be calculated over a large energy range.

Thomas Appelquist and H. David Politzer

1975-09-01T23:59:59.000Z

336

Astrophysical Aspects of Quark-Gluon Plasma  

E-Print Network (OSTI)

This M.Sc. thesis in Engineering Physics is an overview of the present theory of quark-gluon plasma (QGP) as well as an analysis of the stability criterion for possible stable cosmic QGP objects left over from the quark-hadron transition in the early Universe. It covers fundamental ideas of the formation and decay of the plasma, including the standard model, QCD, and the MIT bag model. I discuss the equation of state of a QGP and the possible signatures for a plasma created in heavy-ion collisions. Astrophysical aspects of QGP are put forward, including compact stars and the quark-hadron transition in the early Universe. The possible role of QGP objects as cosmic dark matter is mentioned. The analytic part is an investigation of possible stability among cosmic QGP objects from the early Universe. A model is suggested where a pressure balance makes a QGP stable against gravitational contraction and hadronization. The mass/radius relationship for stability also forbids a direct gravitational collapse. Finally, ...

Enström, D

1998-01-01T23:59:59.000Z

337

Flavor Physics in the Quark Sector  

E-Print Network (OSTI)

One of the major challenges of particle physics has been to gain an in-depth understanding of the role of quark flavor and measurements and theoretical interpretations of their results have advanced tremendously: apart from masses and quantum numbers of flavor particles, there now exist detailed measurements of the characteristics of their interactions allowing stringent tests of Standard Model predictions. Among the most interesting phenomena of flavor physics is the violation of the CP symmetry that has been subtle and difficult to explore. Till early 1990s observations of CP violation were confined to neutral $K$ mesons, but since then a large number of CP-violating processes have been studied in detail in neutral $B$ mesons. In parallel, measurements of the couplings of the heavy quarks and the dynamics for their decays in large samples of $K, D$, and $B$ mesons have been greatly improved in accuracy and the results are being used as probes in the search for deviations from the Standard Model. In the near future, there will be a transition from the current to a new generation of experiments, thus a review of the status of quark flavor physics is timely. This report summarizes the results of the current generation of experiments that is about to be completed and it confronts these results with the theoretical understanding of the field.

M. Antonelli; D. M. Asner; D. Bauer; T. Becher; M. Beneke; A. J. Bevan; M. Blanke; C. Bloise; M. Bona; A. Bondar; C. Bozzi; J. Brod; A. J. Buras; N. Cabibbo; A. Carbone; G. Cavoto; V. Cirigliano; M. Ciuchini; J. P. Coleman; D. P. Cronin-Hennessy; J. P. Dalseno; C. H. Davies; F. DiLodovico; J. Dingfelder; Z. Dolezal; S. Donati; W. Dungel; U. Egede; G. Eigen; R. Faccini; T. Feldmann; F. Ferroni; J. M. Flynn; E. Franco; M. Fujikawa; I. K. Furic; P. Gambino; E. Gardi; T. J. Gershon; S. Giagu; E. Golowich; T. Goto; C. Greub; C. Grojean; D. Guadagnoli; U. A. Haisch; R. F. Harr; A. H. Hoang; T. Hurth; G. Isidori; D. E. Jaffe; A. Jüttner; S. Jäger; A. Khodjamirian; P. Koppenburg; R. V. Kowalewski; P. Krokovny; A. S. Kronfeld; J. Laiho; G. Lanfranchi; T. E. Latham; J. Libby; A. Limosani; D. Lopes Pegna; C. D. Lu; V. Lubicz; E. Lunghi; V. G. Lüth; K. Maltman; W. J. Marciano; E. C. Martin; G. Martinelli; F. Martinez-Vidal; A. Masiero; V. Mateu; F. Mescia; G. Mohanty; M. Moulson; M. Neubert; H. Neufeld; S. Nishida; N. Offen; M. Palutan; P. Paradisi; Z. Parsa; E. Passemar; M. Patel; B. D. Pecjak; A. A. Petrov; A. Pich; M. Pierini; B. Plaster; A. Powell; S. Prell; J. Rademaker; M. Rescigno; S. Ricciardi; P. Robbe; E. Rodrigues; M. Rotondo; R. Sacco; C. J. Schilling; O. Schneider; E. E. Scholz; B. A. Schumm; C. Schwanda; A. J. Schwartz; B. Sciascia; J. Serrano; J. Shigemitsu; I. J. Shipsey; A. Sibidanov; L. Silvestrini; F. Simonetto; S. Simula; C. Smith; A. Soni; L. Sonnenschein; V. Sordini; M. Sozzi; T. Spadaro; P. Spradlin; A. Stocchi; N. Tantalo; C. Tarantino; A. V. Telnov; D. Tonelli; I. S. Towner; K. Trabelsi; P. Urquijo; R. S. Van de Water; R. J. Van Kooten; J. Virto; G. Volpi; R. Wanke; S. Westhoff; G. Wilkinson; M. Wingate; Y. Xie; J. Zupan

2009-07-29T23:59:59.000Z

338

Seismic Search for Strange Quark Nuggets  

E-Print Network (OSTI)

Bounds on masses and abundances of Strange Quark Nuggets (SQNs) are inferred from a seismic search on Earth. Potential SQN bounds from a possible seismic search on the Moon are reviewed and compared with Earth capabilities. Bounds are derived from the data taken by seismometers implanted on the Moon by the Apollo astronauts. We show that the Apollo data implies that the abundance of SQNs in the region of 10 kg to one ton must be at least an order of magnitude less than would saturate the dark matter in the solar neighborhood.

Eugene T. Herrin; Doris C. Rosenbaum; Vigdor L. Teplitz

2005-05-29T23:59:59.000Z

339

ARM - Measurement - Cloud top height  

NLE Websites -- All DOE Office Websites (Extended Search)

to hear from you Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Cloud top height For a given cloud or cloud layer, the highest level of the atmosphere where...

340

Smoke busters WIN TOp HONOURS  

E-Print Network (OSTI)

Smoke busters WIN TOp HONOURS Re-brand continues INE|SPRING2010|UNIVERSITYOFWATERLOOMAGAZINE|SPRING2010|UNIVERSITYOFWATERL RSITYOFWATERLOOMAGAZINE|SPRING2010|UNIVERSITYOFWATERLOOMAGAZINE|SPRING2010|UNIVERSITYOFWATERLOOMAGAZINE|SPRING2010 RING2010|UNIVERSITYOFWATERLOOMAGAZINE|SPRING2010|UNIVERSITYOFWATERLOOMAGAZINE|SPRING

Waterloo, University of

Note: This page contains sample records for the topic "top quark mass" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Review of Top Physics at D Scott Snyder  

E-Print Network (OSTI)

Review of Top Physics at DÃ? Scott Snyder Brookhaven National Laboratory For the DÃ? Collaboration Fermilab Oct 16, 1997 #12; Outline ffl I. Introduction. ffl II. Cross Section Measurement. ffl III. Mass Measurement. ffl IV. Kinematic Distributions. ffl V. Charged Higgs Search. ffl VI. Run 2. 1 #12; I

Quigg, Chris

342

Experimental results on $t\\bar{t}+W/Z/\\gamma$ and SM top couplings from the Tevatron and the LHC  

E-Print Network (OSTI)

Experimental results from the CDF and D0 Collaborations at the Tevatron and the ATLAS and CMS Collaborations at the LHC on the processes related to probing top quark couplings are presented. Evidence of both $t\\bar{t}Z$ and $t\\bar{t}W$ processes is reported. All measurements are in agreement with the SM expectations.

Schröder, Tamara Vázquez; CMS,

2014-01-01T23:59:59.000Z

343

OZI violating eight-quark interactions as a thermometer for chiral transitions  

E-Print Network (OSTI)

This work is a follow-up of our recent observation that in the SU(3) flavor limit with vanishing current quark masses the temperature for the chiral transition is substantially reduced by adding eight-quark interactions to the Nambu - Jona-Lasinio Lagrangian with U_A(1) breaking. Here we generalize the case to realistic light and strange quark masses and confirm our prior result. Additionally, we demonstrate that depending on the strength of OZI violating eight-quark interactions, the system undergoes either a rapid crossover or a first order phase transition. The meson mass spectra of the low lying pseudoscalars and scalars at T=0 are not sensitive to the difference in the parameter settings that correspond to these two alternatives, except for the singlet-octet mixing scalar channels, mainly the sigma meson.

A. A. Osipov; B. Hiller; J. Moreira; A. H. Blin

2007-09-21T23:59:59.000Z

344

NJL-jet model for quark fragmentation functions  

SciTech Connect

A description of fragmentation functions which satisfy the momentum and isospin sum rules is presented in an effective quark theory. Concentrating on the pion fragmentation function, we first explain why the elementary (lowest order) fragmentation process q{yields}q{pi} is completely inadequate to describe the empirical data, although the crossed process {pi}{yields}qq describes the quark distribution functions in the pion reasonably well. Taking into account cascadelike processes in a generalized jet-model approach, we then show that the momentum and isospin sum rules can be satisfied naturally, without the introduction of ad hoc parameters. We present results for the Nambu-Jona-Lasinio (NJL) model in the invariant mass regularization scheme and compare them with the empirical parametrizations. We argue that the NJL-jet model, developed herein, provides a useful framework with which to calculate the fragmentation functions in an effective chiral quark theory.

Ito, T.; Bentz, W. [Department of Physics, School of Science, Tokai University, Hiratsuka-shi, Kanagawa 259-1292 (Japan); Cloeet, I. C. [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States); Thomas, A. W. [Jefferson Lab, 12000 Jefferson Avenue, Newport News, Virginia 23606 (United States) and College of William and Mary, Williamsburg, Virginia 23187 (United States); Yazaki, K. [Radiation Laboratory, Nishina Accelerator Research Center, RIKEN, Wako, Saitama 351-0198 (Japan)

2009-10-01T23:59:59.000Z

345

Hybrid stars within a covariant, nonlocal chiral quark model  

SciTech Connect

We present a hybrid equation of state (EoS) for dense matter in which a nuclear matter phase is described within the Dirac-Brueckner-Hartree-Fock (DBHF) approach and a two-flavor quark matter phase is modelled according to a recently developed covariant, nonlocal chiral quark model. We show that modern observational constraints for compact star masses (M{approx}2M{sub {center_dot}}) can be satisfied when a small vector-like four quark interaction is taken into account. The corresponding isospin symmetric EoS is consistent with flow data analyses of heavy ion collisions and points to a deconfinement transition at about 0.55 fm{sup -3}.

Blaschke, D. B. [Institute for Theoretical Physics, University of Wroclaw, Max Born place 9, PL-50204 Wroclaw (Poland); Bogoliubov Laboratory of Theoretical Physics, JINR Dubna, Joliot-Curie Street 6, RU-141980 Dubna (Russian Federation); Institut fuer Physik, Universitaet Rostock, Universitaetsplatz 3, D-18051 Rostock (Germany); Dumm, D. Gomez [Instituto de Fisica La Plata, CONICET-Departamento de Fisica, Universidad Nacional de La Plata, C.C. 67, 1900 La Plata (Argentina); CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Grunfeld, A. G. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Physics Department, Comision Nacional de Energia Atomica, Av. Libertador 8250, 1429 Buenos Aires (Argentina); Klaehn, T. [Institut fuer Physik, Universitaet Rostock, Universitaetsplatz 3, D-18051 Rostock (Germany); Gesellschaft fuer Schwerionenforschung mbH (GSI), D-64291 Darmstadt (Germany); Physics Division, Argonne National Laboratory, Argonne, Illinois 60439-4843 (United States); Scoccola, N. N. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Physics Department, Comision Nacional de Energia Atomica, Av. Libertador 8250, 1429 Buenos Aires (Argentina); Universidad Favaloro, Solis 453, 1078 Buenos Aires (Argentina)

2007-06-15T23:59:59.000Z

346

Active QuarkNet Centers  

NLE Websites -- All DOE Office Websites (Extended Search)

Active QuarkNet Centers Active QuarkNet Centers       QuarkNet Home - Information - Calendar - Contacts - Projects - Forms: EoI - Teachers Centers on a Google Map @ the PTEC website Mentor List Sorted by: Last Name Institution Name First Year in Program Argonne National Laboratory - On sabbatical Black Hills State University Brown, Northeastern & Brandeis Universities Brookhaven National Laboratory, Columbia & Stony Brook Universities Chicago State University Colorado State University Fermilab & University of Chicago Florida Institute of Technology Florida International University Florida State University Hampton, George Mason, William & Mary Universities Idaho State University Indiana University - On sabbatical Johns Hopkins University

347

Dissipative force on an external quark in heavy quark cloud  

E-Print Network (OSTI)

Within the finite temperature N = 4 strongly coupled super Yang- Mills, we compute the dissipative force on an external quark in the presence of evenly distributed heavy quark cloud. This is computed holographically by constructing the corresponding gravity dual. We study the behaviour of this force as a function of the cloud density. Along the way we also analyze the stability of the gravity dual for vector and tensor perturbations.

Shankhadeep Chakrabortty

2011-10-01T23:59:59.000Z

348

Pion cloud effects on baryon masses  

E-Print Network (OSTI)

In this work we explore the effect of pion cloud contributions to the mass of the nucleon and the delta baryon. To this end we solve a coupled system of Dyson-Schwinger equations for the quark propagator, a Bethe-Salpeter equation for the pion and a three-body Faddeev equation for the baryons. In the quark-gluon interaction we explicitly resolve the term responsible for the back-coupling of the pion onto the quark, representing rainbow-ladder like pion cloud effects in bound states. We study the dependence of the resulting baryon masses on the current quark mass and discuss the internal structure of the baryons in terms of a partial wave decomposition. We furthermore determine values for the nucleon and delta sigma-terms.

Helios Sanchis-Alepuz; Christian S. Fischer; Stanislav Kubrak

2014-04-14T23:59:59.000Z

349

Electromagnetic mass difference on the lattice  

E-Print Network (OSTI)

We calculate electromagnetic mass difference of mesons using a method proposed by Duncan {\\it et al}. The RG-improved gauge action and the non-compact Abelian gauge action are employed to generate configurations. Quark propagators in the range of $m_{PS}/m_{V}=0.76-0.51$ are obtained with the meanfield-improved clover quark action. Chiral and continuum extrapolations are performed and the results are compared with experiments. Finite size effects are also examined. Quark masses are extracted from the measured spectrum. Our preliminary values for light quark masses are $m_{u}^{\\bar{MS}}(\\mu =2 {GeV}) = 3.03(19)$ MeV, $m_{d}^{\\bar{MS}}(\\mu = 2 {GeV}) = 4.44(28)$ MeV, $m_{s}^{\\bar{MS}}(\\mu = 2 {GeV}) = 99.2(52)$ MeV.

Yusuke Namekawa; Yoshio Kikukawa

2005-09-24T23:59:59.000Z

350

Diquark condensation effects on hot quark star configurations  

E-Print Network (OSTI)

The equation of state for quark matter is derived for a nonlocal, chiral quark model within the mean field approximation.We investigate the effects of a variation of the formfactors of the interaction on the phase diagram of quark matter. Special emphasis is on the occurrence of a diquark condensate which signals a phase transition to color superconductivity and its effects on the equation of state under the condition of beta- equilibrium and charge neutrality. We calculate the quark star configurations by solving the Tolman- Oppenheimer- Volkoff equations and obtain for the transition from a hot, normal quark matter core of a protoneutron star to a cool diquark condensed one a release of binding energy of the order of Delta M c^2 ~ 10^{53} erg. We find that this energy could not serve as an engine for explosive phenomena since the phase transition is not first order. Contrary to naive expectations the mass defect increases when for a given temperature we neglect the possibility of diquark condensation.

D. Blaschke; S. Fredriksson; H. Grigorian; A. M. "Oztas

2004-02-07T23:59:59.000Z

351

Los Alamos National Laboratory top  

NLE Websites -- All DOE Office Websites (Extended Search)

top top science news of 2012 December 20, 2012 Scientific advances that caught the world's interest LOS ALAMOS, NEW MEXICO, December 20, 2012-In 2012 Los Alamos National Laboratory made its scientific mark in a wide variety of areas, and the stories that caught the public's attention and that of the science community reflect those broad capabilities. Top science stories for the year traveled from the canyons of Mars to the high desert forests of New Mexico, from cosmic particles to the structure of proteins and enzymes. Computer models of wildfires, and nuclear magnetic resonance signatures of plutonium, it all was fascinating for those following Los Alamos' science news. - 2 - Mars Science Laboratory Curiosity rover and ChemCam 2:12 ChemCam rock laser for the Mars Science Laboratory

352

MTS Table Top Load frame  

NLE Websites -- All DOE Office Websites (Extended Search)

MTS Table Top Load frame MTS Table Top Load frame The Non-destructive Evaluation group operates an MTS Table Top Load frame for ultimate strength and life cycle testing of various ceramic, ceramic-matrix (FGI), carbon, carbon fiber, cermet (CMC) and metal alloy engineering samples. The load frame is a servo-hydraulic type designed to function in a closed loop configuration under computer control. The system can perform non-cyclic, tension, compression and flexure testing and cyclic fatigue tests. The system is comprised of two parts: * The Load Frame and * The Control System. Load Frame The Load Frame (figure 1) is a cross-head assembly which includes a single moving grip, a stationary grip and LVDT position sensor. It can generate up to 25 kN (5.5 kip) of force in the sample under test and can

353

SRNL Microspheres Win Top Honors  

NLE Websites -- All DOE Office Websites (Extended Search)

Microspheres Microspheres Win Top Honors AIKEN, S.C. (July 16, 2012) - Savannah River National Laboratory (SRNL) captured top honors at a symposium spotlighting some of the most innovative research being conducted by the researchers supporting the U.S. Department of Energy's National Nuclear Security Administration (NNSA) . Dr. George Wicks of SRNL was presented the top "Award of Excellence" for the poster presen- tation on SRNL's porous-walled hollow glass microspheres at the NNSA Laboratory Directed Research and Development (LDRD) Symposium on Discovery and Innovation for National Security. The poster described how development of the microspheres began with funding from the Savannah River Site Plant-Directed Research and Development (PDRD) program, which funds

354

Top 10 Energy Efficiency Opportunities  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Top 10 Energy Efficiency Top 10 Energy Efficiency Opportunities Federal Utility Partnership Working Group San Francisco, 5/22/2013 Siva Sethuraman Customer Energy Solutions PG&E 2 Whole Building A comprehensive, performance-based approach to achieving 15+% energy savings in existing commercial buildings - quantification of energy use baselines and estimate savings at the whole building level leveraging the power of interval meter data. Behavioral Operational Retrofit Types of Energy Savings * Simplified, integrated offering * Bigger incentives tied to performance * Flexibility to pursue a range of measures overtime * Transparent and credible bill savings Baseline Analytics, Examples 3 Small Commercial EMS * Energy management system (EMS) products that offer integrated

355

Physics of the Charm Quark  

SciTech Connect

This is a brief summary about the development of the charm quark physics in the area of experimental physics. The summary is centered in what is done by mexican physicists, particularly in the E791 and the FOCUS Experiment at FERMILAB. FOCUS (or E831) was designed to detect states of matter combining one or more charm quarks with light quarks (strange, up, down). The experiment created 10 times as many such particles as in previous experiments and investigated several topics on charm physics including high precision studies of charm semileptonic decays, studies of hadronic charm decays (branching ratios and Daltiz analyses), lifetime measurements of all charm particles, searches for mixing, CP/CPT violation, rare and forbidden decays, spectroscopy of excited charm mesons and baryons, charm production asymmetry measurements, light quark diffractive studies, QCD studies using charm pair events and searches for and upper limits on: charm pentaquarks, double charm baryons, DSJ(2632)

Carrillo Moreno, Salvador [Universidad Iberoamericana (Mexico); Vazquez Valencia, Elsa Fabiola [CINVESTAV (Mexico); Universidad Iberoamericana (Mexico)

2006-09-25T23:59:59.000Z

356

Symmetries of Quarks and Leptons  

Science Journals Connector (OSTI)

The course is divided in four Chapters corresponding to three lectures. After an introductory first chapter, the second deals with the symmetries of strong interactions from a quark point of view. We shall dis...

F. Gürsey

1979-01-01T23:59:59.000Z

357

Study of collisons of supersymmetric top Quark in the channel stop anti-stop -> e+- mu-+ sneutrino anti-sneutrino b anti-b with the experience of D0 at the Tevatron. Callibration of the electromagnetic calorimeter at D0.  

SciTech Connect

Supersymmetry is one of the most natural extensions of the Standard Model. At low energy it may consist in the Minimal Supersymmetric Standard Model which is the framework chosen to perform the search of the stop with 350 pb{sup -1} of data collected by D0 during the RunIIa period of the TeVatron. They selected the events with an electron, a muon, missing transverse energy and non-isolated tracks, signature for the stop decay in 3-body ({bar t} {yields} bl{bar {nu}}). Since no significant excess of signal is seen, the results are interpreted in terms of limit on the stop production cross-sections, in such a way that they extend the existing exclusion region in the parameter space (m{sub {bar t}},m{sub {bar {nu}}}) up to stop masses of 168 (140) GeV for sneutrino masses of 50 (94) GeV. Finally because of the crucial role of the electromagnetic calorimeter, a fine calibration was performed using Z {yields} e{sup +}e{sup -} events, which improved significantly the energy resolution.

Mendes, Aurelien; /Marseille U., Luminy

2006-10-01T23:59:59.000Z

358

Experimental Discrimination between Charge 2e/3 Top Quark and Charge 4e/3 Exotic Quark Production Scenarios  

E-Print Network (OSTI)

. Gavrilov,37 A. Gay,19 P. Gay,13 D. Gele´,19 R. Gelhaus,49 C. E. Gerber,52 Y. Gershtein,50 D. Gillberg,5 G. Ginther,72 N. Gollub,41 B. Go´mez,8 A. Goussiou,56 P. D. Grannis,73 H. Greenlee,51 Z. D. Greenwood,61 E. M. Gregores,4 G. Grenier,20 Ph. Gris,13 J.... Hoeneisen,12 H. Hoeth,26 M. Hohlfeld,16 S. J. Hong,31 R. Hooper,78 P. Houben,34 Y. Hu,73 Z. Hubacek,10 V. Hynek,9 I. Iashvili,70 R. Illingworth,51 A. S. Ito,51 S. Jabeen,63 M. Jaffre´,16 S. Jain,76 K. Jakobs,23 C. Jarvis,62 A. Jenkins,44 R. Jesik,44 K. Johns...

Baringer, Philip S.; Bean, Alice; Coppage, Don; Gardner, J.; Hensel, Carsten; Moulik, Tania; Wilson, Graham Wallace; Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.

2007-01-22T23:59:59.000Z

359

Jet Dipolarity: Top Tagging with Color Flow  

SciTech Connect

A new jet observable, dipolarity, is introduced that can distinguish whether a pair of subjets arises from a color singlet source. This observable is incorporated into the HEPTopTagger and is shown to improve discrimination between top jets and QCD jets for moderate to high p{sub T}. The impressive resolution of the ATLAS and CMS detectors means that a typical QCD jet at the LHC deposits energy in {Omicron}(10-100) calorimeter cells. Such fine-grained calorimetry allows for jets to be studied in much greater detail than previously, with sophisticated versions of current techniques making it possible to measure more than just the bulk properties of jets (e.g. event jet multiplicities or jet masses). One goal of the LHC is to employ these techniques to extend the amount of information available from each jet, allowing for a broader probe of the properties of QCD. The past several years have seen significant progress in developing such jet substructure techniques. A number of general purpose tools have been developed, including: (i) top-tagging algorithms designed for use at both lower and higher p{sub T} as well as (ii) jet grooming techniques such as filtering, pruning, and trimming, which are designed to improve jet mass resolution. Jet substructure techniques have also been studied in the context of specific particle searches, where they have been shown to substantially extend the reach of traditional search techniques in a wide variety of scenarios, including for example boosted Higgses, neutral spin-one resonances, searches for supersymmetry, and many others. Despite these many successes, however, there is every reason to expect that there remains room for refinement of jet substructure techniques.

Hook, Anson; Jankowiak, Martin; /SLAC /Stanford U., Phys. Dept.; Wacker, Jay G.; /SLAC

2011-08-12T23:59:59.000Z

360

Nonperturbative renormalization of overlap quark bilinears on 2+1-flavor domain wall fermion configurations  

Science Journals Connector (OSTI)

We present renormalization constants of overlap quark bilinear operators on 2+1-flavor domain wall fermion configurations. This setup is being used by the ?QCD Collaboration in calculations of physical quantities such as strangeness in the nucleon and the strange and charm quark masses. The scale-independent renormalization constant for the axial-vector current is computed using the Ward identity. The renormalization constants for scalar, pseudoscalar, and vector currents are calculated in the RI-MOM scheme. Results in the MS¯ scheme are also given. The step scaling function of quark masses in the RI-MOM scheme is computed as well. The analysis uses, in total, six different ensembles of three sea quarks, each on two lattices with sizes 243×64 and 323×64 at spacings a=(1.73??GeV)?1 and (2.28??GeV)?1, respectively.

Zhaofeng Liu; Ying Chen; Shao-Jing Dong; Michael Glatzmaier; Ming Gong; Anyi Li; Keh-Fei Liu; Yi-Bo Yang; Jian-Bo Zhang (?QCD Collaboration)

2014-08-19T23:59:59.000Z

Note: This page contains sample records for the topic "top quark mass" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

$Qq\\bar Q\\bar q'$ States in Chiral SU(3) Quark Model  

E-Print Network (OSTI)

In this work, we study the masses of $Qq\\bar Q\\bar q'$ states with J^{PC}=0^{++}, 1^{++}, 1^{+-} and 2^{++} in the chiral SU(3) quark model, where Q is the heavy quark (c or b) and q (q') is the light quark (u, d or s). According to our numerical results, it is improbable to make the interpretation of $[cn\\bar c\\bar n]_{1^{++}}$ and $[cn\\bar c\\bar n]_{2^{++}}$ (n=u, d) states as X(3872) and Y(3940), respectively. However, it is interesting to find the tetraquarks in the $bq\\bar b\\bar q'$ system.

H. X. Zhang; M. Zhang; Z. Y. Zhang

2007-05-17T23:59:59.000Z

362

On the conversion of neutron stars into quark stars  

E-Print Network (OSTI)

The possible existence of two families of compact stars, neutron stars and quark stars, naturally leads to a scenario in which a conversion process between the two stellar objects occurs with a consequent release of energy of the order of $10^{53}$ erg. We discuss recent hydrodynamical simulations of the burning process and neutrino diffusion simulations of cooling of a newly formed strange star. We also briefly discuss this scenario in connection with recent measurements of masses and radii of compact stars.

Giuseppe Pagliara

2013-12-04T23:59:59.000Z

363

SLAC-R-1004 International Linear Collider Technical  

Office of Scientific and Technical Information (OSTI)

mass in supersymmetry, in which the loop corrections are proportional to (m t m W ) 4 . Care must be taken in relating the measured top quark mass to the value of the top quark...

364

New results on CLEO`s heavy quarks - bottom and charm  

SciTech Connect

While the top quark is confined to virtual reality for CLEO, the increased luminosity of the Cornell Electron Storage Ring (CESR) and the improved photon detection capabilities of the CLEO`s {open_quotes}heavy{close_quotes} quarks - bottom and charm. I will describe new results in the B meson sector including the first observation of exclusive b {yields} ulv decays, upper limits on gluonic penguin decay rates, and precise measurements of semileptonic and hadronic b {yields} c branching fractions. The charmed hadron results that are discussed include the observation of isospin violation in D{sub s}*{sup +} decays, an update on measurements of the D{sub s}{sup +} decay constant, and the observation of a new excited {Xi}{sub c} charmed baryon. These measurements have had a large impact on our understanding of heavy quark physics.

Menary, S. [Univ. of California, Santa Barbara, CA (United States)

1997-01-01T23:59:59.000Z

365

Building Technologies Office: Top Innovations 2012  

NLE Websites -- All DOE Office Websites (Extended Search)

Top Innovations 2012 to Top Innovations 2012 to someone by E-mail Share Building Technologies Office: Top Innovations 2012 on Facebook Tweet about Building Technologies Office: Top Innovations 2012 on Twitter Bookmark Building Technologies Office: Top Innovations 2012 on Google Bookmark Building Technologies Office: Top Innovations 2012 on Delicious Rank Building Technologies Office: Top Innovations 2012 on Digg Find More places to share Building Technologies Office: Top Innovations 2012 on AddThis.com... About Take Action to Save Energy Partner With DOE Activities Solar Decathlon Building America Research Innovations Research Tools Building Science Education Climate-Specific Guidance Solution Center Partnerships Meetings Publications Home Energy Score Home Performance with ENERGY STAR Better Buildings Neighborhood Program

366

Modeling and control of top tensioned risers  

E-Print Network (OSTI)

1 Modeling and control of top tensioned risers Anne Marthine Rustad Department of Marine Technology increasing platform size · Constant high top tension is expensive and could result in wear and tear

Nørvåg, Kjetil

367

Heavy quarks in effective field theories  

E-Print Network (OSTI)

Heavy quark physics serves as a probe to understand QCD, measure standard model parameters, and look for signs of new physics. We study several aspects of heavy quark systems in an effective field theory framework, including ...

Jain, Ambar

2009-01-01T23:59:59.000Z

368

Quarks in the looking glass | Jefferson Lab  

NLE Websites -- All DOE Office Websites (Extended Search)

Quarks in the looking glass Jefferson Lab's Experimental Hall A The electron-quark scattering experiment was carried out in Jefferson Lab's Experimental Hall A. In this view from...

369

QuarkNet at Work  

NLE Websites -- All DOE Office Websites (Extended Search)

QuarkNet at Work Information for Active Mentors & Teachers     QuarkNet Home - Information - Calendar - Contacts - Projects - Forms: EoI - Teachers Information Active Centers Calendar Contacts Expectations: for Teachers, for Mentors Information on Other Funding Sources Program Overview Support: for Teachers, for Centers Staff Job Description Activities Essential Practices - Teaching with Inquiry (word.doc) Classroom Activities e-Labs: CMS - Cosmic Ray Boot Camp Project Activities Databases: Data Entry (password only) 2012 Center Reporting Resources Important Findings from Previous Years Mentor Tips Associate Teacher Institute Toolkit Print Bibliography - Online Resources Imaging Detector Principles of Professionalism for Science Educators - NSTA position

370

Flavordynamics of quarks and leptons  

Science Journals Connector (OSTI)

The present theory of flavordynamics is discussed. After giving a general introduction into the field we describe the gauge theory framework and the spontaneous symmetry breaking. Several examples of spontaneously broken theories are studied. We describe the standard theory of leptons and quarks. A special emphasis is given to a discussion of the weak decays of strange and charmed particles. Furthermore the neutral current interaction is studied. We discuss the sequential flavordynamics of leptons and quarks, concentrating on the six flavor scheme, and speculations about extended schemes of flavordynamics. The report concludes with a description of weak interactions at very high energies (production and decays of W, Z or Higgs bosons etc.).

H. Fritzsch; P. Minkowski

1981-01-01T23:59:59.000Z

371

Top Science News of 2014  

NLE Websites -- All DOE Office Websites (Extended Search)

the Energy Technology Division of the Electrochemical Society. Simulation of the cosmic web of the dark matter mass distribution. This region represents about 110,000 of the...

372

Electric polarizability of the neutron in dynamical quark ensembles  

E-Print Network (OSTI)

The background field method for measuring the electric polarizability of the neutron is adapted to the dynamical quark case, resulting in the calculation of (certain space-time integrals over) three- and four-point functions. Particular care is taken to disentangle polarizability effects from the effects of subjecting the neutron to a constant background gauge field; such a field is not a pure gauge on a finite lattice and engenders a mass shift of its own. At a pion mass of m_pi = 759 MeV, a small, slightly negative electric polarizability is found for the neutron.

Michael Engelhardt

2007-10-09T23:59:59.000Z

373

Top Hat Pressure System Hyperbaric Test Analysis | Department...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Top Hat Pressure System Hyperbaric Test Analysis Top Hat Pressure System Hyperbaric Test Analysis This file contains data from pressure measurements inside Top Hat 4....

374

A relativistic constituent quark model  

SciTech Connect

We investigate the predictive power of a relativistic quark model formulated on the light-front. The nucleon electromagnetic form factors, the semileptonic weak decays of the hyperons and the magnetic moments of both baryon octet and decuplet are calculated and found to be in excellent agreement with experiment.

Schlumpf, F.

1993-08-01T23:59:59.000Z

375

MHD Integrated Topping Cycle Project  

SciTech Connect

This eighteenth quarterly technical progress report of the MHD Integrated Topping cycle Project presents the accomplishments during the period November 1, 1991 to January 31, 1992. The precombustor is fully assembled. Manufacturing of all slagging stage components has been completed. All cooling panels were welded in place and the panel/shell gap was filled with RTV. Final combustor assembly is in progress. The low pressure cooling subsystem (LPCS) was delivered to the CDIF. Second stage brazing issues were resolved. The construction of the two anode power cabinets was completed.

Not Available

1992-07-01T23:59:59.000Z

376

Table-top job analysis  

SciTech Connect

The purpose of this Handbook is to establish general training program guidelines for training personnel in developing training for operation, maintenance, and technical support personnel at Department of Energy (DOE) nuclear facilities. TTJA is not the only method of job analysis; however, when conducted properly TTJA can be cost effective, efficient, and self-validating, and represents an effective method of defining job requirements. The table-top job analysis is suggested in the DOE Training Accreditation Program manuals as an acceptable alternative to traditional methods of analyzing job requirements. DOE 5480-20A strongly endorses and recommends it as the preferred method for analyzing jobs for positions addressed by the Order.

Not Available

1994-12-01T23:59:59.000Z

377

Global quark polarization in non-central A+A collisions  

SciTech Connect

Partons produced in the early stage of non-central heavy-ioncollisionscan develop a longitudinal fluid shear because of unequal localnumber densities of participant target and projectile nucleons. Undersuch fluid shear, local parton pairs with non-vanishing impact parameterhave finite local relative orbital angular momentum along the directionopposite to the reaction plane. Such finite relative orbitalangularmomentum among locally interacting quark pairs can lead to global quarkpolarization along the same direction due to spin-orbital coupling. Locallongitudinal fluid shear is estimated within both Landau fireball andBjorken scaling model of initial parton production. Quark polarizationthrough quark-quark scatterings with the exchange of a thermal gluon iscalculated beyond small-angle scattering approximation in a quark-gluonplasma. The polarization is shown to have a non-monotonic dependence onthe local relative orbital angular momentum dictated by the interplaybetween electric and magnetic interaction. It peaks at a value ofrelative orbital angular momentum which scales with the magnetic mass ofthe exchanged gluons. With the estimated small longitudinal fluid shearin semi-peripheral Au+Au collisions at the RHIC energy, the final quarkpolarization is found to be small left hbar P_q right hbar<0.04 inthe weak coupling limit. Possible behavior of the quark polarization inthe strong coupling limit and implications on the experimental detectionof such global quark polarization at RHIC and LHC are alsodiscussed.

Gao, Jian-Hua; Chen, Shou-Wan; Deng, Wei-tian; Tang, Zuo-Tang; Wang, Qun; Wang, Xin-Nian

2007-10-12T23:59:59.000Z

378

Strange and charm quark contributions to the anomalous magnetic moment of the muon  

E-Print Network (OSTI)

We describe a new technique to determine the contribution to the anomalous magnetic moment of the muon coming from the hadronic vacuum polarization using lattice QCD. Our method reconstructs the Adler function, using Pad\\'{e} approximants, from its derivatives at $q^2=0$ obtained simply and accurately from time-moments of the vector current-current correlator at zero spatial momentum. We test the method using strange quark correlators on large-volume gluon field configurations that include the effect of up and down (at physical masses), strange and charm quarks in the sea at multiple values of the lattice spacing and multiple volumes and show that 1% accuracy is achievable. For the charm quark contributions we use our previously determined moments with up, down and strange quarks in the sea on very fine lattices. We find the (connected) contribution to the anomalous moment from the strange quark vacuum polarization to be $a_\\mu^s = 53.41(59) \\times 10^{-10}$, and from charm to be $a_\\mu^c = 14.42(39)\\times 10^{-10}$. These are in good agreement with flavour-separated results from non-lattice methods, given caveats about the comparison. The extension of our method to the light quark contribution and to that from the quark-line disconnected diagram is straightforward.

Bipasha Chakraborty; C. T. H. Davies; G. C. Donald; R. J. Dowdall; J. Koponen; G. P. Lepage; T. Teubner

2014-03-07T23:59:59.000Z

379

MHD Integrated Topping Cycle Project  

SciTech Connect

The overall objective of the project is to design and construct prototypical hardware for an integrated MHD topping cycle, and conduct long duration proof-of-concept tests of integrated system at the US DOE Component Development and Integration Facility in Butte, Montana. The results of the long duration tests will augment the existing engineering design data base on MHD power train reliability, availability, maintainability, and performance, and will serve as a basis for scaling up the topping cycle design to the next level of development, an early commercial scale power plant retrofit. The components of the MHD power train to be designed, fabricated, and tested include: A slagging coal combustor with a rated capacity of 50 MW thermal input, capable of operation with an Eastern (Illinois {number sign}6) or Western (Montana Rosebud) coal, a segmented supersonic nozzle, a supersonic MHD channel capable of generating at least 1.5 MW of electrical power, a segmented supersonic diffuser section to interface the channel with existing facility quench and exhaust systems, a complete set of current control circuits for local diagonal current control along the channel, and a set of current consolidation circuits to interface the channel with the existing facility inverter.

Not Available

1992-01-01T23:59:59.000Z

380

MHD Integrated Topping Cycle Project  

SciTech Connect

The Magnetohydrodynamics (MHD) Integrated Topping Cycle (ITC) Project represents the culmination of the proof-of-concept (POC) development stage in the US Department of Energy (DOE) program to advance MHD technology to early commercial development stage utility power applications. The project is a joint effort, combining the skills of three topping cycle component developers: TRW, Avco/TDS, and Westinghouse. TRW, the prime contractor and system integrator, is responsible for the 50 thermal megawatt (50 MW{sub t}) slagging coal combustion subsystem. Avco/TDS is responsible for the MHD channel subsystem (nozzle, channel, diffuser, and power conditioning circuits), and Westinghouse is responsible for the current consolidation subsystem. The ITC Project will advance the state-of-the-art in MHD power systems with the design, construction, and integrated testing of 50 MW{sub t} power train components which are prototypical of the equipment that will be used in an early commercial scale MHD utility retrofit. Long duration testing of the integrated power train at the Component Development and Integration Facility (CDIF) in Butte, Montana will be performed, so that by the early 1990's, an engineering data base on the reliability, availability, maintainability and performance of the system will be available to allow scaleup of the prototypical designs to the next development level. This Sixteenth Quarterly Technical Progress Report covers the period May 1, 1991 to July 31, 1991.

Not Available

1992-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "top quark mass" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Dilepton production from the quark-gluon plasma using (3+1)-dimensional anisotropic dissipative hydrodynamics  

E-Print Network (OSTI)

We compute dilepton production from the deconfined phase of the quark-gluon plasma using leading-order (3+1)-dimensional anisotropic hydrodynamics. The anisotropic hydrodynamics equa- tions employed describe the full spatiotemporal evolution of the transverse temperature, spheroidal momentum-space anisotropy parameter, and the associated three-dimensional collective flow of the matter. The momentum-space anisotropy is also taken into account in the computation of the dilepton production rate, allowing for a self-consistent description of dilepton production from the quark-gluon plasma. For our final results, we present predictions for high-energy dilepton yields as a function of invariant mass, transverse momentum, and pair rapidity. We demonstrate that high- energy dilepton production is extremely sensitive to the assumed level of initial momentum-space anisotropy of the quark-gluon plasma. As a result, it may be possible to experimentally constrain the early-time momentum-space anisotropy of the quark-gluon...

Ryblewski, Radoslaw

2015-01-01T23:59:59.000Z

382

The First Two Fermion Generations in Twisted Mass Lattice QCD  

SciTech Connect

An account of the status of simulations from the European Twisted Mass Collaboration is given. We show selected results from computations with two mass degenerate quarks, in particular values for the low energy constants of the chiral Lagrangian, the I = 2 scattering length and the {rho}-meson resonance parameters. We also provide first results from simulations where the strange and the charm quarks are included as dynamical degree of freedom in the simulation.

Jansen, Karl [NIC, DESY, Platanenallee 6, 15738 Zeuthen (Germany)

2011-05-24T23:59:59.000Z

383

Search for single-top production in ep collisions at HERA  

E-Print Network (OSTI)

A search for single-top production, $ep \\rightarrow etX$, has been performed with the ZEUS detector at HERA using data corresponding to an integrated luminosity of $0.37\\fbi$. No evidence for top production was found, consistent with the expectation from the Standard Model. Limits were computed for single-top production via flavour changing neutral current transitions. The result was combined with a previous ZEUS result yielding a total luminosity of 0.50fb-1. A 95% credibility level upper limit of 0.13 pb was obtained for the cross section at the centre-of-mass energy of $\\sqrt{s}=315\\gev$.

ZEUS Collaboration; H. Abramowicz; I. Abt; L. Adamczyk; M. Adamus; R. Aggarwal; S. Antonelli; P. Antonioli; A. Antonov; M. Arneodo; V. Aushev; Y. Aushev; O. Bachynska; A. Bamberger; A. N. Barakbaev; G. Barbagli; G. Bari; F. Barreiro; N. Bartosik; D. Bartsch; M. Basile; O. Behnke; J. Behr; U . Behrens; L. Bellagamba; A. Bertolin; S. Bhadra; M. Bindi; C. Blohm; V. Bokhonov; T. Bo?d; K. Bondarenko; E. G. Boos; K. Borras; D. Boscher ini; D. Bot; I. Brock; E. Brownson; R. Brugnera; N. Brümmer; A. Bruni; G. Bruni; B. Brzozowska; P. J. Bussey; B. Bylsma; A. Caldwell; M. Capua; R. Carlin; C. D. Catterall; S. Chekanov; J. Chwastowski; J. Ciborowski; R . Ciesielski; L. Cifarelli; F. Cindolo; A. Contin; A. M. Cooper-Sarkar; N. Coppola; M. Corradi; F. Corriveau; M. Costa; G. D'Agostini; F. Dal Corso; J. del Peso; R. K. Dementiev; S. De Pasquale; M. Derrick; R. C. E. Devenish; D. Dobur; B. A. Dolgoshein; G. Dolinska; A. T. Doyle; V. Drugakov; L. S. Durkin; S. Dusini; Y. Eisenberg; P. F. Ermolov; A. Eskreys; S. Fang; S. Fazio; J. Ferrando; M. I. Ferrero; J. Figiel; M. Forrest; B. Foster; G. Gach; A. Galas; E. Gallo; A. Garfagnini; A. Geiser; I. Gialas; L. K. Gladilin; D. Gladkov; C. Glasman; O. Gogota; Yu. A. Golubkov; P. Göttlicher; I. Grabowska-Bo?d; J. Grebenyuk; I. Gregor; G. Grigorescu; G. Grzelak; O. Gueta; M. Guzik; C. Gwenlan; T. Haas; W. Hain; R. Hamatsu; J. C. Hart; H. Hartmann; G. Hartner; E. Hilger; D. Hochman; R. Hori; K. Horton; A. Hüttmann; Z. A. Ibrahim; Y. Iga; R. Ingbir; M. Ishitsuka; H. -P. Jakob; F. Januschek; T. W. Jones; M. Jüngst; I. Kadenko; B. Kahle; S. Kananov; T. Kanno; U. Karshon; F. Karstens; I. I. Katkov; M. Kaur; P. Kaur; A. Keramidas; L. A. Khein; J. Y. Kim; D. Kisielewska; S. Kitamura; R. Klanner; U. Klein; E. Koffeman; P. Kooijman; Ie. Korol; I. A. Korzhavina; A. Kota?ski; U. Kötz; H. Kowalski; O. Kuprash; M. Kuze; A. Lee; B. B. Levchenko; A. Levy; V. Libov; S. Limentani; T. Y. Ling; M. Lisovyi; E. Lobodzinska; W. Lohmann; B. Löhr; E. Lohrmann; K. R. Long; A. Longhin; D. Lontkovskyi; O. Yu. Lukina; J. Maeda; S. Magill; I. Makarenko; J. Malka; R. Mankel; A. Margotti; G. Marini; J. F. Martin; A. Mastroberardino; M. C. K. Mattingly; I. -A. Melzer-Pellmann; S. Mergelmeyer; S. Miglioranzi; F. Mohamad Idris; V. Monaco; A. Montanari; J. D. Morris; K. Mujkic; B. Musgrave; K. Nagano; T. Namsoo; R. Nania; A. Nigro; Y. Ning; T. Nobe; U. Noor; D. Notz; R. J. Nowak; A. E. Nuncio-Quiroz; B. Y. Oh; N. Okazaki; K. Oliver; K. Olkiewicz; Yu. Onishchuk; K. Papageorgiu; A. Parenti; E. Paul; J. M. Pawlak; B. Pawlik; P. G. Pelfer; A. Pellegrino; W. Perla?ski; H. Perrey; K. Piotrzkowski; P. Pluci?ski; N. S. Pokrovskiy; A. Polini; A. S. Proskuryakov; M. Przybycie?; A. Raval; D. D. Reeder; B. Reisert; Z. Ren; J. Repond; Y. D. Ri; A. Robertson; P. Roloff; I. Rubinsky; M. Ruspa; R. Sacchi; A. Salii; U. Samson; G. Sartorelli; A. A. Savin; D. H. Saxon; M. Schioppa; S. Schlenstedt; P. Schleper; W. B. Schmidke; U. Schneekloth; V. Schönberg; T. Schörner-Sadenius; J. Schwartz; F. Sciulli; L. M. Shcheglova; R. Shehzadi; S. Shimizu; I. Singh; I. O. Skillicorn; W. S?omi?ski; W. H. Smith; V. Sola; A. Solano; D. Son; V. Sosnovtsev; A. Spiridonov; H. Stadie; L. Stanco; A. Stern; T. P. Stewart; A. Stifutkin; P. Stopa; S. Suchkov; G. Susinno; L. Suszycki; J. Sztuk-Dambietz; D. Szuba; J. Szuba; A. D. Tapper; E. Tassi; J. Terrón; T. Theedt; H. Tiecke; K. Tokushuku; O. Tomalak; J. Tomaszewska; T. Tsurugai; M. Turcato; T. Tymieniecka; M. Vázquez; A. Verbytskyi; O. Viazlo; N. N. Vlasov; O. Volynets; R. Walczak; W. A. T. Wan Abdullah; J. J. Whitmore; L. Wiggers; M. Wing; M. Wlasenko; G. Wolf; H. Wolfe; K. Wrona; A. G. Yagües-Molina; S. Yamada; Y. Yamazaki; R. Yoshida; C. Youngman; A. F. ?arnecki; L. Zawiejski; O. Zenaiev; W. Zeuner; B. O. Zhautykov; N. Zhmak; C. Zhou; A. Zichichi; Z. Zolkapli; M. Zolko; D. S. Zotkin

2012-02-04T23:59:59.000Z

384

Search For Heavy, Neutral Gague Bosons Decaying To Boosted Top Quark Pairs At The LHC  

E-Print Network (OSTI)

pixel layer. For high energy muons the impact parametermatches in the muon chambers or energy depositions in thethe selected muon and the missing trans- verse energy of the

Babb, John

2012-01-01T23:59:59.000Z

385

Resonance searches with the $t\\overline{t}$ Invariant Mass Distribution measured with the D\\O\\, Experiment at $\\sqrt{s}=1.96\\,\\textrm{TeV}  

SciTech Connect

Understanding the universe, its birth and its future is one of the biggest motivations in physics. In order to understand the cosmos, the fundamental particles forming the universe, the components our matter is built of need to be known and understood. Over time physicists have built a theory which describes the physics of the known fundamental particles very well: the Standard Model (SM) of particle physics. The SM describes the particles, their interactions and phenomena with high precision. So far no proven deviations from the SM have been found, though recently evidence for possible physics beyond the SM has been observed. The SM is not describing the mass of the elementary particles however and even with the addition of the Higgs mechanism giving mass to the particles, we have no full theory for all four fundamental forces. We know the model needs to be extended or replaced by another one, as gravitation is not included in the SM. Having a theory which describes all fundamental particles found so far and all but one fundamental interaction is a great success. However, all this describes about 4% of the universe we live in. 23% is dark matter and 73% is dark energy. Dark matter is believed to interact only through gravity and maybe the weak force, which makes it hardly observable. Dark energy is even more elusive. Among other theories the cosmologic constant and scalar fields are discussed to describe it. One should also note that other models exist which for example modify the Newtonian law of gravity. The Higgs mechanism has become the most popular model for mass generation. Alternative theories like Super Symmetry (SUSY), large Extra Dimensions, Technicolor, String Theory, to name just a few, have spread to describe the necessary mass generation or new particles. As proof for new physics beyond the SM has not been found yet, one assumes that new physics will manifest itself at a larger energy scale and therefore a higher particle mass. Particles with high masses are therefore presumed to be a window to test the SM for deviations caused by new physics. The heaviest fundamental particle which is in our reach is the top quark. Its mass is almost as large as that of a complete tungsten atom. It is so heavy, that it decays faster than it can hadronize. It seems the perfect probe to study new physics at the moment. In this analysis the top quark is used as a probe to search for a new resonance, whose properties are similar to a SM Z boson but is much more massive. This analysis will study t{bar t} decays to search for an excess in the invariant mass distribution of the t{bar t} pairs. Resonant states are suggested for massive Z-like bosons in extended gauge theories, Kaluza Klein states of the gluon or Z, axigluons, topcolor, and other beyond the Standard Model theories. Independent of the exact model a resonant production mechanism should be visible in the t{bar t} invariant mass distribution. In this thesis a model-independent search for a narrow-width heavy resonance X decaying into t{bar t} is performed. In the SM, the top quark decays into a W boson and a b quark nearly 100% of the time, which has been proven experimentally, too. The t{bar t} event signature is fully determined by the W boson decay modes. In this analysis, only the lepton+jets final state, which results from the leptonic decay of one of the W bosons and the hadronic decay of the other, is considered. The event signature is an isolated electron or muon with high transverse momentum, large transverse energy imbalance due to the undetected neutrino, and at least three jets, two of which result from the hadronization of b quarks.

Schliephake, Thorsten Dirk; /Wuppertal U.

2010-06-01T23:59:59.000Z

386

MHD Integrated Topping Cycle Project  

SciTech Connect

This seventeenth quarterly technical progress report of the MHD Integrated Topping Cycle Project presents the accomplishments during the period August 1, 1991 to October 31, 1991. Manufacturing of the prototypical combustor pressure shell has been completed including leak, proof, and assembly fit checking. Manufacturing of forty-five cooling panels was also completed including leak, proof, and flow testing. All precombustor internal components (combustion can baffle and swirl box) were received and checked, and integration of the components was initiated. A decision was made regarding the primary and backup designs for the 1A4 channel. The assembly of the channel related prototypical hardware continued. The cathode wall electrical wiring is now complete. The mechanical design of the diffuser has been completed.

Not Available

1992-07-01T23:59:59.000Z

387

Top Innovations 2012 | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Top Innovations 2012 Top Innovations 2012 Top Innovations 2012 On this page, you will find Building America's Top Innovations from 1995 through 2012, with links to a profile describing each innovation. Note that some categories may not have a top innovation each year. Flow chart graphic 1. Advanced Technologies and Practices Top Innovations in this category cover research in thermal enclosure improvements, HVAC components, ventilation and other health and safety issues. 1.1 Building Science Solutions Thermal Enclosure: Basement Insulation Systems Advanced Framing Systems and Packages Unvented, Conditioned Attics Unvented, Conditioned Crawlspaces High-R Walls Heating, Ventilation, and Air Conditioning: Integration of HVAC System Design with Simplified Duct Distribution Ducts in Conditioned Space

388

Infrastructure Development- Building America Top Innovations  

Energy.gov (U.S. Department of Energy (DOE))

Top Innovations in this category include research results that have influenced codes and standards and improvements in education and the transaction process.

389

Water Management Guide- Building America Top Innovation  

Energy.gov (U.S. Department of Energy (DOE))

This Top Innovation highlights the DOE-sponsored Water Management Guide, which has proven to be a highly effective tool for disseminating much needed best practices.

390

Mesa Top Photovoltaic Array (Fact Sheet)  

SciTech Connect

Fact sheet overview of the Mesa Top Photovoltaic Array project implemented by the Department of Energy Golden Office and National Renewable Energy Laboratory.

Not Available

2009-07-01T23:59:59.000Z

391

{rho}{phi}{phi} and {omega}{omega} vertex functions within a confined quark model  

SciTech Connect

We report results of an investigation of the p{pi}{pi} vertex function calculated from a quark including the distributed {anti q}q nature of the mesons. The quark propaagator is an entire function of the form recently extracie in a model confining Schwinger-Dyson equation. The parameters of the prop gator are chosen to fit {pi}{pi} scattering lengths. The dependence of the p{pi}{pi} vertex upon the p momentum is extracted the coupling constant is extracted at the mass shell point and compared to a previous approximation based at zero momentum. The model is extended to study the G-parity violating {omega}{pi}{pi} vertex produced by an up-down current quark mass difference. This is a possible contributing`mechanism for p-{omega} mixing.

Mitchell, K.; Tandy, P.C. [and others

1993-10-01T23:59:59.000Z

392

Tuning Fermilab Heavy Quarks in 2+1 Flavor Lattice QCD with Application to Hyperfine Splittings  

E-Print Network (OSTI)

We report the non-perturbative tuning of parameters--- kappa_c, kappa_b, and kappa_crit ---that determine the heavy-quark mass in the Fermilab action. This requires the computation of the masses of Ds^(*) and Bs^(*) mesons comprised of a Fermilab heavy quark and a staggered light quark. Additionally, we report the hyperfine splittings for Ds and Bs mesons as a cross-check of our simulation and analysis methods. We find a splitting of 145 +/- 15 MeV for the Ds system and 40 +/- 9 MeV for the Bs system. These are in good agreement with the Particle Data Group average values of 143.9 +/- 0.4 MeV and 46.1 +/- 1.5 MeV, respectively. The calculations are carried out with the MILC 2+1 flavor gauge configurations at three lattice spacings $a$ approximately 0.15, 0.12, and 0.09 fm.

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

2011-02-22T23:59:59.000Z

393

Four-quark Bound States in Chiral SU(3) Quark Model  

E-Print Network (OSTI)

The possibility of $QQ\\bar{q}\\bar{q}$ heavy-light four-quark bound states has been analyzed by means of the chiral SU(3) quark model, where $Q$ is the heavy quark ($c$ or $b$) and $q$ is the light quark ($u$, $d$ or $s$). We obtain a bound state for the $bb\\bar{n}\\bar{n}$ configuration with quantum number $J^{P}=1^{+},I=0$ and for the $cc\\bar{n}\\bar{n}$ ($J^{P}=1^{+},I=0$) configuration which is not bound but slightly above the $D^{*}D^{*}$ threshold (n is $u$ or $d$ quark). Meanwhile, we also conclude that a weakly bound state in $bb\\bar{n}\\bar{n}$ system can also be found without considering the chiral quark interactions between the two light quarks, yet its binding energy is weaker than that with the chiral quark interactions.

M. Zhang; H. X. Zhang; Z. Y. Zhang

2007-11-07T23:59:59.000Z

394

The strange and charm quark contributions to the anomalous magnetic moment of the muon from lattice QCD  

E-Print Network (OSTI)

We describe a new technique (published in Phys. Rev. D89 114501) to determine the contribution to the anomalous magnetic moment of the muon coming from the hadronic vacuum polarisation using lattice QCD. Our method uses Pad\\'e approximants to reconstruct the Adler function from its derivatives at $q^2=0$. These are obtained simply and accurately from time-moments of the vector current-current correlator at zero spatial momentum. We test the method using strange quark correlators calculated on MILC Collaboration's $n_f = 2+1+1$ HISQ ensembles at multiple values of the lattice spacing, multiple volumes and multiple light sea quark masses (including physical pion mass configurations). We find the (connected) contribution to the anomalous moment from the strange quark vacuum polarisation to be $a^s_\\mu=53.41(59)\\times 10^{-10}$, and the contribution from charm quarks to be $a^c_\\mu=14.42(39)\\times 10^{-10}$ - 1% accuracy is achieved for the strange quark contribution. The extension of our method to the light quark contribution and to that from the quark-line disconnected diagram is straightforward.

Jonna Koponen; Bipasha Chakraborty; Christine T. H. Davies; Gordon Donald; Rachel Dowdall; Pedro Goncalves de Oliveira; G. Peter Lepage; Thomas Teubner

2014-11-03T23:59:59.000Z

395

Top 10 Nano & Chem Eng TMVogel, updated Fall 2012 Top 10 Things UCSD Nanoengineering &  

E-Print Network (OSTI)

Top 10 Nano & Chem Eng TMVogel, updated Fall 2012 Top 10 Things UCSD Nanoengineering & Chemical Engineering Researchers Need to Know http://libguides.ucsd.edu/nano http://libguides.ucsd.edu/chemeng http

Hampton, Randy

396

Top-Down Fragmentation of a Warm Dark Matter Filament  

E-Print Network (OSTI)

We present the first high-resolution n-body simulations of the fragmentation of dark matter filaments. Such fragmentation occurs in top-down scenarios of structure formation, when the dark matter is warm instead of cold. In a previous paper (Knebe et al. 2002, hereafter Paper I), we showed that WDM differs from the standard Cold Dark Matter (CDM) mainly in the formation history and large-scale distribution of low-mass haloes, which form later and tend to be more clustered in WDM than in CDM universes, tracing more closely the filamentary structures of the cosmic web. Therefore, we focus our computational effort in this paper on one particular filament extracted from a WDM cosmological simulation and compare in detail its evolution to that of the same CDM filament. We find that the mass distribution of the halos forming via fragmentation within the filament is broadly peaked around a Jeans mass of a few 10^9 Msun, corresponding to a gravitational instability of smooth regions with an overdensity contrast around 10 at these redshifts. Our results confirm that WDM filaments fragment and form gravitationally bound haloes in a top-down fashion, whereas CDM filaments are built bottom-up, thus demonstrating the impact of the nature of the dark matter on dwarf galaxy properties.

Alexander Knebe; Julien Devriendt; Brad Gibson; Joseph Silk

2003-07-28T23:59:59.000Z

397

Quark Structure of the Nucleon and Angular Asymmetry of Proton-Neutron Hard Elastic Scattering  

E-Print Network (OSTI)

We investigate an asymmetry in the angular distribution of hard elastic proton-neutron scattering with respect to 90deg center of mass scattering angle. We demonstrate that the magnitude of the angular asymmetry is related to the helicity-isospin symmetry of the quark wave function of the nucleon. Our estimate of the asymmetry within the quark-interchange model of hard scattering demonstrates that the quark wave function of a nucleon based on the exact SU(6) symmetry predicts an angular asymmetry opposite to that of experimental observations. On the other hand the quark wave function based on the diquark picture of the nucleon produces an asymmetry consistent with the data. Comparison with the data allowed us to extract the relative sign and the magnitude of the vector and scalar diquark components of the quark wave function of the nucleon. These two quantities are essential in constraining QCD models of a nucleon. Overall, our conclusion is that the angular asymmetry of a hard elastic scattering of baryons provides a new venue in probing quark-gluon structure of baryons and should be considered as an important observable in constraining the theoretical models.

Carlos G. Granados; Misak M. Sargsian

2009-07-29T23:59:59.000Z

398

MHD Integrated Topping Cycle Project  

SciTech Connect

This fourteenth quarterly technical progress report of the MHD Integrated Topping Cycle Project presents the accomplishments during the period November 1, 1990 to January 31, 1991. Testing of the High Pressure Cooling Subsystem electrical isolator was completed. The PEEK material successfully passed the high temperature, high pressure duration tests (50 hours). The Combustion Subsystem drawings were CADAM released. The procurement process is in progress. An equipment specification and RFP were prepared for the new Low Pressure Cooling System (LPCS) and released for quotation. Work has been conducted on confirmation tests leading to final gas-side designs and studies to assist in channel fabrication.The final cathode gas-side design and the proposed gas-side designs of the anode and sidewall are presented. Anode confirmation tests and related analyses of anode wear mechanisms used in the selection of the proposed anode design are presented. Sidewall confirmation tests, which were used to select the proposed gas-side design, were conducted. The design for the full scale CDIF system was completed. A test program was initiated to investigate the practicality of using Avco current controls for current consolidation in the power takeoff (PTO) regions and to determine the cause of past current consolidation failures. Another important activity was the installation of 1A4-style coupons in the 1A1 channel. A description of the coupons and their location with 1A1 channel is presented herein.

Not Available

1992-02-01T23:59:59.000Z

399

Final TOPS Rpt-10pt.PDF  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

TECHNOLOGICAL OPPORTUNITIES TECHNOLOGICAL OPPORTUNITIES TO INCREASE THE PROLIFERATION RESISTANCE OF GLOBAL CIVILIAN NUCLEAR POWER SYSTEMS (TOPS) REPORT BY THE TOPS TASK FORCE OF THE NUCLEAR ENERGY RESEARCH ADVISORY COMMITTEE (NERAC) JANUARY 2001 i TABLE OF CONTENTS INTRODUCTORY NOTE .............................................................................................................iii EXECUTIVE SUMMARY .......................................................................................................ES-1 I. INTRODUCTION ..............................................................................................................1 A. Scope and Purpose ..................................................................................................1 B. The Potential Role of Nuclear Power ......................................................................2

400

A mean field theory for the cold quark gluon plasma applied to stellar structure  

SciTech Connect

An equation of state based on a mean-field approximation of QCD is used to describe the cold quark gluon plasma and also to study the structure of compact stars. We obtain stellar masses compatible with the pulsar PSR J1614-2230 that was determined to have a mass of (1.97 {+-} 0.04 M{sub Circled-Dot-Operator }), and the corresponding radius around 10-11 km.

Fogaca, D. A.; Navarra, F. S.; Franzon, B. [Instituto de Fisica, Universidade de Sao Paulo Rua do Matao, Travessa R, 187, 05508-090 Sao Paulo, SP (Brazil); Horvath, J. E. [Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao, 1226, 05508-090, Sao Paulo, SP (Brazil)

2013-03-25T23:59:59.000Z

Note: This page contains sample records for the topic "top quark mass" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Jet-dilepton conversion in spherical expanding quark-gluon plasma  

E-Print Network (OSTI)

We calculate the production of large mass dileptons from the jet-dilepton conversion in spherical expanding quark-gluon plasma at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies. The jet-dilepton conversion exceeds the thermal dilepton production and Drell-Yan process in the large mass region of 4.5 GeV$energies. The energy loss of jets in the hot and dense medium is also included.

Fu, Yong-Ping

2014-01-01T23:59:59.000Z

402

Jet-dilepton conversion in spherical expanding quark-gluon plasma  

E-Print Network (OSTI)

We calculate the production of large mass dileptons from the jet-dilepton conversion in spherical expanding quark-gluon plasma at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies. The jet-dilepton conversion exceeds the thermal dilepton production and Drell-Yan process in the large mass region of 4.5 GeV$energies. The energy loss of jets in the hot and dense medium is also included.

Yong-Ping Fu; Qin Xi

2014-10-19T23:59:59.000Z

403

Heavy Quark Production in ep Collisions  

E-Print Network (OSTI)

Heavy Quark Production in ep Collisions o Introduction o Charm Production o Beauty Production o in ep collisions 23 February 2007 2/17 Heavy Flavor Production Boson-Gluon Fusion, dominant process Hard of the proton: #12;G. Leibenguth, Heavy Quarks Production in ep collisions 23 February 2007 3/17 HERA, Electron

404

Recent advances in heavy quark theory  

SciTech Connect

Some recent developments in heavy quark theory are reviewed. Particular emphasis is given to inclusive weak decays of hadrons containing a b quark. The isospin violating hadronic decay D{sub s}* {yields} D{sub s}{sup pi}{sup 0} is also discussed.

Wise, M. [California Institute of Technology, Pasadena, CA (United States)

1997-01-01T23:59:59.000Z

405

Friction Coefficient for Quarks in Supergravity Duals  

E-Print Network (OSTI)

We study quarks moving in strongly-coupled plasmas that have supergravity duals. We compute the friction coefficient of strings dual to such quarks for general static supergravity backgrounds near the horizon. Our results also show that a previous conjecture on the bound has to be modified and higher friction coefficients can be achieved.

E. Antonyan

2006-11-22T23:59:59.000Z

406

Heavy quark thermodynamics in full QCD  

E-Print Network (OSTI)

We analyze the large-distance behaviour of static quark-anti-quark pair correlations in QCD. The singlet free energy is calculated and the entropy contribution to it is identified allowing us to calculate the excess internal energy. The free energy has a sharp drop in the critical region, leading to sharp peaks in both excess entropy and internal energy.

Konstantin Petrov; RBC-Bielefeld Collaboration

2007-01-22T23:59:59.000Z

407

Electric top drives gain wide industry acceptance  

SciTech Connect

Since its introduction, the top drive drilling system has gained acceptance as a productive and safe method for drilling oil and gas wells. Originally, the system was used mostly for offshore and higher cost land drilling, and it had to be installed as a permanent installation because of its enormous weight and size. Essentially, a top drive replaces the kelly and rotary table as the means of rotating drillpipe on oil, gas and geothermal rigs and is considered to be 15% to 40% more efficient than a kelly drive. Top drive systems allow the operator to drill and maintain directional orientation for triple stands and provide tripping efficiency because of the ability to ream and circulate with triple stands, to reduce the risk of stuck pipe or lost wells, and to improve well control and pipe handling safety. The paper describes electric top drives with DC motors, top drives with AC motors, top drives with permanent magnet motors, and top drives with permanent magnet brushless synchronous motors.

Riahi, M.L.

1998-05-01T23:59:59.000Z

408

Gamma rays from top-mediated dark matter annihilations  

SciTech Connect

Lines in the energy spectrum of gamma rays are a fascinating experimental signal, which are often considered ''smoking gun'' evidence of dark matter annihilation. The current generation of gamma ray observatories are currently closing in on parameter space of great interest in the context of dark matter which is a thermal relic. We consider theories in which the dark matter's primary connection to the Standard Model is via the top quark, realizing strong gamma ray lines consistent with a thermal relic through the forbidden channel mechanism proposed in the Higgs in Space Model. We consider realistic UV-completions of the Higgs in Space and related theories, and show that a rich structure of observable gamma ray lines is consistent with a thermal relic as well as constraints from dark matter searches and the LHC. Particular attention is paid to the one loop contributions to the continuum gamma rays, which can easily swamp the line signals in some cases, and have been largely overlooked in previous literature.

Jackson, C.B. [University of Texas at Arlington, Arlington, TX 76019 (United States); Servant, Géraldine [CERN Physics Department, Theory Division, CH-1211 Geneva 23 (Switzerland); Shaughnessy, Gabe [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Tait, Tim M.P. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Taoso, Marco, E-mail: geraldine.servant@cern.ch, E-mail: chris@uta.edu, E-mail: gshau@hep.wisc.edu, E-mail: ttait@uci.edu, E-mail: marco.taoso@cea.fr [Institut de Physique Théorique, CEA/Saclay, F-91191 Gif-sur-Yvette Cédex (France)

2013-07-01T23:59:59.000Z

409

EMMI Rapid Reaction Task Force Meeting on 'Quark Matter in Compact Star'  

E-Print Network (OSTI)

The recent measurement of two solar mass pulsars has initiated an intense discussion on its impact on our understanding of the high-density matter in the cores of neutron stars. A task force meeting was held from October 7-10, 2013 at the Frankfurt Institute for Advanced Studies to address the presence of quark matter in these massive stars. During this meeting, the recent oservational astrophysical data and heavy-ion data was reviewed. The possibility of pure quark stars, hybrid stars and the nature of the QCD phase transition were discussed and their observational signals delineated.

Buballa, Michael; Drago, Alessandro; Fraga, Eduardo; Haensel, Pawel; Mishustin, Igor; Pagliara, Giuseppe; Schaffner-Bielich, Jurgen; Schramm, Stefan; Sedrakian, Armen; Weber, Fridolin

2014-01-01T23:59:59.000Z

410

The Particle Adventure | What holds it together? | Quark confinement  

NLE Websites -- All DOE Office Websites (Extended Search)

Quark confinement Quark confinement Quark confinement Color-charged particles cannot be found individually. For this reason, the color-charged quarks are confined in groups (hadrons) with other quarks. These composites are color neutral. The development of the Standard Model's theory of the strong interactions reflected evidence that quarks combine only into baryons (three quark objects), and mesons (quark-antiquark objects), but not, for example, four-quark objects. Now we understand that only baryons (three different colors) and mesons (color and anticolor) are color-neutral. Particles such as ud or uddd that cannot be combined into color-neutral states are never observed. Color-Force Field The quarks in a given hadron madly exchange gluons. For this reason, physicists talk about the color-force field which consists of the gluons holding the bunch of quarks together.

411

The Particle Adventure | What holds it together? | Quarks emit gluons  

NLE Websites -- All DOE Office Websites (Extended Search)

holds it together? > Quarks emit gluons holds it together? > Quarks emit gluons Quarks emit gluons Color charge is always conserved. When a quark emits or absorbs a gluon, that quark's color must change in order to conserve color charge. For example, suppose a red quark changes into a blue quark and emits a red/antiblue gluon (the image below illustrates antiblue as yellow). The net color is still red. This is because - after the emission of the gluon - the blue color of the quark cancels with the antiblue color of the gluon. The remaining color then is the red color of the gluon. Quarks emit and absorb gluons very frequently within a hadron, so there is no way to observe the color of an individual quark. Within a hadron, though, the color of the two quarks exchanging a gluon will change in a way that keeps the bound system in a color-neutral state.

412

NERSC Supports 2013's Top Breakthroughs  

NLE Websites -- All DOE Office Websites (Extended Search)

Supports 2013's Supports 2013's Top Breakthroughs NERSC Supports Top Breakthroughs of 2013 December 20, 2013 | Tags: Astrophysics, Hopper, PDSF, Physics Linda Vu, +1 510 495 2402, lvu@lbl.gov Research supported by NERSC is being honored by end-of-year reviews in two leading magazines: Physics World and WIRED. The IceCube South Pole Neutrino Observatory was notably named to both lists, being honored as the most important discovery by Physics World. Three of Physics World's top 10 breakthroughs of 2013 went to discoveries that used NERSC resources. In addition to the IceCube South Pole Neutrino Observatory's top honor, "breakthrough of the year," the magazine named the European Space Agency's European Planck space telescope, which revealed new information about the age and composition of the universe; and the South

413

LANL named 2010 top corporate volunteer organization  

NLE Websites -- All DOE Office Websites (Extended Search)

2010 top corporate volunteer organization 2010 top corporate volunteer organization LANL named 2010 top corporate volunteer organization The Laboratory ranked ahead of dozens of other qualifying companies with 10,000 or more employees. May 18, 2011 Building and painting birdhouses with children in Santa Fe Building and painting birdhouses with children in Santa Fe. Contact Steve Sandoval Communicatons Office (505) 665-9206 Email LOS ALAMOS, New Mexico, May 18, 2011-Los Alamos National Laboratory has earned an award as the top corporate volunteer organization among large employers in VolunteerMatch's network of more than 140 leading companies and brands. Debbi Wersonick of Los Alamos National Laboratory's Community Programs Office, coordinator of volunteer programs at the Laboratory, traveled to Chicago to receive the Corporate Volunteer Program of the Year Award, given

414

How to rank the top500 list?  

E-Print Network (OSTI)

HOW TO RANK THE TOP500 LIST? Lin-Wang Wang Computationalone question emerged: how to rank the computers according tothe first 10 computers. Old rank (based on speed) New rank (

Wang, Lin-Wang

2008-01-01T23:59:59.000Z

415

Top Low- or No-Cost Improvements  

Energy.gov (U.S. Department of Energy (DOE))

This presentation describes the top low- or no-cost projects to improve energy efficiency as identified in energy assessments performed by DOE and by the Industrial Assessment Centers.

416

Top ECMs for Labs and Data Centers  

Energy.gov (U.S. Department of Energy (DOE))

Presentation—given at at the Fall 2012 Federal Utility Partnership Working Group (FUPWG) meeting—covers the top energy conservation measures (ECMs) laboratories and data centers can apply for energy efficiency and savings.

417

Diesel prices top $4 per gallon  

U.S. Energy Information Administration (EIA) Indexed Site

Diesel prices top 4 per gallon The U.S. average retail price for on-highway diesel fuel surpassed the four dollar mark for the first time this year. Prices rose to 4.02 a gallon...

418

Enter Keyword(s) Today's Ecology Top  

E-Print Network (OSTI)

Enter Keyword(s) Today's Ecology Top News OMG's Business Ecology Initiative BEI Reaches 250 Member Advertisement Ecology Topics Botany Climate Research Ecology Environment Environmental Microbiology Environmental Monitoring Environmental Research Fisheries Research Marine Biology Meteorology Molecular Ecology

419

JLab Cluster Tops 100 Teraflops | Jefferson Lab  

NLE Websites -- All DOE Office Websites (Extended Search)

JLab Cluster Tops 100 Teraflops NEWPORT NEWS, VA, Oct. 14 - The fastest computer system in Hampton Roads has booted up with more than 100 Teraflops of processing power. Located at...

420

HUNTING THE QUARK GLUON PLASMA.  

SciTech Connect

The U.S. Department of Energy's Relativistic Heavy Ion Collider (RHIC) construction project was completed at BNL in 1999, with the first data-taking runs in the summer of 2000. Since then the early measurements at RHIC have yielded a wealth of data, from four independent detectors, each with its international collaboration of scientists: BRAHMS, PHENIX, PHOBOS, and STAR [1]. For the first time, collisions of heavy nuclei have been carried out at colliding-beam energies that have previously been accessible only for high-energy physics experiments with collisions of ''elementary'' particles such as protons and electrons. It is at these high energies that the predictions of quantum chromodynamics (QCD), the fundamental theory that describes the role of quarks and gluons in nuclear matter, come into play, and new phenomena are sought that may illuminate our view of the basic structure of matter on the sub-atomic scale, with important implications for the origins of matter on the cosmic scale. The RHIC experiments have recorded data from collisions of gold nuclei at the highest energies ever achieved in man-made particle accelerators. These collisions, of which hundreds of millions have now been examined, result in final states of unprecedented complexity, with thousands of produced particles radiating from the nuclear collision. All four of the RHIC experiments have moved quickly to analyze these data, and have begun to understand the phenomena that unfold from the moment of collision as these particles are produced. In order to provide benchmarks of simpler interactions against which to compare the gold-gold collisions, the experiments have gathered comparable samples of data from collisions of a very light nucleus (deuterium) with gold nuclei, as well as proton-proton collisions, all with identical beam energies and experimental apparatus. The early measurements have revealed compelling evidence for the existence of a new form of nuclear matter at extremely high density and temperature--a medium in which the predictions of QCD can be tested, and new phenomena explored, under conditions where the relevant degrees of freedom, over nuclear volumes, are expected to be those of quarks and gluons, rather than of hadrons. This is the realm of the quark gluon plasma, the predicted state of matter whose existence and properties are now being explored by the RHIC experiments.

LUDLAM, T.; ARONSON, S.

2005-04-11T23:59:59.000Z

Note: This page contains sample records for the topic "top quark mass" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Nucleon electromagnetic form factors from twisted mass lattice QCD  

E-Print Network (OSTI)

Results on the electromagnetic form factors of the nucleon using twisted mass fermion configurations are presented. These include a gauge field ensemble simulated with two degenerate light quarks yielding a pion mass of around 130 MeV, as well as two ensembles that include strange and charm quarks in the sea yielding pion masses of 210 MeV and 373 MeV. Details of the methods used and systematic errors are discussed, such as noise reduction techniques and the effect of excited states contamination.

Abdou Abdel-Rehim; Constantia Alexandrou; Martha Constantinou; Kyriakos Hadjiyiannakou; Karl Jansen; Giannis Koutsou

2015-01-07T23:59:59.000Z

422

Active QuarkNet Centers  

NLE Websites -- All DOE Office Websites (Extended Search)

first active year) first active year)       QuarkNet Home - Information - Calendar - Contacts - Projects - Forms: EoI - Teachers Institution Contact e-mail Year Brown, Northeastern & Brandeis Universities Richard Dower - rick.dower@roxburylatin.org 1999 Fermilab & University of Chicago Chris Stoughton - stoughto@fnal.gov 1999 Florida State University Horst Wahl - wahl@hep.fsu.edu 1999 Indiana University Rick Van Kooten - rickv@paoli.physics.indiana.edu 1999 University of California - Santa Cruz Steve Ritz - ritz@scipp.ucsc.edu 1999 University of Notre Dame Dan Karmgard - Karmgard.1@nd.edu 1999 University of Oklahoma Michael Strauss - strauss@mail.nhn.ou.edu 1999 University of Rochester Kevin McFarland - ksmcf@pas.rochester.edu 1999

423

Heavy quark physics from SLD  

SciTech Connect

This report covers preliminary measurements from SLD on heavy quark production at the Z{sup 0}, using 150,000 hadronic Z{sup 0} decays accumulated during the 1993-1995 runs. A measurement of R{sub b} with a lifetime double tag is presented. The high electron beam polarization of the SLC is employed in the direct measurement of the parity-violating parameters A{sub b} and A{sub c} by use of the left-right forward-backward asymmetry. The lifetimes of B{sup +} and B{sup 0} mesons have been measured by two analyses. The first identifies semileptonic decays of B mesons with high (p,p{sub t}) leptons; the second analysis isolates a sample of B meson decays with a two-dimensional impact parameter tag and reconstructs the decay length and charge using a topological vertex reconstruction method.

Messner, R. [Stanford Univ., CA (United States)

1997-01-01T23:59:59.000Z

424

Topological susceptibility from twisted mass fermions using spectral projectors  

E-Print Network (OSTI)

We discuss the computation of the topological susceptibility using the method of spectral projectors and dynamical twisted mass fermions. We present our analysis concerning the O(a)-improvement of the topological susceptibility and we show numerical results for Nf=2 and Nf=2+1+1 flavours, performing a study of the quark mass dependence in terms of leading order chiral perturbation theory.

Krzysztof Cichy; Elena Garcia-Ramos; Karl Jansen; Andrea Shindler

2013-12-12T23:59:59.000Z

425

Local coherence and deflation of the low quark modes in lattice QCD  

E-Print Network (OSTI)

The spontaneous breaking of chiral symmetry in QCD is known to be linked to a non-zero density of eigenvalues of the massless Dirac operator near the origin. Numerical studies of two-flavour QCD now suggest that the low quark modes are locally coherent to a certain extent. As a consequence, the modes can be simultaneously deflated, using local projectors, with a total computational effort proportional to the lattice volume (rather than its square). Deflation has potentially many uses in lattice QCD. The technique is here worked out for the case of quark propagator calculations, where large speed-up factors and a flat scaling behaviour with respect to the quark mass are achieved.

Martin Lüscher

2007-06-15T23:59:59.000Z

426

Building Technologies Office: Building America's Top Innovations Advance  

NLE Websites -- All DOE Office Websites (Extended Search)

America's Top America's Top Innovations Advance High Performance Homes to someone by E-mail Share Building Technologies Office: Building America's Top Innovations Advance High Performance Homes on Facebook Tweet about Building Technologies Office: Building America's Top Innovations Advance High Performance Homes on Twitter Bookmark Building Technologies Office: Building America's Top Innovations Advance High Performance Homes on Google Bookmark Building Technologies Office: Building America's Top Innovations Advance High Performance Homes on Delicious Rank Building Technologies Office: Building America's Top Innovations Advance High Performance Homes on Digg Find More places to share Building Technologies Office: Building America's Top Innovations Advance High Performance Homes on AddThis.com...

427

Water Management Guide - Building America Top Innovation | Department...  

Energy Savers (EERE)

Water Management Guide - Building America Top Innovation Water Management Guide - Building America Top Innovation Cover of the EEBA Water Management Guide. As energy codes and...

428

Tankless Gas Water Heater Performance - Building America Top...  

Energy Savers (EERE)

Tankless Gas Water Heater Performance - Building America Top Innovation Tankless Gas Water Heater Performance - Building America Top Innovation This photo shows a hot water heater...

429

The Business Case for Fuel Cells 2011: Energizing America's Top...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

1: Energizing America's Top Companies The Business Case for Fuel Cells 2011: Energizing America's Top Companies This report profiles a select group of nationally recognizable...

430

Next Generation Advanced Framing - Building America Top Innovation...  

Energy Savers (EERE)

Next Generation Advanced Framing - Building America Top Innovation Next Generation Advanced Framing - Building America Top Innovation This photo shows advanced framing on a rim...

431

Heavy quark diffusion from the lattice  

SciTech Connect

We study the diffusion of heavy quarks in the quark gluon plasma using the Langevin equations of motion and estimate the contribution of the transport peak to the Euclidean current-current correlator. We show that the Euclidean correlator is remarkably insensitive to the heavy quark diffusion coefficient and give a physical interpretation of this result using the free streaming Boltzmann equation. However if the diffusion coefficient is smaller than {approx}1/({pi}T), as favored by RHIC phenomenology, the transport contribution should be visible in the Euclidean correlator. We outline a procedure to isolate this contribution.

Petreczky, Peter; Teaney, Derek [Nuclear Theory Group, Department of Physics, Brookhaven National Laboratory, Upton, New York 11973 (United States); Department of Physics and Astronomy, SUNY at Stony Brook, Stony Brook, New York 11764 (United States)

2006-01-01T23:59:59.000Z

432

Fractional electric charge and quark confinement  

E-Print Network (OSTI)

Owing to their fractional electric charges, quarks are blind to transformations that combine a color center phase with an appropriate electromagnetic one. Such transformations are part of a global $Z_6$-like center symmetry of the Standard Model that is lost when quantum chromodynamics (QCD) is treated as an isolated theory. This symmetry and the corresponding topological defects may be relevant to non-perturbative phenomena such as quark confinement, much like center symmetry and ordinary center vortices are in pure SU($N$) gauge theories. Here we report on our investigations of an analogous symmetry in a 2-color model with dynamical Wilson quarks carrying half-integer electric charge.

Sam R. Edwards; André Sternbeck; Lorenz von Smekal

2012-02-07T23:59:59.000Z

433

Heavy quark production from jet conversions in a quark-gluon plasma  

SciTech Connect

Recently, it has been demonstrated that the chemical composition of jets in heavy ion collisions is significantly altered compared to the jets in the vacuum. This signal can be used to probe the medium formed in nuclear collisions. In this study we investigate the possibility that fast light quarks and gluons can convert to heavy quarks when passing through a quark-gluon plasma. We study the rate of light to heavy jet conversions in a consistent Fokker-Planck framework and investigate their impact on the production of high-p{sub T} charm and bottom quarks at the Relativistic Heavy Ion Collider and the Large Hadron Collider.

Liu, W. [Cyclotron Institute and Physics Department, Texas A and M University, College Station, Texas 77843-3366 (United States); Fries, R. J. [Cyclotron Institute and Physics Department, Texas A and M University, College Station, Texas 77843-3366 (United States); RIKEN/BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973 (United States)

2008-09-15T23:59:59.000Z

434

Accelerator probes for new stable quarks  

E-Print Network (OSTI)

The nonbaryonic dark matter of the Universe can consist of new stable double charged particles $O^{--}$, bound with primordial helium in heavy neutral O-helium (OHe)"atoms" by ordinary Coulomb interaction. O-helium dark atoms can play the role of specific nuclear interacting dark matter and provide solution for the puzzles of dark matter searches. The successful development of composite dark matter scenarios appeals to experimental search for the charged constituents of dark atoms. If $O^{--}$ is a "heavy quark cluster" $\\bar U \\bar U \\bar U$, its production at accelerators is virtually impossible and the strategy of heavy quark search is reduced to search for heavy stable hadrons, containing only single heavy quark (or antiquark). Estimates of production cross section of such particles at LHC are presented and the experimental signatures for new stable quarks are outlined.

Konstantin M. Belostky; Maxim Yu. Khlopov; Konstantin I. Shibaev

2011-11-15T23:59:59.000Z

435

Dilepton as a Possible Signature for the Baryon-Rich Quark-Gluon Plasma  

E-Print Network (OSTI)

to the dilepton yield at invariant masses between 2m?and 1 GeV. The total dilepton yield in this invariant mass region increases with the incident energy of the collision, but a saturation is seen once a baryon-rich quark-gluon plasma is formed in the initial... of 2m to about 1 GeV, where m is the mass of pion. It is also found in Refs. 15-17 that the modification of the pion dispersion relation by the dense nuclear matter because of the strong p-wave mN interac- tion can lead to an enhanced production...

Xia, L. H.; Ko, Che Ming; Li, C. T.

1990-01-01T23:59:59.000Z

436

Hunting the Quark Gluon Plasma ASSESSMENTS  

NLE Websites -- All DOE Office Websites (Extended Search)

Hunting the Quark Gluon Plasma Hunting the Quark Gluon Plasma ASSESSMENTS BY THE EXPERIMENTAL COLLABORATIONS Relativistic Heavy Ion Collider (RHIC) * Brookhaven National Laboratory, Upton, NY 11974-5000 RESULTS FROM THE FIRST 3 YEARS AT RHIC managed for the U.S. Department of Energy by Brookhaven Science Associates, a company founded by Stony Brook University and Battelle April 18, 2005 BNL -73847-2005 Formal Report

437

Shear viscosity of the quark matter  

E-Print Network (OSTI)

We discuss shear viscosity of the quark matter by using Kubo formula. The shear viscosity is calculated in the framework of the quasi-particle RPA for the Nambu-Jona-Lasinio model. We obtain a formula that the shear viscosity is expressed by the quadratic form of the quark spectral function in the chiral symmetric phase. The magnitude of the shear viscosity is discussed assuming the Breit-Wigner type for the spectral function.

Masaharu Iwasaki; Hiromasa Ohnishi; Takahiko Fukutome

2007-03-26T23:59:59.000Z

438

Magnetism and superconductivity in quark matter  

E-Print Network (OSTI)

Magnetic properties of quark matter and its relation to the microscopic origin of the magnetic field observed in compact stars are studied. Spontaneous spin polarization appears in high-density region due to the Fock exchange term, which may provide a scenario for the behaviors of magnetars. On the other hand, quark matter becomes unstable to form spin density wave in the moderate density region, where restoration of chiral symmetry plays an important role. Coexistence of magnetism and color superconductivity is also discussed.

T. Tatsumi; E. Nakano; K. Nawa

2005-06-01T23:59:59.000Z

439

Search for Higgs Bosons Produced in Association with b-Quarks  

We present a search for neutral Higgs bosons ? decaying into bb?, produced in association with b quarks in ppb? collisions. This process could be observable in supersymmetric models with high values of tan ?. The event sample corresponds to 2.6 fb-1 of integrated luminosity collected with the CDF II detector at the Fermilab Tevatron collider. We search for an enhancement in the mass of the two leading jets in events with three jets identified as coming from b quarks using a displaced vertex algorithm. A data-driven procedure is used to estimate the dijet mass spectrum of the nonresonant multijet background. The contributions of backgrounds and a possible Higgs boson signal are determined by a two-dimensional fit of the data, using the dijet mass together with an additional variable which is sensitive to the flavor composition of the three tagged jets. We set mass-dependent limits on ?(ppb? = ?b) x ?(?= bb?) which are applicable for a narrow scalar particle ? produced in association with b quarks. We also set limits on tan ? in supersymmetric Higgs models including the effects of the Higgs boson wi