National Library of Energy BETA

Sample records for quarks und leptonen

  1. Quark Masses

    SciTech Connect (OSTI)

    Gasser, Juerg

    2005-10-26

    In my talk, I reviewed some basic aspects of quark masses: what do they mean, how can they be determined, what is our present knowledge on them. The talk was addressed to non specialists in the field, and so is this write up.

  2. Quark matter symmetry energy and quark stars

    SciTech Connect (OSTI)

    Chu, Peng-Cheng; Chen, Lie-Wen

    2014-01-10

    We extend the confined-density-dependent-mass (CDDM) model to include isospin dependence of the equivalent quark mass. Within the confined-isospin-density-dependent-mass (CIDDM) model, we study the quark matter symmetry energy, the stability of strange quark matter, and the properties of quark stars. We find that including isospin dependence of the equivalent quark mass can significantly influence the quark matter symmetry energy as well as the properties of strange quark matter and quark stars. While the recently discovered large mass pulsars PSR J1614–2230 and PSR J0348+0432 with masses around 2 M {sub ☉} cannot be quark stars within the CDDM model, they can be well described by quark stars in the CIDDM model. In particular, our results indicate that the two-flavor u-d quark matter symmetry energy should be at least about twice that of a free quark gas or normal quark matter within the conventional Nambu-Jona-Lasinio model in order to describe PSR J1614–2230 and PSR J0348+0432 as quark stars.

  3. Single Top Quark

    SciTech Connect (OSTI)

    Heidi Schellman and Ann Heinson

    2009-03-12

    Fermilab researchers Heidi Schellman and Ann Heinson take a whimsical look at the recent announcement of the discovery of the single top quark, by Fermilab's CDF and DZero experiments.

  4. Quark-gluon correlation functions relevant to single transverse...

    Office of Scientific and Technical Information (OSTI)

    FUNCTIONS; GLUONS; NUCLEONS; QUARK MODEL; QUARK-GLUON INTERACTIONS; QUARKS; SPIN ANGULAR MOMENTUM; BARYONS; BOSONS; COMPOSITE MODELS; ELEMENTARY PARTICLES; FERMIONS; ...

  5. Cold quark matter in compact stars

    SciTech Connect (OSTI)

    Franzon, B.; Fogaca, D. A.; Navarra, F. S.; Horvath, J. E.

    2013-03-25

    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.

  6. The Discovery of the Top Quark

    DOE R&D Accomplishments [OSTI]

    Sinervo, P.K.

    1995-12-01

    The top quark and the Higgs boson are the heaviest elementary particles predicted by the standard model. The four lightest quark flavours, the up, down, strange and charm quarks, were well-established by the mid-1970's. The discovery in 1977 of the {Tau} resonances, a new family of massive hadrons, required the introduction of the fifth quark flavour. Experimental and theoretical studies have indicated that this quark also has a heavier partner, the top quark.

  7. Thermalization of heavy quarks in the quark-gluon plasma

    SciTech Connect (OSTI)

    Hees, Hendrik van; Rapp, Ralf

    2005-03-01

    Charm- and bottom-quark rescattering in a quark-gluon plasma (QGP) is investigated with the objective of assessing the approach toward thermalization. Employing a Fokker-Planck equation to approximate the collision integral of the Boltzmann equation we augment earlier studies based on perturbative parton cross sections by introducing resonant heavy-light quark interactions. The latter are motivated by recent QCD lattice calculations that indicate the presence of 'hadronic' states in the QGP. We model these states by colorless (pseudo-) scalar and (axial-) vector D and B mesons within a heavy-quark effective theory framework. We find that the presence of these resonances at moderate QGP temperatures substantially accelerates the kinetic equilibration of c quarks as compared to using perturbative interactions. We also comment on consequences for D-meson observables in ultrarelativistic heavy-ion collisions.

  8. Quark Gluon Plasma

    SciTech Connect (OSTI)

    Lincoln, Don

    2015-05-07

    Matter is malleable and can change its properties with temperature. This is most familiar when comparing ice, liquid water and steam, which are all different forms of the same thing. However beyond the usual states of matter, physicists can explore other states, both much colder and hotter. In this video, Fermilab’s Dr. Don Lincoln explains the hottest known state of matter – a state that is so hot that protons and neutrons from the center of atoms can literally melt. This form of matter is called a quark gluon plasma and it is an important research topic being pursued at the LHC.

  9. Press Pass - Press Release - Single top quark

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

    Graphics and photos are available at: http:www.fnal.govpubpresspassimagesSingle-Top-Quark-2009.html Fermilab collider experiments discover rare single top quark Batavia, ...

  10. Quark confinement and hadronic interactions

    SciTech Connect (OSTI)

    Lenz, F.; Londergan, J. T.; Moniz, Ernest J.; Rosenfelder, R.; Stingl, M.; Yazaki, K.

    1986-08-01

    A study of quark models for many-hadron systems is presented. The starting point in the construction of these nonrelativistic models is a proper formal definition of the concept of color singlet and nonsinglet clusters in a multiquark system which respects the exchange symmetry of the quarks. This definition provides a natural way to impose saturation of the confining forces.

  11. Unexpected manifestation of quark condensation

    SciTech Connect (OSTI)

    Zinovjev, G. M.; Molodtsov, S. V.

    2015-05-15

    A comparative analysis of some quark ensembles governed by a four-fermion interaction is performed. Arguments in support of the statement that the presence of a gas-liquid phase transition is a feature peculiar to them are adduced. The instability of small quark droplets is discussed and is attributed to the formation of a chiral soliton. The stability of baryon matter is due to a mixed phase of the vacuum and baryon matter.

  12. Quarks Pair Up in Protons (and Neutrons) | Jefferson Lab

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

    Quarks Pair Up in Protons (and Neutrons) Graph of up quarkdown quark contributions Researchers have published intriguing new observations for how the different kinds of quarks ...

  13. Hormann Energie und Umwelt | Open Energy Information

    Open Energy Info (EERE)

    Hormann Energie und Umwelt Jump to: navigation, search Name: Hormann Energie und Umwelt Place: Munchen, Germany Sector: Geothermal energy Product: Munchen-based energy and...

  14. String model for spinning quark jets

    SciTech Connect (OSTI)

    Artru, X.; Belghobsi, Z.

    2012-06-27

    A string model of quark hadronization, taking the quark spin degree of freedom into account, is proposed. The method for using the model in a Monte-Carlo code for jet generation is given.

  15. Heavy hadrons in quark-gluon plasma

    SciTech Connect (OSTI)

    Narodetskii, I. M. Simonov, Yu. A.; Veselov, A. I.

    2011-03-15

    We use the nonperturbative quark-antiquark potential derived within the Field Correlator Method and the screened Coulomb potential to calculate binding energies and melting temperatures of heavy mesons and baryons in the deconfined phase of quark-gluon plasma.

  16. Structure functions and intrinsic quark orbital motion

    SciTech Connect (OSTI)

    Zavada, Petr

    2007-06-13

    Covariant version of the quark model is studied. It is shown how the polarized and unpolarized structure functions depend on the quark intrinsic motion. The important role of the quark orbital momentum, by which the intrinsic motion is generated, appears as a direct consequence of the covariant description. At the same time, the procedure for obtaining 3D quark momentum distribution from the structure functions is suggested.

  17. Effective hadron theories from a quark model

    SciTech Connect (OSTI)

    Gardner, S.; Moniz, Ernest J.

    1987-12-01

    In the context of the quark exchange model of Lenz et al., effective hadron theories are constructed and the resulting physical observables compared to their ''experimental'' values as defined by the calculations using the exact quark model operators. This model study illustrates convergence issues for an effective hadron basis in a quark model in which all physical observables can be computed exactly.

  18. A relativistic constituent quark model

    SciTech Connect (OSTI)

    Schlumpf, F.

    1993-08-01

    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.

  19. Observation of the Top Quark

    DOE R&D Accomplishments [OSTI]

    Kim, S. B.

    1995-08-01

    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}).

  20. Heavy quark production at CDF

    SciTech Connect (OSTI)

    C. Paus

    2002-11-13

    The contribution summarizes the latest results from CDF on heavy quark production. Results from top, bottom and charm production are included. Some new analysis using Run I (1991-1994) data have become available. More importantly there are a number of results using Run II data which began in April 2001. The data indicate the potential of CDF for bottom and charm production physics in the near future.

  1. Cooking Up Hot Quark Soup

    DOE R&D Accomplishments [OSTI]

    Walsh, Karen McNulty

    2011-03-28

    Near-light-speed collisions of gold ions provide a recipe for in-depth explorations of matter and fundamental forces. The Relativistic Heavy Ion Collider (RHIC) has produced the most massive antimatter nucleus ever discovered—and the first containing an anti-strange quark. The presence of strange antimatter makes this antinucleus the first to be entered below the plane of the classic Periodic Table of Elements, marking a new frontier in physics.

  2. Measurements of Top Quark Properties

    SciTech Connect (OSTI)

    Cerrito, Lucio

    2009-05-01

    Preliminary results on the measurement of four selected properties of the top quark are presented. The relative fraction of t{bar t} production through gluon fusion has been measured in the t{bar t} dilepton decay channel by the CDF Collaboration as F{sub gg} = 0.53{sub -0.38}{sup +0.36}. Using an integrated luminosity of 2.7 fb{sup -1} collected with the CDF II detector, we also determine the t{bar t} differential cross section with respect to values up to {approx}1 TeV of the t{bar t} invariant mass. We present a model-independent measurement of the helicity of W bosons produced in top quark decays, using an integrated luminosity of up to 2.7 fb{sup -1} collected by the D0 detector, and find the fraction of longitudinal W bosons f{sub 0} = 0.49 {+-} 0.14, and the fraction of right-handed W bosons f{sub +} = 0.11 {+-} 0.08. Finally, we measure the parton level forward-backward asymmetry of pair produced top quarks using an integrated luminosity of 3.2 fb{sup -1} collected with the CDF II detector, and find A{sub FB} = 0.19 {+-} 0.07. All results are consistent with the predictions of the standard model.

  3. Quarks in the looking glass | Jefferson Lab

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

    Quarks in the looking glass 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 the floor of the hall, the two High Resolution Spectrometers are shown with their shield house doors (white) open. Photo: Jefferson Lab NEWPORT NEWS, VA, Feb. 5, 2014 - From matching wings on butterflies to the repeating six-point pattern of snowflakes, symmetries echo through nature, even

  4. Top quark mass measurements at CDF

    SciTech Connect (OSTI)

    Maki, Tuula; /Helsinki U. /Helsinki Inst. of Phys.

    2007-10-01

    The top quark mass is interesting both as a fundamental parameter of the standard model as well as an important input to precision electroweak tests. The CDF Collaboration has measured the top quark mass with high precision in all decay channels with complementary methods. A combination of the results from CDF gives a top quark mass of 170.5{+-}1.3(stat.){+-}1.8(syst.) GeV/c{sup 2}.

  5. Top Quark Production Asymmetries AFBt and AFBl

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

    Berger, Edmond L.; Cao, Qing-Hong; Chen, Chuan-Ren; Yu, Jiang-Hao; Zhang, Hao

    2012-02-14

    A large forward-backward asymmetry is seen in both the top quark rapidity distribution AFBt and in the rapidity distribution of charged leptons AFBl from top quarks produced at the Tevatron. We study the kinematic and dynamic aspects of the relationship of the two observables arising from the spin correlation between the charged lepton and the top quark with different polarization states. We emphasize the value of both measurements, and we conclude that a new physics model which produces more right-handed than left-handed top quarks is favored by the present data.

  6. Confinement of quarks in dual superconductor models

    SciTech Connect (OSTI)

    Ripka, Georges

    2005-06-14

    We review some aspects and problems of quark confinement models which are based on a dual super-conductor description of the QCD vacuum.

  7. CP Violation in Single Top Quark Production

    SciTech Connect (OSTI)

    Geng, Weigang

    2012-01-01

    We present a search for CP violation in single top quark production with the DØ experiment at the Tevatron proton-antiproton collider. CP violation in the top electroweak interaction results in different single top quark production cross sections for top and antitop quarks. We perform the search in the single top quark final state using 5.4 fb-1 of data, in the s-channel, t-channel, and for both combined. At this time, we do not see an observable CP asymmetry.

  8. Review of meson spectroscopy: quark states and glueballs

    SciTech Connect (OSTI)

    Chanowitz, M.S.

    1981-11-01

    A group of three lectures on hadron spectroscopy are presented. Topics covered include: light L = 0 mesons, light L = 1 mesons, antiquark antiquark quark quark exotics, a catalogue of higher quark antiquark excitations, heavy quarkonium, and glueballs. (GHT)

  9. Neutrons and Quarks Share Dual Nature | Jefferson Lab

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

    gluons, which glue the quarks together so tightly that no quark can ever be found alone. ... This odd phenomenon is called quark-hadron duality. According to Patricia Solvignon, a ...

  10. Periods of Congestion in Quark Cafe During Lunch Service: June...

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

    Periods of Congestion in Quark Cafe During Lunch Service: June 15-17 Periods of Congestion in Quark Cafe During Lunch Service: June 15-17 Quark Cafe may experience intermittent ...

  11. A measurement of the top quark's charge

    SciTech Connect (OSTI)

    Unalan, Zeynep Gunay; /Michigan State U.

    2007-11-01

    The top quark was discovered in 1995 at the Fermilab National Accelerator Laboratory (Fermilab). One way to confirm if the observed top quark is really the top quark posited in the Standard Model (SM) is to measure its electric charge. In the Standard Model the top quark is the isospin partner of the bottom quark and is expected to have a charge of +2/3. However, an alternative 'exotic' model has been proposed with a fourth generation exotic quark that has the same characteristics, such as mass, as our observed top but with a charge of -4/3. This thesis presents the first CDF measurement of the top quark's charge via its decay products, a W boson and a bottom quark, using {approx} 1 fb{sup -1} of data. The data were collected by the CDF detector from proton anti-proton (p{bar p}) collisions at {radical}s = 1.96 TeV at Fermilab. We classify events depending on the charges of the bottom quark and associated W boson and count the number of events which appear 'SM-like' or 'exotic-like' with a SM-like event decaying as t {yields} W{sup +}b and an exotic event as t {yields} W{sup -}b. We find the p-value under the Standard Model hypothesis to be 0:35 which is consistent with the Standard Model. We exclude the exotic quark hypothesis at an 81% confidence level, for which we have chosen a priori that the probability of incorrectly rejecting the SM would be 1%. The calculated Bayes Factor (BF) is 2 x Ln(BF)=8.54 which is interpreted as the data strongly favors the Standard Model over the exotic quark hypothesis.

  12. Hadronic physics of q anti q light quark mesons, quark molecules and glueballs

    SciTech Connect (OSTI)

    Lindenbaum, S.J.

    1980-10-01

    A brief introduction reviews the development of QCD and defines quark molecules and glueballs. This review is concerned primarily with u, d, and s quarks, which provide practically all of the cross section connected with hadronic interactions. The following topics form the bulk of the paper: status of quark model classification for conventional u, d, s quark meson states; status of multiquark or quark molecule state predictions and experiments; glueballs and how to find them; and the OZI rule in decay and production and how glueballs might affect it. 17 figures, 1 table. (RWR)

  13. Top quark pair production cross section at Tevatron (Conference...

    Office of Scientific and Technical Information (OSTI)

    Conference: Top quark pair production cross section at Tevatron Citation Details In-Document Search Title: Top quark pair production cross section at Tevatron You are accessing ...

  14. Recent Developments in Heavy Quark and Quarkonium Production...

    Office of Scientific and Technical Information (OSTI)

    Conference: Recent Developments in Heavy Quark and Quarkonium Production Citation Details In-Document Search Title: Recent Developments in Heavy Quark and Quarkonium Production ...

  15. Chiral transition and mesonic excitations for quarks with thermal...

    Office of Scientific and Technical Information (OSTI)

    We study the effect of a thermal quark mass, msub T, on the chiral phase transition and ... D QUARKS; EXCITATION; LANDAU DAMPING; MASS; PARTICLE DECAY; PHASE TRANSFORMATIONS; ...

  16. Heavy Quarks, QCD, and Effective Field Theory Thomas Mehen 72...

    Office of Scientific and Technical Information (OSTI)

    Heavy Quarks, QCD, and Effective Field Theory Thomas Mehen 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS Heavy Quarks, Quarkonium,...

  17. Quark structure of chiral solitons (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Conference: Quark structure of chiral solitons Citation Details In-Document Search Title: Quark structure of chiral solitons You are accessing a document from the Department of ...

  18. Quark structure of chiral solitons (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Conference: Quark structure of chiral solitons Citation Details In-Document Search Title: Quark structure of chiral solitons There is a prejudice that the chiral soliton model of ...

  19. Quark Flavors and Conserved Charges at Finite Density in the...

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

    transition from the Quark-Gluon Plasma to a gas of hadrons during the evolution of the universe. Credit: Sandor Katz, Eotvos University Quark Flavors and Conserved Charges ...

  20. Quark mass variation constraints from Big Bang nucleosynthesis...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Quark mass variation constraints from Big Bang nucleosynthesis Citation Details In-Document Search Title: Quark mass variation constraints from Big Bang ...

  1. The Top Quark, Its Discovery, and Subsequent Research

    Office of Scientific and Technical Information (OSTI)

    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 ...

  2. Measurement of cross section of quark pair production top with...

    Office of Scientific and Technical Information (OSTI)

    Measurement of cross section of quark pair production top with the D0 experiment at the Tevatron and determination the top quark mass using this measure Citation Details ...

  3. Heavy Quarks, QCD, and Effective Field Theory (Technical Report...

    Office of Scientific and Technical Information (OSTI)

    Title: Heavy Quarks, QCD, and Effective Field Theory The research supported by this OJI award is in the area of heavy quark and quarkonium production, especially the application ...

  4. Transverse momentum distributions of quarks in the nucleon from the chiral quark soliton model

    SciTech Connect (OSTI)

    Wakamatsu, M.

    2009-05-01

    We report the first calculation of the simplest but most fundamental transverse-momentum-dependent distribution of quarks in the nucleon, i.e. the time-reversal-even unpolarized transverse-momentum-dependent quark and antiquark distribution with isoscalar combination, within the framework of the chiral quark soliton model. The nonperturbative account of the deformed Dirac-sea quarks within the theoretical scheme enables us to make reliable predictions not only for the quark distribution but also for the antiquark distribution. We found that the predicted average transverse momentum square of quarks and antiquarks depends strongly on their longitudinal momentum fraction x, which means that the frequently used assumption of factorization in x and k{sub perpendicular} is significantly violated. It is also found, somewhat unexpectedly, that the average transverse momentum square of antiquarks is considerably larger than that of quarks.

  5. The Top Quark, QCD, And New Physics.

    DOE R&D Accomplishments [OSTI]

    Dawson, S.

    2002-06-01

    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.

  6. HUNTING THE QUARK GLUON PLASMA.

    SciTech Connect (OSTI)

    LUDLAM, T.; ARONSON, S.

    2005-04-11

    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

  7. Heavy-quark physics in quantum chromodynamics

    SciTech Connect (OSTI)

    Brodsky, S.J.

    1991-04-01

    Heavy quarks can expose new symmetries and novel phenomena in QCD not apparent in ordinary hadronic systems. In these lectures I discuss the use of effective-Lagrangian and light-cone Fock methods to analyze exclusive heavy hadron decays such as {Upsilon} {yields} p{bar p} and B {yields} {pi}{pi}, and also to derive effective Schroedinger and Dirac equations for heavy quark systems. Two contributions to the heavy quark structure functions of the proton and other light hadrons are identified: an extrinsic'' contribution associated with leading twist QCD evolution of the gluon distribution, and a higher twist intrinsic'' contribution due to the hardness of high-mass fluctuations of multi-gluon correlations in hadronic wavefunctions. A non-perturbative calculation of the heavy quark distribution of a meson in QCD in one space and one time is presented. The intrinsic higher twist contributions to the pion and proton structure functions can dominate the hadronic production of heavy quark systems at large longitudinal momentum fraction x{sub F} and give anomalous contributions to the quark structure functions of ordinary hadrons at large x{sub bj}. I also discuss a number of ways in which heavy quark production in nuclear targets can test fundamental QCD phenomena and provide constraints on hadronic wavefunctions. The topics include color transparency, finite formation time, and predictions for charm production at threshold, including nuclear-bound quarkonium. I also discuss a number of QCD mechanisms for the suppression of J/{psi} and {Upsilon} production in nuclear collisions, including gluon shadowing, the peripheral excitation of intrinsic heavy quark components at large x{sub F}, and the coalescence of heavy quarks with co-moving spectators at low x{sub F}.

  8. Measurement of top quark polarisation in t-channel single top quark production

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

    Khachatryan, Vardan

    2016-04-13

    Our first measurement of the top quark spin asymmetry, sensitive to the top quark polarisation, in t-channel single top quark production is presented. It is based on a sample of pp collisions at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 19.7 fb-1. A high-purity sample of t-channel single top quark events with an isolated muon is selected. Signal and background components are estimated using a fit to data. Furthermore, a differential cross section measurement, corrected for detector effects, of an angular observable sensitive to the top quark polarisation is performed. The differential distribution is usedmore » to extract a top quark spin asymmetry of 0.26 ± 0.03 (stat) ± 0.10 (syst), which is compatible with a p-value of 4.6% with the standard model prediction of 0.44.« less

  9. Measurement of top quark polarisation in t-channel single top quark production

    SciTech Connect (OSTI)

    Khachatryan, Vardan

    2015-11-09

    Our first measurement of the top quark spin asymmetry, sensitive to the top quark polarisation, in t-channel single top quark production is presented. It is based on a sample of pp collisions at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 19.7 fb-1. A high-purity sample of t-channel single top quark events with an isolated muon is selected. Signal and background components are estimated using a fit to data. Furthermore, a differential cross section measurement, corrected for detector effects, of an angular observable sensitive to the top quark polarisation is performed. The differential distribution is used to extract a top quark spin asymmetry of 0.26 ± 0.03 (stat) ± 0.10 (syst), which is compatible with a p-value of 4.6% with the standard model prediction of 0.44.

  10. Recent Results of Top Quark Physics from the Tevatron

    SciTech Connect (OSTI)

    Peters, R. Y.

    2015-07-09

    Twenty years after its discovery in 1995 by the CDF and D0 collaborations at the Tevatron proton-antiproton collider at Fermilab, the top quark still undergoes intensive studies at the Tevatron and the LHC at CERN. In this article, recent top quark physics results from CDF and D0 are reported. In particular, measurements of single top quark and double top quark production, the $t\\bar{t}$ forward-backward asymmetry and the top quark mass are discussed.

  11. An Unquenched Quark Model of Baryons

    SciTech Connect (OSTI)

    Bijker, Roelof; Santopinto, Elena

    2007-10-26

    We present the formalism for a new generation of unquenched quark models for baryons in which the effects of quark-antiquark pairs are taken into account in an explicit form via a microscopic, QCD-inspired, quark-antiquark creation mechanism. The present approach is an extension of the fiux-tube breaking model of Geiger and Isgur in which now the contribution of quark-antiquark pairs can be studied for any inital baryon, for any fiavor of the qq-bar pair (not only ss-bar but also uu-bar and dd-bar) and for arbitrary hadron wave functions. The method is illustrated with an application to the spin of the proton and the flavor asymmetry of the nucleon sea.

  12. Quark ensembles with the infinite correlation length

    SciTech Connect (OSTI)

    Zinov’ev, G. M.; Molodtsov, S. V.

    2015-01-15

    A number of exactly integrable (quark) models of quantum field theory with the infinite correlation length have been considered. It has been shown that the standard vacuum quark ensemble—Dirac sea (in the case of the space-time dimension higher than three)—is unstable because of the strong degeneracy of a state, which is due to the character of the energy distribution. When the momentum cutoff parameter tends to infinity, the distribution becomes infinitely narrow, leading to large (unlimited) fluctuations. Various vacuum ensembles—Dirac sea, neutral ensemble, color superconductor, and BCS state—have been compared. In the case of the color interaction between quarks, the BCS state has been certainly chosen as the ground state of the quark ensemble.

  13. Nonlocality of the scalar quark condensate

    SciTech Connect (OSTI)

    Ryskin, M. G.; Drukarev, E. G. Sadovnikova, V. A.

    2015-06-15

    We suggest a somewhat indirect method for estimation of the nonlocal scalar quark condensate. The approach is based on analysis of the polarization operator of nucleon current in instanton medium.

  14. Top Quark Physics at the Tevatron

    SciTech Connect (OSTI)

    Jung, Andreas W.

    2015-05-21

    An overview of recent top quark measurements using the full Run II data set of CDF or D0 at the Tevatron is presented. Results are complementary to the ones at the LHC. Recent measurements of the production cross section of top quarks in strong and electroweak production and of top quark production asymmetries are presented. The latter includes the measurement of the tt-bar production asymmetry by D0 in the dilepton decay channel. Within their uncertainties the results from all these measurements agree with their respective Standard Model expectation. Finally latest updates on measurements of the top quark mass are discussed, which at the time of the conference are the most precise determinations.

  15. Dark decay of the top quark

    SciTech Connect (OSTI)

    Kong, Kyoungchul; Lee, Hye -Sung; Park, Myeonghun

    2014-04-01

    We suggest top quark decays as a venue to search for light dark force carriers. Top quark is the heaviest particle in the standard model whose decays are relatively poorly measured, allowing sufficient room for exotic decay modes from new physics. A very light (GeV scale) dark gauge boson (Z') is a recently highlighted hypothetical particle that can address some astrophysical anomalies as well as the 3.6 σ deviation in the muon g-2 measurement. We present and study a possible scenario that top quark decays as t → b W + Z's. This is the same as the dominant top quark decay (t → b W) accompanied by one or multiple dark force carriers. The Z' can be easily boosted, and it can decay into highly collimated leptons (lepton-jet) with large branching ratio. In addition, we discuss the implications for the Large Hadron Collider experiments including the analysis based on the lepton-jets.

  16. Dark Decay of the Top Quark

    SciTech Connect (OSTI)

    Kong, Kyoungchul; Lee, Hye-Sung; Park, Myeonghun

    2014-04-01

    We suggest top quark decays as a venue to search for light dark force carriers. The top quark is the heaviest particle in the standard model whose decays are relatively poorly measured, allowing sufficient room for exotic decay modes from new physics. A very light (GeV scale) dark gauge boson (Z') is a recently highlighted hypothetical particle that can address some astrophysical anomalies as well as the 3.6sigma deviation in the muon g-2 measurement. We present and study a possible scenario that top quark decays as t-->bW+Z's. This is the same as the dominant top quark decay (t-->bW) accompanied by one or multiple dark force carriers. The Z' can be easily boosted, and it can decay into highly collimated leptons (lepton-jet) with large branching ratio. We discuss the implications for the Large Hadron Collider experiments including the analysis based on the lepton-jets.

  17. y scaling in a simple quark model

    SciTech Connect (OSTI)

    Kumano, S.; Moniz, Ernest J.

    1988-05-01

    A simple quark model is used to define a nuclear pair model, that is, two composite hadrons interacting only through quark interchange and bound in an overall potential. An ''equivalent'' hadron model is developed, displaying an effective hadron-hadron interaction which is strongly repulsive. We compare the effective hadron model results with the exact quark model observables in the kinematic region of large momentum transfer, small energy transfer. The nucleon reponse function in this y-scaling region is, within the traditional frame work sensitive to the nucleon momentum distribution at large momentum. We find a surprizingly small effect of hadron substructure. Furthermore, we find in our model that a simple parametrization of modified hadron size in the bound state, motivated by the bound quark momentum distribution, is not a useful way to correlate different observables.

  18. Evidence for production of single top quarks

    SciTech Connect (OSTI)

    Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, M.; Adams, T.; Aguilo, E.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; Alkhazov, G.; /St. Petersburg, INP /Michigan U.

    2008-03-01

    We present first evidence for the production of single top quarks in the D0 detector at the Fermilab Tevatron p{bar p} 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 datasets. In this analysis, we select events from a 0.9 fb{sup -1} dataset 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 t{bar t} 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 {sigma}(p{bar p} {yields} 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 |V{sub tb}f{sub 1}{sup L}| = 1.31{sub -0.21}{sup +0.25}, where f{sub 1}{sup L} is a generic vector coupling. This model-independent measurement translates into 0.68 < |V{sub tb}| {le} 1 at the 95% C.L. in the standard model.

  19. Charmonium with three flavors of synamical quarks

    SciTech Connect (OSTI)

    Massimo Di Pierro et al.

    2003-12-23

    We present a calculation of the charmonium spectrum with three flavors of dynamical staggered quarks from gauge configurations that were generated by the MILC collaboration. We use the Fermilab action for the valence charm quarks. Our calculation of the spin-averaged 1P-1S and 2S-1S splittings yields a determination of the strong coupling, with {alpha}{sub {ovr MS}}(M{sub Z}) = 0.119(4).

  20. New Mechanism for Quark Energy Loss

    SciTech Connect (OSTI)

    Casalderrey-Solana, Jorge; Fernandez, Daniel; Mateos, David

    2010-04-30

    We show that a heavy quark moving sufficiently fast through a quark-gluon plasma may lose energy by Cherenkov-radiating mesons. We demonstrate that this takes place in all strongly coupled, large-N{sub c} plasmas with a gravity dual. The energy loss is exactly calculable in these models despite being an O(1/N{sub c}) effect. We discuss implications for heavy-ion collision experiments.

  1. Two-loop ultrasoft running of the O(v{sup 2}) QCD quark potentials...

    Office of Scientific and Technical Information (OSTI)

    Subject: 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ANNIHILATION; B QUARKS; C QUARKS; FEYNMAN DIAGRAM; PAIR PRODUCTION; POTENTIALS; QUANTUM CHROMODYNAMICS; T QUARKS Word Cloud ...

  2. Giese Energie und Regeltechnik GmbH | Open Energy Information

    Open Energy Info (EERE)

    Giese Energie und Regeltechnik GmbH Jump to: navigation, search Name: Giese Energie- und Regeltechnik GmbH Place: Puchheim bei Mnchen, Germany Zip: 82178 Product: Micro...

  3. G-Zero Finds that Ghostly Strange Quarks Influence Proton Structure...

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

    strange quarks in the proton's quark-gluon sea contribute to a proton's properties. ... They determined that the next-lightest quark, the "strange" quark, would be the most ...

  4. Meson Spectroscopy in the Light Quark Sector

    SciTech Connect (OSTI)

    de Vita, Raffaella

    2014-04-01

    Understanding the hadron spectrum is one of the fundamental issues in modern particle physics. We know that existing hadron configurations include baryons, made of three quarks, and mesons, made of quark-antiquark pairs. However most of the mass of the hadrons is not due to the mass of these elementary constituents but to their binding force. Studying the hadron spectrum is therefore a tool to understand one of the fundamental forces in nature, the strong force, and Quantum Chromo Dynamics (QCD), the theory that describes it. This investigation can provide an answer to fundamental questions as what is the origin of the mass of hadrons, what is the origin of quark confinement, what are the relevant degrees of freedom to describe these complex systems and how the transition between the elementary constituents, quarks and gluons, and baryons and mesons occurs. In this field a key tool is given by meson spectroscopy. Mesons, being made by a quark and an anti-quark, are the simplest quark bound system and therefore the ideal benchmark to study the interaction between quarks and understand what the role of gluons is. In this investigation, it is fundamental to precisely determine the spectrum and properties of mesons but also to search for possible unconventional states beyond the configuration q{anti q} as tetraquarks (qq{anti qq}), hybrids (q{anti q}g) and glueballs. These states can be distinguished unambiguously from regular mesons when they have exotic quantum numbers, i.e. combinations of total angular momentum, spin and parity that are not allowed for q{anti q} states. These are called exotic quantum numbers and the corresponding states are referred to as exotics. The study of the meson spectrum and the search for exotics is among the goals of several experiments in the world that exploit different reaction processes, as e{sup +}e{sup −} annihilation, p{anti p} annihilation, pion scattering, proton-proton scattering and photo-production, to produce meson states

  5. The heavy top quark and supersymmetry

    SciTech Connect (OSTI)

    Hall, L.J.

    1997-01-01

    Three aspects of supersymmetric theories are discussed: electroweak symmetry breaking, the issues of flavor, and gauge unification. The heavy top quark plays an important, sometimes dominant, role in each case. Additional symmetries lead to extensions of the Standard Model which can provide an understanding for many of the outstanding problems of particle physics. A broken supersymmetric extension of spacetime allows electroweak symmetry breaking to follow from the dynamics of the heavy top quark; an extension of isospin provides a constrained framework for understanding the pattern of quark and lepton masses; and a grand unified extension of the Standard Model gauge group provides an elegant understanding of the gauge quantum numbers of the components of a generation. Experimental signatures for each of these additional symmetries are discussed.

  6. Top quark mass measurements at CDF

    SciTech Connect (OSTI)

    Brubaker, Erik; /Chicago U., EFI

    2006-05-01

    The mass of the top quark M{sub top} is interesting both as a fundamental parameter of the standard model and as an important input to precision electroweak tests. The Collider Detector at Fermilab (CDF) has a robust program of top quark mass analyses, including the most precise single measurement, M{sub top} = 173.4 {+-} 2.8 GeV/c{sup 2}, using 680 pb{sup -1} of p{bar p} collision data. A combination of current results from CDF gives M{sub top} = 172.0 {+-} 2.7 GeV/c{sup 2}, surpassing the stated goal of 3 GeV/c{sup 2} precision using 2 fb{sup -1} of data. Finally, a combination with current D0 results gives a world average top quark mass of 172.5 {+-} 2.3 GeV/c{sup 2}.

  7. Pions in the quark matter phase diagram

    SciTech Connect (OSTI)

    Zablocki, D.; Blaschke, D.; Anglani, R.

    2008-08-29

    The relationship between mesonic correlations and quantum condensates in the quark matter phase diagram is explored within a quantum field theoretical approach of the Nambu and Jona-Lasinio (NJL) type. Mean-field values in the scalar meson and diquark channels are order parameters signaling the occurrence of quark condensates, entailing chiral symmetry breaking ({chi}SB) and color superconductivity (2SC) in quark matter. We investigate the spectral properties of scalar and pseudoscalar meson excitations in the phase diagram in Gaussian approximation and show that outside the {chi}SB region where the pion is a zero-width bound state, there are two regions where it can be considered as a quasi-bound state with a lifetime exceeding that of a typical heavy-ion collision fireball: (A) the high-temperature {chi}SB crossover region at low densities and (B) the high-density color superconducting phase at temperatures below 100 MeV.

  8. Essence of the Vacuum Quark Condensate

    SciTech Connect (OSTI)

    Brodsky, Stanley J.; Roberts, Craig D.; Shrock, Robert; Tandy, Peter C.; /Kent State U.

    2010-08-25

    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.

  9. Measurement of cross section of quark pair production top with...

    Office of Scientific and Technical Information (OSTI)

    cross section of quark pair production top with the D0 experiment at the Tevatron and determination the top quark mass using this measure Citation Details In-Document Search Title: ...

  10. Thermodynamics of Quark Flavors from Lattice QCD | Argonne Leadership...

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

    Ian McVicar, University of Glasgow (Courtesy of ALICE and CERN) Thermodynamics of Quark ... that ordinary hadronic matter will undergo a phase transition to quark-gluon plasma (QGP). ...

  11. Measurement of the top quark pair production cross section in...

    Office of Scientific and Technical Information (OSTI)

    Measurement of the top quark pair production cross section in proton-proton collisions at sqrts13 TeV Citation Details In-Document Search Title: Measurement of the top quark...

  12. Debye mass and heavy quark potential in a PNJL quark plasma

    SciTech Connect (OSTI)

    Jankowski, J. Blaschke, D.

    2012-07-15

    We calculate the Debye mass for the screening of the heavy quark potential in a plasma of massless quarks coupled to the temporal gluon background governed by the Polyakov loop potential within the PNJL model in RPA approximation. We give a physical motivation for a recent phenomenological fit of lattice data by applying the calculated Debye mass with its suppression in the confined phase due to the Polyakov loop to a description of the temperature dependence of the singlet free energy for QCD with a heavy quark pair at infinite separation. We compare the result to lattice data.

  13. Quark mass variation constraints from Big Bang nucleosynthesis (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Journal Article: Quark mass variation constraints from Big Bang nucleosynthesis Citation Details In-Document Search Title: Quark mass variation constraints from Big Bang nucleosynthesis We study the impact on the primordial abundances of light elements created of a variation of the quark masses at the time of Big Bang nucleosynthesis (BBN). In order to navigate through the particle and nuclear physics required to connect quark masses to binding energies and

  14. Dissociation of a heavy meson in the quark medium

    SciTech Connect (OSTI)

    Park, Chanyong

    2010-02-15

    We investigate the dissociation of a heavy meson in the medium composed of light quarks and gluons. In the quark-gluon plasma, the dissociation length of the heavy meson becomes short as the temperature or quark chemical potential increases. On the contrary, in the hadronic phase the dissociation length becomes large as the chemical potential increases, due to the different dissociation mechanism with one used in the quark-gluon plasma.

  15. Adomian Decomposition Method for Quark Gluon Plasma Model

    SciTech Connect (OSTI)

    Constantinescu, Radu; Ionescu, Carmen; Stoicescu, Mihai

    2011-10-03

    The paper investigates the possibility of obtaining analytical solutions for the Quark Gluon Plasma model using the Adomian decomposition method.

  16. Precision Determination of the Top Quark Mass

    SciTech Connect (OSTI)

    Movilla Fernandez, Pedro A.; /LBL, Berkeley

    2007-05-01

    The CDF and D0 collaborations have updated their measurements of the mass of the top quark using proton-antiproton collisions at {radical}s = 1.96 TeV produced at the Tevatron. The uncertainties in each of the top-antitop decay channels have been reduced. The new Tevatron average for the mass of the top quark based on about 1 fb{sup -1} of data per experiment is 170.9 {+-} 1.8 GeV/c{sup 2}.

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

    SciTech Connect (OSTI)

    Gomez Dumm, D.; Contrera, G. A.

    2012-06-15

    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.

  18. Dark decay of the top quark

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

    Kong, Kyoungchul; Lee, Hye -Sung; Park, Myeonghun

    2014-04-01

    We suggest top quark decays as a venue to search for light dark force carriers. Top quark is the heaviest particle in the standard model whose decays are relatively poorly measured, allowing sufficient room for exotic decay modes from new physics. A very light (GeV scale) dark gauge boson (Z') is a recently highlighted hypothetical particle that can address some astrophysical anomalies as well as the 3.6 σ deviation in the muon g-2 measurement. We present and study a possible scenario that top quark decays as t → b W + Z's. This is the same as the dominant topmore » quark decay (t → b W) accompanied by one or multiple dark force carriers. The Z' can be easily boosted, and it can decay into highly collimated leptons (lepton-jet) with large branching ratio. In addition, we discuss the implications for the Large Hadron Collider experiments including the analysis based on the lepton-jets.« less

  19. Quark-gluon plasma (Selected Topics)

    SciTech Connect (OSTI)

    Zakharov, V. I.

    2012-09-15

    Introductory lectures to the theory of (strongly interacting) quark-gluon plasma given at the Winter School of Physics of ITEP (Moscow, February 2010). We emphasize theoretical issues highlighted by the discovery of the low viscosity of the plasma. The topics include relativistic hydrodynamics, manifestations of chiral anomaly in hydrodynamics, superfluidity, relativistic superfluid hydrodynamics, effective stringy scalars, holographic models of Yang-Mills theories.

  20. Quark-Gluon Plasma Model and Origin of Magic Numbers

    SciTech Connect (OSTI)

    Ghahramany, N.; Ghanaatian, M.; Hooshmand, M.

    2008-04-21

    Using Boltzman distribution in a quark-gluon plasma sample it is possible to obtain all existing magic numbers and their extensions without applying the spin and spin-orbit couplings. In this model it is assumed that in a quark-gluon thermodynamic plasma, quarks have no interactions and they are trying to form nucleons. Considering a lattice for a central quark and the surrounding quarks, using a statistical approach to find the maximum number of microstates, the origin of magic numbers is explained and a new magic number is obtained.

  1. Energy loss of charm quarks in the quark-gluon plasma: Collisional vs radiative losses

    SciTech Connect (OSTI)

    Mustafa, Munshi G.

    2005-07-01

    In considering the collisional energy loss rates of heavy quarks from hard light parton interactions, we computed the total energy loss of a charm quark for a static medium. For the energy range E{approx}5-10 GeV of charm quark, it proved to be almost the same order as that of radiative ones estimated to a first-order opacity expansion. The collisional energy loss becomes much more important for lower energy charm quarks, and this feature could be very interesting for the phenomenology of hadrons spectra. Using such collisional energy loss rates, we estimate the momentum loss distribution employing a Fokker-Planck equation and the total energy loss of a charm quark for an expanding quark-gluon plasma under conditions resembling the energies presently available at the BNL Relativistic Heavy Ion Collider. The fractional collisional energy loss is found to be suppressed by a factor of 5 as compared to the static case and does not depend linearly on the system size. We also investigate the heavy to light hadrons D/{pi} ratio at moderately large (5-10 GeV/c) transverse momenta and comment on its enhancement.

  2. Quarkyonic Matter and Quark Number Scaling of Elliptic Flow

    SciTech Connect (OSTI)

    Csernai, L. P.; Zschocke, S.; Horvat, Sz.; Cheng Yun; Mishustin, I. N.

    2011-05-23

    The constituent quark number scaling of elliptic flow is studied in a non-equilibrium hadronization and freeze-out model with rapid dynamical transition from ideal, deconfined and chirally symmetric Quark Gluon Plasma, to final non-interacting hadrons. In this transition a Bag model of constituent quarks is considered, where the quarks gain constituent quark mass while the background Bag-field breaks up and vanishes. The constituent quarks then recombine into simplified hadron states, while chemical, thermal and flow equilibrium break down one after the other. In this scenario the resulting temperatures and flow velocities of baryons and mesons are different. Using a simplified few source model of the elliptic flow, we are able to reproduce the constituent quark number scaling, with assumptions on the details of the non-equilibrium processes.

  3. Quark-hadron duality in neutrino scattering

    SciTech Connect (OSTI)

    W. Melnitchouk; O. Lalakulich; E. A. Paschos

    2006-07-24

    We present a phenomenological model of the quark-hadron transition in neutrino-nucleon scattering. Using recently extracted weak nucleon transition form factors, we investigate the extent to which local and global quark-hadron duality is applicable in the neutrino F{sub 1}, F{sub 2} and F{sub 3} structure functions, and contrast this with duality in electron scattering. Our findings suggest that duality works relatively well for neutrino-nucleon scattering for the F{sub 2} and F{sub 3} structure functions, but not as well for F{sub 1}. We also calculate the quasi-elastic, resonance and deep inelastic contributions to the Adler sum rule, and find it to be satisfied to within 10% for 0.5 < Q{sup 2} < 2 GeV{sup 2}.

  4. Quarkonia and heavy-quark relaxation times in the quark-gluon plasma

    SciTech Connect (OSTI)

    Riek, F.; Rapp, R.

    2010-09-15

    A thermodynamic T-matrix approach for elastic two-body interactions is employed to calculate spectral functions of open and hidden heavy-quark systems in the quark-gluon plasma. This enables the evaluation of quarkonium bound-state properties and heavy-quark diffusion on a common basis and thus to obtain mutual constraints. The two-body interaction kernel is approximated within a potential picture for spacelike momentum transfers. An effective field-theoretical model combining color-Coulomb and confining terms is implemented with relativistic corrections and for different color channels. Four pertinent model parameters, characterizing the coupling strengths and screening, are adjusted to reproduce the color-average heavy-quark free energy as computed in thermal lattice QCD. The approach is tested against vacuum spectroscopy in the open (D, B) and hidden ({Psi} and {Upsilon}) flavor sectors, as well as in the high-energy limit of elastic perturbative QCD scattering. Theoretical uncertainties in the static reduction scheme of the four-dimensional Bethe-Salpeter equation are elucidated. The quarkonium spectral functions are used to calculate Euclidean correlators which are discussed in light of lattice QCD results, while heavy-quark relaxation rates and diffusion coefficients are extracted utilizing a Fokker-Planck equation.

  5. Rare top quark decays in extended models

    SciTech Connect (OSTI)

    Gaitan, R.; Miranda, O. G.; Cabral-Rosetti, L. G.

    2006-09-25

    Flavor changing neutral currents (FCNC) decays t {yields} H0 + c, t {yields} Z + c, and H0 {yields} t + c-bar are discussed in the context of Alternative Left-Right symmetric Models (ALRM) with extra isosinglet heavy fermions where FCNC decays may take place at tree-level and are only suppressed by the mixing between ordinary top and charm quarks, which is poorly constraint by current experimental values. The non-manifest case is also briefly discussed.

  6. Magnetic Phases in Dense Quark Matter

    SciTech Connect (OSTI)

    Incera, Vivian de la

    2007-10-26

    In this paper I discuss the magnetic phases of the three-flavor color superconductor. These phases can take place at different field strengths in a highly dense quark system. Given that the best natural candidates for the realization of color superconductivity are the extremely dense cores of neutron stars, which typically have very large magnetic fields, the magnetic phases here discussed could have implications for the physics of these compact objects.

  7. Baryon Spectroscopy and the Constituent Quark Model

    SciTech Connect (OSTI)

    A.W. Thomas; R.D. Young

    2005-07-26

    We explore further the idea that the lattice QCD data for hadron properties in the region m[^2][_pi] > 0.2GeV^2 can be described by the constituent quark model. This leads to a natural explanation of the fact that nucleon excited states are generally stable for pion masses greater than their physical excitation energies. Finally, we apply these same ideas to the problem of how pentaquarks might behave in lattice QCD, with interesting conclusions.

  8. Exotic quarks in Twin Higgs models

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

    Cheng, Hsin -Chia; Jung, Sunghoon; Salvioni, Ennio; Tsai, Yuhsin

    2016-03-14

    The Twin Higgs model provides a natural theory for the electroweak symmetry breaking without the need of new particles carrying the standard model gauge charges below a few TeV. In the low energy theory, the only probe comes from the mixing of the Higgs fields in the standard model and twin sectors. However, an ultraviolet completion is required below ~ 10 TeV to remove residual logarithmic divergences. In non-supersymmetric completions, new exotic fermions charged under both the standard model and twin gauge symmetries have to be present to accompany the top quark, thus providing a high energy probe of themore » model. Some of them carry standard model color, and may therefore be copiously produced at current or future hadron colliders. Once produced, these exotic quarks can decay into a top together with twin sector particles. If the twin sector particles escape the detection, we have the irreducible stop-like signals. On the other hand, some twin sector particles may decay back into the standard model particles with long lifetimes, giving spectacular displaced vertex signals in combination with the prompt top quarks. This happens in the Fraternal Twin Higgs scenario with typical parameters, and sometimes is even necessary for cosmological reasons. We study the potential displaced vertex signals from the decays of the twin bottomonia, twin glueballs, and twin leptons in the Fraternal Twin Higgs scenario. As a result, depending on the details of the twin sector, the exotic quarks may be probed up to ~ 2.5 TeV at the LHC and beyond 10 TeV at a future 100 TeV collider, providing a strong test of this class of ultraviolet completions.« less

  9. Observation of Single Top Quark Production

    SciTech Connect (OSTI)

    Gerber, Cecilia E.; /Illinois U., Chicago

    2009-09-01

    The author reports on the observation of electroweak production of single top quarks in p{bar p} collisions at {radical}s = 1.96 Tev using 2.3 fb{sup -1} of data collected with the D0 detector at the fermilab Tevatron Collider. Using events containing an isolated electron or muon, missing transverse energy, two, three or four jets, with one or two of them identified as originating from the fragmentation of a b quark, the measured cross section for the process p{bar p} {yields} tb + X, tqb + X is 3.94 {+-} 0.88 pb (for a top quark mass of 170 GeV). the probability to measure a cross section at this value or higher in the absence of signal is 2.5 x 10{sup -7}, corresponding to a 5.0 standard deviation significance. Using the same dataset, the measured cross sections for the t- and the s-channel processes when determined simultaneously with no assumption on their relative production rate are 3.14{sub -0.80}{sup +0.94} pb and 1.05 {+-} 0.81 pb respectively, consistent with standard model expectations. The measured t-channel cross section has a significance of 4.8 standard deviations, representing the first evidence for the production of an individual single top process to be detected.

  10. Tracking down hyper-boosted top quarks

    SciTech Connect (OSTI)

    Larkoski, Andrew J.; Maltoni, Fabio; Selvaggi, Michele

    2015-06-05

    The identification of hadronically decaying heavy states, such as vector bosons, the Higgs, or the top quark, produced with large transverse boosts has been and will continue to be a central focus of the jet physics program at the Large Hadron Collider (LHC). At a future hadron collider working at an order-of-magnitude larger energy than the LHC, these heavy states would be easily produced with transverse boosts of several TeV. At these energies, their decay products will be separated by angular scales comparable to individual calorimeter cells, making the current jet substructure identification techniques for hadronic decay modes not directly employable. In addition, at the high energy and luminosity projected at a future hadron collider, there will be numerous sources for contamination including initial- and final-state radiation, underlying event, or pile-up which must be mitigated. We propose a simple strategy to tag such "hyper-boosted" objects that defines jets with radii that scale inversely proportional to their transverse boost and combines the standard calorimetric information with charged track-based observables. By means of a fast detector simulation, we apply it to top quark identification and demonstrate that our method efficiently discriminates hadronically decaying top quarks from light QCD jets up to transverse boosts of 20 TeV. Lastly, our results open the way to tagging heavy objects with energies in the multi-TeV range at present and future hadron colliders.

  11. Tracking down hyper-boosted top quarks

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

    Larkoski, Andrew J.; Maltoni, Fabio; Selvaggi, Michele

    2015-06-05

    The identification of hadronically decaying heavy states, such as vector bosons, the Higgs, or the top quark, produced with large transverse boosts has been and will continue to be a central focus of the jet physics program at the Large Hadron Collider (LHC). At a future hadron collider working at an order-of-magnitude larger energy than the LHC, these heavy states would be easily produced with transverse boosts of several TeV. At these energies, their decay products will be separated by angular scales comparable to individual calorimeter cells, making the current jet substructure identification techniques for hadronic decay modes not directlymore » employable. In addition, at the high energy and luminosity projected at a future hadron collider, there will be numerous sources for contamination including initial- and final-state radiation, underlying event, or pile-up which must be mitigated. We propose a simple strategy to tag such "hyper-boosted" objects that defines jets with radii that scale inversely proportional to their transverse boost and combines the standard calorimetric information with charged track-based observables. By means of a fast detector simulation, we apply it to top quark identification and demonstrate that our method efficiently discriminates hadronically decaying top quarks from light QCD jets up to transverse boosts of 20 TeV. Lastly, our results open the way to tagging heavy objects with energies in the multi-TeV range at present and future hadron colliders.« less

  12. Exotic decays of heavy B quarks

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

    Fox, Patrick J.; Tucker-Smith, David

    2016-01-08

    Heavy vector-like quarks of charge –1/3, B, have been searched for at the LHC through the decays B → bZ, bh, tW. In models where the B quark also carries charge under a new gauge group, new decay channels may dominate. We focus on the case where the B is charged under a U(1)' and describe simple models where the dominant decay mode is B → bZ' → b(bb¯¯). With the inclusion of dark matter such models can explain the excess of gamma rays from the Galactic center. We develop a search strategy for this decay chain and estimate thatmore » with integrated luminosity of 300 fb–1 the LHC will have the potential to discover both the B and the Z' for B quarks with mass below ~ 1.6 TeV, for a broad range of Z' masses. Furthermore, a high-luminosity run can extend this reach to 2 TeV.« less

  13. GM Umwelt und Energiewirtschaft GmbH | Open Energy Information

    Open Energy Info (EERE)

    Umwelt und Energiewirtschaft GmbH Jump to: navigation, search Name: GM Umwelt- und Energiewirtschaft GmbH Place: Dresden, Germany Zip: 1257 Sector: Wind energy Product: German wind...

  14. Moving Quarks Help Solve Proton Spin Puzzle | Jefferson Lab

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

    Moving Quarks Help Solve Proton Spin Puzzle Moving Quarks Help Solve Proton Spin Puzzle NEWPORT NEWS, VA., Sept. 11, 2008 - New theory work at the U.S. Department of Energy's Thomas Jefferson National Accelerator Facility has shown that more than half of the spin of the proton is the result of the movement of its building blocks: quarks. The result, published in the Sept. 5 issue of Physical Review Letters, agrees with recent experiments and supercomputer calculations. It was thought that the

  15. Top Quark Pair Production Cross Section at the Tevatron

    SciTech Connect (OSTI)

    Peters, Reinhild Yvonne

    2015-09-25

    The top quark, discovered in 1995 by the CDF and D0 collaborations at the Tevatron proton antiproton collider at Fermilab, has undergone intense studies in the last 20 years. Currently, CDF and D0 converge on their measurements of top-antitop quark production cross sections using the full Tevatron data sample. In these proceedings, the latest results on inclusive and differential measurements of top-antitop quark production cross sections at the Tevatron are reported.

  16. Quark-Gluon Plasma: a New State of Matter

    ScienceCinema (OSTI)

    Brookhaven Lab

    2010-01-08

    Physicist Peter Steinberg explains the nature of the quark gluon plasma (QGP), a new state of matter produced at Brookhaven Lab's Relativistic Heavy Ion Collider (RHIC).

  17. Top Quark Anomalous Couplings at the International Linear Collider...

    Office of Scientific and Technical Information (OSTI)

    to a precision of approximately 1% for each of two choices of beam polarization. ... INTERMEDIATE BOSONS; LINEAR COLLIDERS; POLARIZATION; PROBES; QUARKS; SILICON; SIMULATION; ...

  18. Recent Results on Top-Quark Physics at D0

    SciTech Connect (OSTI)

    Bloom, Kenneth

    2015-10-23

    We present the most recent measurements on top-quark physics obtained with Tevatron $p\\bar{p}$ collisions recorded by the D0 experiment at $\\sqrt{s}= 1.96$ TeV. The full Run II data set of 9.7 fb$^{-1}$ is analyzed. Both lepton+jets and dilepton channels of top-quark pair production are used to measure the differential and inclusive cross sections, the forward-backward asymmetries, the top-quark mass, the spin correlations, and the top-quark polarization.

  19. Sea quark transverse momentum distributions and dynamical chiral...

    Office of Scientific and Technical Information (OSTI)

    The qualitative difference between valence and sea quark intrinsic psub T. distributions ... May 2013 Publisher: World Scientific Research Org: Thomas Jefferson National ...

  20. Electromagnetic form factors and the hypercentral constituent quark model

    SciTech Connect (OSTI)

    Sanctis, M. De; Giannini, M. M.; Santopinto, E.; Vassallo, A.

    2007-12-15

    We present new results concerning the electromagnetic form factors of the nucleon using a relativistic version of the hypercentral constituent quark model and a relativistic current.

  1. Quark-Gluon Plasma: a New State of Matter

    SciTech Connect (OSTI)

    Brookhaven Lab

    2009-07-08

    Physicist Peter Steinberg explains the nature of the quark gluon plasma (QGP), a new state of matter produced at Brookhaven Lab's Relativistic Heavy Ion Collider (RHIC).

  2. Erratum: Chiral transition and mesonic excitations for quarks...

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Search Results Journal Article: Erratum: Chiral transition and mesonic excitations for quarks with thermal masses Phys. Rev. D 75, 011901 (2007) Citation Details ...

  3. Flavor Physics in the Quark Sector

    SciTech Connect (OSTI)

    Antonelli, Mario; Asner, David Mark; Bauer, Daniel Adams; Becher, Thomas G.; Beneke, M.; Bevan, Adrian John; Blanke, Monika; Bloise, C.; Bona, Marcella; Bondar, Alexander E.; Bozzi, Concezio; Brod, Joachim; Buras, Andrzej J.; Cabibbo, N.; Carbone, A.; Cavoto, Gianluca; Cirigliano, Vincenzo; Ciuchini, Marco; Coleman, Jonathon P.; Cronin-Hennessy, Daniel P.; Dalseno, J.P.; /KEK, Tsukuba /Glasgow U. /Queen Mary, U. of London /Freiburg U. /Charles U. /Pisa U. /Vienna, OAW /Imperial Coll., London /Bergen U. /INFN, Rome /Rome U. /Munich, Tech. U. /INFN, Rome /Rome U. /Southampton U. /INFN, Rome /Nara Women's U. /Florida U. /INFN, Turin /Turin U. /Edinburgh U. /Warwick U. /INFN, Rome /Rome U. /Massachusetts U., Amherst /KEK, Tsukuba /Bern U. /CERN /Munich, Tech. U. /Mainz U., Inst. Phys. /Wayne State U. /Munich, Max Planck Inst. /CERN /Frascati /Brookhaven /Mainz U., Inst. Kernphys. /Munich, Tech. U. /Siegen U. /Imperial Coll., London /Victoria U. /KEK, Tsukuba /Fermilab /Washington U., St. Louis /Frascati /Warwick U. /Indian Inst. Tech., Madras /Melbourne U. /Princeton U. /Beijing, Inst. High Energy Phys. /INFN, Rome /INFN, Rome3 /Fermilab /SLAC /York U., Canada /Brookhaven /UC, Irvine /INFN, Rome /Rome U. /Valencia U., IFIC /INFN, Padua /Padua U. /Munich, Max Planck Inst. /Barcelona U. /Warwick U. /Tata Inst. /Frascati /Mainz U., Inst. Phys. /Vienna U. /KEK, Tsukuba /Orsay, LPT /Frascati /Munich, Tech. U. /Brookhaven /Bern U. /CERN /Mainz U., Inst. Phys. /Wayne State U. /Valencia U., IFIC /CERN /Kentucky U. /Oxford U. /Iowa State U. /Bristol U. /INFN, Rome /Rutherford /CERN /Orsay, LAL /Glasgow U. /INFN, Padua /Queen Mary, U. of London /Texas U. /LPHE, Lausanne /Fermilab /UC, Santa Cruz /Vienna, OAW /Cincinnati U. /Frascati /Orsay, LAL /Ohio State U. /Purdue U. /Novosibirsk, IYF /Frascati /INFN, Rome /Padua U. /INFN, Rome /Bern U. /Karlsruhe U. /Brookhaven /CERN /Paris U., VI-VII /Zurich, ETH /Pisa U. /Frascati /Oxford U. /Orsay, LAL /INFN, Rome2 /INFN, Rome /INFN, Rome3 /Princeton U. /Fermilab /Queen's U., Kingston /KEK, Tsukuba /Melbourne U. /Brookhaven /Indiana U. /INFN, Rome /Rome U. /Pisa U. /Mainz U., Inst. Phys. /Karlsruhe U. /Oxford U. /Cambridge U., DAMTP /Edinburgh U. /CERN

    2010-08-26

    In the past decade, one of the major challenges of particle physics has been to gain an in-depth understanding of the role of quark flavor. In this time frame, measurements and the theoretical interpretation of their results have advanced tremendously. A much broader understanding of flavor particles has been achieved, apart from their masses and quantum numbers, 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. In the past, observations of CP violation were confined to neutral K mesons, but since the early 1990s, 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 is the result of the work of the physicists attending the 5th CKM workshop, hosted by the University of Rome 'La Sapienza', September 9-13, 2008. It 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 which has greatly improved in the past decade.

  4. Top quark mass measurement at the Tevatron

    SciTech Connect (OSTI)

    Guimaraes da Costa, Joao; /Harvard U.

    2004-12-01

    The authors report on the latest experimental measurements of the top quark mass by the CDF and D0 Collaborations at the Fermilab Tevatron. They present a new top mass measurement using the t{bar t} events collected by the D0 Collaboration in Run I between 1994 and 1996. This result is combined with previous measurements to yield a new world top mass average. They also describe several preliminary results using up to 193 pb{sup -1} of t{bar t} events produced in {bar p}p collisions at {radical}s = 1.96 TeV during the Run II of the Tevatron.

  5. Top Quark Spin Correlations at the Tevatron

    SciTech Connect (OSTI)

    Head, Tim; /Manchester U.

    2010-07-01

    Recent measurements of the correlation between the spin of the top and the spin of the anti-top quark produced in proton anti-proton scattering at a center of mass energy of {radical}s = 1.96 Tev by the CDF and D0 collaborations are discussed. using up to 4.3 fb{sup -1} of data taken with the CDF and D0 detectors the spin correlation parameter C, the degree to which the spins are correlated, is measured in dileptonic and semileptonic final states. The measurements are found to be in agreement with Standard Model predictions.

  6. Chromodynamic fluctuations in quark-gluon plasma

    SciTech Connect (OSTI)

    Mrowczynski, Stanislaw

    2008-05-15

    Fluctuations of chromodynamic fields in the collisionless quark-gluon plasma are found as a solution of the initial value linearized problem. The plasma initial state is on average colorless, stationary, and homogeneous. When the state is stable, the initial fluctuations decay exponentially and in the long-time limit a stationary spectrum of fluctuations is established. For the equilibrium plasma it reproduces the spectrum which is provided by the fluctuation-dissipation relation. Fluctuations in the unstable plasma, where the memory of initial fluctuations is not lost, are also discussed.

  7. Geek-Up[11.05.10]: Quark Gluon Plasma, Solar-Power Generating...

    Broader source: Energy.gov (indexed) [DOE]

    which will be used to investigate the quark gluon plasma - a state of matter ... The LHC experiments' investigations into how the quark gluon plasma behaves at such ...

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

    Office of Scientific and Technical Information (OSTI)

    ... FERMILAB TEVATRON; INTERMEDIATE BOSONS; LEPTONS; LUMINOSITY; MATRIX ELEMENTS; NEURAL NETWORKS; QUARKS; RESOLUTION; T QUARKS Experiment-HEP Word Cloud More Like This Full Text ...

  9. VariableR reclustering in multiple top quark events - Oral Presentatio...

    Office of Scientific and Technical Information (OSTI)

    VariableR reclustering in multiple top quark events - Oral Presentation Citation Details In-Document Search Title: VariableR reclustering in multiple top quark events - Oral...

  10. Nucleon g{sub 2} Structure Function and Quark-Gluon Correlations...

    Office of Scientific and Technical Information (OSTI)

    Country of Publication: United States Language: English Subject: 72 PHYSICS OF ELEMENTARY ... QUARK-GLUON INTERACTIONS; QUARKS; SPIN; STRUCTURE FUNCTIONS Word Cloud More Like This Full ...

  11. Quark masses, the Dashen phase, and gauge field topology

    SciTech Connect (OSTI)

    Creutz, Michael

    2013-12-15

    The CP violating Dashen phase in QCD is predicted by chiral perturbation theory to occur when the up–down quark mass difference becomes sufficiently large at fixed down-quark mass. Before reaching this phase, all physical hadronic masses and scattering amplitudes are expected to behave smoothly with the up-quark mass, even as this mass passes through zero. In Euclidean space, the topological susceptibility of the gauge fields is positive at positive quark masses but diverges to negative infinity as the Dashen phase is approached. A zero in this susceptibility provides a tentative signal for the point where the mass of the up quark vanishes. I discuss potential ambiguities with this determination. -- Highlights: •The CP violating Dashen phase in QCD occurs when the up quark mass becomes sufficiently negative. •Before reaching this phase, all physical hadronic masses and scattering amplitudes behave smoothly with the up-quark mass. •The topological susceptibility of the gauge fields diverges to negative infinity as the Dashen phase is approached. •A zero in the topological susceptibility provides a tentative signal for the point where the mass of the up quark vanishes. •The universality of this definition remains unproven. Potential ambiguities are discussed.

  12. The Thomas–Fermi quark model: Non-relativistic aspects

    SciTech Connect (OSTI)

    Liu, Quan Wilcox, Walter

    2014-02-15

    The first numerical investigation of non-relativistic aspects of the Thomas–Fermi (TF) statistical multi-quark model is given. We begin with a review of the traditional TF model without an explicit spin interaction and find that the spin splittings are too small in this approach. An explicit spin interaction is then introduced which entails the definition of a generalized spin “flavor”. We investigate baryonic states in this approach which can be described with two inequivalent wave functions; such states can however apply to multiple degenerate flavors. We find that the model requires a spatial separation of quark flavors, even if completely degenerate. Although the TF model is designed to investigate the possibility of many-quark states, we find surprisingly that it may be used to fit the low energy spectrum of almost all ground state octet and decuplet baryons. The charge radii of such states are determined and compared with lattice calculations and other models. The low energy fit obtained allows us to extrapolate to the six-quark doubly strange H-dibaryon state, flavor symmetric strange states of higher quark content and possible six quark nucleon–nucleon resonances. The emphasis here is on the systematics revealed in this approach. We view our model as a versatile and convenient tool for quickly assessing the characteristics of new, possibly bound, particle states of higher quark number content. -- Highlights: • First application of the statistical Thomas–Fermi quark model to baryonic systems. • Novel aspects: spin as generalized flavor; spatial separation of quark flavor phases. • The model is statistical, but the low energy baryonic spectrum is successfully fit. • Numerical applications include the H-dibaryon, strange states and nucleon resonances. • The statistical point of view does not encourage the idea of bound many-quark baryons.

  13. Basic features of the pion valence-quark distribution function

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

    Chang, Lei; Mezrag, Cdric; Moutarde, Herv; Roberts, Craig D.; Rodrguez-Quintero, Jose; Tandy, Peter C.

    2014-10-07

    The impulse-approximation expression used hitherto to define the pion's valence-quark distribution function is flawed because it omits contributions from the gluons which bind quarks into the pion. A corrected leading-order expression produces the model-independent result that quarks dressed via the rainbowladder truncation, or any practical analogue, carry all the pion's light-front momentum at a characteristic hadronic scale. Corrections to the leading contribution may be divided into two classes, responsible for shifting dressed-quark momentum into glue and sea-quarks. Working with available empirical information, we use an algebraic model to express the principal impact of both classes of corrections. This enables amorerealistic comparison with experiment that allows us to highlight the basic features of the pion's measurable valence-quark distribution, q?(x); namely, at a characteristic hadronic scale, q?(x)~(1-x)2 for x?0.85; and the valence-quarks carry approximately two-thirds of the pion's light-front momentum.less

  14. S-wave QQqq state in the constituent quark model

    SciTech Connect (OSTI)

    Yang Youchang; Deng Chengrong; Ping Jialun; Goldman, T.

    2009-12-01

    Many proposals have been put forward to explore four-quark states QQqq (Q=s, c, b; q=u, d) by experiment, so a systematic study of QQqq spectrum with different constituent quark models by a high precision, few-body method, the Gaussian expression method, is useful. Three quark models: the Bhaduri, Cohler, Nogami quark model, the chiral quark model (ChQM), and the quark delocalization color screening model are all employed for a systematic calculation of the S-wave QQqq spectrum with different color structures, using the Gaussian expression method. The results show that only the bbqq state with (I,J)=(0,1) is bound in different color structures within the different quark models. The binding energy varies from several MeV for a di-meson structure to over 100 MeV for a diquark-antidiquark structure. For the ccqq system, the state with (I,J)=(0,1) is bound in a di-meson structure, and also bound in a diquark-antidiquark structure if pseudoscalar meson exchanges are accounted for. All are weakly bound states. The mixture of diquark-antidiquark and molecular structures is discussed in the framework of quark models for the first time; ccqq with (I,J)=(0,1) is below the threshold in addition to bbqq in both the ChQM and the Bhaduri, Cohler, Nogami quark model. In the same channel, ssqq is also a possible bound state with mass around 1.4 GeV in ChQM.

  15. Theory of hadronic production of heavy quarks

    SciTech Connect (OSTI)

    Peterson, C.

    1981-07-01

    Conventional theoretical predictions for hadronic production of heavy quarks (Q anti Q) are reviewed and confronted with data. Perturbative hard scattering predictions agree qualitatively well with hidden Q anti Q production (e.g., psi, chi, T) whereas for open Q anti Q-production (e.g., pp ..-->.. ..lambda../sub c//sup +/X) additional mechanisms or inputs are needed to explain the forwardly produced ..lambda../sub c//sup +/ at ISR. It is suggested that the presence of c anti c-pairs on the 1 to 2% level in the hadron Fock state decomposition (intrinsic charm) gives a natural description of the ISR data. The theoretical foundations of the intrinsic charm hypotheses together with its consequences for lepton-induced reactions is discussed in some detail.

  16. Top quark and SUSY (supersymmetric) searches at CDF

    SciTech Connect (OSTI)

    Yeh, G.P.

    1990-05-17

    Searches for the top quark in p{bar p} collisions at {radical}s = 1.8 TeV are described. The analyses are based on data with an integrated luminosity of 4.4 pb{sup {minus}1} recorded with the Collider Detector at Fermilab in the 1988--1989 run. An upper limit on the t{bar t} cross section is obtained. The top quark with mass below 89 GeV/c{sup 2} is excluded at the 95% CL. Prospects for searches for the top quark in the future are presented. We also briefly present results on searches for supersymmetric particles. 14 refs., 10 figs.

  17. Top quark production and properties at the Tevatron

    SciTech Connect (OSTI)

    Fiedler, Frank; /Munich U.

    2005-06-01

    The precise measurement of top quark production and properties is one of the primary goals of the Tevatron during Run II. The total t{bar t} production cross-section has been measured in a large variety of decay channels and using different selection criteria. Results from differential cross-section measurements and searches for new physics in t{bar t} production and top quark decays are available. Electroweak production of single top quarks has been searched for. The results from all these analyses, using typically 200 pb{sup -1} of data, are presented.

  18. B-Bbar Mixing and Matching with Fermilab Heavy Quarks

    SciTech Connect (OSTI)

    Evans, Richard Todd; Gamiz, Elvira; El-Khadra, Aida; Kronfeld, Andreas; /Fermilab

    2009-11-01

    We discuss the matching procedure for heavy-light 4-quark operators using the Fermilab method for heavy quarks and staggered fermions for light quarks. These ingredients enable us to construct the continuum-limit operator needed to determine the oscillation frequency of neutral B mesons. The matching is then carried out at the one-loop level. We also present an updated preliminary result for the SU(3)-breaking ratio {zeta}, based on calculations using the MILC Collaboration's ensembles of lattice gauge fields.

  19. Quarkonium in a weakly-coupled quark-gluon plasma

    SciTech Connect (OSTI)

    Vairo, Antonio

    2010-12-22

    We report about a recent calculation of the heavy quarkonium mass and decay width in a quark-gluon plasma, whose temperature T and screening mass m{sub D} satisfy the hierarchy m{alpha}{sub s}>>T>>m{alpha}{sub s}{sup 2}>>m{sub D}, m being the heavy-quark mass, up to order m{alpha}{sub s}{sup 5}. The calculation may be relevant to understand the behavior of the {Upsilon}(1S) in a quark-gluon plasma at present-day colliders.

  20. Union zur F rderung von Oel und Proteinpflanzen Ufop | Open Energy...

    Open Energy Info (EERE)

    zur F rderung von Oel und Proteinpflanzen Ufop Jump to: navigation, search Name: Union zur Frderung von Oel- und Proteinpflanzen (Ufop) Place: Germany Product: Germany-based...

  1. Quark mass variation constraints from Big Bang nucleosynthesis...

    Office of Scientific and Technical Information (OSTI)

    In order to navigate through the particle and nuclear physics required to connect quark masses to binding energies and reaction rates in a model-independent way we use lattice QCD ...

  2. Time evolution of the quark-gluon plasma

    SciTech Connect (OSTI)

    Cooper, F. |

    1993-03-01

    We review progress in our understanding the production and time evolution of the quark gluon plasma starting with boost invariant initial conditions in a filed theory model based on the Schwinger mechanism of particle production via tunneling.

  3. Recent results in b quark physics at CDF

    SciTech Connect (OSTI)

    Farrington, Sinead M.; /Liverpool U.

    2007-12-01

    The summer 2007 results in b quark physics in 0.7 to 2.2 fb{sup -1} of CDFII data are summarized. Results in b production, mixing, new observations and branching ratio measurements are discussed.

  4. The top quark, 20 years after its discovery

    SciTech Connect (OSTI)

    Denisov, Dmitri; Vellidis, Costas

    2015-04-15

    The heaviest of nature’s elementary particles plays an outsized role in many fundamental processes. But because the top quark is so massive, it eluded experimental detection for nearly two decades.

  5. Quark mass functions and pion structure in Minkowski space

    SciTech Connect (OSTI)

    Biernat, Elmer P.; Gross, Franz L.; Pena, Maria Teresa; Stadler, Alfred

    2014-03-01

    We present a study of the dressed quark mass function and the pion structure in Minkowski space using the Covariant Spectator Theory (CST). The quark propagators are dressed with the same kernel that describes the interaction between different quarks. We use an interaction kernel in momentum space that is a relativistic generalization of the linear confining q-qbar potential and a constant potential shift that defines the energy scale. The confining interaction has a Lorentz scalar part that is not chirally invariant by itself but decouples from the equations in the chiral limit and therefore allows the Nambu--Jona-Lasinio (NJL) mechanism to work. We adjust the parameters of our quark mass function calculated in Minkowski-space to agree with LQCD data obtained in Euclidean space. Results of a calculation of the pion electromagnetic form factor in the relativistic impulse approximation using the same mass function are presented and compared with experimental data.

  6. Top Quark Anomalous Couplings at the International Linear Collider...

    Office of Scientific and Technical Information (OSTI)

    This process probes the elementary couplings of the top quark to the photon, the Z and the W bosons at a level of precision that is difficult to achieve at hadron colliders. ...

  7. Top quark properties from the Tevatron (Conference) | SciTech...

    Office of Scientific and Technical Information (OSTI)

    about 172 GeVcsup 2, the top quark provides a unique environment for tests of the Standard Model and is believed to yield sensitivity to new physics beyond the Standard Model. ...

  8. Evidence for electroweak top quark production in proton-antiproton...

    Office of Scientific and Technical Information (OSTI)

    acceptance, background, and observed data we measure the single top quark cross section: sigma(pbar p yields tb + tqb + X) 4.6sub -1.5sup +1.8 pb. The probability for...

  9. Fermilab | Newsroom | Press Releases | September 27, 2012: QuarkNet...

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

    RELEASE QuarkNet program receives 6.1 million NSF award to advance science education Hi-res | Med-res Steven Grosland, physics teacher at Glenbrook South High School in...

  10. Observation of $t$-channel electroweak top quark production

    SciTech Connect (OSTI)

    Triplett, Nathan; /Iowa State U.

    2011-04-01

    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

  11. The top quark (20 years after the discovery)

    SciTech Connect (OSTI)

    Boos, Eduard; Brandt, Oleg; Denisov, Dmitri; Denisov, Sergey; Grannis, Paul

    2015-09-10

    On the twentieth anniversary of the observation of the top quark, we trace our understanding of this heaviest of all known particles from the prediction of its existence, through the searches and discovery, to the current knowledge of its production mechanisms and properties. We also discuss the central role of the top quark in the Standard Model and the windows that it opens for seeking new physics beyond the Standard Model.

  12. Equilibrium Distribution of Heavy Quarks in Fokker-Planck Dynamics

    SciTech Connect (OSTI)

    Walton, D. Brian; Rafelski, Johann

    2000-01-03

    We obtain an explicit generalization, within Fokker-Planck dynamics, of Einstein's relation between drag, diffusion, and the equilibrium distribution for a spatially homogeneous system, considering both the transverse and longitudinal diffusion for dimension n>1 . We provide a complete characterization of the equilibrium distribution in terms of the drag and diffusion transport coefficients. We apply this analysis to charm quark dynamics in a thermal quark-gluon plasma for the case of collisional equilibration. (c) 1999 The American Physical Society.

  13. Reconstructing top quark-antiquark events with one lost jet

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

    Demina, Regina; Harel, Amnon; Orbaker, Douglas

    2015-04-02

    We present a technique for reconstructing the kinematics of pair-produced top quarks that decay to a charged lepton, a neutrino and four final state quarks in the subset of events where only three jets are reconstructed. We present a figure of merit that allows for a fair comparison of reconstruction algorithms without requiring their calibration. The new reconstruction of events with only three jets is fully competitive with the full reconstruction typically used for four-jet events.

  14. Probing a "Sea" of Quarks | Jefferson Lab

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

    Probing a &quot;Sea&quot; of Quarks Probing a "Sea" of Quarks March 1999 Scientists who conducted the Department of Energy's Thomas Jefferson National Accelerator Facility (Jefferson Lab) Hall A Proton Parity Experiment, or HAPPEX, believe they may have at least a partial answer for an outstanding question in nuclear physics: Where does a proton's spin come from? Syracuse University professor of Physics Paul Souder, a primary HAPPEX architect and co-spokesman for the

  15. Dark matter and dark energy from quark bag model

    SciTech Connect (OSTI)

    Brilenkov, Maxim; Eingorn, Maxim; Jenkovszky, Laszlo; Zhuk, Alexander E-mail: maxim.eingorn@gmail.com E-mail: ai.zhuk2@gmail.com

    2013-08-01

    We calculate the present expansion of our Universe endowed with relict colored objects quarks and gluons that survived hadronization either as isolated islands of quark-gluon ''nuggets'' or spread uniformly in the Universe. In the first scenario, the QNs can play the role of dark matter. In the second scenario, we demonstrate that uniform colored objects can play the role of dark energy providing the late-time accelerating expansion of the Universe.

  16. Anomalies of quark diagrams in the decay eta. --> pi. /sup 0/. gamma gamma. and the quark structure of the scalar meson delta(980)

    SciTech Connect (OSTI)

    Ivanov, A.N.; Troitskaya, N.I.

    1982-08-01

    The width of the decay eta..--> pi../sup 0/..gamma gamma.. is calculated in the model of dominance of quark loop anomalies. We investigate the contribution of the scalar meson delta(980) for two versions of its quark structure: a) the delta meson is a /sup 2/P/sub 0/ state of a quark-antiquark pair, b) the delta meson is a quark molecule of the type qqqq. We discuss the results.

  17. Big Bang Day: 5 Particles - 2. The Quark

    SciTech Connect (OSTI)

    None

    2009-10-07

    Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 2. The Quark "Three Quarks for Master Mark! Sure he hasn't got much of a bark." James Joyce's Finnegans Wake left its mark on modern physics when physicist Murray Gell Mann proposed this name for a group of hypothetical subatomic particles that were revealed in 1960 as the fundamental units of matter. Basic particles it seems are made up of even more basic units called quarks that make up 99.9% of visible material in the universe.. But why do we know so little about them? Quarks have never been seen as free particles but instead, inextricably bound together by the Strong Force that in turn holds the atomic nucleus together. This is the hardest of Nature's fundamental forces to crack, but recent theoretical advances, mean that the properties of the quark are at last being revealed.

  18. Improved determination of the width of the top quark

    SciTech Connect (OSTI)

    Abazov V. M.; Abbott B.; Acharya B. S.; Adams M.; Adams T.; Alexeev G. D.; Alkhazov G.; Alton A.; Alverson G.; Aoki M.; Askew A.; Asman B.; Atkins S.; Atramentov O.; Augsten K.; Avila C.; BackusMayes J.; Badaud F.; Bagby L.; Baldin B.; Bandurin D. V.; Banerjee S.; Barberis E.; Baringer P.; Barreto J.; Bartlett J. F.; Bassler U.; Bazterra V.; Bean A.; Begalli M.; Belanger-Champagne C.; Bellantoni L.; Beri S. B.; Bernardi G.; Bernhard R.; Bertram I.; Besancon M.; Beuselinck R.; Bezzubov V. A.; Bhat P. C.; Bhatia S.; Bhatnagar V.; Blazey G.; Blessing S.; Bloom K.; Boehnlein A.; Boline D.; Boos E. E.; Borissov G.; Bose T.; Brandt A.; Brandt O.; Brock R.; Brooijmans G.; Bross A.; Brown D.; Brown J.; Bu X. B.; Buehler M.; Buescher V.; Bunichev V.; Burdin S.; Burnett T. H.; Buszello C. P.; Calpas B.; Camacho-Perez E.; Carrasco-Lizarraga M. A.; Casey C. K.; Castilla-Valdez H.; Chakrabarti S.; Chakraborty D.; Chan M.; Chandra A.; Chapon E.; Chen G.; Chevalier-Thery S.; Cho D. K.; Cho S. W.; Choi S.; Choudhary B.; Cihangir S.; Claes D.; Clutter J.; Cooke M.; Cooper W. E.; Corcoran M.; Couderc F.; Cousinou M. -C.; Croc A.; Cutts D.; Das A.; Davies G.; de Jong S. J.; De La Cruz-Burelo E.; Deliot F.; Demina R.; Denisov D.; Denisov S. P.; Desai S.; Deterre C.; DeVaughan K.; Diehl H. T.; Diesburg M.; Ding P. F.; Dominguez A.; Dorland T.; Dubey A.; Dudko L. V.; Duggan D.; Duperrin A.; Dutt S.; Dyshkant A.; Eads M.; Edmunds D.; Ellison J.; Elvira V. D.; Enari Y.; Evans H.; Evdokimov A.; Evdokimov V. N.; Facini G.; Ferbel T.; Fiedler F.; Filthaut F.; Fisher W.; Fisk H. E.; Fortner M.; Fox H.; Fuess S.; Garcia-Bellido A.; Garcia-Guerra G. A.; Gavrilov V.; Gay P.; Geng W.; Gerbaudo D.; Gerber C. E.; Gershtein Y.; Ginther G.; Golovanov G.; Goussiou A.; Graf C. P.; Grannis P. D.; Greder S.; Greenlee H.; Greenwood Z. D.; Gregores E. M.; Grenier G.; Gris Ph.; Grivaz J. -F.; Grohsjean A.; Gruenendahl S.; Gruenewald M. W.; Guillemin T.; Gutierrez G.; Gutierrez P.; Haas A.; Hagopian S.; Haley J.; Han L.; Harder K.; Harel A.; Hauptman J. M.; Hays J.; Head T.; Hebbeker T.; Hedin D.; Hegab H.; Heinson A. P.; Heintz U.; Hensel C.; La Cruz I. Heredia-De; Herner K.; Hesketh G.; Hildreth M. D.; Hirosky R.; Hoang T.; Hobbs J. D.; Hoeneisen B.; Hohlfeld M.; Hubacek Z.; Hynek V.; Iashvili I.; Ilchenko Y.; Illingworth R.; Ito A. S.; Jabeen S.; Jaffre M.; Jamin D.; Jayasinghe A.; Jesik R.; Johns K.; Johnson M.; Jonckheere A.; Jonsson P.; Joshi J.; Jung A. W.; Juste A.; Kaadze K.; Kajfasz E.; Karmanov D.; Kasper P. A.; Katsanos I.; Kehoe R.; Kermiche S.; Khalatyan N.; Khanov A.; Kharchilava A.; Kharzheev Y. N.; Kohli J. M.; Kozelov A. V.; Kraus J.; Kulikov S.; Kumar A.; Kupco A.; Kurca T.; Kuzmin V. A.; Lammers S.; Landsberg G.; Lebrun P.; Lee H. S.; Lee S. W.; Lee W. M.; Lellouch J.; Li H.; Li L.; Li Q. Z.; Lietti S. M.; Lim J. K.; Lincoln D.; Linnemann J.; Lipaev V. V.; Lipton R.; Liu Y.; Lobodenko A.; Lokajicek M.; de Sa R. Lopes; Lubatti H. J.; Luna-Garcia R.; Lyon A. L.; Maciel A. K. A.; Mackin D.; Madar R.; Magana-Villalba R.; Malik S.; Malyshev V. L.; Maravin Y.; Martinez-Ortega J.; McCarthy R.; McGivern C. L.; Meijer M. M.; Melnitchouk A.; Menezes D.; Mercadante P. G.; Merkin M.; et al.

    2012-05-04

    We present an improved determination of the total width of the top quark, {Gamma}{sub t}, using 5.4 fb{sup -1} of integrated luminosity collected by the D0 Collaboration at the Tevatron p{bar p} Collider. The total width {Gamma}{sub t} is extracted from the partial decay width {Gamma}(t {yields} Wb) and the branching fraction {Beta}(t {yields} Wb). {Gamma}(t {yields} Wb) is obtained from the t-channel single top-quark production cross section and {Beta}(t {yields} Wb) is measured in t{bar t} events. For a top mass of 172.5 GeV, the resulting width is {Gamma}{sub t} = 2.00{sub -0.43}{sup +0.47} GeV. This translates to a top-quark lifetime of {tau}{sub t} = (3.29{sub -0.63}{sup +0.90}) x 10{sup -25} s. We also extract an improved direct limit on the Cabibbo-Kobayashi-Maskawa quark-mixing matrix element 0.81 < |V{sub tb}| {le} 1 at 95% C.L. and a limit of |V{sub tb}| < 0.59 for a high-mass fourth-generation bottom quark assuming unitarity of the fourth-generation quark-mixing matrix.

  19. Big Bang Day: 5 Particles - 2. The Quark

    ScienceCinema (OSTI)

    None

    2011-04-25

    Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 2. The Quark "Three Quarks for Master Mark! Sure he hasn't got much of a bark." James Joyce's Finnegans Wake left its mark on modern physics when physicist Murray Gell Mann proposed this name for a group of hypothetical subatomic particles that were revealed in 1960 as the fundamental units of matter. Basic particles it seems are made up of even more basic units called quarks that make up 99.9% of visible material in the universe.. But why do we know so little about them? Quarks have never been seen as free particles but instead, inextricably bound together by the Strong Force that in turn holds the atomic nucleus together. This is the hardest of Nature's fundamental forces to crack, but recent theoretical advances, mean that the properties of the quark are at last being revealed.

  20. Constituent quark scaling violation due to baryon number transport

    SciTech Connect (OSTI)

    Dunlop J. C.; Lisa, M.A., Sorensen, P.

    2011-10-31

    In ultrarelativistic heavy-ion collisions at {radical}s{sub NN} {approx} 200 GeV, the azimuthal emission anisotropy of hadrons with low and intermediate transverse momentum (p{sub T} {approx}< 4 GeV/c) displays an intriguing scaling. In particular, the baryon (meson) emission patterns are consistent with a scenario in which a bulk medium of flowing quarks coalesces into three-quark (two-quark) 'bags.' While a full understanding of this number-of-constituent-quark (NCQ) scaling remains elusive, it is suggestive of a thermalized bulk system characterized by colored dynamical degrees of freedom - a quark-gluon plasma (QGP). In this scenario, one expects the scaling to break down as the central energy density is reduced below the QGP formation threshold; for this reason, NCQ-scaling violation searches are of interest in the energy scan program at the Relativistic Heavy Ion Collider. However, as {radical}s{sub NN} is reduced, it is not only the initial energy density that changes; there is also an increase in the net baryon number at midrapidity, as stopping transports entrance-channel partons to midrapidity. This phenomenon can result in violations of simple NCQ scaling. Still in the context of the quark coalescence model, we describe a specific pattern for the breakdown of the scaling that includes different flow strengths for particles and their antipartners. Related complications in the search for recently suggested exotic phenomena are also discussed.

  1. Jet conversions in a quark-gluon plasma

    SciTech Connect (OSTI)

    Liu, W.; Ko, C. M.; Zhang, B. W.

    2007-05-15

    Quark and gluon jets traversing through a quark-gluon plasma not only lose their energies but also can undergo flavor conversions. The conversion rates via the elastic q(q)g{yields}gq(q) and the inelastic qq{r_reversible}gg scatterings are evaluated in the lowest order in QCD. Including both jet energy loss and conversions in the expanding quark-gluon plasma produced in relativistic heavy ion collisions, we have found a net of quark jets to gluon jets. This reduces the difference between the nuclear modification factors for quark and gluon jets in central heavy ion collisions and thus enhances the p/{pi}{sup +} and p/{pi}{sup -} ratios at high transverse momentum. However, a much larger net quark-to-gluon jet conversion rate than the one given by the lowest order QCD is needed to account for the observed similar ratios in central Au+Au and p+p collisions at the same energy. Implications of our results are discussed.

  2. Sketching the pion's valence-quark generalised parton distribution

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

    Mezrag, C.; Chang, L.; Moutarde, H.; Roberts, C. D.; Rodrguez-Quintero, J.; Sabati, F.; Schmidt, S. M.

    2015-02-01

    In order to learn effectively from measurements of generalised parton distributions (GPDs), it is desirable to compute them using a framework that can potentially connect empirical information with basic features of the Standard Model. We sketch an approach to such computations, based upon a rainbow-ladder (RL) truncation of QCDs DysonSchwinger equations and exemplified via the pions valence dressed-quark GPD, Hv?(x, ?, t). Our analysis focuses primarily on ?=0, although we also capitalise on the symmetry-preserving nature of the RL truncation by connecting Hv?(x, ?=1, t)with the pions valence-quark parton distribution amplitude. We explain that the impulse-approximation used hitherto to definemorethe pions valence dressed-quark GPD is generally invalid owing to omission of contributions from the gluons which bind dressed-quarks into the pion. A simple correction enables us to identify a practicable improvement to the approximation for Hv?(x, 0, t), expressed as the Radon transform of a single amplitude. Therewith we obtain results for Hv?(x, 0, t) and the associated impact-parameter dependent distribution, qv?(x, |b?|), which provide a qualitatively sound picture of the pions dressed-quark structure at a hadronic scale. We evolve the distributions to a scale ? = 2 GeV, so as to facilitate comparisons in future with results from experiment or other nonperturbative methods.less

  3. Top quark mass measurement using the template method at CDF

    SciTech Connect (OSTI)

    Aaltonen, T; Alvarez Gonzalez, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Apresyan, A; Arisawa, T

    2011-06-03

    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 = 172.11.1 (stat)0.9 (syst) GeV/c2.

  4. Top quark mass measurement using the template method at CDF

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

    Aaltonen, T

    2011-06-03

    We present a measurement of the top quark mass in the lepton+jets and dilepton channels of tmore » $$\\bar{t}$$ decays using the template method. The data sample corresponds to an integrated luminosity of 5.6 fb-1 of p$$\\bar{p}$$ 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.« less

  5. Determination of the width of the top quark

    SciTech Connect (OSTI)

    Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Abolins, Maris A.; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Alexeev, Guennadi D.; Alkhazov, Georgiy D.; Alton, Andrew K.; Alverson, George O.; Alves, Gilvan Augusto; /Rio de Janeiro, CBPF /Nijmegen U.

    2010-09-01

    We extract the total width of the top quark, {Lambda}{sub t}, from the partial decay width {Lambda}(t {yields} Wb) measured using the t-channel cross section for single top quark production and from the branching fraction B(t {yields} Wb) measured in t{bar t} events using up to 2.3 fb{sup -1} of integrated luminosity collected by the D0 Collaboration at the Tevatron p{bar p} Collider. The result is {Lambda}{sub t} = 1.99{sub -0.55}{sup +0.69} GeV, which translates to a top-quark lifetime of {tau}{sub t} = (3.3{sub -0.9}{sup +1.3}) x 10{sup -25} s. Assuming a high mass fourth generation b{prime} quark and unitarity of the four-generation quark-mixing matrix, we set the first upper limit on |V{sub tb{prime}}| < 0.63 at 95% C.L.

  6. Search for baryon number violation in top-quark decays

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

    Chatrchyan, Serguei

    2014-02-20

    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 electron), two jets, but no neutrino in the final state. Data used for the analysis were collected by the CMS detector and correspond to an integrated luminosity of 19.5 inverse femtobarns. The event selection is optimized for top quarks produced in pairs, with one undergoing the BNV decay and the other the standard model hadronic decay to three jets. No significant excessmore » of events over the expected yield from standard model processes is observed. The upper limits at 95% confidence level on the branching fraction of the BNV top-quark decay are calculated to be 0.0016 and 0.0017 for the muon and the electron channels, respectively. Assuming lepton universality, an upper limit of 0.0015 results from the combination of the two channels. These limits are the first that have been obtained on a BNV process involving the top quark.« less

  7. Spin Measurement in Top Quark Events at the LHC

    SciTech Connect (OSTI)

    Linacre, Jacob

    2015-01-01

    Measurements of polarisation and spin correlations are presented in events with top quarks produced in pp collisions at the LHC. The data correspond to integrated luminosities of $5 fb^{-1}$ at $\\sqrt{s}$ = 7 TeV and 20 $fb^{-1}$ at $\\sqrt{s}$ = 8 TeV collected with the ATLAS and CMS detectors. The top quark polarization is measured in both single top quark production in the t-channel and $t\\bar{t}$ pair-production, from the angular distributions of charged leptons in the rest frame of their parent top quark. The spin correlations are measured in $t\\bar{t}$ events using various angular distributions of the decay products. The measurements are made using both template fitting methods and by unfolding the distributions to the parton-level, where differential measurements with respect to the invariant mass, rapidity, and transverse momentum of the $t\\bar{t}$ system are also made. The spin correlation measurements are used to search for new physics in the form of a light top squark or an anomalous top quark chromo-magnetic dipole moment. All measurements are found to be in agreement with predictions of the standard model.

  8. Measurements of the top quark mass and decay width with the D0 detector

    SciTech Connect (OSTI)

    Ilchenko, Yuriy

    2011-11-01

    The top quark discovery in 1995 at Fermilab is one of the major proofs of the standard model (SM). Due to its unique place in SM, the top quark is an important particle for testing the theory and probing for new physics. This article presents most recent measurements of top quark properties from the D0 detector. In particular, the measurement of the top quark mass, the top antitop mass difference and the top quark decay width. The discovery of the top quark in 1995 confirmed the existence of a third generation of quarks predicted in the standard model (SM). Being the heaviest elementary particle known, the top quark appears to become an important particle in our understanding of the standard model and physics beyond it. Because of its large mass the top quark has a very short lifetime, much shorter than the hadronization time. The predicted lifetime is only 3.3 {center_dot} 10{sup -25}s. Top quark is the only quark whose properties can be studied in isolation. A Lorentz-invariant local Quantum Field Theory, the standard model is expected to conserve CP. Due to its unique properties, the top quark provides a perfect test of CPT invariance in the standard model. An ability to look at the quark before being hadronized allows to measure directly mass of the top quark and its antiquark. An observation of a mass difference between particle and antiparticle would indicate violation of CPT invariance. Top quark through its radiative loop correction to the W mass constrains the mass of the Higgs boson. A precise measurement of the top quark mass provides useful information to the search of Higgs boson by constraining its region of possible masses. Another interesting aspect is that the top quark's Yukawa coupling to the Higgs boson is very close to unity (0.996 {+-} 0.006). That implies it may play a special role in the electroweak symmetry breaking mechanism.

  9. Measurements of the Top Quark at the Tevatron Collider

    SciTech Connect (OSTI)

    Cerrito, Lucio

    2007-01-01

    The authors present recent preliminary measurements of the top-antitop pair production cross section and determinations of the top quark pole mass, performed using the data collected by the CDF and D0 Collaborations at the Tevatron Collider. In the lepton plus jets final state, with semileptonic B decay, the pair production cross section has now been measured at CDF using {approx} 760 pb{sup -1} of proton-antiproton collisions at a center-of-mass energy of {radical}s = 1.96 TeV. A measurement of the production cross section has also been made with {approx} 1 fb{sup -1} of data in the all-jets final state by the CDF Collaboration. The mass of the top quark has now been measured using {approx} 1 fb{sup -1} of collision data using all decay channels of the top quark pair, yielding the most precise measurements of the top mass to date.

  10. Neural Networks for Analysis of Top Quark Production

    SciTech Connect (OSTI)

    B. Abbott et al.

    1999-08-04

    Neural networks (NNs) provide a powerful and flexible tool for selecting a signal from a larger background. The D0 collaboration has used them extensively in studying t{anti t} decays. NNs were essential to the measurement of the t{anti t} production cross section in the all-jets channel (t{anti t} {yields} b {anti b}qqqq), and were also used in the measurement of the mass of the top quark in the lepton+jets channel (t{anti t} {yields} b{anti b}l{nu}q{anti q}). This paper will describe two new applications of neural networks to top quark analysis: the search for single top quark production, and an effort to increase the sensitivity in the dilepton channel t{anti t} {yields} b{anti b}e{anti {mu}}{nu}{anti {nu}} beyond that achieved in the published analysis.

  11. Measurement of the top quark mass in the dilepton channel

    SciTech Connect (OSTI)

    Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, M.; Adams, T.; Agelou, M.; Aguilo, E.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; /Buenos Aires U. /Rio de Janeiro, CBPF /Rio de Janeiro State U. /Sao Paulo, IFT /Alberta U. /Simon Fraser U. /York U., Canada /McGill U. /Hefei, CUST /Andes U., Bogota /Charles U.

    2006-09-01

    We present a measurement of the top quark mass in the dilepton channel based on approximately 370 pb{sup -1} of data collected by the D0 experiment during Run II of the Fermilab Tevatron collider. We employ two different methods to extract the top quark mass. We show that both methods yield consistent results using ensemble tests of events generated with the D0 Monte Carlo simulation. We combine the results from the two methods to obtain a top quark mass m{sub t} = 178.1 {+-} 8.2 GeV. The statistical uncertainty is 6.7 GeV and the systematic uncertainty is 4.8 GeV.

  12. INTERACTING QUARK MATTER EQUATION OF STATE FOR COMPACT STARS

    SciTech Connect (OSTI)

    Fraga, Eduardo S.; Kurkela, Aleksi; Vuorinen, Aleksi

    2014-02-01

    Lattice quantum chromodynamics (QCD) studies of the thermodynamics of hot quark-gluon plasma demonstrate the importance of accounting for the interactions of quarks and gluons if one wants to investigate the phase structure of strongly interacting matter. Motivated by this observation and using state-of-the-art results from perturbative QCD, we construct a simple, effective equation of state (EOS) for cold quark matter that consistently incorporates the effects of interactions and furthermore includes a built-in estimate of the inherent systematic uncertainties. This goes beyond the MIT bag model description in a crucial way, yet leads to an EOS that is equally straightforward to use. We also demonstrate that, at moderate densities, our EOS can be made to smoothly connect to hadronic EOSs, with the two exhibiting very similar behavior near the matching region. The resulting hybrid stars are seen to have masses similar to those predicted by the purely nucleonic EOSs.

  13. Nucleation of quark matter in the PQM model

    SciTech Connect (OSTI)

    Mintz, Bruno W.; Stiele, Rainer; Schaffner-Bielich, Juergen; Ramos, Rudnei O.

    2013-03-25

    We use Langer's theory to calculate the surface tension of critical bubbles in a first-order quark-hadron phase transition at moderate and high baryon chemical potential, as predicted by the Polyakov-Quark-Meson (PQM) model at the mean-field level. We define an effective 4-dimensional order parameter, which is used to overestimate the surface tension of nucleating bubbles within the thin-wall approximation. We find relatively low values for the surface tension, {Sigma} Less-Than-Or-Equivalent-To 15MeV/fm{sup 2}. This implies that a metastable state, such as a supercooled quark-gluon plasma (QGP), quickly decays even in regions relatively close to the coexistence line of the phase diagram. Possible consequences for cosmology are briefly outlined.

  14. Murray Gell-Mann, the Eightfold Way, Quarks, and Quantum Chromodynamic...

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

    Michael Riordan, "The Hunting of the Quark" Although he is a theoretical physicist, ... Murray Gell-Mann is author of the popular science book, The Quark and the Jaguar, ...

  15. G-Zero Experiment Proves Strange Quark Effects Not That Big ...

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

    G-Zero Experiment Proves Strange Quark Effects Not That Big G-Zero Experiment Proves Strange Quark Effects Not That Big Strange Wheel - This ferris wheel is part of a system that ...

  16. Pion cloud and sea quark flavor asymmetry in the impact parameter...

    Office of Scientific and Technical Information (OSTI)

    Pion cloud and sea quark flavor asymmetry in the impact parameter representation Citation Details In-Document Search Title: Pion cloud and sea quark flavor asymmetry in the impact ...

  17. Rare {Lambda}{sub b} decays in a quark model

    SciTech Connect (OSTI)

    Mott, L.; Roberts, W.

    2010-08-05

    Hadronic form factors for the rare weak transitions {Lambda}{sub b{yields}{Lambda}}{sup (*)} are calculated using a nonrelativistic quark model. The form factors obtained in this way are found to satisfy the relationships expecetd from the heavy quark effective theory. Differential decay rates and branching ratios are calculated for the dileptonic decays {Lambda}{sub b{yields}{Lambda}}{sup (*)}l{sup +}l{sup -}, for both ground state and excited daughter baryons. Inclusion of the long distance contributions from charmonium resonances significantly enhances the decay rates. Future work is outlined.

  18. Integral equation for gauge invariant quark Green's function

    SciTech Connect (OSTI)

    Sazdjian, H.

    2008-08-29

    We consider gauge invariant quark two-point Green's functions in which the gluonic phase factor follows a skew-polygonal line. Using a particular representation for the quark propagator in the presence of an external gluon field, functional relations between Green's functions with different numbers of segments of the polygonal lines are established. An integral equation is obtained for the Green's function having a phase factor along a single straight line. The related kernels involve Wilson loops with skew-polygonal contours and with functional derivatives along the sides of the contours.

  19. Nuclear-matter--quark-matter phase diagram with strangeness

    SciTech Connect (OSTI)

    Barz, H. W.; Friman, B. L.; Knoll, J.; Schulz, H.

    1989-07-01

    A phenomenological equation of state of strongly interacting matter, including strange degrees of freedom, is presented. It is shown that the hyperon and kaon interactions must be included, in order to obtain a reasonable description of the deconfinement transition at high baryon densities. The consequences of kaon condensation on the nuclear-matter--quark-matter phase diagram are explored. The relative particle abundances obtained in an isentropic expansion of a blob of quark-gluon plasma are presented for different initial conditions. Implications for ultrarelativistic heavy-ion collisions are briefly discussed.

  20. 2013 JSA Postdoctoral Research Grant Winner to Compute Quarks | Jefferson

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

    Lab 2013 JSA Postdoctoral Research Grant Winner to Compute Quarks 2013 JSA Postdoctoral Research Grant Winner to Compute Quarks Chris Monahan Chris Monahan NEWPORT NEWS, Va., March 27 - Scientists have long puzzled over how the smallest bits of matter add up to the world around us. Now, Chris Monahan will use the power of a video gaming system to attempt a new method of exploring those bits. Monahan is the recipient of the 2013 JSA Postdoctoral Research Grant at the U.S. Department of

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

    SciTech Connect (OSTI)

    Contrera, G. A.; Gomez Dumm, D.; Scoccola, N. N.

    2010-11-12

    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.

  2. Top quark and higgs physics at the tevatron

    SciTech Connect (OSTI)

    Yao, WeiMing

    2004-10-01

    This is a writeup of my lectures given at the International Workshop on Frontiers of High Energy Physics, held at CCAST, Beijing, China during July 2-10. I discuss some basic experimental techniques for studying the Top quark and Higgsboson at the Tevatron, and review some recent results from CDF and D0 and their future prospects.

  3. Sea quark transverse momentum distributions and dynamical chiral symmetry breaking

    SciTech Connect (OSTI)

    Schweitzer, Peter; Strikman, Mark; Weiss, Christian

    2014-01-01

    Recent theoretical studies have provided new insight into the intrinsic transverse momentum distributions of valence and sea quarks in the nucleon at a low scale. The valence quark transverse momentum distributions (q - qbar) are governed by the nucleon's inverse hadronic size R{sup -1} ~ 0.2 GeV and drop steeply at large p{sub T}. The sea quark distributions (qbar) are in large part generated by non-perturbative chiral-symmetry breaking interactions and extend up to the scale rho{sup -1} ~ 0.6 GeV. These findings have many implications for modeling the initial conditions of perturbative QCD evolution of TMD distributions (starting scale, shape of p{sub T}. distributions, coordinate-space correlation functions). The qualitative difference between valence and sea quark intrinsic p{sub T}. distributions could be observed experimentally, by comparing the transverse momentum distributions of selected hadrons in semi-inclusive deep-inelastic scattering, or those of dileptons produced in pp and pbar-p scattering.

  4. Quark and lepton mixing as manifestations of violated mirror symmetry

    SciTech Connect (OSTI)

    Dyatlov, I. T.

    2015-06-15

    The existence of heavy mirror analogs of ordinary fermions would provide deeper insight into the gedanken paradox appearing in the Standard Model upon direct parity violation and consisting in a physical distinguishability of left- and right-hand coordinate frames. Arguments are presented in support of the statement that such mirror states may also be involved in the formation of observed properties of the system of Standard Model quarks and leptons—that is, their mass spectra and their weak-mixing matrices: (i) In the case of the involvement of mirror generations, the quark mixing matrix assumes the experimentally observed form. It is determined by the constraints imposed by weak SU(2) symmetry and by the quark-mass hierarchy. (ii) Under the same conditions and upon the involvement of mirror particles, the lepton mixing matrix (neutrino mixing) may become drastically different from its quark analog—the Cabibbo-Kobayashi-Maskawa matrix; that is, it may acquire properties suggested by experimental data. This character of mixing is also indicative of an inverse mass spectrum of Standard Model neutrinos and their Dirac (not Majorana) nature.

  5. Dynamics of pentaquarks in constituent quark models: recent developments

    SciTech Connect (OSTI)

    Stancu, Fl.

    2005-06-14

    Some recent developments in the study of light and heavy pentaquarks are reviewed, mainly within constituent quark models. Emphasis is made on results obtained in the flavor-spin model where a nearly ideal octet-antidecuplet mixing is obtained. The charmed antisextet is reviewed in the context of an SU(4) classification.

  6. Precision Top-Quark Mass Measurements at CDF

    SciTech Connect (OSTI)

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

    2012-07-01

    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}.

  7. Equation of state and heavy-quark free energy at finite temperature and density in two flavor lattice QCD with Wilson quark action

    SciTech Connect (OSTI)

    Ejiri, S.; Maezawa, Y.; Ukita, N.; Aoki, S.; Hatsuda, T.; Ishii, N.; Kanaya, K.; Umeda, T.

    2010-07-01

    We study the equation of state at finite temperature and density in two-flavor QCD with the renormalization group improved gluon action and the clover-improved Wilson quark action on a 16{sup 3}x4 lattice. Along the lines of constant physics at m{sub PS}/m{sub V}=0.65 and 0.80, we compute the second and forth derivatives of the grand canonical partition function with respect to the quark chemical potential {mu}{sub q}=({mu}{sub u}+{mu}{sub d})/2 and the isospin chemical potential {mu}{sub I}=({mu}{sub u}-{mu}{sub d})/2 at vanishing chemical potentials, and study the behaviors of thermodynamic quantities at finite {mu}{sub q} using these derivatives for the case {mu}{sub I}=0. In particular, we study density fluctuations at nonezero temperature and density by calculating the quark number and isospin susceptibilities and their derivatives with respect to {mu}{sub q}. To suppress statistical fluctuations, we also examine new techniques applicable at low densities. We find a large enhancement in the fluctuation of the quark number when the density increased near the pseudocritical temperature, suggesting a critical point at finite {mu}{sub q} terminating the first order transition line between hadronic and quark-gluon-plasma phases. This result agrees with the previous results using staggered-type quark actions qualitatively. Furthermore, we study heavy-quark free energies and Debye screening masses at finite density by measuring the first and second derivatives of these quantities for various color channels of heavy quark-quark and quark-antiquark pairs. The results suggest that, to the leading order of {mu}{sub q}, the interaction between two quarks becomes stronger at finite densities, while that between quark and antiquark becomes weaker.

  8. Uncovering the single top: observation of electroweak top quark production

    SciTech Connect (OSTI)

    Benitez, Jorge Armando; /Michigan State U.

    2009-08-01

    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.

  9. Final Report for Project. Quark matter under extreme conditions

    SciTech Connect (OSTI)

    Incera, Vivian; Ferrer, Efrain

    2015-12-31

    The results obtained in the two years of the grant have served to shine new light on several important questions about the phases of quantum chromodynamics (QCD) under extreme conditions that include quark matter at high density, as well quark-gluon plasma at high temperatures, both in the presence of strong magnetic fields. The interest in including an external magnetic field on these studies is motivated by the generation of large magnetic fields in off-central heavy-ion collisions and by their common presence in astrophysical compact objects, the two scenarios where the physics of quark matter becomes relevant. The tasks carried out in this DOE project led us, among other things, to discover the first connection between the physics of very dense quark matter and novel materials as for instance topological insulators and Weyl semimetals; they allowed us to find a physical explanation for and a solution to a standing puzzle in the apparent effect of a magnetic field on the critical temperature of the QCD chiral transition; and they led us to establish by the first time that the core of the observed two-solar-mass neutron stars could be made up of quark matter in certain inhomogeneous chiral phases in a magnetic field and that this was consistent with current astrophysical observations. A major goal established by the Nuclear Science Advisory committee in its most recent report “Reaching for the Horizon” has been “to truly understand how nuclei and strongly interacting matter in all its forms behave and can predict their behavior in new settings.” The results found in this DOE project have all contributed to address this goal, and thus they are important for advancing fundamental knowledge in the area of nuclear physics and for enhancing our understanding of the role of strong magnetic fields in the two settings where they are most relevant, neutron stars and heavy-ion collisions.

  10. Hadron structure in a simple model of quark/nuclear matter

    SciTech Connect (OSTI)

    Horowitz, C. J.; Moniz, Ernest J.; Negele, J. W.

    1985-04-01

    We study a simple model for one-dimensional hadron matter with many of the essential features needed for examining the transition from nuclear to quark matter and the limitations of models based upon hadron rather than quark degrees of freedom. The dynamics are generated entirely by the quark confining force and exchange symmetry. Using Monte Carlo techniques, the ground-state energy, single-quark momentum distribution, and quark correlation function are calculated for uniform matter as a function of density. The quark confinement scale in the medium increases substantially with increasing density. This change is evident in the correlation function and momentum distribution, in qualitative agreement with the changes observed in deep-inelastic lepton scattering. Nevertheless, the ground-state energy is smooth throughout the transition to quark matter and is described remarkably well by an effective hadron theory based on a phenomenological hadron-hadron potential.

  11. CSC/UND Team 3 | Open Energy Information

    Open Energy Info (EERE)

    CSCUND Team 3 < CSC Jump to: navigation, search Geothermal Case Study Challenge Geothermal CSC About Judging Schedule Areas How To Sign Up Connect UND Team 3 Team Info School:...

  12. CSC/UND Team 2 | Open Energy Information

    Open Energy Info (EERE)

    CSCUND Team 2 < CSC Jump to: navigation, search Geothermal Case Study Challenge Geothermal CSC About Judging Schedule Areas How To Sign Up Connect UND Team 2 Team Info School:...

  13. ELBE Betreuungs und Verwaltungsgesellschaft mbH | Open Energy...

    Open Energy Info (EERE)

    Betreuungs- und Verwaltungsgesellschaft mbH Place: Germany Product: Company created for tax purposes by M. Denker and M. Wulf to manages their shares in RE-Power References: ELBE...

  14. Shell Solar GmbH formerly Siemens und Shell Solar GmbH | Open...

    Open Energy Info (EERE)

    GmbH formerly Siemens und Shell Solar GmbH Jump to: navigation, search Name: Shell Solar GmbH (formerly Siemens und Shell Solar GmbH) Place: Munich, Bavaria, Germany Zip: 80807...

  15. Paradigma Energie und Umwelttechnik GmbH Co KG | Open Energy...

    Open Energy Info (EERE)

    Paradigma Energie und Umwelttechnik GmbH Co KG Jump to: navigation, search Name: Paradigma Energie- und Umwelttechnik GmbH & Co KG Place: Karlsbad, Germany Zip: 76307 Sector: Solar...

  16. Geothermie Unterhaching GmbH und Co KG | Open Energy Information

    Open Energy Info (EERE)

    Geothermie Unterhaching GmbH und Co KG Jump to: navigation, search Name: Geothermie Unterhaching GmbH und Co KG Place: Unterhaching, Bavaria, Germany Zip: 82008 Sector: Geothermal...

  17. NLO evolution of 3-quark Wilson loop operator

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

    Balitsky, I.; Grabovsky, A. V.

    2015-01-07

    It is well known that high-energy scattering of a meson from some hadronic target can be described by the interaction of that target with a color dipole formed by two Wilson lines corresponding to fast quark-antiquark pair. Moreover, the energy dependence of the scattering amplitude is governed by the evolution equation of this color dipole with respect to rapidity. Similarly, the energy dependence of scattering of a baryon can be described in terms of evolution of a three-Wilson-lines operator with respect to the rapidity of the Wilson lines. We calculate the evolution of the 3-quark Wilson loop operator in themore » next-to-leading order (NLO) and present a quasi-conformal evolution equation for a composite 3-Wilson-lines operator. Thus we also obtain the linearized version of that evolution equation describing the amplitude of the odderon exchange at high energies.« less

  18. Why should we care about the top quark Yukawa coupling?

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

    Shapshnikov, Mikhail; Bezrukov, Fedor

    2015-04-15

    In the cosmological context, for the Standard Model to be valid up to the scale of inflation, the top quark Yukawa coupling yt should not exceed the critical value ytcrit , coinciding with good precision (about 0.2‰) with the requirement of the stability of the electroweak vacuum. So, the exact measurements of yt may give an insight on the possible existence and the energy scale of new physics above 100 GeV, which is extremely sensitive to yt. In this study, we overview the most recent theoretical computations of and the experimental measurements of ytcrit and the experimental measurements ofmore » yt. Within the theoretical and experimental uncertainties in yt, the required scale of new physics varies from 10⁷ GeV to the Planck scale, urging for precise determination of the top quark Yukawa coupling.« less

  19. Angular correlations in top quark decays in standard model extensions

    SciTech Connect (OSTI)

    Batebi, S.; Etesami, S. M.; Mohammadi-Najafabadi, M.

    2011-03-01

    The CMS Collaboration at the CERN LHC has searched for the t-channel single top quark production using the spin correlation of the t-channel. The signal extraction and cross section measurement rely on the angular distribution of the charged lepton in the top quark decays, the angle between the charged lepton momentum and top spin in the top rest frame. The behavior of the angular distribution is a distinct slope for the t-channel single top (signal) while it is flat for the backgrounds. In this Brief Report, we investigate the contributions which this spin correlation may receive from a two-Higgs doublet model, a top-color assisted technicolor (TC2) and the noncommutative extension of the standard model.

  20. Forward-backward asymmetry in top quark-antiquark production

    SciTech Connect (OSTI)

    Abazov, V.M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G. A.; Aoki, M.; Arov, M.; Askew, A.; Asman, B.; Atramentov, O.; Avila, C.; BackusMayes, J.; Badaud, F.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Barberis, E.; Baringer, P.; Barreto, J.; Bartlett, J. F.; Bassler, U.; Bazterra, V.; Beale, S.; Bean, A.; Begalli, M.; Begel, M.; Belanger-Champagne, C.; Bellantoni, L.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besancon, M.; Beuselinck, R.; Bezzubov, V. A.; Bhat, P. C.; Bhatnagar, V.; Blazey, G.; Blessing, S.; Bloom, K.; Boehnlein, A.; Boline, D.; Boos, E. E.; Borissov, G.; Bose, T.; Brandt, A.; Brandt, O.; Brock, R.; Brooijmans, G.; Bross, A.; Brown, D.; Brown, J.; Bu, X. B.; Buehler, M.; Buescher, V.; Bunichev, V.; Burdin, S.; Burnett, T. H.; Buszello, C. P.; Calpas, B.; Camacho-Perez, E.; Carrasco-Lizarraga, M. A.; Casey, B. C. K.; Castilla-Valdez, H.; Chakrabarti, S.; Chakraborty, D.; Chan, K. M.; Chandra, A.; Chen, G.; Chevalier-Thery, S.; Cho, D. K.; Cho, S. W.; Choi, S.; Choudhary, B.; Cihangir, S.; Claes, D.; Clutter, J.; Cooke, M.; Cooper, W. E.; Corcoran, M.; Couderc, F.; Cousinou, M. -C.; Croc, A.; Cutts, D.; Das, A.; Davies, G.; De, K.; de Jong, S. J.; De La Cruz-Burelo, E.; Deliot, F.; Demarteau, M.; Demina, R.; Denisov, D.; Denisov, S. P.; Desai, S.; Deterre, C.; DeVaughan, K.; Diehl, H. T.; Diesburg, M.; Ding, P. F.; Dominguez, A.; Dorland, T.; Dubey, A.; Dudko, L. V.; Duggan, D.; Duperrin, A.; Dutt, S.; Dyshkant, A.; Eads, M.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Enari, Y.; Evans, H.; Evdokimov, A.; Evdokimov, V. N.; Facini, G.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Fortner, M.; Fox, H.; Fuess, S.; Garcia-Bellido, A.; Gavrilov, V.; Gay, P.; Geng, W.; Gerbaudo, D.; Gerber, C. E.; Gershtein, Y.; Ginther, G.; Golovanov, G.; Goussiou, A.; Grannis, P. D.; Greder, S.; Greenlee, H.; Greenwood, Z. D.; Gregores, E. M.; Grenier, G.; Gris, Ph; Grivaz, J. -F.; Grohsjean, A.; Gruenendahl, S.; Gruenewald, M. W.; Guillemin, T.; Guo, F.; Gutierrez, G.; Gutierrez, P.; Haas, A.; Hagopian, S.; Haley, J.; Han, L.; Harder, K.; Harel, A.; Hauptman, J. M.; Hays, J.; Head, T.; Hebbeker, T.; Hedin, D.; Hegab, H.; Heinson, A. P.; Heintz, U.; Hensel, C.; Heredia-De La Cruz, I.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hoang, T.; Hobbs, J. D.; Hoeneisen, B.; Hohlfeld, M.; Hubacek, Z.; Huske, N.; Hynek, V.; Iashvili, I.; Ilchenko, Y.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffre, M.; Jamin, D.; Jayasinghe, A.; Jesik, R.; Johns, K.; Johnson, M.; Johnston, D.; Jonckheere, A.; Jonsson, P.; Joshi, J.; Jung, A. W.; Juste, A.; Kaadze, K.; Kajfasz, E.; Karmanov, D.; Kasper, P. A.; Katsanos, I.; Kehoe, R.; Kermiche, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. N.; Kirby, M. H.; Kohli, J. M.; Kozelov, A. V.; Kraus, J.; Kulikov, S.; Kumar, A.; Kupco, A.; Kurca, T.; Kuzmin, V. A.; Kvita, J.; Lammers, S.; Landsberg, G.; Lebrun, P.; Lee, H. S.; Lee, S. W.; Lee, W. M.; Lellouch, J.; Li, L.; Li, Q. Z.; Lietti, S. M.; Lim, J. K.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, Y.; Liu, Z.; Lobodenko, A.; Lokajicek, M.; de Sa, R. Lopes; Lubatti, H. J.; Luna-Garcia, R.; Lyon, A. L.; Maciel, A. K. A.; Mackin, D.; Madar, R.; Magana-Villalba, R.; Malik, S.; Malyshev, V. L.; Maravin, Y.; Martinez-Ortega, J.; McCarthy, R.; McGivern, C. L.; Meijer, M. M.; Melnitchouk, A.; Menezes, D.; Mercadante, P. G.; Merkin, M.; Meyer, A.; Meyer, J.; Miconi, F.; Mondal, N. K.; Muanza, G. S.; Mulhearn, M.; Nagy, E.; Naimuddin, M.; Narain, M.; Nayyar, R.; Neal, H. A.; Negret, J. P.; Neustroev, P.; Novaes, S. F.; Nunnemann, T.; Obrant, G.; Orbaker, D.; Orduna, J.; Osman, N.; Osta, J.; et. al.

    2011-12-12

    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 data set corresponding to an integrated luminosity of 5.4 fb{sup -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.

  1. Forward-backward asymmetry in top quark-antiquark production

    SciTech Connect (OSTI)

    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.

    2011-12-12

    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.

  2. Thermal axion production in the primordial quark-gluon plasma

    SciTech Connect (OSTI)

    Graf, Peter; Steffen, Frank Daniel

    2011-04-01

    We calculate the rate for thermal production of axions via scattering of quarks and gluons in the primordial quark-gluon plasma. To obtain a finite result in a gauge-invariant way that is consistent to leading order in the strong gauge coupling, we use systematic field theoretical methods such as hard thermal loop resummation and the Braaten-Yuan prescription. The thermally produced yield, the decoupling temperature, and the density parameter are computed for axions with a mass below 10 meV. In this regime, with a Peccei-Quinn scale above 6x10{sup 8} GeV, the associated axion population can still be relativistic today and can coexist with the axion cold dark matter condensate.

  3. Quantum simulations of strongly coupled quark-gluon plasma

    SciTech Connect (OSTI)

    Filinov, V. S.; Ivanov, Yu. B.; Bonitz, M.; Levashov, P. R.; Fortov, V. E.

    2011-09-15

    A strongly coupled quark-gluon plasma (QGP) of heavy constituent quasiparticles is studied by a path-integral Monte-Carlo method. This approach is a quantum generalization of the model developed by B.A. Gelman, E.V. Shuryak, and I. Zahed. It is shown that this method is able to reproduce the QCD lattice equation of state and also yields valuable insight into the internal structure of the QGP. The results indicate that the QGP reveals liquid-like rather than gas-like properties. At temperatures just above the critical one it was found that bound quark-antiquark states still survive. These states are bound by effective string-like forces and turn out to be colorless. At the temperature as large as twice the critical one no bound states are observed. Quantum effects turned out to be of prime importance in these simulations.

  4. The physics of hot and dense quark-gluon matter

    SciTech Connect (OSTI)

    Kharzeev, Dmitri E

    2012-05-10

    This technical report describes the work done under the DOE grant DE-FG-88ER41723 (final award number DE-SC0005645), "The physics of hot and dense quark-gluon matter", during the year of 12/01/2010 through 11/30/2011. As planned in the proposal, the performed research focused along two main thrusts: 1) topological effects in hot quark-gluon matter and 2) phenomenology of relativistic heavy ion collisions. The results of research are presented in 12 papers published in reputable refereed journals (Physical Review Letters, Physical Review, Physics Letters and Nuclear Physics). All of the performed research is directly related to the experimental programs of DOE, especially at the Relativistic Heavy Ion Collider. Much of it also has broader interdisciplinary implications - for example, the work on the non-dissipative chiral magnetic current is directly relevant for quantum computing. The attached report describes the performed work in detail.

  5. P-Wave hyperons in nonperturbative quark dynamics

    SciTech Connect (OSTI)

    Driga, O. N. Narodetskii, I. M. Veselov, A. I.

    2008-02-15

    We carry out an investigation of the P-wave hyperons {lambda} {sigma}, and {xi} employing the field correlator method in QCD. This method allows us to derive the effective Hamiltonian (EH) approach successfully applied to the meson and ground-state baryon spectra. The EH is written in the form of the nonrelativistic three-quark Hamiltonian with perturbative Coulomb-like and nonperturbative string interactions and the specific mass term. We solve the three-quark problem using the hyperspherical approach. With only two parameters, the string tension {sigma} and the strong coupling constant {alpha}{sub s}, a unified quantitative description of the ground and excited hyperon states is achieved. In particular, we predict that all the hyperon states have the similar cost (in {delta}) {approx}460 MeV.

  6. P-Wave hyperons in nonperturbative quark dynamics

    SciTech Connect (OSTI)

    Driga, O. N. Narodetskii, I. M. Veselov, A. I.

    2008-02-15

    We carry out an investigation of the P-wave hyperons {Lambda} {Sigma}, and {xi} employing the field correlator method in QCD. This method allows us to derive the effective Hamiltonian (EH) approach successfully applied to the meson and ground-state baryon spectra. The EH is written in the form of the nonrelativistic three-quark Hamiltonian with perturbative Coulomb-like and nonperturbative string interactions and the specific mass term. We solve the three-quark problem using the hyperspherical approach. With only two parameters, the string tension {sigma} and the strong coupling constant {alpha}{sub s}, a unified quantitative description of the ground and excited hyperon states is achieved. In particular, we predict that all the hyperon states have the similar cost (in {Delta}) {approx}460 MeV.

  7. Top Quark Production Cross Section at the Tevatron

    SciTech Connect (OSTI)

    Shabalina, E.; /Chicago U.

    2006-05-01

    An overview of the preliminary results of the top quark pair production cross section measurements at a center-of-mass energy of 1.96 TeV carried out by the CDF and D0 collaborations is presented. The data samples used for the analyses are collected in the current Tevatron run and correspond to an integrated luminosity from 360 pb{sup -1} up to 760 pb{sup -1}.

  8. Deepening the Understanding of Interactions between Quarks and Gluons |

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

    Argonne Leadership Computing Facility A frame from an animation illustrating the typical four-dimensional structure of gluon-field configurations used in describing the vacuum properties of QCD. A frame from an animation illustrating the typical four-dimensional structure of gluon-field configurations used in describing the vacuum properties of QCD. Deepening the Understanding of Interactions between Quarks and Gluons PI Name: Bob Sugar PI Email: sugar@physics.ucsb.edu Institution:

  9. Partial Quark-Lepton Universality and Neutrino CP Violation

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

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

    2015-01-01

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

  10. Top quark pair production cross section at the Tevatron

    SciTech Connect (OSTI)

    Cortiana, Giorgio; /INFN, Padua /Padua U.

    2008-04-01

    Top quark pair production cross section has been measured at the Tevatron by CDF and D0 collaborations using different channels and methods, in order to test standard model predictions, and to search for new physics hints affecting the t{bar t} production mechanism or decay. Measurements are carried out with an integrated luminosity of 1.0 to 2.0 fb{sup -1}, and are found to be consistent with standard model expectations.

  11. Two-component quark-gluon plasma in stringy models

    SciTech Connect (OSTI)

    Verschelde, H.; Zakharov, V. I.

    2011-05-23

    The two-component liquid model reproduces the basic properties of the quark-gluon plasma as observed in heavy-ion collisions. The key dynamic element of the model is existence of a light scalar. We argue that existence of such a scalar is a generic feature of the stringy models of quantum chromodynamics. The lattice data provides evidence for a condensed, three-dimensional scalar field as well. We outline a possible crucial check of the model on the lattice.

  12. Classical strongly coupled quark-gluon plasma. V. Structure factors

    SciTech Connect (OSTI)

    Cho, Sungtae; Zahed, Ismail

    2010-10-15

    We show that the classical and strongly coupled quark-gluon plasma is characterized by a multiple of structure factors that obey generalized Orstein-Zernicke equations. We use the canonical partition function and its associated density functional to derive analytical equations for the density and charge monopole structure factors for arbitrary values of {Gamma}=V/K, the ratio of the mean potential to the Coulomb energy. The results are compared with SU(2) molecular dynamics simulations.

  13. Quantum simulations of strongly coupled quark-gluon plasma

    SciTech Connect (OSTI)

    Filinov, V. S.; Ivanov, Yu. B.; Bonitz, M.; Levashov, P. R.; Fortov, V. E.

    2012-06-15

    A strongly coupled quark-gluon plasma (QGP) of heavy constituent quasi-particles is studied by a path-integral Monte-Carlo method. This approach is a quantum generalization of the classical molecular dynamics by Gelman, Shuryak, and Zahed. It is shown that this method is able to reproduce the QCD lattice equation of state. The results indicate that the QGP reveals liquid-like rather than gaslike properties. Quantum effects turned out to be of prime importance in these simulations.

  14. CP violating anomalous top-quark couplings at the LHC

    SciTech Connect (OSTI)

    Gupta, Sudhir Kumar; Mete, Alaettin Serhan; Valencia, G.

    2009-08-01

    We study the T odd correlations induced by CP violating anomalous top-quark couplings at both production and decay level in the process gg{yields}tt{yields}(b{mu}{sup +}{nu}{sub {mu}})(b{mu}{sup -}{nu}{sub {mu}}). We consider several counting asymmetries at the parton level and find the ones with the most sensitivity to each of these anomalous couplings at the LHC.

  15. Top quark physics at the Tevatron results and prospects

    SciTech Connect (OSTI)

    K. Sliwa

    2002-10-16

    The methodology of CDF and D0 top quark analyses and their underlying assumptions are summarized. The CDF and D0 top mass averages, obtained from measurements in several channels and based on about 100 pb{sup -1} of data from p{bar p} collisions at {radical}s = 1.8 TeV collected by each experiment in Run-I, are: M{sub t} = 176.1 {+-} 4.0(stat) {+-} 5.1(syst) GeV/c{sup 2} and M{sub t} = 172.1 {+-} 5.2(stat) {+-} 4.9(syst) Gev/C{sup 2}, respectively. The combined Tevatron measurement of the top quark mass is M{sub t} = 174.3 {+-} 3.2(stat) {+-} 4.0(syst) GeV/c{sup 2}. The CDF measurement of the t{bar t} cross section (assuming M{sub t} = 175 GeV/c{sup 2}) is {sigma}{sub tt} = 6.5 {+-} {sub 1.4}{sup 1.6} pb, and the D0 value (assuming M{sub t} = 172.1 GeV/c{sup 2}) is {sigma}{sub tt} = 5.9 {+-} 1.7 pb. In anticipation of much larger statistics, prospects for top physics in Tevatron Run-II are summarized. The fact that top quark analyses are among the best windows to physics beyond the Standard Model is emphasized.

  16. B*Bπ coupling using relativistic heavy quarks

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

    Flynn, J. M.; Fritzsch, P.; Kawanai, T.; Lehner, C.; Sachrajda, C. T.; Samways, B.; Van de Water, R. S.; Witzel, O.

    2016-01-27

    Here, we report on a calculation of the B*Bπ coupling in three-flavor lattice QCD. This coupling, defined from the strong-interaction matrix element , is related to the leading order low-energy constant in heavy meson chiral perturbation theory. We carry out our calculation directly at the b-quark mass using a nonperturbatively tuned clover action that controls discretization effects of order |more » $$\\vec{p}$$a| and (ma)n for all n. Our analysis is performed on RBC/UKQCD gauge configurations using domain-wall fermions and the Iwasaki gauge action at two lattice spacings of a-1=1.729(25) GeV, a-1=2.281(28) GeV, and unitary pion masses down to 290 MeV. We achieve good statistical precision and control all systematic uncertainties, giving a final result for the coupling gb=0.56(3)stat(7)sys in the continuum and at the physical light-quark masses. Moreover, this is the first calculation performed directly at the physical b-quark mass and lies in the region one would expect from carrying out an interpolation between previous results at the charm mass and at the static point.« less

  17. Numerical simulation of the hydrodynamical combustion to strange quark matter

    SciTech Connect (OSTI)

    Niebergal, Brian; Ouyed, Rachid; Jaikumar, Prashanth

    2010-12-15

    We present results from a numerical solution to the burning of neutron matter inside a cold neutron star into stable u,d,s quark matter. Our method solves hydrodynamical flow equations in one dimension with neutrino emission from weak equilibrating reactions, and strange quark diffusion across the burning front. We also include entropy change from heat released in forming the stable quark phase. Our numerical results suggest burning front laminar speeds of 0.002-0.04 times the speed of light, much faster than previous estimates derived using only a reactive-diffusive description. Analytic solutions to hydrodynamical jump conditions with a temperature-dependent equation of state agree very well with our numerical findings for fluid velocities. The most important effect of neutrino cooling is that the conversion front stalls at lower density (below {approx_equal}2 times saturation density). In a two-dimensional setting, such rapid speeds and neutrino cooling may allow for a flame wrinkle instability to develop, possibly leading to detonation.

  18. B*Bπ coupling using relativistic heavy quarks

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

    Flynn, J. M.; Fritzsch, P.; Kawanai, T.; Lehner, C.; Samways, B.; Sachrajda, C. T.; Van de Water, R. S.; Witzel, O.

    2016-01-27

    We report on a calculation of the B*Bπ coupling in lattice QCD. The strong matrix element (Bπ|B*) is directly related to the leading order low-energy constant in heavy meson chiral perturbation theory (HMΧPT) for B mesons. We carry out our calculation directly at the b-quark mass using a non-perturbatively tuned clover action that controls discretization effects of order |p→a| and (ma)n for all n. Our analysis is performed on RBC/UKQCD gauge configurations using domain-wall fermions and the Iwasaki gauge action at two lattice spacings of a–1 = 1.729(25) GeV, a–1 = 2.281 (28) GeV, and unitary pion masses down tomore » 290 MeV. We achieve good statistical precision and control all systematic uncertainties, giving a final result for the HMΧPT coupling gb = 0.56(3)stat(7)sys in the continuum and at the physical light-quark masses. Furthermore, this is the first calculation performed directly at the physical b-quark mass and lies in the region one would expect from carrying out an interpolation between previous results at the charm mass and at the static point.« less

  19. The B*Bπ coupling using relativistic heavy quarks

    SciTech Connect (OSTI)

    Flynn, J. M.; Fritzsch, P.; Kawanai, T.; Lehner, C.; Samways, B.; Sachrajda, C. T.; Van de Water, R. S.; Witzel, O.

    2015-06-23

    We report on a calculation of the B*Bπ coupling in lattice QCD. The strong matrix element (Bπ|B*) is directly related to the leading order low-energy constant in heavy meson chiral perturbation theory (HMΧPT) for B mesons. We carry out our calculation directly at the b-quark mass using a non-perturbatively tuned clover action that controls discretization effects of order |pa| and (ma)n for all n. Our analysis is performed on RBC/UKQCD gauge configurations using domain-wall fermions and the Iwasaki gauge action at two lattice spacings of a–1 = 1.729(25) GeV, a–1 = 2.281 (28) GeV, and unitary pion masses down to 290 MeV. We achieve good statistical precision and control all systematic uncertainties, giving a final result for the HMΧPT coupling gb = 0.56(3)stat(7)sys in the continuum and at the physical light-quark masses. Furthermore, this is the first calculation performed directly at the physical b-quark mass and lies in the region one would expect from carrying out an interpolation between previous results at the charm mass and at the static point.

  20. Searches for new physics in the top quark samples at the CDF experiment

    SciTech Connect (OSTI)

    Scodellaro, Luca; /Cantabria Inst. of Phys.

    2007-10-01

    Twelve years after the discovery of the top quark at Fermilab's Tevatron, they are now finally beginning to shed light on this peculiarily massive quark. With 1-1.7 fb{sup -1} of integrated luminosity collected by the CDF detector, they are able to probe the knowledge of the top quark physics, and to search for signals of physics beyond the Standard Model. In this paper, they present results of measurements of top quark properties, as well as tests for the production mechanism of the top quark. They also describe CDF latest searches for beyond Standard Model couplings of the top quark. Finally, they present the most recent searches for direct production of new particles in the collected data samples.

  1. Nonfactorization of four-quark condensates at low energies within chiral perturbation theory

    SciTech Connect (OSTI)

    Gomez Nicola, A.; Pelaez, J. R.; Ruiz de Elvira, J.

    2010-10-01

    Four-quark correlators and the factorization hypothesis are analyzed in the meson sector within chiral perturbation theory. We define the four-quark condensate as lim{sub x{yields}0}, which is equivalent to other definitions commonly used in the literature. Factorization of the four-quark condensate holds to leading and next to leading order. However, at next to next to leading order, a term with a nontrivial space-time dependence in the four-quark correlator yields a divergent four-quark condensate, whereas the two-quark condensate and the scalar susceptibility are finite. Such a nonfactorization term vanishes only in the chiral limit. We also comment on how factorization still holds in the large N{sub c} limit, provided such a limit is taken before renormalization.

  2. Viscosity and dilepton production of a chemically equilibrating quark-gluon plasma at finite baryon density

    SciTech Connect (OSTI)

    Guan Nana; Li Jianwei; He Zejun; Long Jiali; Cai Xiangzhou; Ma Yugang; Shen Wenqing

    2009-07-15

    By considering the effect of shear viscosity we have investigated the evolution of a chemically equilibrating quark-gluon plasma at finite baryon density. Based on the evolution of the system we have performed a complete calculation for the dilepton production from the following processes: qq{yields}ll, qq{yields}gll, Compton-like scattering (qg{yields}qll,qg{yields}qll), gluon fusion (gg{yields}cc), annihilation (qq{yields}cc), as well as the multiple scattering of quarks. We have found that quark-antiquark annihilation, Compton-like scatterring, gluon fusion, and multiple scattering of quarks give important contributions. Moreover, we have also found that the dilepton yield is an increasing function of the initial quark chemical potential, and the increase of the quark phase lifetime because of the viscosity also obviously raises the dilepton yield.

  3. Heavy Quarks, QCD, and Effective Field Theory (Technical Report) | SciTech

    Office of Scientific and Technical Information (OSTI)

    Connect Heavy Quarks, QCD, and Effective Field Theory Citation Details In-Document Search Title: Heavy Quarks, QCD, and Effective Field Theory The research supported by this OJI award is in the area of heavy quark and quarkonium production, especially the application Soft-Collinear E ective Theory (SCET) to the hadronic production of quarkonia. SCET is an e ffective theory which allows one to derive factorization theorems and perform all order resummations for QCD processes. Factorization

  4. Structure functions and pair correlations of the quark-gluon plasma

    SciTech Connect (OSTI)

    Thoma, Markus H.

    2005-11-01

    Recent experiments at RHIC and theoretical considerations indicate that the quark-gluon plasma, present in the fireball of relativistic heavy-ion collisions, might be in a liquid phase. The liquid state can be identified by characteristic correlation and structure functions. Here definitions of the structure functions and pair correlations of the quark-gluon plasma are presented as well as perturbative results. These definitions might be useful for verifying the quark-gluon-plasma liquid in QCD lattice calculations.

  5. Electroweak production of top-quark pairs in e + e - annihilation...

    Office of Scientific and Technical Information (OSTI)

    Electroweak production of top-quark pairs in e + e - annihilation at NNLO in QCD: The vector current contributions Citation Details In-Document Search Title: Electroweak production ...

  6. Comparison of jet quenching formalisms for a quark-gluon plasma...

    Office of Scientific and Technical Information (OSTI)

    Title: Comparison of jet quenching formalisms for a quark-gluon plasma "brick" Authors: Armesto, Nestor ; Cole, Brian ; Gale, Charles ; Horowitz, William A. ; Jacobs, Peter ; Jeon, ...

  7. Exotic Physics with the Top Quark at the LHC. End of grant report

    SciTech Connect (OSTI)

    Black, Kevin

    2013-07-29

    The grant supported two main activities : searching for new physics with the top quark at the LHC and development of the ATLAS muon trigger.

  8. Improving the Top Quark Forward-Backward Asymmetry Measurement at the LHC

    SciTech Connect (OSTI)

    Bai, Yang; Han, Zhenyu; /Harvard U., Phys. Dept.

    2011-08-15

    At the LHC, top quark pairs are dominantly produced from gluons, making it difficult to measure the top quark forward-backward asymmetry. To improve the asymmetry measurement, we study variables that can distinguish between top quarks produced from quarks and those from gluons: the invariant mass of the top pair, the rapidity of the top-antitop system in the lab frame, the rapidity of the top quark in the top-antitop rest frame, the top quark polarization and the top-antitop spin correlation. We combine all the variables in a likelihood discriminant method to separate quark-initiated events from gluon-initiated events. We apply our method on models including G-prime's and W-prime's motivated by the recent observation of a large top quark forward-backward asymmetry at the Tevatron. We have found that the significance of the asymmetry measurement can be improved by 10% to 30%. At the same time, the central values of the asymmetry increase by 40% to 100%. We have also analytically derived the best spin quantization axes for studying top quark polarization as well as spin-correlation for the new physics models.

  9. Search for vector-like T quarks decaying to top quarks and Higgs bosons in the all-hadronic channel using jet substructure

    SciTech Connect (OSTI)

    Khachatryan, Vardan

    2015-06-12

    We performed a search for a vector-like heavy T quark that is produced in pairs and that decays to a top quark and a Higgs boson. The data analysed correspond to an integrated luminosity of 19.7 fb-1collected with the CMS detector in proton-proton collisions at √s=8 TeV. For T quarks with large mass values the top quarks and Higgs bosons can have significant Lorentz boosts, so that their individual decay products often overlap and merge. Methods are applied to resolve the substructure of such merged jets. We also derived upper limits on the production cross section of a T quark with mass between 500 and 1000 GeV/c 2. If the T quark decays exclusively to tH, the observed (expected) lower limit on the mass of the T quark is 745 (773) GeV/c 2 at 95% confidence level. For the first time an algorithm is used for tagging boosted Higgs bosons that is based on a combination of jet substructure information and b tagging.

  10. Search for vector-like T quarks decaying to top quarks and Higgs bosons in the all-hadronic channel using jet substructure

    SciTech Connect (OSTI)

    Khachatryan, V.

    2015-06-12

    A search is performed for a vector-like heavy T quark that is produced in pairs and that decays to a top quark and a Higgs boson. The data analysed correspond to an integrated luminosity of 19.7 fb? collected with the CMS detector in proton-proton collisions at ?s = 8 TeV. For T quarks with large mass values the top quarks and Higgs bosons can have significant Lorentz boosts, so that their individual decay products often overlap and merge. Methods are applied to resolve the substructure of such merged jets. Upper limits on the production cross section of a T quark with mass between 500 and 1000 GeV/c are derived. If the T quark decays exclusively to tH, the observed (expected) lower limit on the mass of the T quark is 745 (773) GeV/c at 95% confidence level. For the first time an algorithm is used for tagging boosted Higgs bosons that is based on a combination of jet substructure information and b tagging.

  11. Measurement of W Boson Polarization in Top Quark Decay

    SciTech Connect (OSTI)

    Vickey, Trevor Neil

    2004-11-01

    A measurement of the polarization of the W boson from top quark decay is an excellent test of the V-A form of the charged-current weak interaction in the standard model. Since the longitudinal W boson is intimately related to the electroweak symmetry breaking mechanism, and the standard model gives a specific prediction for the fraction of longitudinal W bosons from top decays, it is of particular interest for study. This thesis presents a measurement of W boson polarization in top quark decays through an analysis of the cos{theta}* distribution in the lepton-plus-jets channel of t{bar t} candidate events from p{bar p} collisions at {radical}s = 1.96 TeV. This measurement uses an integrated luminosity of {approx} 162 pb{sup -1} of data collected with the CDF Run II detector, resulting in 31 t{bar t} candidate events with at least one identified b jet. Using a binned likelihood fit to the cos{theta}* distribution from the t{bar t} candidate events found in this sample, the fraction of W bosons with longitudinal polarization is determined to be F{sub 0} = 0.99{sub -0.35}{sup +0.29}(stat.) {+-} 0.19(syst.), F{sub 0} > 0.33 {at} 95% CL. This result is consistent with the standard model prediction, given a top quark mass of 174.3 GeV/c{sup 2}, of F{sub 0} = 0.701 {+-} 0.012.

  12. Unified spin gauge model and the top quark mass

    SciTech Connect (OSTI)

    Chisholm, J.S.R.; Farwell, R.S.

    1995-10-01

    Spin gauge models use a real Clifford algebraic structure R{sub p,q} associated with a real manifold of dimension p + q to describe the fundamental interactions of elementary particles. This review provides a comparison between those models and the standard model, indicating their similarities and differences. By contrast with the standard model, the spin gauge model based on R{sub 3,8} generates intermediate boson mass terms without the need to use the Higgs-Kibble mechanism and produces a precise prediction for the mass of the top quark. The potential of this model to account for exactly three families of fermions is considered.

  13. Probing Quark-Gluon Interactions with Transverse Polarized Scattering

    SciTech Connect (OSTI)

    Slifer, K.; Rondon, O. A.; Crabb, D.; Day, D.; Frlez, E.; Lindgren, R.; McKee, P.; Norum, B.; Pocanic, D.; Prok, Y.; Sawatzky, B.; Smith, C.; Tajima, S.; Wang, K.; Zeier, M.; Zhu, H.; Aghalaryan, A.; Asaturyan, R.; Mkrtchyan, H.; Ahmidouch, A.

    2010-09-03

    We have extracted QCD matrix elements from our data on doubly polarized inelastic scattering of electrons on nuclei. We find the higher twist matrix element d{sub 2}-tilde, which arises strictly from quark-gluon interactions, to be unambiguously nonzero. The data also reveal an isospin dependence of higher twist effects if we assume that the Burkhardt-Cottingham sum rule is valid. The fundamental Bjorken sum rule obtained from the a{sub 0} matrix element is satisfied at our low momentum transfer.

  14. Constraints on anomalous top quark couplings at the LHC

    SciTech Connect (OSTI)

    Rizzo, T.G.

    1996-09-01

    Measurements of distributions associated with the pair production of top quarks at the LHC can be used to constrain (or observe) the anomalous chromomagnetic dipole moment(k) of the top. For example, using either the tt(bar) invariant mass or the Pt distribution of top we find that sensitivities to ; k; of order 0.05 are obtainable with 100 /fb of integrated luminosity. This is similar in magnitude to what can be obtained at a 500 GeV NLC with an integrated luminosity of 50 /fb through an examination of the e(+)e(-) right arrow tt(bar)g process.

  15. Exotic eikosiheptaplet in the chiral quark soliton model

    SciTech Connect (OSTI)

    Praszalowicz, Michal; Goeke, Klaus

    2007-11-01

    We use the chiral quark soliton model to estimate masses and widths of the two eikosiheptaplets (27-plets of SU(3) flavor) of spin 3/2 and 1/2 that emerge in the rigid rotator quantization. We use as input: hyperon decays, {theta}{sup +} mass, and width. While 27{sub 3/2} has small widths (although much larger than the values allowed by the partial wave analysis), 27{sub 1/2} has large decay widths to antidecuplet. However, exactly for this decay channel the widths are suppressed in the large N{sub c} limit.

  16. Top quark mass measurement at CDF Run-II

    SciTech Connect (OSTI)

    T. Maruyama

    2004-05-11

    CDF has resumed the top quark mass measurement with upgraded detectors and Tevatron complex. High statistics should allow us to determine the top mass with an uncertainty of a few GeV/c{sup 2} by the end of Run II. The current measured value, using an integrated luminosity of {approx} 108 pb{sup -1}, is 177.5{sub -9.4}{sup +12.7} (stat.) {+-} 7.1(syst.) GeV/c{sup 2} (lepton + jets with one b-jet tagged mode: the current best mode), which is consistent with RunI measurements.

  17. B1487(01)Quarks FM.i-xvi

    National Nuclear Security Administration (NNSA)

    Committee on the Physics of the Universe Board on Physics and Astronomy Division on Engineering and Physical Sciences THE NATIONAL ACADEMIES PRESS Washington, D.C. www.nap.edu Quarks Eleven Science Questions for the New Century with the Cosmos Connecting THE NATIONAL ACADEMIES PRESS 500 Fifth Street, N.W. Washington, DC 20001 NOTICE: The project that is the subject of this report was approved by the Govern- ing Board of the National Research Council, whose members are drawn from the councils of

  18. Yoctosecond Photon Pulses from Quark-Gluon Plasmas

    SciTech Connect (OSTI)

    Ipp, Andreas; Keitel, Christoph H.; Evers, Joerg

    2009-10-09

    Present ultrafast laser optics is at the frontier between atto- and zeptosecond photon pulses, giving rise to unprecedented applications. We show that high-energetic photon pulses down to the yoctosecond time scale can be produced in heavy-ion collisions. We focus on photons produced during the initial phase of the expanding quark-gluon plasma. We study how the time evolution and properties of the plasma may influence the duration and shape of the photon pulse. Prospects for achieving double-peak structures suitable for pump-probe experiments at the yoctosecond time scale are discussed.

  19. Viscous quark-gluon plasma model through fluid QCD approach

    SciTech Connect (OSTI)

    Djun, T. P.; Soegijono, B.; Mart, T.; Handoko, L. T. E-mail: Laksana.tri.handoko@lipi.go.id

    2014-09-25

    A Lagrangian density for viscous quark-gluon plasma has been constructed within the fluid-like QCD framework. Gauge symmetry is preserved for all terms inside the Lagrangian, except for the viscous term. The transition mechanism from point particle field to fluid field, and vice versa, are discussed. The energy momentum tensor that is relevant to the gluonic plasma having the nature of fluid bulk of gluon sea is derived within the model. By imposing conservation law in the energy momentum tensor, shear viscosity appears as extractable from the equation.

  20. Radiative energy loss in an anisotropic quark-gluon plasma

    SciTech Connect (OSTI)

    Roy, Pradip; Dutt-Mazumder, Abhee K.

    2011-04-15

    We calculate radiative energy loss of heavy and light quarks in an anisotropic medium (static) in a first-order opacity expansion. Such an anisotropy can result from the initial rapid longitudinal expansion of the matter created in relativistic heavy-ion collisions. Significant dependency of the energy loss on the anisotropy parameter {xi} and the direction of propagation of the partons with respect to the anisotropy axis is found. It is shown that the introduction of early-time momentum-space anisotropy can enhance the fractional energy loss in the direction of the anisotropy, whereas it decreases when the parton propagates perpendicular to the direction of the anisotropy.

  1. Spectral sum rules for the quark-gluon plasma

    SciTech Connect (OSTI)

    Romatschke, P.; Son, D. T.

    2009-09-15

    We derive sum rules involving the spectral density of the stress-energy tensor in N=4 super-Yang-Mills theory and pure Yang-Mills theory. The sum rules come from the hydrodynamic behavior at small momenta and the conformal (in the case of N=4 super-Yang-Mills theory) or asymptotically free (as for the pure Yang-Mills theory) behavior at large momenta. These sum rules may help constrain quark-gluon plasma transport coefficients obtained from lattice QCD.

  2. Quasilinear transport approach to equilibration of quark-gluon plasmas

    SciTech Connect (OSTI)

    Mrowczynski, Stanislaw; Mueller, Berndt

    2010-03-15

    We derive the transport equations of quark-gluon plasma in the quasilinear approximation. The equations are either of the Balescu-Lenard or Fokker-Planck form. The plasma's dynamics is assumed to be governed by longitudinal chromoelectric fields. The isotropic plasma, which is stable, and the two-stream system, which is unstable, are considered in detail. A process of equilibration is briefly discussed in both cases. The peaks of the two-stream distribution are shown to rapidly dissolve in time.

  3. Direct photon production from viscous quark-gluon plasma

    SciTech Connect (OSTI)

    Chaudhuri, A. K.; Sinha, Bikash

    2011-03-15

    We simulate direct photon production in the evolution of viscous quark-gluon plasma medium. Photons from Compton and annihilation processes are considered. The viscous effect on photon production is very strong and reliable simulation is possible only in a limited p{sub T} range. For minimally viscous fluid ({eta}/s=0.08), direct photons can be reliably computed only up to p{sub T}{<=}1.3 GeV. With reduced viscosity ({eta}/s=0.04), the limit increases to p{sub T}{<=}2 GeV.

  4. The heavy Top Quark Partner in Little Higgs Models

    SciTech Connect (OSTI)

    Larios, F.; Perez, M. A.; Penunuri, F.

    2008-07-02

    Little Higgs models provide a natural explanation for the lightness of the Higgs mass. Through the mechanism of collective symmetry breaking, one loop quadratic divergent contributions to the Higgs mass are avoided. In these models a heavy partner of the Top quark appears as required to cancel out the Top's loop contribution. This heavy Top could be produced at the LHC mainly in the single mode. Because of flavor mixing a large FCNC gtT coupling can be generated at one loop that could boost the single T production mode through gg fusion.

  5. Status of the top quark: Top production cross section and top properties

    SciTech Connect (OSTI)

    Boisvert, V.; /Rochester U.

    2006-08-01

    This report describes the latest cross section and property measurements associated with the top quark at the Tevatron Run II. The largest data sample used is 760 pb{sup -1} of integrated luminosity. Due to its large mass, the top quark might be involved in the process of electroweak symmetry breaking, making it a useful probe for signs of new physics.

  6. Characteristics of multimuon events from fourth generation quarks at the SSC (superconducting super collider)

    SciTech Connect (OSTI)

    Baer, H.

    1987-08-14

    Multimuon events can be a distinctive signature for pair production of t-quarks or 4th generation quarks at the SSC. In this paper we address aspects of the multimuon event topology relevant to detector design for the SSC. In particular, we discuss energy measurement, rapidity range, segmentation and the need for hadronic calorimetry in a dedicated muon detector.

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

    SciTech Connect (OSTI)

    Pagura, V.; Dumm, D. G.; Scoccola, N. N.

    2013-03-25

    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.

  8. Production of b-quark jets at the large Hadron Collider in the parton-reggeization approach

    SciTech Connect (OSTI)

    Saleev, V. A. Shipilova, A. V.

    2013-11-15

    The inclusive hadroproduction of b-quark jets and bb-bar-quark dijets at the Large Hadron Collider is considered by using the hypothesis of gluon Reggeization in t-channel exchanges at high energies. Experimental data obtained by the ATLAS Collaboration are described well within all of the presented kinematical regions for single b-quark jets and bb-bar-quark dijets without resort to any free parameters.

  9. Initial conditions dependency in heavy-quarks suppression in ultra-relativistic collisions

    SciTech Connect (OSTI)

    Alves Garcia Prado, Caio; Alarcon do Passo Suaide, Alexandre

    2013-05-06

    Heavy quark suppression in central Au+Au collisions is expected to be smaller than that of light quarks. However experimental data suggest that they are evenly suppressed. We propose considering fluctuations in the medium as they may lead to high-density regions which in turn can cause a considerable quark suppression at the early stages of the collision evolution. To analyse the overall effect of these fluctuations we perform computer simulations of charm and bottom propagating through the quark-gluon plasma and obtain estimates of the nuclear modification factor R{sub AA}. This quantity gives us information about the heavy quark suppression that can be compared to published experimental data from the STAR experiment.

  10. Adler function and hadronic contribution to the muon g-2 in a nonlocal chiral quark model

    SciTech Connect (OSTI)

    Dorokhov, Alexander E.

    2004-11-01

    The behavior of the vector Adler function at spacelike momenta is studied in the framework of a covariant chiral quark model with instantonlike quark-quark interaction. This function describes the transition between the high-energy asymptotically free region of almost massless current quarks to the low-energy hadronized regime with massive constituent quarks. The model reproduces the Adler function and V-A correlator extracted from the ALEPH and OPAL data on hadronic {tau} lepton decays, transformed into the Euclidean domain via dispersion relations. The leading order contribution from the hadronic part of the photon vacuum polarization to the anomalous magnetic moment of the muon, a{sub {mu}}{sup hvp(1)}, is estimated.

  11. Successes and failures of the constituent quark model

    SciTech Connect (OSTI)

    Lipkin, H.J.

    1982-01-01

    Our approach considers the model as a possible bridge between QCD and the experimental data and examines its predictions to see where these succeed and where they fail. We also attempt to improve the model by looking for additional simple assumptions which give better fits to the experimental data. But we avoid complicated models with too many ad hoc assumptions and too many free parameters; these can fit everything but teach us nothing. We define our constituent quark model by analogy with the constituent electron model of the atom and the constituent nucleon model of the nucleus. In the same way that an atom is assumed to consist only of constituent electrons and a central Coulomb field and a nucleus is assumed to consist only of constituent nucleons hadrons are assumed to consist only of their constituent valence quarks with no bag, no glue, no ocean, nor other constituents. Although these constituent models are oversimplified and neglect other constituents we push them as far as we can. Atomic physics has photons and vacuum polarization as well as constituent electrons, but the constituent model is adequate for calculating most features of the spectrum when finer details like the Lamb shift are neglected. 54 references.

  12. Forward-backward asymmetry in top quark-antiquark production

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

    Abazov, Victor Mukhamedovich

    2011-12-12

    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)%.more » 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.« less

  13. Top quark mass measurement from dilepton events at CDF II

    SciTech Connect (OSTI)

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

    2005-12-01

    We report a measurement of the top quark mass using events collected by the CDF II Detector from p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron. We calculate a likelihood function for the top mass in events that are consistent with t{bar t} {yields} {bar b}{ell}{sup -}{bar {nu}}{sub {ell}}b{ell}{prime}{sup +}{nu}{sub {ell}}{prime} decays. The likelihood is formed as the convolution of the leading-order matrix element and detector resolution functions. The joint likelihood is the product of likelihoods for each of 33 events collected in 340 pb{sup -1} of integrated luminosity, yielding a top quark mass M{sub t} = 165.2 {+-} 6.1(stat.) {+-} 3.4(syst.) GeV/c{sup 2}. This first application of a matrix-element technique to t{bar t} {yields} b{ell}{sup +}{nu}{sub {ell}}{bar b}{ell}{prime}{sup -}{bar {nu}}{sub {ell}}, decays gives the most precise single measurement of M{sub t} in dilepton events. Combined with other CDF Run II measurements using dilepton events, we measure M{sub t} = 167.9 {+-} 5.2(stat.) {+-} 3.7(syst.) GeV/c{sup 2}.

  14. Why should we care about the top quark Yukawa coupling?

    SciTech Connect (OSTI)

    Shapshnikov, Mikhail; Bezrukov, Fedor

    2015-04-15

    In the cosmological context, for the Standard Model to be valid up to the scale of inflation, the top quark Yukawa coupling yt should not exceed the critical value ytcrit , coinciding with good precision (about 0.2‰) with the requirement of the stability of the electroweak vacuum. So, the exact measurements of yt may give an insight on the possible existence and the energy scale of new physics above 100 GeV, which is extremely sensitive to yt. In this study, we overview the most recent theoretical computations of and the experimental measurements of ytcrit and the experimental measurements of yt. Within the theoretical and experimental uncertainties in yt, the required scale of new physics varies from 10⁷ GeV to the Planck scale, urging for precise determination of the top quark Yukawa coupling.

  15. Search for vector-like T quarks decaying to top quarks and Higgs bosons in the all-hadronic channel using jet substructure

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

    Khachatryan, Vardan

    2015-06-12

    We performed a search for a vector-like heavy T quark that is produced in pairs and that decays to a top quark and a Higgs boson. The data analysed correspond to an integrated luminosity of 19.7 fb-1collected with the CMS detector in proton-proton collisions at √s=8 TeV. For T quarks with large mass values the top quarks and Higgs bosons can have significant Lorentz boosts, so that their individual decay products often overlap and merge. Methods are applied to resolve the substructure of such merged jets. We also derived upper limits on the production cross section of a T quarkmore » with mass between 500 and 1000 GeV/c 2. If the T quark decays exclusively to tH, the observed (expected) lower limit on the mass of the T quark is 745 (773) GeV/c 2 at 95% confidence level. For the first time an algorithm is used for tagging boosted Higgs bosons that is based on a combination of jet substructure information and b tagging.« less

  16. Search for vector-like T quarks decaying to top quarks and Higgs bosons in the all-hadronic channel using jet substructure

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

    Khachatryan, V.

    2015-06-12

    A search is performed for a vector-like heavy T quark that is produced in pairs and that decays to a top quark and a Higgs boson. The data analysed correspond to an integrated luminosity of 19.7 fb? collected with the CMS detector in proton-proton collisions at ?s = 8 TeV. For T quarks with large mass values the top quarks and Higgs bosons can have significant Lorentz boosts, so that their individual decay products often overlap and merge. Methods are applied to resolve the substructure of such merged jets. Upper limits on the production cross section of a T quarkmorewith mass between 500 and 1000 GeV/c are derived. If the T quark decays exclusively to tH, the observed (expected) lower limit on the mass of the T quark is 745 (773) GeV/c at 95% confidence level. For the first time an algorithm is used for tagging boosted Higgs bosons that is based on a combination of jet substructure information and b tagging.less

  17. B-meson decay constants from 2+1-flavor lattice QCD with domain-wall light quarks and relativistic heavy quarks

    SciTech Connect (OSTI)

    Christ, Norman H.; Flynn, Jonathan M.; Izubuchi, Taku; Kawanai, Taichi; Lehner, Christoph; Soni, Amarjit; Van de Water, Ruth S.; Witzel, Oliver

    2015-03-10

    We calculate the B-meson decay constants fB, fBs, and their ratio in unquenched lattice QCD using domain-wall light quarks and relativistic b-quarks. We use gauge-field ensembles generated by the RBC and UKQCD collaborations using the domain-wall fermion action and Iwasaki gauge action with three flavors of light dynamical quarks. We analyze data at two lattice spacings of a ≈ 0.11, 0.086 fm with unitary pion masses as light as Mπ ≈ 290 MeV; this enables us to control the extrapolation to the physical light-quark masses and continuum. For the b-quarks we use the anisotropic clover action with the relativistic heavy-quark interpretation, such that discretization errors from the heavy-quark action are of the same size as from the light-quark sector. We renormalize the lattice heavy-light axial-vector current using a mostly nonperturbative method in which we compute the bulk of the matching factor nonperturbatively, with a small correction, that is close to unity, in lattice perturbation theory. We also improve the lattice heavy-light current through O(αsa). We extrapolate our results to the physical light-quark masses and continuum using SU(2) heavy-meson chiral perturbation theory, and provide a complete systematic error budget. We obtain fB0 = 196.2(15.7) MeV, fB+ = 195.4(15.8) MeV, fBs = 235.4(12.2) MeV, fBs/fB0 = 1.193(59), and fBs/fB+ = 1.220(82), where the errors are statistical and total systematic added in quadrature. In addition, these results are in good agreement with other published results and provide an important independent cross check of other three-flavor determinations of B-meson decay constants using staggered light quarks.

  18. Heavy quark diffusion in strong magnetic fields at weak coupling and implications for elliptic flow

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

    Fukushima, Kenji; Hattori, Koichi; Yee, Ho -Ung; Yin, Yi

    2016-04-20

    In this paper, we compute the momentum diffusion coefficients of heavy quarks, κ∥ and κ⊥, in a strong magnetic field B along the directions parallel and perpendicular to B, respectively, at the leading order in QCD coupling constant αs. We consider a regime relevant for the relativistic heavy ion collisions, αseB << T2 << eB, so that thermal excitations of light quarks are restricted to the lowest Landau level (LLL) states. In the vanishing light-quark mass limit, we find κLO⊥ ∝ α2sTeB in the leading order that arises from screened Coulomb scatterings with (1+1)-dimensional LLL quarks, while κ∥ gets nomore » contribution from the scatterings with LLL quarks due to kinematic restrictions. We show that the first nonzero leading order contributions to κLO∥ come from the two separate effects: 1) the screened Coulomb scatterings with thermal gluons, and 2) a finite light-quark mass mq. The former leads to κLO,gluon∥ ∝ α2sT3 and the latter to κLO,massive∥ ∝ αs(αseB)1/2m2q. Based on our results, we propose a new scenario for the large value of heavy-quark elliptic flow observed in RHIC and LHC. Namely, when κ⊥ >> κ∥, an anisotropy in drag forces gives rise to a sizable amount of the heavy-quark elliptic flow even if heavy quarks do not fully belong to an ellipsoidally expanding background fluid.« less

  19. The Top Quark as a Window to Beyond the Standard Model Physics

    SciTech Connect (OSTI)

    Yu, Chiu-Tien

    2013-01-01

    The top quark was the last of the Standard Model quarks to be discovered, and is of considerable interest. The closeness of the top quark mass to the electroweak scale is suggestive that the top quark could be closely related to the mechanisms for electroweak symmetry breaking. Any new physics in electroweak symmetry breaking models could then preferentially couple to the top quark, making the top quark a promising probe for new physics. In this thesis, we will explore two aspects of the top quark as a harbinger to new physics: the top forward-backward asymmetry as seen at the Tevatron and the search for stops. In this thesis, we will discuss the Asymmetric Left-Right Model (ALRM), a model that is based on the gauge group $U'(1)\\times SU(2)\\times SU'(2)$ with couplings $g_1^\\prime, g_2^\\prime,$ and $g'$ associated with the fields $B',W,W'$, respectively, and show how this model can explain the top forward-backward asymmetry. We will then explore the scalar sector of the ALRM, and provide a specific Higgs mechanism that provides the masses for the $W'$ and $Z'$ bosons. The top forward-backward asymmetry is a test of invariance of charge-conjugation. Thus, we look at the $X$-gluon model, a model that was motivated by the top forward-backward asymmetry, and show that one can look at the longitudinal polarization of the top-quark to test parity conservation. Finally, we investigate searches for stop squarks, the supersymmetric partner of the top quark, at the Large Hadron Collider (LHC) using shape-based analyses.

  20. Selected problems of baryon spectroscopy: Chiral soliton versus quark models

    SciTech Connect (OSTI)

    Kopeliovich, V. B.

    2009-05-15

    The inconsistency between the rigid rotator and bound state models at an arbitrary number of colors, the rigid rotator-soft rotator dilemma, and some other problems of baryon spectroscopy are discussed in the framework of the chiral soliton approach (CSA). Consequences of the comparison of CSA results with simple quark models are considered and the 1/N{sub c} expansion for the effective strange antiquark mass is presented, as it follows from the CSA. Strong dependence of the effective strange antiquark mass on the SU(3) multiplet is required to fit the CSA predictions. The difference between 'good' and 'bad' diquark masses, which is about 100 MeV, is in reasonable agreement with other estimates. Multibaryons (hypernuclei) with strangeness are described and some states of interest are also predicted within the CSA.

  1. Charm degrees of freedom in the quark gluon plasma

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

    Mukherjee, Swagato; Petreczky, Peter; Sharma, Sayantan

    2016-01-11

    The lattice QCD studies on fluctuations and correlations of charm quantum number have established that deconfinement of charm degrees of freedom sets in around the chiral crossover temperature, Tc; i.e., charm degrees of freedom carrying fractional baryonic charge start to appear. When we reexamine those same lattice QCD data we show that, in addition to the contributions from quarklike excitations, the partial pressure of charm degrees of freedom may still contain significant contributions from open-charm-meson- and baryonlike excitations associated with integral baryonic charges for temperatures up to 1.2Tc. Finally, charm-quark quasiparticles become the dominant degrees of freedom for temperatures T>1.2Tc.

  2. GEWI Planungs und Vertriebsgesellschaft mbH Co KG | Open Energy...

    Open Energy Info (EERE)

    Vertriebsgesellschaft mbH & Co KG Place: Husum Nordsee, Germany Zip: 25813 Sector: Wind energy Product: Wind energy project developer. References: GEWI Planungs- und...

  3. Ger te und Akkumulatorwerk Zwickau GmbH GAZ | Open Energy Information

    Open Energy Info (EERE)

    Zwickau GmbH (GAZ) Place: Germany Product: GAZ manufactures special nickel-based batteries mainly used in the energy, rail, telecom and UPS sectors. References: Gerte- und...

  4. Mixings of four-quark components in light nonsinglet scalar mesons in QCD sum rules

    SciTech Connect (OSTI)

    Sugiyama, J.; Nakamura, T.; Nishikawa, T.; Oka, M.; Ishii, N.

    2007-12-01

    Mixings of four-quark components in the nonsinglet scalar mesons are studied in the QCD sum rules. We propose a formulation to evaluate the cross correlators of qq and qqqq operators and to define the mixings of different Fock states in the sum rule. It is applied to the nonsinglet scalar mesons, a{sub 0} and K{sub 0}*. It is found that the four-quark operators predict lower masses than the qq operators and that the four-quark states occupy about 70%-90% of the lowest mass states.

  5. Effect of top quark spin on the Wtb couplings in e{sup +}p collisions

    SciTech Connect (OSTI)

    Atag, S.; Sahin, B.

    2006-04-01

    In our previous work [Phys. Rev. D 70, 037503 (2004)] for the e{sup +}p{yields}t{nu}+X process, we have shown that the top quark possesses a high degree of spin polarization when its spin decomposition axis is along the incoming lepton beam. In this work, the potential of ep collisions to probe an anomalous Wtb vertex is investigated via the polarized single top quark production process for TESLA+HERAp energy. The effects of the top quark polarization to Wtb couplings F{sub 2L} and F{sub 2R} are discussed. It is possible to define a polarization axis for the top quark that is more sensitive to new physics than the unpolarized case.

  6. ABSORPTION OF HARD AND THERMAL PHOTONS IN A QUARK-GLUON PLASMA...

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

    * 1 R. J. Fries, B. Muller, D. K. Srivastava, "High-energy photons from passage of jets through quark gluon plasma", Phys. Rev. Lett. 90, 132301 (2003). * 2 P.B. Arnold,...

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

    SciTech Connect (OSTI)

    Abazov, Victor Mukhamedovich; et al.

    2014-09-08

    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.

  8. Charm and strange quark masses and f D s from overlap fermions...

    Office of Scientific and Technical Information (OSTI)

    Title: Charm and strange quark masses and f D s from overlap fermions Authors: Yang, Yi-Bo ; Chen, Ying ; Alexandru, Andrei ; Dong, Shao-Jing ; Draper, Terrence ; Gong, Ming ; Lee, ...

  9. VariableR reclustering in multiple top quark events - Oral Presentation

    SciTech Connect (OSTI)

    Hyde, Jeremy; /SLAC

    2015-08-22

    VariableR jet reclustering is an innovative technique that allows for the reconstruction of boosted object over a wide range of kinematic regimes. Such capability enables the efficient identification of events with multiple boosted top quarks which is a typical signature for new physics processes such as the production of the supersymmetric partner of the gluon. In order to evaluate the performance of the algorithm, the VariableR reclustered jets are compared with fixed radius reclustered jets. The flexibility of the algorithm is tested by reconstructing both boosted top quarks and boosted W bosons. The VariableR reclustering method is found to be more efficient than the fixed radius algorithm at identifying top quarks and W bosons in events with four top quarks, therefore enhancing the sensitivity for gluino searches.

  10. VariableR Reclustering in Multiple Top Quark and W Boson Events

    SciTech Connect (OSTI)

    Hyde, Jeremy

    2015-08-14

    VariableR jet reclustering is an innovative technique that allows for the reconstruction of boosted object over a wide range of kinematic regimes. Such capability enables the efficient identification of events with multiple boosted top quarks which is a typical signature for new physics processes such as the production of the supersymmetric partner of the gluon. In order to evaluate the performance of the algorithm, the VariableR reclustered jets are compared with fixed radius reclustered jets. The flexibility of the algorithm is tested by reconstructing both boosted top quarks and boosted W bosons. The VariableR reclustering method is found to be more efficient than the fixed radius algorithm at identifying top quarks and W bosons in events with four top quarks, therefore enhancing the sensitivity for gluino searches.