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Parton Distributions and Spin-Orbital Correlations

Description: In this talk, I summarize a recent study showing that the large-x parton distributions contain important information on the quark orbital angular momentum of nucleon. This contribution could explain the conflict between the experimental data and the theory predictions for the polarized quark distributions. Future experiments at JLab shall provide further test for our predictions.
Date: September 24, 2007
Creator: Yuan, Feng
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Partner: UNT Libraries Government Documents Department
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Progress in Finite Temperature Lattice Qcd.

Description: I review recent progress in finite temperature lattice calculations, including the determination of the transition temperature, equation of state, screening of static quarks and meson spectral functions.
Date: June 24, 2007
Creator: Petreczky, P.
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Partner: UNT Libraries Government Documents Department
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Measurement of the strange quark distribution function in W + charm quark events

Description: We investigate the prospects of measuring the strange quark distribution function at the Tevatron, using W plus charm quark events. The W plus charm quark events. The W plus charm quark signal produced by strange quark - gluon fusion, sg {yields} W {sup {minus}}c and {bar s}g {yields} W {sup +} W+ charm quark cross section to the parametrization of the strange quark distribution function, and evaluate the various background processes. The different prospects of tagging the charm quark with the … more
Date: June 24, 1993
Creator: Baur, U.; Keller, S.; Halzen, F.; Riesselmann, K. & Mangano, M. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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LATTICE QCD AT HIGH TEMPERATURE AND THE QGP.

Description: We review recent progress in studies of bulk thermodynamics of strongly interacting matter, present results on the QCD equation of state and discuss the status of studies of the phase diagram at non-vanishing quark chemical potential.
Date: October 24, 2005
Creator: KARSCH, F.
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Partner: UNT Libraries Government Documents Department
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Dihadron correlations at high pT

Description: Jet quenching in the matter created in high energy nucleus/nucleus collisions provides a tomographic tool to probe the medium properties. Recent experimental results from the Relativistic Heavy-Ion Collider (RHIC) on characterization of jet production via dihadron correlations at high transverse momentum are reviewed. Expectations from the dihadron measurements for the lower energy {radical}s{sub NN} = 62.4 GeV RHIC run are discussed.
Date: July 24, 2004
Creator: Filimonov, Kirill
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Partner: UNT Libraries Government Documents Department
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Searches for physics beyond the standard model in ttbar events

Description: The top quark is currently only observed at the Tevatron, where it is mainly produced in t{bar t} pairs. Due to the very high mass of the top quark compared to the other quarks and the gauge bosons, it is expected to play a special role in electroweak symmetry breaking. Therefore it might be especially sensitive to new physics. Measurements of various production and decay quantities of the top quark could lead to discoveries of physics beyond the standard model. Several such measurements were p… more
Date: February 24, 2004
Creator: Merkel, P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Measurements of Z{sup 0} to Heavy-quark couplings at SLD

Description: We present measurements of Z{sup 0} to heavy-quark coupling electroweak parameters, R{sub b}, R{sub c}, and parity-violation parameter A{sub c}, from SLD. The measurements are based on approximately 550k hadronic Z{sup 0} events collected in 1993-98. Obtained preliminary results of R{sub b} and R{sub c} measurements are R{sub b} = 0.2159 {+-} 0.0014 {+-} 0.0014 and R{sub c} = 0.1685 {+-} 0.0047 {+-} 0.0043. In the A{sub c} measurement, we use four methods to determine the initial-quark charge: … more
Date: May 24, 1999
Creator: Iwasaki, Masako
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The Form Factors of the Gauge-Invariant Three-Gluon Vertex

Description: The gauge-invariant three-gluon vertex obtained from the pinch technique is characterized by thirteen nonzero form factors, which are given in complete generality for unbroken gauge theory at one loop. The results are given in d dimensions using both dimensional regularization and dimensional reduction, including the effects of massless gluons and arbitrary representations of massive gauge bosons, fermions, and scalars. We find interesting relations between the functional forms of the contribut… more
Date: February 24, 2006
Creator: Binger, Michael & Brodsky, Stanley J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Single Transverse-Spin Asymmetries at Large-x

Description: The large-x behavior of the transverse-momentum dependent quark distributions is analyzed in the factorization-inspired perturbative QCD framework, particularly for the naive time-reversal-odd quark Sivers function which is responsible for the single transverse-spin asymmetries in various semi-inclusive hard processes. By examining the dominant hard gluon exchange Feynman diagrams, and using the resulting power counting rule, we find that the Sivers function has power behavior (1-x){sup 4} at x… more
Date: October 24, 2006
Creator: Brodsky, Stanley J. & Yuan, Feng
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Measurement of |V(Ub)| Using Inclusing Semileptonic B Meson Decays

Description: This dissertation presents a measurement of the CKM matrix element |V{sub ub}| made with a sample of 64 million B{bar B} events collected with the BABAR detector. Using Heavy Quark theory, we combine the observed yield of leptons from semileptonic B decay in the electron energy interval 2.1-2.6 GeV with a recent CLEO measurement of the B {yields} X{sub s}{gamma} photon spectrum to find |V{sub ub}| = (4.25 {+-} 0.35 {+-} 0.45 {+-} 0.20) x 10{sup -3}, where the first uncertainty is experimental a… more
Date: March 24, 2006
Creator: Kim, Hojeong
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Rare B Decays

Description: Recent results from Belle and BaBar on rare B decays involving flavor-changing neutral currents or purely leptonic final states are presented. Measurements of the CP asymmetries in B {yields} K*{gamma} and b {yields} s{gamma} are reported. Also reported are updated limits on B{sup +} {yields} K{sup +}{nu}{bar {nu}}, B{sup +} {yields} {tau}{sup +}{nu}, B{sup +} {yields} {mu}{sup +}{nu} and the recent measurement of B {yields} X{sub s}{ell}{sup +}{ell}{sup -}.
Date: February 24, 2006
Creator: Jackson, P.D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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QCD THERMODYNAMICS WITH AN ALMOST REALISTIC QUARK MASS SPECTRUM.

Description: 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 int… more
Date: October 24, 2005
Creator: SCHMIDT, C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Top physics at CDF

Description: Precision studies of top quark properties are a primary goal of the Run II physics program at the Fermilab Tevatron. Marking the first stages of this program, the CDF collaboration presents recent results on top pair production cross section, single top physics and top mass, using between 109 and 200 pb{sup -1} of Run II data.
Date: June 24, 2004
Creator: Thom, Julia
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Partner: UNT Libraries Government Documents Department
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B-factory signals for a warped extra dimension

Description: We study predictions for B-physics in a class of models, recently introduced, with a non-supersymmetric warped extra dimension. In these models few ({approx} 3) TeV Kaluza-Klein masses are consistent with electroweak data due to bulk custodial symmetry. Furthermore, there is an analog of GIM mechanism which is violated by the heavy top quark (just as in SM) leading to striking signals at B-factories: (1) New Physics (NP) contributions to {Delta}F = 2 transitions are comparable to SM. This impli… more
Date: August 24, 2004
Creator: Agashe, Kaustubh; Perez, Gilad & Soni, Amarjit
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Top quark physics

Description: The top quark, when it was finally discovered at Fermilab in 1995 completed the three-generation structure of the Standard Model (SM) and opened up the new field of top quark physics. Viewed as just another SM quark, the top quark appears to be a rather uninteresting species. Produced predominantly, in hadron-hadron collisions, through strong interactions, it decays rapidly without forming hadrons, and almost exclusively through the single mode t {r_arrow} Wb. The relevant CKM coupling V{sub tb… more
Date: March 24, 2000
Creator: Ahmadov, A.; Azuelos, G.; Bauer, U.; Belyaev, A.; Berger, E. L.; Sullivan, Z. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Continuum strong QCD: Confinement and dynamical chiral symmetry breaking

Description: Continuum strong QCD is the application of models and continuum quantum field theory to the study of phenomena in hadronic physics, which includes; e.g., the spectrum of QCD bound states and their interactions. Herein the author provides a Dyson-Schwinger equation perspective, focusing on qualitative aspects of confinement and dynamical chiral symmetry breaking in cold, sparse QCD, and also elucidating consequences of the axial-vector Ward-Takahashi identity and features of the heavy-quark limi… more
Date: July 24, 2000
Creator: Roberts, C. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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