While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

1

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

Dariusz Miskowiec

2007-07-06T23:59:59.000Z

2

HUNTING THE QUARK GLUON PLASMA.

The U.S. Department of Energy's Relativistic Heavy Ion Collider (RHIC) construction project was completed at BNL in 1999, with the first data-taking runs in the summer of 2000. Since then the early measurements at RHIC have yielded a wealth of data, from four independent detectors, each with its international collaboration of scientists: BRAHMS, PHENIX, PHOBOS, and STAR [1]. For the first time, collisions of heavy nuclei have been carried out at colliding-beam energies that have previously been accessible only for high-energy physics experiments with collisions of ''elementary'' particles such as protons and electrons. It is at these high energies that the predictions of quantum chromodynamics (QCD), the fundamental theory that describes the role of quarks and gluons in nuclear matter, come into play, and new phenomena are sought that may illuminate our view of the basic structure of matter on the sub-atomic scale, with important implications for the origins of matter on the cosmic scale. The RHIC experiments have recorded data from collisions of gold nuclei at the highest energies ever achieved in man-made particle accelerators. These collisions, of which hundreds of millions have now been examined, result in final states of unprecedented complexity, with thousands of produced particles radiating from the nuclear collision. All four of the RHIC experiments have moved quickly to analyze these data, and have begun to understand the phenomena that unfold from the moment of collision as these particles are produced. In order to provide benchmarks of simpler interactions against which to compare the gold-gold collisions, the experiments have gathered comparable samples of data from collisions of a very light nucleus (deuterium) with gold nuclei, as well as proton-proton collisions, all with identical beam energies and experimental apparatus. The early measurements have revealed compelling evidence for the existence of a new form of nuclear matter at extremely high density and temperature--a medium in which the predictions of QCD can be tested, and new phenomena explored, under conditions where the relevant degrees of freedom, over nuclear volumes, are expected to be those of quarks and gluons, rather than of hadrons. This is the realm of the quark gluon plasma, the predicted state of matter whose existence and properties are now being explored by the RHIC experiments.

LUDLAM, T.; ARONSON, S.

2005-04-11T23:59:59.000Z

3

Hunting the Quark Gluon Plasma ASSESSMENTS

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

Hunting the Quark Gluon Plasma Hunting the Quark Gluon Plasma ASSESSMENTS BY THE EXPERIMENTAL COLLABORATIONS Relativistic Heavy Ion Collider (RHIC) * Brookhaven National Laboratory, Upton, NY 11974-5000 RESULTS FROM THE FIRST 3 YEARS AT RHIC managed for the U.S. Department of Energy by Brookhaven Science Associates, a company founded by Stony Brook University and Battelle April 18, 2005 BNL -73847-2005 Formal Report

4

Quark-gluon plasma (Selected Topics)

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.

Zakharov, V. I., E-mail: vzakharov@itep.ru [Institute for Theoretical and Experimental Physics (Russian Federation)

2012-09-15T23:59:59.000Z

5

Dissipative phenomena in quark-gluon plasmas

Transport coefficients of small-chemical-potential quark-gluon plasmas are estimated and dissipative corrections to the scaling hydrodynamic equations for ultrarelativistic nuclear collisions are studied. The absence of heat-conduction phenomena is clarified. Lower and upper bounds on the shear-viscosity coefficient are derived. QCD phenomenology is used to estimate effects of color-electric and -magnetic shielding, and nonperturbative antiscreening. Bulk viscosity associated with the plasma-to-hadron transition is estimated within the relaxation-time approximation. Finally, effects of dissipative phenomena on the relation between initial energy density and final rapidity density are estimated.

Danielewicz, P.; Gyulassy, M.

1985-01-01T23:59:59.000Z

6

Astrophysical Aspects of Quark-Gluon Plasma

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

Enström, D

1998-01-01T23:59:59.000Z

7

Jet conversions in a quark-gluon plasma

Science Journals Connector (OSTI)

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?gq(q¯) and the inelastic qq¯?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/?+ and p¯/?- 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.

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

2007-05-04T23:59:59.000Z

8

Jet conversions in a quark-gluon plasma

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.

Liu, W.; Ko, C. M.; Zhang, B. W. [Cyclotron Institute and Physics Department, Texas A and M University, College Station, Texas 77843-3366 (United States)

2007-05-15T23:59:59.000Z

9

Jet conversions in a quark-gluon plasma

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 $q(\\bar q)g\\to gq(\\bar q)$ and the inelastic $q\\bar q\\leftrightarrow gg$ 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 conversion of quark 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 $p/\\pi^+$ and ${\\bar p}/\\pi^-$ 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 same energy. Implications of our results are discussed.

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

2006-07-21T23:59:59.000Z

10

Momentum broadening in weakly coupled quark-gluon plasma

We calculate the probability distribution P(k [subscript ?]) for the momentum perpendicular to its original direction of motion that an energetic quark or gluon picks up as it propagates through weakly coupled quark-gluon ...

D'Eramo, F.

11

Onset of cavitation in the quark-gluon plasma

We study the onset of bubble formation (cavitation) in the quark-gluon plasma as a result of the reduction of the effective pressure from bulk-viscous corrections. By calculating velocity gradients in typical models for quark-gluon plasma evolution in heavy-ion collisions, we obtain results for the critical bulk viscosity above which cavitation occurs. Since present experimental data for heavy-ion collisions seems inconsistent with the presence of bubbles above the phase transition temperature of QCD, our results may be interpreted as an upper limit of the bulk viscosity in nature. Our results indicate that bubble formation must occur at temperatures below 140 MeV, consistent with the expectation of hadronisation in low temperature QCD.

Habich, Mathis

2014-01-01T23:59:59.000Z

12

Anomalous viscosity of an expanding quark-gluon plasma

We argue that an expanding quark-gluon plasma has an anomalous viscosity, which arises from interactions with dynamically generated colour fields. The anomalous viscosity dominates over the collisional viscosity for large velocity gradients or weak coupling. This effect may provide an explanation for the apparent near perfect liquidity of the matter produced in nuclear collisions at RHIC without the assumption that it is a strongly coupled state.

M. Asakawa; S. A. Bass; B. Müller

2007-02-02T23:59:59.000Z

13

Heavy quark production from jet conversions in a quark-gluon plasma

Recently, it has been demonstrated that the chemical composition of jets in heavy ion collisions is significantly altered compared to the jets in the vacuum. This signal can be used to probe the medium formed in nuclear collisions. In this study we investigate the possibility that fast light quarks and gluons can convert to heavy quarks when passing through a quark-gluon plasma. We study the rate of light to heavy jet conversions in a consistent Fokker-Planck framework and investigate their impact on the production of high-p{sub T} charm and bottom quarks at the Relativistic Heavy Ion Collider and the Large Hadron Collider.

Liu, W. [Cyclotron Institute and Physics Department, Texas A and M University, College Station, Texas 77843-3366 (United States); Fries, R. J. [Cyclotron Institute and Physics Department, Texas A and M University, College Station, Texas 77843-3366 (United States); RIKEN/BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973 (United States)

2008-09-15T23:59:59.000Z

14

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

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...

Riek, F.; Rapp, Ralf.

2010-01-01T23:59:59.000Z

15

Quark-Gluon Plasma: from lattice simulations to experimental results

Theoretical studies of quarkonia can elucidate some of the important properties of the quark--gluon plasma, the state of matter realised when the temperature exceeds 150 MeV, currently probed by heavy-ion collisions experiments at BNL and the LHC. We report on our results of lattice studies of bottomonia for temperatures in the range 100 MeV < T < 450 MeV, introducing and discussing the methodologies we have applied. Of particular interest is the analysis of the spectral functions, where Bayesian methods borrowed and adapted from nuclear and condensed matter physics have proven very successful.

G. Aarts; C. Allton; A. Kelly; J. -I. Skullerud; S. Kim; T. Harris; S. M. Ryan; M. P. Lombardo

2014-03-20T23:59:59.000Z

16

Heavy quark collisional energy loss in the quark-gluon plasma including finite relaxation time

In this paper, we calculate the soft-collisional energy loss of heavy quarks traversing the viscous quark-gluon plasma including the effects of a finite relaxation time $\\tau_\\pi$ on the energy loss. We find that the collisional energy loss depends appreciably on $\\tau_\\pi$ . In particular, for typical values of the viscosity-to-entropy ratio, we show that the energy loss obtained using $\\tau_\\pi$ = 0 can be $\\sim$ 10$\\%$ larger than the one obtained using $\\tau_\\pi$ = 0. Moreover, we find that the energy loss obtained using the kinetic theory expression for $\\tau_\\pi$ is much larger that the one obtained with the $\\tau_\\pi$ derived from the Anti de Sitter/Conformal Field Theory correspondence. Our results may be relevant in the modeling of heavy quark evolution through the quark-gluon plasma.

Mauro Elias; J. Peralta-Ramos; E. Calzetta

2014-04-30T23:59:59.000Z

17

The approach to equilibrium in a quark-gluon plasma

The basic questions to be addressed in this paper are: How does the quark-gluon plasma, once formed in heavy-ion collisions, approach equilibrium. What are the basic equilibrium time scales - how do they compare with the plasma lifetime before hadronization and freeze-out set in. In particular, how do the strong color anisotropies, which are presumably present in the initial formation stage disappear and how fast, if at all, do the color degrees of freedom attain local equilibrium. The approach that I wish to present here involves the following chain of arguments: equilibration is related to dissipation of energy and creation of entropy; it is determined by the dissipative, i.e., imaginary part of certain response functions - for example, to calculate the rate of dissipation for a density perturbation in an equilibrium plasma we need to work out the imaginary part of the retarded density-density correlation function; this imaginary part of the response function is dominated by its poles which signal collective modes - for example, phonons in the density-density correlation function, (colored) plasmons in the electric and magnetic response functions, etc.; from the imaginary part one can calculate a damping rate ..gamma.. for these collective modes which in turn yields an estimate for the equilibration time scale tau/sub equ/ approx. h-bar/..gamma... In this contribution I will concentrate on color equilibration and thus focus on color electric and magnetic plasma oscillations and their damping rates. 21 refs.

Heinz, U.

1987-01-01T23:59:59.000Z

18

The phase transition from hadrons to quark-gluon plasma for lighter ions

Science Journals Connector (OSTI)

The phase transition from hadrons to quark-gluon plasma is...b|?0) collisions of ultrarelativistic lighter-ion beams. A hydrodynamical model is formulated and its consequences are applied to several ions includin...

L. E. Roberts

1989-12-01T23:59:59.000Z

19

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

Ryblewski, Radoslaw

2015-01-01T23:59:59.000Z

20

Geek-Up[11.05.10]: Quark Gluon Plasma, Solar-Power Generating Windows and

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

05.10]: Quark Gluon Plasma, Solar-Power Generating 05.10]: Quark Gluon Plasma, Solar-Power Generating Windows and CCS Field Studies Geek-Up[11.05.10]: Quark Gluon Plasma, Solar-Power Generating Windows and CCS Field Studies November 5, 2010 - 4:08pm Addthis A simulated collision of lead-ions, courtesy the ALICE experiment at CERN A simulated collision of lead-ions, courtesy the ALICE experiment at CERN Elizabeth Meckes Elizabeth Meckes Director of User Experience & Digital Technologies, Office of Public Affairs More than 1,700 scientists, engineers, technicians and students from seven Department of Energy national laboratories, 89 American universities and one supercomputer center celebrated progress this week when the Large Hadron Collider's (LHC) first record-setting run of high-energy proton collisions ended.

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

21

What does it mean to have `seen' the quark-gluon plasma?

Identifying the quark-gluon plasma requires convincing experimental evidence that partons move independently throughout the environment created in a heavy ion collision and with densities expected from equilibrium considerations. In lattice calculations, charge correlations suggest that quarks exist independently, and are not merely exchanged from hadronic object to another. Many experimental signatures (J/Psi suppression, quark number scaling, etc.) suggest that quarks are not confined to their original singlets, but these signatures do not make a clear case that quarks move independently or that they have the expected densities. I discuss a class of measurements that parallel lattice observables and has the prospect of investigating whether partonic charges move independently.

Scott Pratt

2012-10-01T23:59:59.000Z

22

Science Journals Connector (OSTI)

The dependence of dilepton production on total transverse energy in nuclear collisions is proposed as a signature of quark- gluon plasma formation. In particular the ratio of dilepton production in central (large transverse energy) to that in peripheral (low transverse energy) gives information about the presence of hydrodynamical space-time evolution of the quark-gluon plasma or of a mixed phase.

J. Masarik; N. Pišútová; J. Pišút

1991-01-01T23:59:59.000Z

23

Dilepton emission at temperature dependent baryonic quark-gluon plasma

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

S. Somorendro Singh; Yogesh Kumar

2012-08-04T23:59:59.000Z

24

Chiral Magnetic Effect in the Anisotropic Quark-Gluon Plasma

An anisotropic thermal plasma phase of a strongly coupled gauge theory can be holographically modelled by an anisotropic AdS black hole. The temperature and anisotropy parameter of the AdS black hole background of interest [1] is specified by the location of the horizon and the value of the Dilaton field at the horizon. Interestingly, for the first time, we obtain two functions for the values of the horizon and Dilaton field in terms of the temperature and anisotropy parameter. Then by introducing a number of spinning probe D7-branes in the anisotropic background, we compute the value of the chiral magnetic effect (CME). We observe that in the isotropic and anisotropic plasma the value of the CME is equal for the massless quarks. However, at fixed temperature, raising the anisotropy in the system will increase the value of the CME for the massive quarks.

Mohammad Ali-Akbari; Seyed Farid Taghavi

2014-08-27T23:59:59.000Z

25

Thermal photons as a quark-gluon plasma thermometer revisited

Photons are a penetrating probe of the hot medium formed in heavy-ion collisions, but they are emitted from all collision stages. At photon energies below 2-3 GeV, the measured photon spectra are approximately exponential and can be characterized by their inverse logarithmic slope, often called "effective temperature" $T_\\mathrm{eff}$. Modelling the evolution of the radiating medium hydrodynamically, we analyze the factors controlling the value of $T_\\mathrm{eff}$ and how it is related to the evolving true temperature $T$ of the fireball. We find that at RHIC and LHC energies most photons are emitted from fireball regions with $T{\\,\\sim\\,}T_\\mathrm{c}$ near the quark-hadron phase transition, but that their effective temperature is significantly enhanced by strong radial flow. Although a very hot, high pressure early collision stage is required for generating this radial flow, we demonstrate that the experimentally measured large effective photon temperatures $T_\\mathrm{eff}{\\,>\\,}T_\\mathrm{c}$, taken alone, do not prove that any electromagnetic radiation was actually emitted from regions with true temperatures well above $T_\\mathrm{c}$. We explore tools that can help to provide additional evidence for the relative weight of photon emission from the early quark-gluon and late hadronic phases. We find that the recently measured centrality dependence of the total thermal photon yield requires a larger contribution from late emission than presently encoded in our hydrodynamic model.

Chun Shen; Ulrich W. Heinz; Jean-Francois Paquet; Charles Gale

2014-03-28T23:59:59.000Z

26

Thermalization and collective flow of charm (c) and bottom (b) quarks in ultrarelativistic heavy-ion collisions are evaluated based on elastic parton rescattering in an expanding quark-gluon plasma (QGP). We show that resonant interactions in a...

van Hees, H.; Greco, V.; Rapp, Ralf.

2006-01-01T23:59:59.000Z

27

Electric conductivity is sensitive to effective cross sections among the particles of the partonic medium. We investigate the electric conductivity of a hot plasma of quarks and gluons, solving the relativistic Boltzmann equation. In order to extract this transport coefficient, we employ the Green-Kubo formalism and, independently, a method motivated by the classical definition of electric conductivity. To this end we evaluate the static electric diffusion current upon the influence of an electric field. Both methods give identical results. For the first time, we obtain numerically the Drude electric conductivity formula for an ultrarelativistic gas of quarks and gluons employing constant isotropic binary cross sections. Furthermore, we extract the electric conductivity for a system of massless quarks and gluons including screened binary and inelastic, radiative $2\\leftrightarrow 3$ perturbative QCD scattering. Comparing with recent lattice results, we find an agreement in the temperature dependence of the conductivity.

Moritz Greif; Ioannis Bouras; Zhe Xu; Carsten Greiner

2014-11-17T23:59:59.000Z

28

A New Phase of Matter: Quark-Gluon Plasma Beyond the Hagedorn Critical Temperature

I retrace the developments from Hagedorn's concept of a limiting temperature for hadronic matter to the discovery and characterization of the quark-gluon plasma as a new state of matter. My recollections begin with the transformation more than 30 years ago of Hagedorn's original concept into its modern interpretation as the "critical" temperature separating the hadron gas and quark-gluon plasma phases of strongly interacting matter. This was followed by the realization that the QCD phase transformation could be studied experimentally in high-energy nuclear collisions. I describe here my personal effort to help develop the strangeness experimental signatures of quark and gluon deconfinement and recall how the experimental program proceeded soon to investigate this idea, at first at the SPS, then at RHIC, and finally at LHC. As it is often the case, the experiment finds more than theory predicts, and I highlight the discovery of the "perfectly" liquid quark-gluon plasma at RHIC. I conclude with an outline of fu...

Müller, Berndt

2015-01-01T23:59:59.000Z

29

Radiative parton energy loss in expanding quark-gluon plasma with magnetic monopoles

We study radiative parton energy loss in an expanding quark-gluon plasma with magnetic monopoles. We find that for realistic number density of thermal monopoles obtained in lattice simulations parton rescatterings on monopoles can considerably enhance energy loss for plasma produced in $AA$ collisions at RHIC and LHC energies. However, contrary to previous expectations, monopoles do not lead to the surface dominance of energy loss.

B. G. Zakharov

2014-12-19T23:59:59.000Z

30

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: $q\\bar{q}{\\to}l\\bar{l}$, $q\\bar{q}{\\to}gl\\bar{l}$, Compton-like scattering ($qg{\\to}ql\\bar{l}$, $\\bar{q}g{\\to}{\\bar{q}}l\\bar{l}$), gluon fusion $g\\bar{g}{\\to}c\\bar{c}$, annihilation $q\\bar{q}{\\to}c\\bar{c}$ 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.

N. N. Guan; Z. J. He; J. L. Long; X. Z. Cai; Y. G. Ma; J. W. Li; W. Q. Shen

2009-09-02T23:59:59.000Z

31

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

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

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

2013-03-25T23:59:59.000Z

32

Jet-dilepton conversion in spherical expanding quark-gluon plasma

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

Fu, Yong-Ping

2014-01-01T23:59:59.000Z

33

Jet-dilepton conversion in spherical expanding quark-gluon plasma

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

Yong-Ping Fu; Qin Xi

2014-10-19T23:59:59.000Z

34

Event-by-event hydrodynamics: A better tool to study the Quark-Gluon plasma

Hydrodynamics has been established as a good tool to describe many data from relativistic heavyion collisions performed at RHIC and LHC. More recently, it has become clear that it is necessary to use event-by-event hydrodynamics (i.e. describe each collision individually using hydrodynamics), an approach first developed in Brazil. In this paper, I review which data require the use of event-by-event hydrodynamics and what more we may learn on the Quark-Gluon Plasma with this.

Grassi, Frederique [Instituto de Fisica, Universidade de Sao Paulo (Brazil)

2013-03-25T23:59:59.000Z

35

The sound generated by a fast parton in the quark-gluon plasma is a crescendo

The total energy deposited into the medium per unit length by a fast parton traversing a quark-gluon plasma is calculated. We take the medium excitation due to collisions to be given by the well known expression for the collisional drag force. The parton's radiative energy loss contributes to the energy deposition because each radiated gluon acts as an additional source of collisional energy loss in the medium. In our model, this leads to a length dependence on the differential energy loss due to the interactions of radiated gluons with the medium. The final result, which is a sum of the primary and the secondary contributions, is then treated as the coefficient of a local hydrodynamic source term. Results are presented for energy density wave induced by two fast, back-to-back partons created in an initial hard interaction.

R. B. Neufeld; B. Muller

2009-07-16T23:59:59.000Z

36

Transport properties of the quark-gluon plasma from lattice QCD

I review the progress made in extracting transport properties of the quark-gluon plasma from lattice QCD simulations. The information on shear and bulk viscosity, the "low-energy constants" of hydrodynamics, is encoded in the retarded correlators of Tmunu, the energy-momentum tensor. Euclidean correlators, computable on the lattice, are related to the retarded correlators by an integral transform. The most promising strategy to extract shear and bulk viscosity is to study the shear and sound channel correlators where the hydrodynamic modes dominate. I present preliminary results from a comprehensive study of the gluonic plasma between 0.95Tc and 4.0Tc.

Harvey B. Meyer

2009-07-23T23:59:59.000Z

37

Two-photon intensity interferometry is shown to provide an accurate measurement of lifetime of quark-gluon plasma created in ultra-relativistic heavy ion collisions via the difference of outward and sidewardcorrelation radii. Under the assumption of a longitudinal, boost invariant expansion of the plasma, we obtain analytical expressions for the correlations from the quark-gluon plasma phase. A $3+1$ dimensional expansion of the plasma along with a first order phase transition to hadrons is next considered, and, leads to a source with two characteristic lifetimes, one for the quark-gluon plasma phase, and the other for the longer lived mixed phase. This may even help us to {\\em experimentally} determine the order of the phase transition.

Dinesh K. Srivastava; Charles Gale

1993-11-10T23:59:59.000Z

38

Magnetic properties of holographic multiquarks in the quark-gluon plasma

We study the magnetic properties of the coloured multiquark states in the quark-gluon plasma where the gluons are deconfined and the chiral symmetry is still broken, using the Sakai-Sugimoto model. There are two possible magnetized multiquark configurations. Both configurations converge to the same configuration at the critical field and temperature before they dissociate altogether either into less coloured multiquarks or into other phases for a fixed density. It is also found that the multiquarks with higher colour charges respond more to the external magnetic field in both the magnetization and the degree of chiral symmetry breaking. Magnetic field also makes it more difficult for multiquark states with large colour charges to satisfy the equilibrium condition of the configuration in the gravity dual picture. As long as the chemical potential $\\mu > \\mu_{onset}$, the magnetized multiquarks phase is thermodynamically preferred over the magnetized vacuum. Pure pion gradient and the chiral-symmetric quark-gluon plasma ($\\chi_S$-QGP) phase for the general Sakai-Sugimoto model are discussed and compared with the multiquark phase in the presence of the magnetic field. It is found that at large densities and moderate fields, the mixed phase of multiquarks and the pion gradient is thermodynamically preferred over the $\\chi_S$-QGP.

Piyabut Burikham

2009-09-03T23:59:59.000Z

39

Thermal photons as a quark-gluon plasma thermometer revisited

Photons are a penetrating probe of the hot medium formed in heavy-ion collisions, but they are emitted from all collision stages. At photon energies below 2-3 GeV, the measured photon spectra are approximately exponential and can be characterized by their inverse logarithmic slope, often called "effective temperature" T_eff. Modeling the evolution of the radiating medium hydrodynamically, we analyze the factors controlling the value of T_eff and how it is related to the evolving true temperature T of the fireball. We find that at RHIC and LHC energies most photons are emitted from fireball regions with T ~ T_c near the quark-hadron phase transition, but that their effective temperature is significantly enhanced by strong radial flow. Although a very hot, high pressure early collision stage is required for generating this radial flow, we demonstrate that the experimentally measured large effective photon temperatures T_eff > T_c do not prove that any electromagnetic radiation was actually emitted from regions ...

Shen, Chun; Paquet, Jean-Francois; Gale, Charles

2013-01-01T23:59:59.000Z

40

Dilepton as a Possible Signature for the Baryon-Rich Quark-Gluon Plasma

to the dilepton yield at invariant masses between 2m?and 1 GeV. The total dilepton yield in this invariant mass region increases with the incident energy of the collision, but a saturation is seen once a baryon-rich quark-gluon plasma is formed in the initial... of 2m to about 1 GeV, where m is the mass of pion. It is also found in Refs. 15-17 that the modification of the pion dispersion relation by the dense nuclear matter because of the strong p-wave mN interac- tion can lead to an enhanced production...

Xia, L. H.; Ko, Che Ming; Li, C. T.

1990-01-01T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

41

Estimation of electric conductivity of the quark gluon plasma via asymmetric heavy-ion collisions

We show that in asymmetric heavy-ion collisions, especially off-central Cu+Au collisions, a sizable strength of electric field directed from Au nucleus to Cu nucleus is generated in the overlapping region, because of the difference in the number of electric charges between the two nuclei. This electric field would induce an electric current in the matter created after the collision, which result in a dipole deformation of the charge distribution. The directed flow parameters $v_1^{\\pm}$ of charged particles turn out to be sensitive to the charge dipole and provide us with information about electric conductivity of the quark gluon plasma.

Yuji Hirono; Masaru Hongo; Tetsufumi Hirano

2014-12-08T23:59:59.000Z

42

What hard probes tell us about the quark-gluon plasma: Theory

In the study of the quark-gluon plasma in high-energy heavy-ion collisions, hard and electromagnetic (EM) processes play an essential role as probes of the properties of the dense medium. They can be used to study a wide range of properties of the dense medium in high-energy heavy-ion collisions, from space-time profiles of the dense matter, bulk transport coefficients to EM responses and the jet transport parameter. I review in this talk these medium properties, how they can be studied through hard and EM probes and the status of recent theoretical and phenomenological investigations.

Xin-Nian Wang

2014-04-08T23:59:59.000Z

43

What hard probes tell us about the quark-gluon plasma: Theory

In the study of the quark-gluon plasma in high-energy heavy-ion collisions, hard and electromagnetic (EM) processes play an essential role as probes of the properties of the dense medium. They can be used to study a wide range of properties of the dense medium in high-energy heavy-ion collisions, from space-time profiles of the dense matter, bulk transport coefficients to EM responses and the jet transport parameter. I review in this talk these medium properties, how they can be studied through hard and EM probes and the status of recent theoretical and phenomenological investigations.

Wang, Xin-Nian

2014-01-01T23:59:59.000Z

44

Bag model of hadrons, dual QCD thermodynamics and Quark-Gluon Plasma

Using the grand canonical ensemble formulation of a multi-particle statistical system, the thermodynamical description of the dual QCD has been presented in terms of the bag model of hadrons and analyzed for the quark-gluon plasma phase of hadronic matter. The dual QCD bag construction has been shown to lead to the radial pressure on the bag surface in terms of the vector glueball masses of the magnetically condensed QCD vacuum. Constructing the grand canonical partition function to deal with the quark-gluon plasma phase of the non-strange hadrons, the energy density and the plasma pressure have been derived and used to understand the dynamics of the associated phase transition. The critical temperature for QGP-hadron phase transition has been derived and numerically estimated by using various thermodynamic considerations. A comparison of the values of the critical temperatures for QGP-hadron phase transition with those obtained for the deconfinement-phase transition, has been shown to lead to the relaxation ...

Chandola, H C; Dehnen, H

2015-01-01T23:59:59.000Z

45

Generalized Emission Functions for Photon Emission from Quark-Gluon Plasma

The Landau-Pomeranchuk-Migdal effects on photon emission from the quark gluon plasma have been studied as a function of photon mass, at a fixed temperature of the plasma. The integral equations for the transverse vector function (${\\bf \\tilde{f}(\\tilde{p}_\\perp)}$) and the longitudinal function ($\\tilde{g}({\\bf \\tilde{p}_\\perp})$) consisting of multiple scattering effects are solved by the self consistent iterations method and also by the variational method for the variable set \\{$p_0,q_0,Q^2$\\}, considering the bremsstrahlung and the $\\bf aws$ processes. We define four new dynamical scaling variables, $x^b_T$,$x^a_T$,$x^b_L$,$x^a_L$ for bremsstrahlung and {\\bf aws} processes and analyse the transverse and longitudinal components as a function of \\{$p_0,q_0,Q^2$\\}. We generalize the concept of photon emission function and we define four new emission functions for massive photon emission represented by $g^b_T$, $g^a_T$, $g^b_L$, $g^a_L$. These have been constructed using the exact numerical solutions of the integral equations. These four emission functions have been parameterized by suitable simple empirical fits. In terms of these empirical emission functions, the virtual photon emission from quark gluon plasma reduces to one dimensional integrals that involve folding over the empirical $g^{b,a}_{T,L}$ functions with appropriate quark distribution functions and the kinematic factors. Using this empirical emission functions, we calculated the imaginary part of the photon polarization tensor as a function of photon mass and energy.

S. V. Suryanarayana

2006-06-06T23:59:59.000Z

46

Fluctuating Heavy Quark Energy Loss in Strongly-Coupled Quark-Gluon Plasma

Results from an energy loss model that includes thermal fluctuations in the energy loss for heavy quarks in a strongly-coupled plasma are shown to be qualitatively consistent with single particle data from both RHIC and LHC. The model used is the first to properly include the fluctuations in heavy quark energy loss as derived in string theory and that do not obey the usual fluctuation-dissipation relations. These fluctuations are crucial for simultaneously describing both RHIC and LHC data; leading order drag results without fluctuations are falsified by current data. Including the fluctuations is non-trivial and relies on the Wong-Zakai theorem to fix the numerical Langevin implementation. The fluctuations lead to surprising results: B meson anisotropy is similar to that for D mesons at LHC, and the double ratio of D to B meson nuclear modification factors approaches unity more rapidly than even predictions from perturbative energy loss models. It is clear that future work in improving heavy quark energy los...

Horowitz, W A

2015-01-01T23:59:59.000Z

47

Quark-gluon plasma in the early Universe and in ultra-relativistic heavy-ion collisions

We briefly give an elementary introduction to the expansion of the Early Universe till when the phase transition of the quark-gluon plasma to a hadronic matter takes place. Then we describe some main element of the study of QGP by mean of ultra-relativistic heavy-ion collisions (uRHIC's)

Greco, V. [Department of Physics and Astronomy, University of Catania, Catania, Italy and INFN - Laboratori Nazionali del Sud, Catania (Italy)

2014-05-09T23:59:59.000Z

48

Electrical Conductivity of an Anisotropic Quark Gluon Plasma : A Quasiparticle Approach

The study of transport coefficients of strongly interacting matter got impetus after the discovery of perfect fluid ever created at ultrarelativistic heavy ion collision experiments. In this article, we have calculated one such coefficient viz. electrical conductivity of the quark gluon plasma (QGP) phase which exhibits a momentum anisotropy. Relativistic Boltzmann's kinetic equation has been solved in the relaxation-time approximation to obtain the electrical conductivity. We have used the quasiparticle description to define the basic properties of QGP. We have compared our model results with the corresponding results obtained in different lattice as well as other model calculations. Furthermore, we extend our model to calculate the electrical conductivity at finite chemical potential.

Srivastava, P K; Patra, Binoy Krishna

2015-01-01T23:59:59.000Z

49

From Color Glass Condensate to Quark Gluon Plasma through the event horizon

We propose a new thermalization scenario for heavy ion collisions which at sufficiently high energies implies the phase transition to the quark--gluon plasma. The key ingredient of our approach is the Hawking--Unruh effect: an observer moving with an acceleration $a$ experiences the influence of a thermal bath with an effective temperature $T = a / 2\\pi$, similar to the one present in the vicinity of a black hole horizon. For electric charges moving in external electromagnetic fields of realistic strength, the resulting temperature appears too small to be detected. However for partons in strong color fields the effect should be observable: in the Color Glass Condensate picture, the strength of the color-electric field is $E \\sim Q_s^2/g$ ($Q_s$ is the saturation scale, and $g$ is the strong coupling), the typical acceleration is $a \\sim Q_s$, and the heat bath temperature is $T = Q_s / 2\\pi \\sim 200$ MeV. In nuclear collisions at sufficiently high energies the effect can induce a rapid thermalization over the time period of $\\tau \\simeq 2\\pi/Q_s \\simeq 1\\ {\\rm fm}$ accompanied by phase transitions. We consider a specific example of chiral symmetry restoration induced by a rapid deceleration of the colliding nuclei. We argue that parton saturation in the initial nuclear wave functions is a necessary pre--condition for the formation of quark--gluon plasma. We discuss the implications of our "black hole thermalization" scenario for various observables in relativistic heavy ion collisions.

Dmitri Kharzeev; Kirill Tuchin

2005-01-25T23:59:59.000Z

50

A T-Matrix Approach to Heavy Quark Interaction with Thermal Gluons in a Quark Gluon Plasma

: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 51 viii LIST OF FIGURES FIGURE Page 2.1 In-medium HQ free and internal energies determined using lattice data [12] in the triplet (solid lines), sextet (dotted lines), and 15-plet (dashed lines) channels at temperatures T = 1:2Tc (left) and 2Tc...) for charm-gluon at 1:2Tc (thick) and 2:0Tc (thin). Diagrams illustrate the s-wave (left) and p-wave (right) for charm-gluon in potential U for the triplet (top), sextet (2nd row), and 15-plet (3rd row) color channels. The bottom diagram corresponds...

Huggins, Kyle

2012-10-19T23:59:59.000Z

51

3D Jet Tomography of Twisted Strongly Coupled Quark Gluon Plasmas

The triangular enhancement of the rapidity distribution of hadrons produced in p+A reactions relative to p+p is a leading order in A^{1/3}/log(s) violation of longitudinal boost invariance at high energies. In A+A reactions this leads to a trapezoidal enhancement of the local rapidity density of produced gluons. The local rapidity gradient is proportional to the local participant number asymmetry, and leads to an effective rotation in the reaction plane. We propose that three dimensional jet tomography, correlating the long range rapidity and azimuthal dependences of the nuclear modification factor, R_{AA}(\\eta,\\phi,p_\\perp; b>0), can be used to look for this intrinsic longitudinal boost violating structure of $A+A$ collisions to image the produced twisted strongly coupled quark gluon plasma (sQGP). In addition to dipole and elliptic azimuthal moments of R_{AA}, a significant high p_\\perp octupole moment is predicted away from midrapidity. The azimuthal angles of maximal opacity and hence minima of R_{AA} are rotated away from the normal to the reaction plane by an `Octupole Twist' angle, \\theta_3(\\eta), at forward rapidities.

A. Adil; M. Gyulassy

2005-05-01T23:59:59.000Z

52

Resummation of Jet Shapes and Extracting Properties of the Quark-Gluon Plasma

Understanding the properties of the quark-gluon plasma (QGP) that is produced in ultra-relativistic nucleus-nucleus collisions has been one of the top priorities of the heavy ion program at the LHC. Energetic jets are produced and subsequently quenched in the collisions. Such jet quenching phenomena provide promising tools to probe the medium properties by studying the modification of jets due to the medium interactions. Significant modifications of jet shapes have been measured. In this talk we focus on the calculation of jet shapes in both proton-proton and lead-lead collisions using soft-collinear effective theory (SCET), with Glauber gluon interactions in the medium. Large logarithms in jet shapes are resummed at next-to-leading logarithmic (NLL) accuracy by the renormalization-group evolution between hierarchical jet scales. The medium interactions contribute as power corrections, and we calculate the modification of jet shapes at leading order in opacity with the static QGP model. Preliminary results are presented with good agreement with the recent CMS jet shape measurements.

Yang-Ting Chien

2014-11-04T23:59:59.000Z

53

Resummation of Jet Shapes and Extracting Properties of the Quark-Gluon Plasma

Understanding the properties of the quark-gluon plasma (QGP) that is produced in ultra-relativistic nucleus-nucleus collisions has been one of the top priorities of the heavy ion program at the LHC. Energetic jets are produced and subsequently quenched in the collisions. Such jet quenching phenomena provide promising tools to probe the medium properties by studying the modification of jets due to the medium interactions. Significant modifications of jet shapes have been measured. In this talk we focus on the calculation of jet shapes in both proton-proton and lead-lead collisions using soft-collinear effective theory (SCET), with Glauber gluon interactions in the medium. Large logarithms in jet shapes are resummed at next-to-leading logarithmic (NLL) accuracy by the renormalization-group evolution between hierarchical jet scales. The medium interactions contribute as power corrections, and we calculate the modification of jet shapes at leading order in opacity with the static QGP model. Preliminary results ar...

Chien, Yang-Ting

2014-01-01T23:59:59.000Z

54

Energy dependence of jet transport parameter and parton saturationin quark-gluon plasma

We study the evolution and saturation of the gluondistribution function in the quark-gluon plasma as probed by apropagating parton and its effect on the computation of jet quenching ortransport parameter $\\hat q $. For thermal partons, the saturation scale$Q2_s$ is found to be proportional to the Debye screening mass $\\mu_D2$.For hard probes, evolution at small $x=Q2_s/6ET$ leads to jet energydependence of hat q. We study this dependence for both a conformal gaugetheory in weak and strong coupling limit and for (pure gluon) QCD. Theenergy dependence can be used to extract the shear viscosity $\\eta$ ofthe medium since $\\eta$ can be related to the transport parameter forthermal partons in a transport description. We also derive upper boundson the transport parameter for both energetic and thermal partons. Thelater leads to a lower bound on shear viscosity-to-entropy density ratiowhich is consistent with the conjectured lower bound $\\eta/s\\geq 1/4\\pi$.Implications on the study of jet quenching at RHIC and LHC and the bulkproperties of the dense matter are discussed.

Casalderrey-Solana, Jorge; Wang, Xin-Nian

2007-06-24T23:59:59.000Z

55

Shear viscosity of the Quark-Gluon Plasma from a virial expansion

We calculate the shear viscosity $\\eta$ in the quark-gluon plasma (QGP) phase within a virial expansion approach with particular interest in the ratio of $\\eta$ to the entropy density $s$, i.e. $\\eta/s$. The virial expansion approach allows us to include the interactions between the partons in the deconfined phase and to evaluate the corrections to a single-particle partition function. In the latter approach we start with an effective interaction with parameters fixed to reproduce thermodynamical quantities of QCD such as energy and/or entropy density. We also directly extract the effective coupling $\\ga_{\\rm V}$ for the determination of $\\eta$. Our numerical results give a ratio $\\eta/s\\approx 0.097$ at the critical temperature $T_{\\rm c}$, which is very close to the theoretical bound of $1/(4\\pi)$. Furthermore, for temperatures $T\\leq 1.8 T_{\\rm c}$ the ratio $\\eta/s$ is in the range of the present experimental estimates $0.1-0.3$ at RHIC. When combining our results for $\\eta/s$ in the deconfined phase with those from chiral perturbation theory or the resonance gas model in the confined phase we observe a pronounced minimum of $\\eta/s$ close to the critical temperature $T_{\\rm c}$.

S. Mattiello; W. Cassing

2009-11-24T23:59:59.000Z

56

The viscosity of quark-gluon plasma at RHIC and the LHC

The specific shear viscosity (eta/s)_QGP of quark-gluon plasma (QGP) can be extracted from elliptic flow data in heavy-ion collisions by comparing them with the dynamical model VISHNU which couples a viscous fluid dynamic description of the QGP with a microscopic kinetic description of the late hadronic rescattering and freeze-out stage. A robust method for fixing (eta/s)_QGP from the collision centrality dependence of the eccentricity-scaled charged hadron elliptic flow is presented. The systematic uncertainties associated with this extraction method are discussed, with specific attention to our presently restricted knowledge of initial conditions. With the (eta/s)_QGP extracted in this way, VISHNU yields an excellent description of all soft-hadron data from Au+Au collisions at top RHIC energy. Extrapolations to Pb+Pb collisions at the LHC, using both a purely hydrodynamic approach and VISHNU, are presented and compared with recent experimental results from the ALICE Collaboration. The LHC data are again well described by VISHNU, with the same (eta/s)_QGP value as at RHIC energies.

Ulrich W. Heinz; Chun Shen; Huichao Song

2011-08-26T23:59:59.000Z

57

Two Photon Correlation in Anisotropic Quark-gluon plasma (aQGP)

The only way to obtain the space-time structure of heavy ion collision is through the study of two-particle momentum correlations. Thus we have studied the intensity correlation for the photons having fixed transverse momentum of one of the photons ($k_{1T}$= 2 GeV) in anisotropic Quark Gluon Plasma (aQGP) to have an idea about emission zone in presence of initial momentum anisotropy. The {\\em free streaming interpolating} model with fixed initial condition has been used for the space-time evolution for most central collision at RHIC energy. The variation of Bose-Einstein correlation function (BECF), $C_2$, for two identical photons as a function of $q_{out}$, $q_{side}$ and $q_{long}$ is evaluated. We have restricted our analysis only to QGP phase to know the effect of anisotropy on the correlation function and HBT radii extracted. It is observed that the longitudinal dimension of the reaction zone is mostly affected due to the presence of momentum space anisotropy.

Payal Mohanty; Mahatsab Mandal; Pradip K Roy

2014-07-16T23:59:59.000Z

58

Vaporization of color-singlet pairs from a quark-gluon plasma

Science Journals Connector (OSTI)

We consider the hadronization of a QCD plasma by diffusion of quark-antiquark pairs through the plasma's surface. We apply the principle of detailed balance to argue that the surface is readily penetrable by color-singlet pairs. The resulting blackbody surface brightness exceeds that of other hadronization mechanisms. We note that the volume increase, needed to accommodate the plasma's high entropy in the dilute hadronic phase, compensates most of the combinatoric and statistical factors needed to select such pairs from the plasma. We conclude that the rate of evaporation of preformed pairs is ample to maintain phase equilibrium with a freely expanding meson gas outside the plasma.

Axel P. Vischer; Jitendra C. Parikh; Philip J. Siemens

1991-01-01T23:59:59.000Z

59

We investigate the influence of a temperature-dependent shear viscosity over entropy density ratio {eta}/s on the transverse momentum spectra and elliptic flow of hadrons in ultrarelativistic heavy-ion collisions. We find that the elliptic flow in {radical}(s{sub NN})=200 GeV Au+Au collisions at RHIC is dominated by the viscosity in the hadronic phase and in the phase transition region, but largely insensitive to the viscosity of the quark-gluon plasma (QGP). At the highest LHC energy, the elliptic flow becomes sensitive to the QGP viscosity and insensitive to the hadronic viscosity.

Niemi, H. [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, D-60438 Frankfurt am Main (Germany); Denicol, G. S.; Huovinen, P. [Institut fuer Theoretische Physik, Johann Wolfgang Goethe-Universitaet, Max-von-Laue-Strasse 1, D-60438 Frankfurt am Main (Germany); Molnar, E. [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, D-60438 Frankfurt am Main (Germany); MTA-KFKI, Research Institute for Particle and Nuclear Physics, H-1525 Budapest, P.O. Box 49 (Hungary); Rischke, D. H. [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, D-60438 Frankfurt am Main (Germany); Institut fuer Theoretische Physik, Johann Wolfgang Goethe-Universitaet, Max-von-Laue-Strasse 1, D-60438 Frankfurt am Main (Germany)

2011-05-27T23:59:59.000Z

60

Quark-Gluon Bags with Surface Tension

The temperature and chemical potential dependent surface tension of bags is introduced into the gas of quark-gluon bags model. This resolves a long standing problem of a unified description of the first and second order phase transition with the cross-over. Such an approach is necessary to model the complicated properties of quark-gluon plasma and hadronic matter from the first principles of statistical mechanics. The suggested model has an exact analytical solution and allows one to rigorously study the vicinity of the critical endpoint of the deconfinement phase transition. The existence of higher order phase transitions at the critical endpoint is discussed. In addition, we found that at the curve of a zero surface tension coefficient there must exist the surface induced phase tranition of the 2$^{nd}$ or higher order, which separates the pure quark gluon plasma (QGP) from the cross-over states, that are the mixed states of hadrons and QGP bags. Thus, the present model predicts that the critical endpoint of quantum chromodynamics is the tricritical endpoint.

Kyrill Bugaev

2007-03-20T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

61

The Particle Adventure | What holds it together? | Quarks emit gluons

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

holds it together? > Quarks emit gluons holds it together? > Quarks emit gluons Quarks emit gluons Color charge is always conserved. When a quark emits or absorbs a gluon, that quark's color must change in order to conserve color charge. For example, suppose a red quark changes into a blue quark and emits a red/antiblue gluon (the image below illustrates antiblue as yellow). The net color is still red. This is because - after the emission of the gluon - the blue color of the quark cancels with the antiblue color of the gluon. The remaining color then is the red color of the gluon. Quarks emit and absorb gluons very frequently within a hadron, so there is no way to observe the color of an individual quark. Within a hadron, though, the color of the two quarks exchanging a gluon will change in a way that keeps the bound system in a color-neutral state.

62

Hydrodynamic transport coefficients for the non-conformal quark-gluon plasma from holography

In this paper we obtain holographic formulas for the transport coefficients $\\kappa$ and $\\tau_\\pi$ present in the second-order derivative expansion of relativistic hydrodynamics in curved spacetime associated with a non-conformal strongly coupled plasma described holographically by an Einstein+Scalar action in the bulk. We compute these coefficients as functions of the temperature in a bottom-up non-conformal model that is tuned to reproduce lattice QCD thermodynamics at zero baryon chemical potential. We directly compute, besides the speed of sound, 6 other transport coefficients that appear at second-order in the derivative expansion. We also give an estimate for the temperature dependence of 11 other transport coefficients taking into account the simplest contribution from non-conformal effects that appear near the QCD crossover phase transition. Using these results, we construct an Israel-Stewart-like theory in flat spacetime containing 13 of these 17 transport coefficients that should be suitable for ph...

Finazzo, Stefano I; Marrochio, Hugo; Noronha, Jorge

2014-01-01T23:59:59.000Z

63

We introduce a new scenario for heavy ion collisions that could solve the lingering problems associated with the so-called HBT puzzle. We postulate that the system starts expansion as the perfect quark-gluon fluid but close to freeze-out it splits into clusters, due to a sharp rise of bulk viscosity in the vicinity of the hadronization transition. We then argue that the characteristic cluster size is determined by the viscosity coefficient and the expansion rate. Typically it is much smaller and independent of the total system volume. These clusters maintain the pre-existing outward-going flow, as a spray of droplets, but develop no flow of their own, and hadronize by evaporation. We provide an ansatz for converting the hydrodynamic output into clusters.

Giorgio Torrieri; Boris Tomasik; Igor Mishustin

2008-02-26T23:59:59.000Z

64

We introduce a new scenario for heavy ion collisions that could solve the lingering problems associated with the so-called HBT puzzle. We postulate that the system starts expansion as the perfect quark-gluon fluid but close to freeze-out it splits into clusters, due to a sharp rise of bulk viscosity in the vicinity of the hadronization transition. We then argue that the characteristic cluster size is determined by the viscosity coefficient and the expansion rate. Typically it is much smaller and independent of the total system volume. These clusters maintain the pre-existing outward-going flow, as a spray of droplets, but develop no flow of their own, and hadronize by evaporation. We provide an ansatz for converting the hydrodynamic output into clusters.

Torrieri, G; Mishustin, I

2007-01-01T23:59:59.000Z

65

In this article, we present a state-of-the-art algorithm for solving the relativistic viscous hydrodynamics equation with the QCD equation of state. The numerical method is based on the second-order Godunov method and has less numerical dissipation, which is crucial in describing of quark–gluon plasma in high-energy heavy-ion collisions. We apply the algorithm to several numerical test problems such as sound wave propagation, shock tube and blast wave problems. In sound wave propagation, the intrinsic numerical viscosity is measured and its explicit expression is shown, which is the second-order of spatial resolution both in the presence and absence of physical viscosity. The expression of the numerical viscosity can be used to determine the maximum cell size in order to accurately measure the effect of physical viscosity in the numerical simulation.

Akamatsu, Yukinao, E-mail: akamatsu@kmi.nagoya-u.ac.jp [Kobayashi–Maskawa Institute for the Origin of Particles and the Universe (KMI), Nagoya University, Nagoya 464-8602 (Japan)] [Kobayashi–Maskawa Institute for the Origin of Particles and the Universe (KMI), Nagoya University, Nagoya 464-8602 (Japan); Inutsuka, Shu-ichiro [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan)] [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Nonaka, Chiho [Kobayashi–Maskawa Institute for the Origin of Particles and the Universe (KMI), Nagoya University, Nagoya 464-8602 (Japan) [Kobayashi–Maskawa Institute for the Origin of Particles and the Universe (KMI), Nagoya University, Nagoya 464-8602 (Japan); Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Takamoto, Makoto [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan) [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Max-Planck-Institut für Kernphysik, Postfach 103980, 69029 Heidelberg (Germany)

2014-01-01T23:59:59.000Z

66

Quark and Gluon Tagging at the LHC

Science Journals Connector (OSTI)

Being able to distinguish light-quark jets from gluon jets on an event-by-event basis could significantly enhance the reach for many new physics searches at the Large Hadron Collider. Through an exhaustive search of existing and novel jet substructure observables, we find that a multivariate approach can filter out over 95% of the gluon jets while keeping more than half of the light-quark jets. Moreover, a combination of two simple variables, the charge track multiplicity and the pT-weighted linear radial moment (girth), can achieve similar results. Our study is only Monte Carlo based, so other observables constructed using different jet sizes and parameters are used to highlight areas that deserve further theoretical and experimental scrutiny. Additional information, including distributions of around 10?000 variables, can be found at http://jets.physics.harvard.edu/qvg/.

Jason Gallicchio and Matthew D. Schwartz

2011-10-17T23:59:59.000Z

67

Consequences Of Fully Dressing Quark-Gluon Vertex Function With Two-Point Gluon Lines

We extend recent studies of the effects of quark-gluon vertex dressing upon the solutions of the Dyson-Schwinger equation for the quark propagator. A momentum delta function is used to represent the dominant infrared strength of the effective gluon propagator so that the resulting integral equations become algebraic. The quark-gluon vertex is constructed from the complete set of diagrams involving only 2-point gluon lines. The additional diagrams, including those with crossed gluon lines, are shown to make an important contribution to the DSE solutions for the quark propagator, because of their large color factors and the rapid growth in their number.

Hrayr H. Matevosyan; Anthony W. Thomas; Peter C. Tandy

2007-06-16T23:59:59.000Z

68

Gluon Radiation and Energy Losses in Top Quark Production

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

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

1994-05-06T23:59:59.000Z

69

The comments raised in Ref. [1] by Mishra et al aim at two papers contained in Ref. [2]. We show that those comments on Ref. [2] pointed out by Mishra et al in Ref.[1] are not relevant and the concept used in Ref.[2] is consistent and in compliance with the classical approximation of the transport coefficients [3]. We would also like to note that most of the comments in Ref. [1] were meant for light quarks, but are not even appropriate for heavy quarks.

Munshi G. Mustafa; Markus H. Thoma

2007-09-05T23:59:59.000Z

70

We compute the energy and momentum deposited by a fast moving parton in a quark-gluon plasma using linear viscous hydrodynamics with an energy loss per unit length profile proportional to the path length and with different values of the shear viscosity to entropy density ratio. We show that when varying these parameters, the transverse modes still dominate over the longitudinal ones and thus energy and momentum is preferentially deposited along the head-shock, as in the case of a constant energy loss per unit length profile and the lowest value for the shear viscosity to entropy density ratio.

Alejandro Ayala; Jorge David Castano-Yepes; Isabel Dominguez; Maria Elena Tejeda-Yeomans

2014-12-18T23:59:59.000Z

71

The Role of Surface Tension for the Equation of State of Quark-Gluon Bags

The temperature and chemical potential dependent surface tension of bags is introduced into the gas of quark-gluon bags model. The suggested model is solved analytically. It resolves a long standing problem of a unified description of the first and second order phase transition with the cross-over. Such an approach is necessary to model the complicated properties of quark-gluon plasma and hadronic matter from the first principles of statistical mechanics. In addition to the deconfinement phase transition, we found that at the curve of a zero surface tension coefficient there must exist the surface induced phase tranition of the 2-nd or higher order, which separates the pure quark gluon plasma (QGP) from the cross-over states. Thus, the present model predicts that the critical endpoint of quantum chromodynamics is the tricritical endpoint.

K. A. Bugaev

2007-11-20T23:59:59.000Z

72

Color Glass Condensates in dense quark matter and quantum Hall states of gluons

We apply the effective theory of color glass condensate to the analysis of gluon states in dense quark matter, in which the saturation region of gluons is also present. We find that in the region two point function of gluons shows algebraic long range order. The order is completely the same as the one gluons show in the dense quark matter, which form quantum Hall states. The order leads to the vanishing of massless gluon pole. We also find that the saturation region of gluons extends from small $x$ to even large $x\\lesssim 1$ in much dense quark matter. We point out a universality that the color glass condensate is a property of hadrons at high energy and of quark matter at high baryon density.

Aiichi Iwazaki

2006-04-26T23:59:59.000Z

73

Comment on ``Damping of energetic gluons and quarks in high-temperature QCD''

Burgess and Marini have recently pointed out that the leading contribution to the damping rate of energetic gluons and quarks in the QCD plasma, given by $\\gamma=c g^2\\ln(1/g)T$, can be obtained by simple arguments obviating the need of a fully resummed perturbation theory as developed by Braaten and Pisarski. Their calculation confirmed previous results of Braaten and Pisarski, but contradicted those proposed by Lebedev and Smilga. While agreeing with the general considerations made by Burgess and Marini, I correct their actual calculation of the damping rates, which is based on a wrong expression for the static limit of the resummed gluon propagator. The effect of this, however, turns out to be cancelled fortuitously by another mistake, so as to leave all of their conclusions unchanged. I also verify the gauge independence of the results, which in the corrected calculation arises in a less obvious manner.

Anton Rebhan

1992-03-16T23:59:59.000Z

74

Shear viscosity of a nonperturbative gluon plasma

Shear viscosity is evaluated within a model of the gluon plasma, which is based entirely on the stochastic nonperturbative fields. We consider two types of excitations of such fields, which are characterized by the thermal correlation lengths ~ 1/(g^2 T) and ~ 1/(g^4 T), where "g" is the finite-temperature Yang-Mills coupling. Excitations of the first type correspond to the genuine nonperturbative stochastic Yang-Mills fields, while excitations of the second type mimic the known result for the shear viscosity of the perturbative Yang-Mills plasma. We show that the excitations of the first type produce only an O(g^{10})-correction to this result. Furthermore, a possible interference between excitations of these two types yields a somewhat larger, O(g^7), correction to the leading perturbative Yang-Mills result. Our analysis is based on the Fourier transformed Euclidean Kubo formula, which represents an integral equation for the shear spectral density. This equation is solved by seeking the spectral density in the form of the Lorentzian Ans\\"atze, whose widths are defined by the two thermal correlation lengths and by their mean value, which corresponds to the said interference between the two types of excitations. Thus, within one and the same formalism, we reproduce the known result for the shear viscosity of the perturbative Yang-Mills plasma, and account for possible nonperturbative corrections to it.

Dmitri Antonov

2012-02-10T23:59:59.000Z

75

Based on the Dyson-Schwinger Equations (DSEs) with zero- and finite temperature, the two quark condensate, the four quark condensate and quark gluon mixed condensate in non-perturbative QCD state are investigated by solving the DSEs respectively at zero and finite temperature. These condensates are important input parameters in QCD sum rule with zero and finite temperature and properties of hadronic study. The calculated results manifest that the three condensates are almost independent of the temperature below the critical point temperature $T_{c}$. The results also show that the chiral symmetry restoration is obtained above $T_{c}$. At the same time, we also calculate the ratio of the quark gluon mixed condensate to the two quark condensate which could be quark virtuality. The calculations show that the ratio $m^{2}_{0}(T)$ is almost flat in the region of temperature from $0$ to $T_{c}$, although there are drastic changes of the quark condensate and the quark gluon mixed condensate at this region of $T_{c}$.The predicted ratio comes out to be $m^{2}_{0}(T)= 2.41GeV^{2}$ for vacuum state at the Chiral limit, which suggests the significance that the quark gluon mixed condensate has played in OPE.

Zhou Li-Juan; Zheng Bo; Zhong Hong-wei; Ma Wei-xing

2014-03-27T23:59:59.000Z

76

Color coherence in a heavy quark antenna radiating gluons inside a QCD medium

We compute the color coherence effects for soft gluon radiation off antennas containing heavy quarks in the presence of a QCD medium - in color singlet, triplet or octet global states. This work completes the studies of antenna radiation inside a medium which provide a useful picture of the relevance of interference effects in jet parton showers for the jet quenching phenomenon observed in high-energy nuclear collisions. The analysis is performed resumming the multiple scatterings of the partonic system with the medium. The main conclusion is that decorrelation due to color rotation is more effective in the case in which at least one of the emitters of the antenna is a heavy quark. This effect, present both for a heavy-quark-antiquark or a heavy-quark-gluon antenna is more relevant for the later or for the case in which the energies of the quark and antiquark are very different. The parameter controlling these effects involves the dead-cone angle. We find that interferences are cancelled, spoiling the color correlation of the pair, when $\\theta_{ DC}=M/E >>1/\\sqrt{\\omega L}$ where E and {\\omega} are the energies of the heavy quark and the radiated gluon and L is the medium length. In the case of a heavy-quark-antiquark antenna $t_{form}$ appears instead of L if the original splitting is symmetric. The presence or absence of interferences modifies the energy loss pattern.

Manoel R. Calvo; Manoel R. Moldes; Carlos A. Salgado

2014-03-19T23:59:59.000Z

77

Maximal Wavelength of Confined Quarks and Gluons and Properties of Quantum Chromodynamics

Because quarks and gluons are confined within hadrons, they have a maximum wavelength of order the confinement scale. Propagators, normally calculated for free quarks and gluons using Dyson-Schwinger equations, are modified by bound-state effects in close analogy to the calculation of the Lamb shift in atomic physics. Because of confinement, the effective quantum chromodynamic coupling stays finite in the infrared. The quark condensate which arises from spontaneous chiral symmetry breaking in the bound state Dyson-Schwinger equation is the expectation value of the operator {bar q}q evaluated in the background of the fields of the other hadronic constituents, in contrast to a true vacuum expectation value. Thus quark and gluon condensates reside within hadrons. The effects of instantons are also modified. We discuss the implications of the maximum quark and gluon wavelength for phenomena such as deep inelastic scattering and annihilation, the decay of heavy quarkonia, jets, and dimensional counting rules for exclusive reactions. We also discuss implications for the zero-temperature phase structure of a vectorial SU(N) gauge theory with a variable number N{sub f} of massless fermions.

Brodsky, Stanley J.; /SLAC /YITP, Stony Brook /Durham U.; Shrock, Robert; /YITP, Stony Brook

2008-08-01T23:59:59.000Z

78

Magnetic component of gluon plasma and its viscosity

We discuss the role of the magnetic degrees of freedom of the gluon plasma in its viscosity. The main assumption is that motions of the magnetic component and of the rest of the plasma can be considered as independent. The magnetic component in the deconfined phase is described by a three-dimensional (Euclidean) field theory. The parameters of the theory can be estimated phenomenologically, from the lattice data. It is not ruled out that the magnetic component is superfluid.

M. N. Chernodub; H. Verschelde; V. I. Zakharov

2009-05-15T23:59:59.000Z

79

Thermalization of heavy quarks in the quark-gluon plasma

+ 2v ? k mc +O ( p2 m2c )] ? v ? k = s ?m2c 2mc +O ( p2 m2c ) . (12) Applying the Feynman rules, and after some (Dirac) algebra, the dimensionally regularized polarization tensor for the axial vector becomes ??D? (p) = ??D1 (p...+ 2v ? k mc +O ( p2 m2c )] ? v ? k = s ?m2c 2mc +O ( p2 m2c ) . (12) Applying the Feynman rules, and after some (Dirac) algebra, the dimensionally regularized polarization tensor for the axial vector becomes ??D? (p) = ??D1 (p...

van Hees, H.; Rapp, Ralf.

2005-01-01T23:59:59.000Z

80

Bulk viscosity of quark-gluon matter in a magnetic field

On the basis of low-energy QCD theorems, the bulk viscosity {zeta}(T, Micro-Sign , H) is expressed in terms of basic thermodynamic quantities that characterizes quark-gluon matter at finite temperature and a finite baryon density in a magnetic field. Various limiting cases are considered.

Agasian, N. O., E-mail: agasian@itep.ru [Institute of Theoretical and Experimental Physics (Russian Federation)

2013-11-15T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

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81

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

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

Hrayr Matevosyan; Anthony Thomas; Peter Tandy

2007-04-01T23:59:59.000Z

82

Exploring the Quark-Gluon Content of Hadrons: From Mesons to Nuclear Matter

Even though Quantum Chromodynamics (QCD) was formulated over three decades ago, it poses enormous challenges for describing the properties of hadrons from the underlying quark-gluon degrees of freedom. Moreover, the problem of describing the nuclear force from its quark-gluon origin is still open. While a direct solution of QCD to describe the hadrons and nuclear force is not possible at this time, we explore a variety of developed approaches ranging from phenomenology to first principle calculations at one or other level of approximation in linking the nuclear force to QCD. The Dyson Schwinger formulation (DSE) of coupled integral equations for the QCD Green’s functions allows a non-perturbative approach to describe hadronic properties, starting from the level of QCD n-point functions. A significant approximation in this method is the employment of a finite truncation of the system of DSEs, that might distort the physical picture. In this work we explore the effects of including a more complete truncation of the quark-gluon vertex function on the resulting solutions for the quark 2-point functions as well as the pseudoscalar and vector meson masses. The exploration showed strong indications of possibly large contributions from the explicit inclusion of the gluon 3- and 4-point functions that are omitted in this and previous analyses. We then explore the possibility of extrapolating state of the art lattice QCD calculations of nucleon form factors to the physical regime using phenomenological models of nucleon structure. Finally, we further developed the Quark Meson Coupling model for describing atomic nuclei and nuclear matter, where the quark-gluon structure of nucleons is modeled by the MIT bag model and the nucleon many body interaction is mediated by the exchange of scalar and vector mesons. This approach allows us to formulate a fully relativistic theory, which can be expanded in the nonrelativistic limit to reproduce the well known phenomenological Skyrme-type interaction density functional, thus providing a direct link to well modeled nuclear forces. Moreover, it allows for a derivation of the equation of state for cold uniform dense nuclear matter for application to calculations of the properties of neutron stars.

Hrayr Matevosyan

2007-07-09T23:59:59.000Z

83

Subjet multiplicity of gluon and quark jets reconstructed with the k? algorithm in pp¯ collisions

Science Journals Connector (OSTI)

The DØ Collaboration has studied for the first time the properties of hadron-collider jets reconstructed with a successive-combination algorithm based on relative transverse momenta (k?) of energy clusters. Using the standard value D=1.0 of the jet-separation parameter in the k? algorithm, we find that the pT of such jets is higher than the ET of matched jets reconstructed with cones of radius R=0.7, by about 5 (8) GeV at pT?90?(240)?GeV. To examine internal jet structure, the k? algorithm is applied within D=0.5 jets to resolve any subjets. The multiplicity of subjets in jet samples at s=1800?GeV and 630 GeV is extracted separately for gluons (Mg) and quarks (Mq), and the ratio of average subjet multiplicities in gluon and quark jets is measured as (?Mg?-1)/(?Mq?-1)=1.84±0.15?(stat)±0.180.22?(syst). This ratio is in agreement with the expectations from the HERWIG Monte Carlo event generator and a resummation calculation, and with observations in e+e- annihilations, and is close to the naive prediction for the ratio of color charges of CA/CF=9/4=2.25.

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

2002-02-07T23:59:59.000Z

84

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

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

Stephan Narison

2011-10-13T23:59:59.000Z

85

Quark-gluon state of matter and positive excess of cosmic-ray muons at high energies

Science Journals Connector (OSTI)

The problem of the relationship between the numbers of positively and negatively charged particles in the flux of cosmic-ray muons arriving at sea level with energies in excess of 0.1 TeV (up ... quark—gluon matt...

L. V. Volkova; G. T. Zatsepin

2008-10-01T23:59:59.000Z

86

Probing the Quark Sea and Gluons: the Electron-Ion Collider Projects

EIC is the generic name for the nuclear science-driven Electron-Ion Collider presently considered in the US. Such an EIC would be the world’s first polarized electron-proton collider, and the world’s first e-A collider. Very little remains known about the dynamical basis of the structure of hadrons and nuclei in terms of the fundamental quarks and gluons of Quantum Chromodynamics (QCD). A large community effort to sharpen a compelling nuclear science case for an EIC occurred during a ten-week program taking place at the Institute for Nuclear Theory (INT) in Seattle from September 13 to November 19, 2010. The critical capabilities of a stage-I EIC are a range in center-of-mass energies from 20 to 70 GeV and variable, full polarization of electrons and light ions (the latter both longitudinal and transverse), ion species up to A=200 or so, multiple interaction regions, and a high luminosity of about 10{sup 34} electron-nucleons per cm{sup 2} and per second. The physics program of such a stage-I EIC encompass inclusive measurements (ep/A{yields}e'+X), which require detection of the scattered lepon and/or the full scattered hadronic debris with high precision, semi-inclusive processes (ep/A{yields}e'+h+X), which require detection in coincidence with the scattered lepton of at least one (current or target region) hadron; and exclusive processes (ep/A{yields}e'+N'/A'+{gamma}/m), which require detection of all particles in the reaction. The main science themes of an EIC are to i) map the spin and spatial structure of quarks and gluons in nucleons, ii) discover the collective effects of gluons in atomic nuclei, and (iii) understand the emergence of hadronic matter from color charge. In addition, there are opportunities at an EIC for fundamental symmetry and nucleon structure measurements using the electroweak probe. To truly make headway to image the sea quarks and gluons in nucleons and nuclei, the EIC needs high luminosity over a range of energies as more exclusive scattering probabilities are small, and any integrated detector/interaction region design needs to provide uniform coverage to detect spectator and diffractive products. This is because e-p and even more e-A colliders have a large fraction of their science related to what happens to the nucleon or ion beams. As a result, the philosophy of integration of complex detectors into an extended interaction region faces challenging constraints. Designs feature crossing angles between the protons or heavy ions during collisions with electrons, to remove potential problems for the detector induced by synchrotron radiation. Designs allocate quite some detector space before the final-focus ion quads, at the cost of luminosity, given that uniform detection coverage is a must for deep exclusive and diffractive processes. The integrated EIC detector/interaction region design at JLab focused on establishing full acceptance for such processes over a wide range of proton energies (20-100 GeV) with well achievable interaction region magnets. The detector design at BNL uses the higher ion beam energies to achieve good detection efficiency for instance for protons following a DVCS reaction, for proton beam energies starting from 100 GeV. Following a recommendation of the 2007 US Nuclear Science Long-Range Planning effort, the DOE Office of Nuclear Physics (DOE/NP) has allocated accelerator R&D funds to lay the foundation for a polarized EIC. BNL, in association with JLab and DOE/NP, has also established a generic detector R&D program to address the scientific requirements for measurements at a future EIC.

Rolf Ent

2012-04-01T23:59:59.000Z

87

Science Journals Connector (OSTI)

We present a mechanism for the separation of strangeness from antistrangeness in the deconfinement transition. For a net strangeness of zero in the total system, the population of s quarks is greatly enriched in the quark-gluon plasma, while the s¯ quarks drift into the hadronic phase. This separation could result in ‘‘strangelet’’ formation, i.e., metastable blobs of strange-quark matter, which could serve as a unique signature for quark-gluon plasma formation in heavy-ion collisions.

Carsten Greiner; Peter Koch; Horst Stöcker

1987-05-04T23:59:59.000Z

88

EXPLORING THE QUARK GLUON PLASMA WITH BIKASH SINHA.

This paper presents a personal account of the scientific and professional adventures of Bikash Sinha on the occasion of the celebration of his 60th birthday held in Calcutta on Feb 7, 2005.

MCLERRAN, L.

2005-02-01T23:59:59.000Z

89

Jet conversions in a quark-gluon plasma

. Wang, Phys. Rev. C 58, 2321 (1998). [9] R. C. Hwa and C. B. Yang, Phys. Rev. C 67, 034902 (2003); 67, 064902 (2003). [10] V. Greco, C. M. Ko, and P. Le?vai, Phys. Rev. Lett. 90, 202302 (2003); Phys. Rev. C 68, 034904 (2003). [11] R. J. Fries, B. Mu?ller... 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. DOI: 10.1103/PhysRevC.75.051901 PACS number(s): 12.38.Mh, 25...

Liu, W.; Ko, Che Ming; Zhang, B. W.

2007-01-01T23:59:59.000Z

90

Toward the Theory of Strongly Coupled Quark-Gluon Plasma

Science Journals Connector (OSTI)

......in Anti-de-Sitter space (AdS) in weak coupling...moving to the left, heating the matter (in shadowed...M in which electric sector is still strongly coupled...have the same moduli space as instantons, the solutions...interesting AdS/CFT brane construction.36) Many more exotic......

Edward Shuryak

2007-03-01T23:59:59.000Z

91

Baryon number fluctuation and the quark-gluon plasma

baryon number per event is given by ^B&eq5b0^n&5b0 ]g~1 ! ]x 5b0 Ae I1I0 .b0Ae . ~5! Baryon number fluctuation Zi-wei Lin an Cyclotron Institute and Physics Department, Texas ~Received 28 March 2001; We show that vB or vB? , the squared baryon... volume of the system. The equilibrium solution to Eq. ~1! is Pn ,eq5 en I0~2Ae!~n! !2 , ~2! where I0 is the modified Bessel function, and e[ G^Nm1&^Nm2& L . ~3! ?2001 The American Physical Society1 RAPID COMMUNICATIONS ZI-WEI LIN AND C. M. KO...

Lin, ZW; Ko, Che Ming.

2001-01-01T23:59:59.000Z

92

Quark-gluon plasma phenomenology from anisotropic lattice QCD

The FASTSUM collaboration has been carrying out simulations of N_f=2+1 QCD at nonzero temperature in the fixed-scale approach using anisotropic lattices. Here we present the status of these studies, including recent results for electrical conductivity and charge diffusion, and heavy quarkonium (charm and beauty) physics.

Jon-Ivar Skullerud; Gert Aarts; Chris Allton; Alessandro Amato; Yannis Burnier; P. Wynne M. Evans; Pietro Giudice; Simon Hands; Tim Harris; Aoife Kelly; Seyong Kim; Maria Paola Lombardo; Mehmet B. Oktay; Alexander Rothkopf; Sinéad M. Ryan

2014-12-30T23:59:59.000Z

93

Quark-gluon plasma phenomenology from anisotropic lattice QCD

The FASTSUM collaboration has been carrying out simulations of N_f=2+1 QCD at nonzero temperature in the fixed-scale approach using anisotropic lattices. Here we present the status of these studies, including recent results for electrical conductivity and charge diffusion, and heavy quarkonium (charm and beauty) physics.

Skullerud, Jon-Ivar; Allton, Chris; Amato, Alessandro; Burnier, Yannis; Evans, P Wynne M; Giudice, Pietro; Hands, Simon; Harris, Tim; Kelly, Aoife; Kim, Seyong; Lombardo, Maria Paola; Oktay, Mehmet B; Rothkopf, Alexander; Ryan, Sinéad M

2015-01-01T23:59:59.000Z

94

OZI violation in low energy omega and phi production in the pp system in a quark-gluon model

We investigate OZI violation in near-threshold omega and phi production in the pp system. Assuming ideal omega/phi mixing (corrections are estimated), the energy dependence of the ratio R(omega/phi) is analyzed in a perturbative quark-gluon exchange model up to the third other in the strong coupling constant alpha(s) with the proton represented as a quark - scalar diquark system. We give a very natural explanation of the violation of the OZI rule in omega/phi production and its energy dependence near the production thresholds.

M. Dillig

2006-04-24T23:59:59.000Z

95

Gluons and the quark sea at high energies: distributions, polarization, tomography

This report is based on a ten-week program on Gluons and the quark sea at high-energies, which took place at the Institute for Nuclear Theory (INT) in Seattle in Fall 2010. The principal aim of the program was to develop and sharpen the science case for an Electron-Ion Collider (EIC), a facility that will be able to collide electrons and positrons with polarized protons and with light to heavy nuclei at high energies, offering unprecedented possibilities for in-depth studies of quantum chromodynamics (QCD). This report is organized around the following four major themes: (i) the spin and flavor structure of the proton, (ii) three dimensional structure of nucleons and nuclei in momentum and configuration space, (iii) QCD matter in nuclei, and (iv) Electroweak physics and the search for physics beyond the Standard Model. Beginning with an executive summary, the report contains tables of key measurements, chapter overviews for each of the major scientific themes, and detailed individual contributions on various aspects of the scientific opportunities presented by an EIC.

Boer, D.; Venugopalan, R.; Diehl, M.; Milner, R.; Vogelsang, W.; et al.

2011-09-30T23:59:59.000Z

96

The critical indices of the Quark-Gluon Bags with Surface Tension Model with tricritical endpoint

The critical indices \\alpha', \\beta, \\gamma' and \\delta of the Quark Gluon Bags with Surface Tension Model with the tricritical endpoint are calculated as functions of the usual parameters of this model and two newly introduces parameters (indices). They are compared with the critical exponents of other models. It is shown that for the newly introduced indices \\chi = 0 and \\xi^T < 1 there is a branch of solutions for which the critical exponents of the present model and the statistical multifragmentation model coincide, otherwise these models belong to different universality classes. It is shown that for realistic values of the parameter \\varkappa the critical exponents \\alpha', \\beta, \\gamma' and \\delta of simple liquids and 3-dimensional Ising model can be only described by the branch of solutions in which all indices except for \\alpha' correspond to their values within the statistical multifragmentation model. The scaling relations for the found critical exponents are verified and it is demonstrated that for the standard definition of the index \\alpha' the Fisher and Griffiths scaling inequalities are not fulfilled for some values of the model parameters, whereas the Liberman scaling inequality is always obeyed. Although it is shown that the specially defined index \\alpha'_s recovers the scaling relations, another possibility, an existence of the non-Fisher universality classes, is also discussed.

A. I. Ivanytskyi

2011-04-11T23:59:59.000Z

97

Screening of quark-monopole in N=4 plasma

We study a quark-monopole bound system moving in N=4 SYM plasma with a constant velocity by the AdS/CFT correspondence. The screening length of this system is calculated, and is smaller than that of the quark-antiquark bound state.

Wei-shui Xu; Ding-fang Zeng

2014-09-08T23:59:59.000Z

98

Shear viscosity of the gluon plasma in the stochastic-vacuum approach

Shear viscosity of the gluon plasma in SU(3) YM theory is calculated nonperturbatively, within the stochastic vacuum model. The result for the ratio of the shear viscosity to the entropy density, proportional to the squared chromo-magnetic gluon condensate and the fifth power of the correlation length of the chromo-magnetic vacuum, falls off with the increase of temperature. At temperatures larger than the deconfinement critical temperature by a factor of 2, this fall-off is determined by the sixth power of the temperature-dependent strong-coupling constant and yields an asymptotic approach to the conjectured lower bound of 1/(4\\pi), achievable in {\\cal N}=4 SYM theory. As a by-product of the calculation, we find a particular form of the two-point correlation function of gluonic field strengths, which is the only one consistent with the Lorentzian shape of the shear-viscosity spectral function.

Dmitri Antonov

2009-05-20T23:59:59.000Z

99

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

Werner Bernreuther; Michael Fuecker; Zong-Guo Si

2008-04-08T23:59:59.000Z

100

Heavy quark production from jet conversions in a quark-gluon plasma

Recently, it has been demonstrated that the chemical composition of jets in heavy ion collisions is significantly altered compared to the jets in the vacuum. This signal can be used to probe the medium formed in nuclear collisions. In this study we...

Liu, W.; Fries, Rainer J.

2008-01-01T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

101

Resonance recombination model and quark distribution functions in the quark-gluon plasma

. Voloshin, Phys. Rev. Lett. 91, 092301 (2003). [9] Z.-W. Lin, C. M. Ko, B.-A. Li, B. Zhang, and S. Pal, Phys. Rev. C 72, 064901 (2005). [10] J. Zimanyi, P. Levai, and T. S. Biro, J. Phys. G 31, 711 (2005). [11] H. Miao, C. Gao, and P. Zhuang, Phys. Rev...

Ravagli, L.; van Hees, H.; Rapp, Ralf.

2009-01-01T23:59:59.000Z

102

Total cross section of neutron-proton scattering at low energies in quark-gluon model

We show that analysis of nonrelativistic neutron-proton scattering in a framework of relativistic QCD based quark model can give important information about QCD vacuum structure. In this model we describe total cross section of neutron-proton scattering at kinetic energies of projectile neutron from 1 eV up to 1 MeV.

V. A. Abramovsky; N. V. Radchenko

2011-07-30T23:59:59.000Z

103

On Relation Between the Quark Gluon Bag Surface Tension and the Colour Tube String Tension

Here we revisit the bag phenomenology of the deconfining phase transition to replenish it by introducing systematically the bag surface tension. Comparing the free energy of such bags and that one of the strings confining the static quark-antiquark pair, we express the string tension in terms of the bag surface tension and thermal pressure in order to estimate the bag characteristics using the lattice QCD data. Our analysis of the bag entropy density demonstrates that the surface tension coefficient is amazingly negative at the cross-over (continuous transition). This approach allows us to naturally account for an appearance of a very pronounced maximum (observed in the lattice QCD simulations) of the entropy of the bound static quark-antiquark pair. The vicinity of the (tri)critical endpoint is also analyzed to clarify the meaning of vanishing surface tension coefficient.

K. A. Bugaev; G. M. Zinovjev

2010-05-17T23:59:59.000Z

104

Constituent Quarks and Gluons, Polyakov loop and the Hadron Resonance Gas Model

Based on first principle QCD arguments, it has been argued in arXiv:1204.2424[hep-ph] that the vacuum expectation value of the Polyakov loop can be represented in the hadron resonance gas model. We study this within the Polyakov-constituent quark model by implementing the quantum and local nature of the Polyakov loop hep-ph/0412308, hep-ph/0607338. The existence of exotic states in the spectrum is discussed.

E. Megias; E. Ruiz Arriola; L. L. Salcedo

2013-07-29T23:59:59.000Z

105

The measurement of particle correlations and fluctuations has been suggested as a method to search for the existence of a phase transition in relativistic heavy ion collisions. If quark-gluon matter is formed in the collision of relativistic heavy ions, measuring these correlations could lead to a determination of the presence of partonic degrees of freedom within the collision. Additionally, non-statistical fluctuations in global quantities such as baryon number, strangeness, or charge may be observed near a QCD critical point. Results for short and long-range multiplicity correlations (forward-backward) are presented for several systems (Au+Au and Cu+Cu) and energies (e.g. $\\sqrt{s_{NN}}$ = 200, 62.4, and 22.4 GeV). For the highest energy central A+A collisions, the correlation strength maintains a constant value across the measurement region. In peripheral collisions, at lower energies, and in pp data, the maximum appears at midrapidity. Comparison to models with short-range (HIJING) and both short and long-range interactions (Parton String Model) do not fully reproduce central Au+Au data. Preliminary results for K/$\\pi$ fluctuations are also shown as a function of centrality in Cu+Cu collisions at $\\sqrt{s_{NN}}$ = 22.4 GeV.

Terence J. Tarnowsky; for the STAR Collaboration

2009-10-19T23:59:59.000Z

106

We calculate P (k [subscript ?]), the probability distribution for an energetic parton that propagates for a distance L through a medium without radiating to pick up transverse momentum k [subscript ?], for a medium ...

D’Eramo, Francesco

107

The RIKEN School on ''Quark-Gluon Structure of the Nucleon and QCD'' was held from March 29th through 31st at the Nishina Memorial Hall of RIKEN, Wako, Saitama, Japan, sponsored by RIKEN (the Institute of Physical and Chemical Research). The school was the second of a new series with a broad perspective of hadron and nuclear physics. The purpose of the school was to offer young researchers an opportunity to learn theoretical aspects of hadron physics based on QCD and related experimental programs being or to be carried out by Japanese groups. We had 3 theoretical courses, each consisting of 3 one-hour lectures, and 6 experimental courses, each consisting of a one-hour lecture.

EN YO,H.; SAITO,N.; SHIBATA,T.A.; YAZAKI,K.; BUNCE,G.

2002-03-29T23:59:59.000Z

108

A non-abelian quasi-particle model for gluon plasma

We propose a quasi-particle model which takes into account the non-abelian characteristics of the gluonic field in a twofold way. Firstly, in counting the gluonic density of states we assume that the microstates of the gluon field are non-linear plane waves in a finite volume. Secondly, inspired by the fact that the gluon mass is a dynamically generated quantity, we assume microstates with different masses for the gluon field. To describe the associated mass distribution we use a quasi-Gaussian ansatz with mean value and standard deviation depending on the temperature. The temperature dependence of the mean mass in the critical region is determined via recent results of lattice $SU(3)$ calculations of the gluon propagator at finite temperature. The temperature dependence of the standard deviation is used to fit the lattice results for the equation of state of pure SU(3) as reported in latest lattice results. Thus, our model being also free from thermodynamic inconsistencies, is in very good agreement with two...

Politis, E P; Diakonos, F K; Maintas, X N; Tsapalis, A

2015-01-01T23:59:59.000Z

109

Radial flow from electromagnetic probes and signal of quark gluon plasma

An attempt has been made to extract the evolution of radial flow from the analysis of the experimental data on electromagnetic probes measured at the energies available at the CERN Super Proton Synchrotron (SPS) and the BNL Relativistic Heavy Ion Collider (RHIC). The transverse momentum (p{sub T}) spectra of photons and dileptons measured by the WA98 and NA60 Collaborations, respectively, at the SPS and the photon and dilepton spectra obtained by the PHENIX Collaboration at the RHIC have been used to constrain the theoretical models. We use the ratio of photon to dilepton spectra to extract the flow, where some model dependence is canceled out. Within the ambit of the present analysis we argue that the variation of the radial velocity with invariant mass is indicative of a phase transition from the initially produced partons to hadrons at SPS and RHIC energies.

Mohanty, Payal; Nayak, Jajati K.; Alam, Jan-e; Das, Santosh K. [Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata 700064 (India)

2010-09-15T23:59:59.000Z

110

Radial flow from electromagnetic probes and signal of quark gluon plasma

Science Journals Connector (OSTI)

An attempt has been made to extract the evolution of radial flow from the analysis of the experimental data on electromagnetic probes measured at the energies available at the CERN Super Proton Synchrotron (SPS) and the BNL Relativistic Heavy Ion Collider (RHIC). The transverse momentum (pT) spectra of photons and dileptons measured by the WA98 and NA60 Collaborations, respectively, at the SPS and the photon and dilepton spectra obtained by the PHENIX Collaboration at the RHIC have been used to constrain the theoretical models. We use the ratio of photon to dilepton spectra to extract the flow, where some model dependence is canceled out. Within the ambit of the present analysis we argue that the variation of the radial velocity with invariant mass is indicative of a phase transition from the initially produced partons to hadrons at SPS and RHIC energies.

Payal Mohanty; Jajati K. Nayak; Jan-e Alam; Santosh K. Das

2010-09-07T23:59:59.000Z

111

Geek-Up[12.03.2010]: Halomonadaceae Bacteria and the Return of Quark Gluon Plasma

Broader source: Energy.gov [DOE]

The toxic element arsenic sustains growth of a bacteria instead of phosphorus and CERN's Collider gives researchers a look into the matter that may have existed in the very first moments of the universe.

112

Energy dependence of jet transport parameter and parton saturation in quark-gluon plasma

hep-ph/0605183]. [47] P. Danielewicz and M. Gyulassy, Phys.to the bound found by Danielewicz and Gyulassy [47] from

Casalderrey-Solana, Jorge; Wang, Xin-Nian

2008-01-01T23:59:59.000Z

113

The physics of dense nuclear matter from supernovae to quark gluon plasma

Science Journals Connector (OSTI)

... 3, and the maximum mass would be the well-known Chandrasekhar limit of 1.4 solar masses (M©) (refs 12, 13). But neutron stars of up to ... p0 and exploding into non-interacting hadrons at p cycle is a sequence of shock compression, fireball, expansion and freezing out.

Reinhard Stock

1989-01-26T23:59:59.000Z

114

Heavy quark diffusion from the lattice

We study the diffusion of heavy quarks in the quark gluon plasma using the Langevin equations of motion and estimate the contribution of the transport peak to the Euclidean current-current correlator. We show that the Euclidean correlator is remarkably insensitive to the heavy quark diffusion coefficient and give a physical interpretation of this result using the free streaming Boltzmann equation. However if the diffusion coefficient is smaller than {approx}1/({pi}T), as favored by RHIC phenomenology, the transport contribution should be visible in the Euclidean correlator. We outline a procedure to isolate this contribution.

Petreczky, Peter; Teaney, Derek [Nuclear Theory Group, Department of Physics, Brookhaven National Laboratory, Upton, New York 11973 (United States); Department of Physics and Astronomy, SUNY at Stony Brook, Stony Brook, New York 11764 (United States)

2006-01-01T23:59:59.000Z

115

Polyakov-loop suppression of colored states in a quark-meson-diquark plasma

A quark-meson-diquark plasma is considered within the PNJL model for dynamical chiral symmetry breaking and restoration in quark matter. Based on a generalized Beth-Uhlenbeck approach to mesons and diquarks we present the thermodynamics of this system including the Mott dissociation of mesons and diquarks at finite temperature. A striking result is the suppression of the diquark abundance below the chiral restoration temperature by the coupling to the Polyakov loop, because of their color degree of freedom. This is understood in close analogy to the suppression of quark distributions by the same mechanism. Mesons as color singlets are unaffected by the Polyakov-loop suppression. At temperatures above the chiral restoration mesons and diquarks are both suppressed due to the Mott effect, whereby the positive resonance contribution to the pressure is largely compensated by the negative scattering contribution in accordance with the Levinson theorem.

Blaschke, D; Buballa, M

2014-01-01T23:59:59.000Z

116

Color correlations in QCD plasma

Science Journals Connector (OSTI)

Perturbative QCD and the random-phase approximation are used to study the current-current correlation function in quark-gluon plasma. The calculations show that there are damped collective oscillations in the system. An estimate of the Debye screening length gives a value of about 0.5 fm at a temperature of 250 MeV.

Jitendra C. Parikh and Philip J. Siemens

1988-06-01T23:59:59.000Z

117

Nonabelian plasma instabilities in Bjorken expansion

Plasma instabilities are parametrically the dominant nonequilibrium dynamics of a weakly coupled quark-gluon plasma. In recent years the time evolution of the corresponding collective colour fields has been studied in stationary anisotropic situations. Here I report on recent numerical results on the time evolution of the most unstable modes in a longitudinally expanding plasma as they grow from small rapidity fluctuations to amplitudes where non-Abelian self-interactions become important.

Anton Rebhan

2008-10-15T23:59:59.000Z

118

The quark-hadron phase transition in weakly isospin-asymmetric nuclear matter

We consider the transition from quark to hadronic matter which may result during the cooling/expansion of the quark-gluon plasma formed in energetic collisions of weakly isospin-asymmetric ions. This transition involves the energy density of u and d quark matter and the one of nearly isospin-symmetric nuclear matter. Within bag models, the former entails knowledge of the bag pressure, a poorly constrained quantity. The bag pressure at high density can be fixed imposing equality of quark and nucleonic energy densities at the (assumed known) transition point. We find this value to be very model dependent.

Francesca Sammarruca

2010-09-06T23:59:59.000Z

119

Unquenching the gluon propagator with Schwinger-Dyson equations

Science Journals Connector (OSTI)

In this article we use the Schwinger–Dyson equations to compute the nonperturbative modifications caused to the infrared finite gluon propagator (in the Landau gauge) by the inclusion of a small number of quark families. Our basic operating assumption is that the main bulk of the effect stems from the “one-loop dressed” quark loop contributing to the full gluon self-energy. This quark loop is then calculated, using as basic ingredients the full quark propagator and quark-gluon vertex; for the quark propagator we use the solution obtained from the quark-gap equation, while for the vertex we employ suitable Ansätze, which guarantee the transversality of the answer. The resulting effect is included as a correction to the quenched gluon propagator, obtained in recent lattice simulations. Our main finding is that the unquenched propagator displays a considerable suppression in the intermediate momentum region, which becomes more pronounced as we increase the number of active quark families. The influence of the quarks on the saturation point of the propagator cannot be reliably computed within the present scheme; the general tendency appears to be to decrease it, suggesting a corresponding increase in the effective gluon mass. The renormalization properties of our results, and the uncertainties induced by the unspecified transverse part of the quark-gluon vertex, are discussed. Finally, the gluon propagator is compared with the available unquenched lattice data, showing rather good agreement.

A. C. Aguilar; D. Binosi; J. Papavassiliou

2012-07-27T23:59:59.000Z

120

Gluon Fusion Contribution to $VHj$ Production at Hadron Colliders

We study the associated production of an electroweak vector boson and the Higgs boson with a jet via gluon-gluon fusion. At the leading order, these processes occur at one-loop level. The amplitudes of these one-loop processes are gauge invariant and finite. Therefore, their contributions towards the corresponding hadronic cross sections and kinematic distributions can be calculated separately. We present results for the Large Hadron Collider and its discussed upgrades. We find that the gluon-gluon one-loop process gives dominant contribution to the $\\gamma H j$ production. We observe a destructive interference effect in the $gg\\to Z H j$ amplitude. We also find that in the high transverse momentum and central rapidity region, the $ZHj$ production cross section via gluon-gluon fusion becomes comparable to the cross section contributions coming from quark-quark and quark-gluon channels.

Agrawal, Pankaj

2014-01-01T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

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121

Manifestations of magnetic vortices in equation of state of Yang-Mills plasma

The vacuum of Yang-Mills theory contains singular stringlike objects identified with center (magnetic) vortices. Percolation of magnetic vortices is known to be responsible for the color confinement in the low-temperature phase of the theory. In our work we study properties of the vortices at finite temperature using lattice simulations of SU(2) gauge theory. We show that magnetic vortices provide a numerically large contribution to thermodynamic quantities of the gluon plasma in Yang-Mills theory. In particular, we observe that in the deconfinement phase at temperatures T_c energy-momentum tensor. In the confinement phase the vortex contribution is positive. The thermodynamical significance of the magnetic objects allows us to suggest that the quark-gluon plasma may contain a developed network of magnetic flux tubes. The existence of the vortex network may lead to observable effects in the quark-gluon plasma because the chromomagnetic field of the vortices should scatter and drag quarks.

M. N. Chernodub; Atsushi Nakamura; V. I. Zakharov

2008-07-31T23:59:59.000Z

122

Entropy production in the compression stage of heavy ion collisions is discussed within three distinct macroscopic models (i.e. generalized RHTA, geometrical overlap model and three-fluid hydrodynamics). We find that within these models \\sim 80% or more of the experimentally observed final-state entropy is created in the early stage. It is thus likely followed by a nearly isentropic expansion. We employ an equation of state with a first-order phase transition. For low net baryon density, the entropy density exhibits a jump at the phase boundary. However, the excitation function of the specific entropy per net baryon, S/A, does not reflect this jump. This is due to the fact that for final states (of the compression) in the mixed phase, the baryon density \\rho_B increases with \\sqrt{s}, but not the temperature T. Calculations within the three-fluid model show that a large fraction of the entropy is produced by nuclear shockwaves in the projectile and target. With increasing beam energy, this fraction of S/A decreases. At \\sqrt{s}=20 AGeV it is on the order of the entropy of the newly produced particles around midrapidity. Hadron ratios are calculated for the entropy values produced initially at beam energies from 2 to 200 AGeV.

M. Reiter; A. Dumitru; J. Brachmann; J. A. Maruhn; H. Stöcker; W. Greiner

1998-06-03T23:59:59.000Z

123

What have we learned about the Quark-Gluon Plasma with the ATLAS detector at the LHC?

Recent results from lead-lead and proton-lead collisions, measured by the ATLAS experiment at the LHC, are presented. Electroweak bosons are found to be produced proportionally to the number of binary nucleon-nucleon collisions, and to have rapidity distributions compatible with perturbative QCD calculations, suggesting no need for large nPDF effects. Conversely the large suppression of inclusive jets, the elliptic flow of hadrons at high $p_{\\mathrm{T}}$ and the direct measurements of jet $v_2$ support the need for a path-length dependent energy loss in the hot, dense medium. Proton-lead measurements provide new insights on particle production in small, longitudinally asymmetric systems, but require further insights into the fluctuating nature of proton-proton collisions. The suppression factors for charged hadrons show a non-trivial dependence on centrality and rapidity, with a ``Cronin'' peak appearing only in the most central events, and in the lead-going direction. Finally the measurements of inclusive j...

Steinberg, P; The ATLAS collaboration

2014-01-01T23:59:59.000Z

124

Measurements of hard probes of the quark-gluon plasma with the ATLAS experiment at the LHC

ATLAS results on the production of high-transverse momentum probes in Pb+Pb and p+Pb collisions at the LHC are presented. The focus is on the jet measurements, which provide a useful tool to study the hot, dense and coloured matter created in ultra-relativistic heavy ion collisions. The ATLAS experiment has measured inclusive jet yields in pp and Pb+Pb collisions at sqrt(s_NN) = 2.76 TeV and in p+Pb collisions at sqrt(s_NN) = 5.02 TeV. The jet nuclear modification factor, RAA, is shown as a function of jet pT, rapidity and collision centrality. The RAA weakly increases with pT, shows no dependence on rapidity and smoothly decreases with the collision centrality. In 10% of the most central collisions, jet production is suppressed by a factor of two relative to pp yields scaled by the number of binary nucleonnucleon collisions. Charged-particle fragmentation functions of jets are also measured and ratios of fragmentation functions between di erent centrality intervals show a centrality-dependent modification. T...

Wosiek, B; The ATLAS collaboration

2014-01-01T23:59:59.000Z

125

Cooking Up Hot Quark Soup | U.S. DOE Office of Science (SC)

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

Cooking Up Hot Quark Soup Cooking Up Hot Quark Soup Stories of Discovery & Innovation Cooking Up Hot Quark Soup Enlarge Photo Image courtesy of Brookhaven National Laboratory These images contrast the degree of interaction and collective motion, or "flow," among quarks in the predicted gaseous quark-gluon plasma state (Figure on left, see mpeg animation ) vs. the liquid state that has been observed in gold-gold collisions at RHIC (Figure on right, see mpeg animation ). The green "force lines" and collective motion (visible on the animated version only) show the much higher degree of interaction and flow among the quarks in what is now being described as a nearly "perfect" liquid. Enlarge Photo Photo courtesy of Brookhaven National Laboratory Brookhaven National Laboratory's Relativistic

126

Heavy quarks in the jet calculus

Science Journals Connector (OSTI)

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

L. M. Jones

1983-07-01T23:59:59.000Z

127

Pre-equilibrium plasma dynamics

Approaches towards understanding and describing the pre-equilibrium stage of quark-gluon plasma formation in heavy-ion collisions are reviewed. Focus is on a kinetic theory approach to non-equilibrium dynamics, its extension to include the dynamics of color degrees of freedom when applied to the quark-gluon plasma, its quantum field theoretical foundations, and its relationship to both the particle formation stage at the very beginning of the nuclear collision and the hydrodynamic stage at late collision times. The usefulness of this approach to obtain the transport coefficients in the quark-gluon plasma and to derive the collective mode spectrum and damping rates in this phase are discussed. Comments are made on the general difficulty to find appropriated initial conditions to get the kinetic theory started, and a specific model is given that demonstrates that, once given such initial conditions, the system can be followed all the way through into the hydrodynamical regime. 39 refs., 7 figs. (LEW)

Heinz, U.

1986-01-01T23:59:59.000Z

128

Parton energy loss due to synchrotron-like gluon emission

We develop a quasiclassical theory of the synchrotron-like gluon radiation. Our calculations show that the parton energy loss due to the synchrotron gluon emission may be important in the jet quenching phenomenon if the plasma instabilities generate a sufficiently strong chromomagnetic field. Our gluon spectrum disagrees with that obtained by Shuryak and Zahed within the Schwinger's proper time method.

B. G. Zakharov

2008-09-03T23:59:59.000Z

129

Nuclear Physics A 757 (2005) 127 Quarkgluon plasma and color glass condensate at

Nuclear Physics A 757 (2005) 1Â27 QuarkÂgluon plasma and color glass condensate at RHIC:10.1016/j.nuclphysa.2005.02.130 #12;2 I. Arsene et al. / Nuclear Physics A 757 (2005) 1Â27 Abstract Institut de Recherches Subatomiques et UniversitÃ© Louis Pasteur, Strasbourg, France c Institute of Nuclear

130

Nucleation of quark matter in the PQM model

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.

Mintz, Bruno W. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, RJ 21945-970 (Brazil); Stiele, Rainer; Schaffner-Bielich, Juergen [Institut fuer Theoretische Physik, Ruprecht-Karls-Universitaet, Philosophenweg 16, D-69120, Heidelberg, Germany and ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstrasse 1, D-64291 D (Germany); Ramos, Rudnei O. [Departamento de Fisica Teorica, Universidade do Estado do Rio de Janeiro, 20550-013 Rio de Janeiro, RJ (Brazil)

2013-03-25T23:59:59.000Z

131

An in-Medium Heavy-Quark Potential from the $Q\\bar{Q}$ Free Energy

We investigate the problem of extracting a static potential between a quark and its antiquark in a quark-gluon plasma (QGP) from lattice-QCD computations of the singlet free energy, $F_{Q\\bar{Q}}(r)$. We utilize the thermodynamic $T$-matrix formalism to calculate the free energy from an underlying potential ansatz resummed in ladder approximation. Imaginary parts of both $Q\\bar Q$ potential-type and single-quark selfenergies are included as estimated from earlier results of the $T$-matrix approach. We find that the imaginary parts, and in particular their (low-) energy dependence, induce marked deviations of the (real part of the) potential from the calculated free energy. When fitting lattice results of the latter, the extracted potential is characterized by significant long-range contributions from remnants of the confining force. We briefly discuss consequences of this feature for the heavy-quark transport coefficient in the QGP.

Liu, Shuai Y F

2015-01-01T23:59:59.000Z

132

Single Photon Production in Relativisitic Heavy Ion Collisions and Quark Hadron Phase Transition

We discuss the recent developments in the study of single photon production in relativistic heavy ion collisions. In particular their production at SPS, RHIC, and LHC energies is re-examined in view of the results of Aurenche et al which show that the rate of photon production from quark gluon plasma, evaluated at the order of two loops far exceeds the rates evaluated at one-loop level which have formed the basis of all the estimates of photons so far. We find that the production of photons from quark matter could easily out-shine those from the hadronic matter in certain ideal conditions. We further show that the earlier results lending support to the possibility of quark-hadron phase transition from the measured yield of single photons in $S+Au$ collisions at CERN SPS remain valid when an account is made for these developments, though they leave a scope for the formation of (chemically) non-equilibrated plasma.

Dinesh Kumar Srivastava

1999-11-15T23:59:59.000Z

133

The Particle Adventure | What holds it together? | Quark confinement

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

Quark confinement Quark confinement Quark confinement Color-charged particles cannot be found individually. For this reason, the color-charged quarks are confined in groups (hadrons) with other quarks. These composites are color neutral. The development of the Standard Model's theory of the strong interactions reflected evidence that quarks combine only into baryons (three quark objects), and mesons (quark-antiquark objects), but not, for example, four-quark objects. Now we understand that only baryons (three different colors) and mesons (color and anticolor) are color-neutral. Particles such as ud or uddd that cannot be combined into color-neutral states are never observed. Color-Force Field The quarks in a given hadron madly exchange gluons. For this reason, physicists talk about the color-force field which consists of the gluons holding the bunch of quarks together.

134

Chiral symmetry, massive gluons and confinement

It is quite difficult to obtain non-trivial chiral symmetry breaking solutions for the quark gap equation in the presence of dynamically generated gluon masses. An effective confining propagator has recently been proposed by Cornwall in order to solve this problem. We study phenomenological consequences of this approach, showing its compatibility with the experimental data. We argue that this confining propagator should be restricted to a small region of momenta, leading to effective four-fermion interactions at low energy.

Natale, A. A. [Instituto de Fisica Teorica - UNESP Rua Dr. Bento T. Ferraz, 271, Bl.II - 01140-070, Sao Paulo, SP (Brazil)

2013-03-25T23:59:59.000Z

135

Heavy Quark Production in ep Collisions

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

136

Quark condensate for various heavy flavors

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

Dmitri Antonov; Jose Emilio F. T. Ribeiro

2012-10-04T23:59:59.000Z

137

Color screening in cold quark matter

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

Kojo, Toru

2014-01-01T23:59:59.000Z

138

Thermal charm production in a quark-gluon plasma in Pb-Pb collisions at root S(NN)=5.5 TeV

. Wetzorke, Phys. Rev. D 69, 094507 (2004). [8] B. Zhang, C. M. Ko, B. A. Li, Z. W. Lin, and B. H. Sa, Phys. Rev. C 62, 054905 (2000); B. Zhang, C. M. Ko, B. A. Li, Z. W. Lin, and S. Pal, ibid. 65, 054909 (2002). [9] H. Satz, J. Phys. G 32, R25 (2006.... Phys. G 31, S421 (2005). [42] C. M. Ko and L. Xia, Phys. Rev. C 38, 179 (1988); Z. W. Lin and C. M. Ko, ibid. 62, 034903 (2000); W. Liu and C. M. Ko, Nucl. Phys. A765, 401 (2006). [43] L. Alvarez-Ruso and V. Koch, Phys. Rev. C 65, 054901 (2002...

Zhang, Ben-Wei; Ko, Che Ming; Liu, Wei.

2008-01-01T23:59:59.000Z

139

Bulk viscosity of anisotropically expanding hot QCD plasma

The bulk viscosity, {zeta} and its ratio with the shear viscosity, {zeta}/{eta} have been studied in an anisotropically expanding pure glue plasma in the presence of turbulent color fields. It has been shown that the anisotropy in the momentum distribution function of gluons, which has been determined from a linearized transport equation eventually leads to the bulk viscosity. For the isotropic (equilibrium) state, a recently proposed quasiparticle model of pure SU(3) lattice QCD equation of state has been employed where the interactions are encoded in the effective fugacity. It has been argued that the interactions present in the equation of state, significantly contribute to the bulk viscosity. Its ratio with the shear viscosity is significant even at 1.5T{sub c}. Thus, one needs to take in account the effects of the bulk viscosity while studying the hydrodynamic expansion of quark-gluon plasma in the Relativistic Heavy Ion Collider and the Large Hadron Collider.

Chandra, Vinod [Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai-400005 (India)

2011-11-01T23:59:59.000Z

140

Exploration of nucleon structure in lattice QCD with chiral quarks

In this work, we calculate various nucleon structure observables using the fundamental theory of quarks and gluons, QCD, simulated on a lattice. In our simulations, we use the full QCD action including Nf = 2+ 1 dynamical ...

Syritsyn, Sergey Nikolaevich

2010-01-01T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

141

Heavy quark diffusion in pre-equilibrium stage of heavy ion collisions

The drag and diffusion coefficients of the heavy quarks have been evaluated in the pre-equilibrium phase which is expected to be formed in the early stages of the evolving fire ball produced in heavy ion collisions at RHIC and LHC energies. The interaction of the probe with the gluon in the pre-equilibrium phase has been treated within the framework of perturbative QCD. For the pre-equilibrium gluon distribution function we have used the KLN and Classical Yang Mills(CYM) models. It is observed that the magnitude of both the transport coefficients have significant values in the pre-equilibrium phase and comparable to the magnitudes obtained for kinetically equilibrated gluonic system. However, these values are larger than the value estimated for a chemically equilibrated quark gluon plasma. The results may have significant impact on the experimental observable like the suppression and elliptic flow of single electron spectra originating from the decays of heavy mesons produced in heavy ion collisions at RHIC a...

Das, Santosh K; Mazumder, Surasree; Greco, Vincenzo; Alam, Jan-e

2015-01-01T23:59:59.000Z

142

Looking for quark droplets in ultrarelativistic collisions

Science Journals Connector (OSTI)

Heavy ion collisions at ultrarelativistic energies are expected to provide an environment where quarks and gluons replace hadrons as the appropriate degrees of freedom. As the excited region expands and cools, the transition to the hadronic state might be characterized by phase separation with hadrons being emitted from dense droplets of quark-gluon matter. Here we study four techniques to search for such droplets: rapidity correlations, identical kaon correlations, ? meson production, and proton correlations. We conclude that rapidity correlations are the clearest signal of such fluctuations, and that proton correlations and ? production can also be strongly affected by drop formation.

Scott Pratt

1994-05-01T23:59:59.000Z

143

Single Photons from Relativistic Heavy Ion Collisions and Quark-Hadron Phase Transition

The present status of theoretical expectations of studies of single photons from relativistic heavy ion collisions is discussed. It is argued that the upper limit of single photon radiation from S+Au collisions at CERN SPS obtained by the WA80 collaboration perhaps rules out any reasonable description of the collision process which does not involve a phase transition to quark gluon plasma. Predictions for single photons from the quark-matter likely to be created in collision of two lead nuclei at RHIC and LHC energies are given with a proper accounting of chemical equilibration and transverse expansion. Finally, it is pointed out that, contrary to the popular belief of a quadrilateral dependence of electromagnetic radiations ($N_\\gamma$) from such collisions on the number of charged particles ($N_{ch})$, we may only have $N_\\gamma \\propto N_{ch}^{1.2}$.

Dinesh Kumar Srivastava

1997-05-29T23:59:59.000Z

144

The effect of partonic wind on charm quark correlations in high-energy nuclear collisions

In high-energy collisions, massive heavy quarks are produced back-to-back initially and they are sensitive to early dynamical conditions. The strong collective partonic wind from the fast expanding quark-gluon plasma created in high-energy nuclear collisions modifies the correlation pattern significantly. As a result, the angular correlation function for D$\\bar{\\rm D}$ pairs is suppressed at the angle $\\Delta\\phi=\\pi$. While the hot and dense medium in collisions at RHIC ($\\sqrt{s_{NN}}=200$ GeV) can only smear the initial back-to-back D$\\bar {\\rm D}$ correlation, a clear and strong near side D$\\bar{\\rm D}$ correlation is expected at LHC ($\\sqrt{s_{NN}}=5500$ GeV).

X. Zhu; N. Xu; P. Zhuang

2007-09-03T23:59:59.000Z

145

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

Dilip Jana; for the ATLAS Collaboration

2008-10-20T23:59:59.000Z

146

Transverse momentum resummation for Higgs production via gluon fusion in the MSSM

The resummed transverse momentum distribution of supersymmetric Higgs bosons produced through gluon fusion at NLO+NLL is presented, including the exact quark and squark mass dependences. Considering various MSSM scenarios, we compare our results to previous ones within the POWHEG approach. We analyze the impact of the bottom loop which becomes the dominant contribution to the gluon fusion cross section for a wide range of the parameter space for the pseudo-scalar and heavy Higgs.

Robert V. Harlander; Hendrik Mantler; Marius Wiesemann

2014-09-01T23:59:59.000Z

147

Manifestations of magnetic vortices in equation of state of Yang-Mills plasma

The vacuum of Yang-Mills theory contains singular stringlike objects identified with center (magnetic) vortices. The percolation of the magnetic vortices is known to be responsible for the color confinement in the low-temperature phase of the theory. In our work we study properties of the vortices at finite temperature using lattice simulations of SU(2) gauge theory. We show that magnetic vortices provide numerically large contribution to thermodynamic quantities of gluon plasma in Yang-Mills theory. In particular, we observe that in the deconfinement phase at temperatures Tc energy-momentum tensor. In the confinement phase the vortex contribution is positive. The thermodynamical significance of the magnetic objects allows us to suggest that the quark gluon plasma may contain a developed network of the magnetic flux tubes. The existence of the vortex network may lead to observable eff...

Chernodub, M N; Zakharov, V I

2008-01-01T23:59:59.000Z

148

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

(November 2011). Quark-gluon plasma: from QCD thermodynamics to heavy ion collision phenomenology, M. He, Shanghai Jiaotong University, Shanghai, China (October 2011). Quark-gluon...

149

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

Interacciones del quark Interacciones del quark Volver Principal ESTOY PERDIDO!!! Los quarks tienen carga elÃ©ctrica, por lo que sufren interacciones electromagnÃ©ticas. Los quarks tienen carga de color, de modo que sufren las interacciones fuertes. Las interacciones fuertes causan que los quarks se combinen formando hadrones. Las interacciones fuertes residuales mantienen a los hadrones juntos, para formar nÃºcleos. Los diferentes tipos de quark (u, d, c, ...) se denominan sabores. El sabor sÃ³lo se altera por medio de interacciones debiles cargadas. Por ejemplo: Todos los quarks del lado izquierdo tambiÃ©n aparecen del lado derecho . Sin embargo, cuando un quark emite un bosÃ³n ( virtual) W+ o W-, debe cambiar su carga elÃ©ctrica y, por lo tanto, su sabor. El proceso dÃ©bil predominante es el que involucra transiciones entre quarks de la misma

150

CP-violating Higgs boson production in association with three jets via gluon fusion

In these proceedings, we present results for Higgs production at the LHC via gluon fusion with triple real emission corrections and the validity range of the heavy-top effective theory approximation for this process. For a general CP-violating Higgs boson, we show that bottom-quark loop corrections in combination with large values of $\\tan \\beta $ significantly distort differential distributions.

Campanario, Francisco

2014-01-01T23:59:59.000Z

151

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

graciosos quarks graciosos quarks Volver Principal ESTOY PERDIDO!!! Un poco de la historia del quark: En 1964 Murray Gell-Mann y George Zweig sugirieron que cientos de las partÃculas conocidas hasta el momento, podrÃan ser explicadas como una combinaciÃ³n de sÃ³lo 3 partÃculas fundamentales. Gell-Mann eligiÃ³ el nombre caprichoso de "quarks" para estos constituyentes. Esta palabra aparece en la frase "three quarks for Muster Mark" en la novela de James Joyce, Finnegan's Wake. La parte revolucionaria de la idea era que ellos debieron asignarle a los quarks cargas elÃ©ctricas de 2/3 y -1/3 (en unidades de la carga del protÃ³n): nunca habÃan sido observadas cargas como esas. Primero los quarks fueron considerados como un truco matemÃ¡tico, pero los experimentos

152

Color screening in cold quark matter

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

Toru Kojo; Gordon Baym

2014-04-04T23:59:59.000Z

153

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

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

154

Quantum Hall States of Gluons in Quark Matter

Science Journals Connector (OSTI)

......Particle and Nuclear Studies, High Energy Accelerator Research Organization...Japan Savvidy vacuum of SU(2...modes in the vacuum condense to...Particle and Nuclear Studies, High Energy Accelerator Research Organization...Savvidy vacuum of SU(2......

Aiichi Iwazaki; Osamu Morimatsu; Tetsuo Nishikawa; Munehisa Ohtani

2004-01-01T23:59:59.000Z

155

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

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

Apyan, Aram

156

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

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.

Saleev, V. A., E-mail: saleev@samsu.ru; Shipilova, A. V., E-mail: alexshipilova@samsu.ru [Samara State University (Russian Federation)

2013-11-15T23:59:59.000Z

157

Heavy quark masses from Fermilab Fermions

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

Matthew Nobes; Howard Trottier

2005-09-26T23:59:59.000Z

158

Friction Coefficient for Quarks in Supergravity Duals

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

E. Antonyan

2006-11-22T23:59:59.000Z

159

Heavy Quark Production in Deep-Inelastic Scattering at HERA

We discuss two topics in the production of heavy quarks in deep-inelastic scattering: the next-to-leading order Monte-Carlo HVQDIS and the next-to-leading logarithmic resummation of soft gluon effects, including estimates of next-to-next-to-leading order corrections therefrom.

B. W. Harris; E. Laenen; S. Moch; J. Smith

1999-05-18T23:59:59.000Z

160

Constraints from jet calculus on quark recombination

Science Journals Connector (OSTI)

Within the quantum-chromodynamic jet-calculus formalism, we deduce an equation describing recombination of quarks and antiquarks into mesons within a quark or gluon jet. This equation relates the recombination function R(x1,x2,x) used in current literature to the fragmentation function for producing that same meson out of the parton initiating the jet. We submit currently used recombination functions to our consistency test, taking as input mainly the u-quark fragmentation "data" into ?+ mesons. The qq¯?? recombination functions popular in the literature are consistent with measured fragmentation functions, but they must be supplemented by other contributions to provide the full Du?+. We also discuss the Q2 dependence of the resulting fragmentation functions.

L. M. Jones; K. E. Lassila; U. Sukhatme; D. Willen

1981-02-01T23:59:59.000Z

While these samples are representative of the content of NLE

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We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

161

Colour coherence of soft gluons in the fully unintegrated NLO singlet kernels

Feynman diagrams with two real partons contributing to the next-to-leading-order singlet gluon-quark DGLAP kernel are analysed. The infra-red singularities of unintegrated distributions are examined numerically. The analytical formulae are also given in some cases. The role of the colour coherence effects is found to be crucial for cancellations of the double- and single-logarithmic infra-red singularities.

M. Slawinska; A. Kusina; S. Jadach; M. Skrzypek

2011-10-04T23:59:59.000Z

162

Remarks on quark-quark and quark-antiquark potentials

Science Journals Connector (OSTI)

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

Suraj N. Gupta and Stanley F. Radford

1982-06-15T23:59:59.000Z

163

Parton energy loss and momentum broadening at NLO in high temperature QCD plasmas

We present an overview of a perturbative-kinetic approach to jet propagation, energy loss, and momentum broadening in a high temperature quark-gluon plasma. The leading-order kinetic equations describe the interactions between energetic jet-particles and a non-abelian plasma, consisting of on-shell thermal excitations and soft gluonic fields. These interactions include 22 scatterings, collinear bremsstrahlung, and drag and momentum diffusion. We show how the contribution from the soft gluonic fields can be factorized into a set of Wilson line correlators on the light cone. We review recent field-theoretical developments, rooted in the causal properties of these correlators, which simplify the calculation of the appropriate Wilson lines in thermal field theory. With these simplifications lattice measurements of transverse momentum broadening have become possible, and the kinetic equations describing parton transport have been extended to next-to-leading order in the coupling g.

Ghiglieri, Jacopo

2015-01-01T23:59:59.000Z

164

Sea Quark Flavor Asymmetry of Hadrons in Statistical Balance Model

We derive a Menta Carlo method to simulate kinetic equilibrium ensemble, and get the same sea-quark flavor asymmetry as the linear equations method in statistical model. In the recent paper, we introduce the spilt factors to indicate the quarks' or gluons' spilt $g\\rightarrow q\\bar{q}(gg)$ and $q\\rightarrow qg$ ability. We obtain the almost fixed asymmetry value $0.12-0.16$ which consists with experimental measurements for proton, when the spilt factors vary in a very wide range over four orders of magnitude. So, we proof the sea quark asymmetry can be derived from statistic principle and not sensitively dependents on the dynamics details of quarks and gluons in proton. We also apply the Menta Carlo method of statistical model to predict the sea-quark asymmetry values for $K$ mesons, octet baryons $\\Sigma$,$\\Xi$ and $\\Delta$ baryons, even for exotic pentaquark states. All these asymmetry values just only dependent on the valence quarks numbers in those hadrons.

Bin Zhang; Yong-Jun Zhang

2010-08-03T23:59:59.000Z

165

Effect of quark antisymmetrization on the binding energy of nuclear matter

Science Journals Connector (OSTI)

We estimate, to leading order in the nuclear matter density, the effect of antisymmetrizing quarks belonging to different nucleons upon the binding energy per nucleon in nuclear matter. A simple Gaussian model for the nucleon quark wave function, together with a one-gluon-exchange potential between quarks, is assumed. Using a linked cluster expansion developed earlier for nuclear matter, we calculate separately the effect of quark interchanges upon the kinetic, hyperfine, Coulomb, and contact terms in the Hamiltonian. A strong net repulsion is found which grows rapidly with the dimensionless parameter ?=r0kF, where kF is the nuclear Fermi momentum and r0 the nucleon size.

Mohammad Nzar and Pervez Hoodbhoy

1990-10-01T23:59:59.000Z

166

The equation of state of neutron star matter is examined in terms of the relativistic mean-field theory, including a scalar-isovector $\\delta$-meson effective field. The constants of the theory are determined numerically so that the empirically known characteristics of symmetric nuclear matter are reproduced at the saturation density. The thermodynamic characteristics of both asymmetric nucleonic matter and $\\beta$-equilibrium hadron-electron $npe$-plasmas are studied. Assuming that the transition to strange quark matter is an ordinary first-order phase transition described by Maxwell's rule, a detailed study is made of the variations in the parameters of the phase transition owing to the presence of a $\\delta$-meson field. The quark phase is described using an improved version of the bag model, in which interactions between quarks are accounted for in a one-gluon exchange approximation. The characteristics of the phase transition are determined for various values of the bag parameter within the range $B\\in[60,120]$ $MeV/fm^{3}$ and it is shown that including a $\\delta$-meson field leads to a reduction in the phase transition pressure $P_{0}$ and in the concentrations $n_{N}$ and $n_{Q}$ at the phase transition point.

G. B. Alaverdyan

2009-07-23T23:59:59.000Z

167

Secondary Production of Massive Quarks in Thrust

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

Andre H. Hoang; Vicent Mateu; Piotr Pietrulewicz

2014-12-22T23:59:59.000Z

168

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

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

2013-05-28T23:59:59.000Z

169

Electric and magnetic screenings of gluons in a model with dimension-2 gluon condensate

Electric and magnetic screenings of the thermal gluons are studied by using the background expansion method in a gluodynamic model with dimension-2 gluon condensate. At low temperature, the electric and magnetic gluons are degenerate. With the increasing of temperature, it is found that the electric and magnetic gluons start to split at certain temperature $T_0$. The electric screening mass changes rapidly with temperature when $T>T_0$, and the Polyakov loop expectation value rises sharply around $T_0$ from zero in the vacuum to a value around 0.8 at high temperature. This suggests that the color electric deconfinement phase transition is driven by electric gluons. It is also observed that the magnetic screening mass keeps almost the same as its vacuum value, which manifests that the magnetic gluons remains confined. Both the screening masses and the Polyakov loop results are qualitatively in agreement with the Lattice calculations.

Fukun Xu; Mei Huang

2011-11-22T23:59:59.000Z

170

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

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

Naganoma, Junji; /Waseda U.

2008-03-01T23:59:59.000Z

171

We suggest a method for probing the quark content of the photon using $b$ tagging at high energy $e^+e^-$ and $e\\gamma$ colliders. We find that heavy quark tagging provides a sensitive and effective probe of the quark content of the photon especially in the low $x$-region where the various models differ the most. This process is complementary to others that have been studied in the literature and can contribute to more precise determinations of quark and gluon distributions inside the photon.

Michael A. Doncheski; Stephen Godfrey; K. Andrew Peterson

1994-07-21T23:59:59.000Z

172

Dynamical equation of the effective gluon mass

In this article, we derive the integral equation that controls the momentum dependence of the effective gluon mass in the Landau gauge. This is accomplished by means of a well-defined separation of the corresponding ''one-loop dressed'' Schwinger-Dyson equation into two distinct contributions, one associated with the mass and one with the standard kinetic part of the gluon. The entire construction relies on the existence of a longitudinally coupled vertex of nonperturbative origin, which enforces gauge invariance in the presence of a dynamical mass. The specific structure of the resulting mass equation, supplemented by the additional requirement of a positive-definite gluon mass, imposes a rather stringent constraint on the derivative of the gluonic dressing function, which is comfortably satisfied by the large-volume lattice data for the gluon propagator, both for SU(2) and SU(3). The numerical treatment of the mass equation, under some simplifying assumptions, is presented for the aforementioned gauge groups, giving rise to a gluon mass that is a nonmonotonic function of the momentum. Various theoretical improvements and possible future directions are briefly discussed.

Aguilar, A. C. [Federal University of ABC, CCNH, Rua Santa Adelia 166, CEP 09210-170, Santo Andre (Brazil); Binosi, D. [European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT) and Fondazione Bruno Kessler, Villa Tambosi, Strada delle Tabarelle 286, I-38123 Villazzano (Trento) (Italy); Papavassiliou, J. [Department of Theoretical Physics and IFIC, University of Valencia E-46100, Valencia (Spain)

2011-10-15T23:59:59.000Z

173

What does low energy physics tell us about the zero momentum gluon propagator?

The connection between QCD, a nonlocal Nambu-Jona-Lasinio type model and the Landau gauge gluon propagator is explored. This two point function is parameterized by a functional form which is compatible with Dyson-Schwinger and lattice QCD results. Demanding the nonlocal model to reproduce the experimental values for the pion mass, the pion decay constant, {Gamma}{sub {pi}{yields}{gamma}{gamma}} and the light quark condensate we conclude that low energy physics does not distinguish between the so-called decoupling and scaling solutions of the Dyson-Schwinger equations. This result means that, provided that the model parameters are chosen appropriately, one is free to choose any of the above scenarios. Furthermore, the nonlocal Nambu-Jona-Lasinio quark model considered here is chiral invariant and satisfies the GMOR relation at the 1% level of precision.

Costa, P. [Centro de Fisica Computacional, Rua Larga, Universidade de Coimbra, P-3004-516 Coimbra (Portugal); E.S.T.G., Instituto Politecnico de Leiria, Morro do Lena - Alto do Vieiro, 2411-901 Leiria (Portugal); Oliveira, O. [Centro de Fisica Computacional, Rua Larga, Universidade de Coimbra, P-3004-516 Coimbra (Portugal); Departamento de Fisica, Instituto Tecnologico de Aeronautica, 12.228-900, Sao Jose dos Campos, SP (Brazil); Silva, P. J. [Centro de Fisica Computacional, Rua Larga, Universidade de Coimbra, P-3004-516 Coimbra (Portugal)

2011-05-23T23:59:59.000Z

174

Murray Gell-Mann, the Eightfold Way, Quarks, and Quantum Chromodynamics

Office of Scientific and Technical Information (OSTI)

Murray Gell-Mann, the Eightfold Way, and Quantum Chromodynamics Murray Gell-Mann, the Eightfold Way, and Quantum Chromodynamics Resources with Additional Information Murray Gell-Mann Courtesy of the Santa Fe Institute 'In 1969, Professor Gell-Mann received the Nobel Prize in physics for his work on the theory of elementary particles. Professor Gell-Mann's "eightfold way" theory brought order to the chaos created by the discovery of some 100 particles in the atom's nucleus. Then he found that all of those particles, including the neutron and proton, are composed of fundamental building blocks that he named "quarks." The quarks are permanently confined by forces coming from the exchange of "gluons." He and others later constructed the quantum field theory of quarks and gluons, called "quantum chromodynamics," which seems to account for all the nuclear particles and their strong interactions." ...

175

Global quark polarization in non-central A+A collisions

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

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

2007-10-12T23:59:59.000Z

176

We report recent results of a non-perturbative determination of the static heavy-quark potential in quenched and dynamical lattice QCD at finite temperature. The real and imaginary part of this complex quantity are extracted from the spectral function of Wilson line correlators in Coulomb gauge. To obtain spectral information from Euclidean time numerical data, our study relies on a novel Bayesian prescription that differs from the Maximum Entropy Method. We perform simulations on quenched $32^3\\times N_\\tau$ $(\\beta=7.0,\\xi=3.5)$ lattices with $N_\\tau=24,...,96$, which cover $839{\\rm MeV} \\geq T\\geq 210 {\\rm MeV}$. To investigate the potential in a quark-gluon plasma with light u,d and s quarks we utilize $N_f=2+1$ ASQTAD lattices with $m_l=m_s/20$ by the HotQCD collaboration, giving access to temperatures between $286 {\\rm MeV} \\geq T\\geq 148{\\rm MeV}$. The real part of the potential exhibits a clean transition from a linear, confining behavior in the hadronic phase to a Debye screened form above deconfinement. Interestingly its values lie close to the color singlet free energies in Coulomb gauge at all temperatures. We estimate the imaginary part on quenched lattices and find that it is of the same order of magnitude as in hard-thermal loop perturbation theory. From among all the systematic checks carried out in our study, we discuss explicitly the dependence of the result on the default model and the number of datapoints.

Yannis Burnier; Olaf Kaczmarek; Alexander Rothkopf

2014-11-12T23:59:59.000Z

177

Shear Viscosity in a Gluon Gas

Science Journals Connector (OSTI)

The relation of the shear viscosity coefficient to the recently introduced transport rate is derived within relativistic kinetic theory. We calculate the shear viscosity over entropy ratio ?/s for a gluon gas, which involves elastic gg?gg perturbative QCD (PQCD) scatterings as well as inelastic gg?ggg PQCD bremsstrahlung. For ?s=0.3 we find ?/s=0.13 and for ?s=0.6, ?/s=0.076. The small ?/s values, which suggest strongly coupled systems, are due to the gluon bremsstrahlung incorporated.

Zhe Xu and Carsten Greiner

2008-04-29T23:59:59.000Z

178

Associated production of a top quark and a charged Higgs boson

Science Journals Connector (OSTI)

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

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

2005-06-28T23:59:59.000Z

179

Heavy quarks and long-lived hadrons

Science Journals Connector (OSTI)

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

Thomas Appelquist and H. David Politzer

1975-09-01T23:59:59.000Z

180

Jet calculus beyond leading order for the gluon sector

Science Journals Connector (OSTI)

We report results for the order-CA2?s2 jet-calculus three-, two-, and one-gluon distributions of the pure gluon singlet channel. Included is an independent calculation of the CA2 part of the gluon?gluon inclusive distribution which has been a subject of controversy for several years. We confirm the results of Furmanski and Petronzio for scheme-independent observables.

J. F. Gunion and J. Kalinowski

1984-04-01T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

181

Gluon Condensate in Pion Superfluid beyond Mean Field Approximation

We study gluon condensate in a pion superfluid, through calculating the equation of state of the system in the Nambu-Jona-Lasinio model. While in mean field approximation the growing pion condensate leads to an increasing gluon condensate, meson fluctuations reduce the gluon condensate and the broken scalar symmetry can be smoothly restored at finite isospin density.

Yin Jiang; Pengfei Zhuang

2011-03-04T23:59:59.000Z

182

Bulk viscosity of the gluon plasma in a holographic approach

A gravity-scalar model in 5-dim. Riemann space is adjusted to the thermodynamics of SU(3) gauge field theory in the temperature range 1 - 10 $T/T_c$ to calculate holographically the bulk viscosity in 4-dim. Minkowski space. Various settings are compared, and it is argued that, upon an adjustment of the scalar potential to reproduce exactly the lattice data within a restricted temperature interval above $T_c$, rather robust values of the bulk viscosity to entropy density ratio are obtained.

R. Yaresko; B. Kampfer

2014-03-14T23:59:59.000Z

183

We discuss perturbative O(g^2a) matching with static heavy quarks and domain-wall light quarks for lattice operators relevant to B-meson decays and $B^0$-$\\bar{B}^0$ mixing. The chiral symmetry of the light domain-wall quarks does not prohibit operator mixing at O(a) for these operators. The O(a) corrections to physical quantities are non-negligible and must be included to obtain high-precision simulation results for CKM physics. We provide results using plaquette, Symanzik, Iwasaki and DBW2 gluon actions and applying APE, HYP1 and HYP2 link-smearing for the static quark action.

Tomomi Ishikawa; Yasumichi Aoki; Jonathan M. Flynn; Taku Izubuchi; Oleg Loktik

2011-01-05T23:59:59.000Z

184

Quark Condensates: Flavour Dependence

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

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

2007-03-23T23:59:59.000Z

185

Science Journals Connector (OSTI)

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

A. P. Heinson; CDF Collaboration; DØ Collaboration

2006-01-01T23:59:59.000Z

186

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

A. Juste

2005-12-20T23:59:59.000Z

187

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

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

188

Neutral Higgs Boson Pair Production in Standard Model with the Fourth Generation Quarks at LHC

Science Journals Connector (OSTI)

We investigated the neutral Higgs boson pair production at the CERN Large Hadron Collider (LHC) in the SM with four families. We found that the gluon-gluon fusion mode is the most dominant one in producing neutral Higgs boson pair at the LHC, and it can be used to probe the trilinear Higgs coupling. If the heavy quarks of the fourth generation really exist within the SM, they can manifest their effect on the cross section of the Higgs pair production process at the LHC. Our numerical results show that there will be neutral Higgs boson pair production events per year if the next generation heavy quarks really exist, while there will be only events produced per year if there are only three families in the SM.

Sun Hao; Ma Wen-Gan; Zhou Ya-Jin; Sun Yan-Bin; Zhang Ren-You; Hou Hong-Sheng

2004-01-01T23:59:59.000Z

189

Forward-backward asymmetry in top quark-antiquark production

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

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

2011-12-12T23:59:59.000Z

190

Calculation of the cross section for top quark production

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

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

1996-06-21T23:59:59.000Z

191

Challenges to quantum chromodynamics: Anomalous spin, heavy quark, and nuclear phenomena

The general structure of QCD meshes remarkably well with the facts of the hadronic world, especially quark-based spectroscopy, current algebra, the approximate point-like structure of large momentum transfer inclusive reactions, and the logarithmic violation of scale invariance in deep inelastic lepton-hadron reactions. QCD has been successful in predicting the features of electron-positron and photon-photon annihilation into hadrons, including the magnitude and scaling of the cross sections, the shape of the photon structure function, the production of hadronic jets with patterns conforming to elementary quark and gluon subprocesses. The experimental measurements appear to be consistent with basic postulates of QCD, that the charge and weak currents within hadrons are carried by fractionally-charged quarks, and that the strength of the interactions between the quarks, and gluons becomes weak at short distances, consistent with asymptotic freedom. Nevertheless in some cases, the predictions of QCD appear to be in dramatic conflict with experiment. The anomalies suggest that the proton itself as a much more complex object than suggested by simple non-relativistic quark models. Recent analyses of the proton distribution amplitude using QCD sum rules points to highly-nontrival proton structure. Solutions to QCD in one-space and one-time dimension suggest that the momentum distributions of non-valence quarks in the hadrons have a non-trival oscillatory structure. The data seems also to be suggesting that the intrinsic'' bound state structure of the proton has a non- negligible strange and charm quark content, in addition to the extrinsic'' sources of heavy quarks created in the collision itself. 144 refs., 46 figs., 2 tabs.

Brodsky, S.J.

1989-11-01T23:59:59.000Z

192

Gluon Saturation in QCD at High Energy: Beyond Leading Logarithms

Progresses towards the calculation and the understanding of NLO/NLL contributions to Deep Inelastic Scattering at low x with gluon saturation are being reviewed.

Beuf G.

2011-07-24T23:59:59.000Z

193

Stirring Strongly Coupled Plasma

We determine the energy it takes to move a test quark along a circle of radius L with angular frequency ? through the strongly coupled plasma of $\\mathcal{N}=4$ supersymmetric Yang–Mills (SYM) theory. We find that for most ...

Fadafan, Kazem Bitaghsir

194

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

Science Journals Connector (OSTI)

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

Jonathan Grigo; Kirill Melnikov; Matthias Steinhauser

2014-01-01T23:59:59.000Z

195

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

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

196

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

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

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

2014-03-07T23:59:59.000Z

197

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

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

2013-10-24T23:59:59.000Z

198

Matched predictions for Higgs production via heavy-quark loops in the standard model and beyond

Science Journals Connector (OSTI)

The main Higgs production channel at hadron colliders is gluon fusion via heavy-quark loops. We present the results of a fully exclusive simulation of gluon fusion Higgs production based on the matrix elements for h+0, 1, 2 partons including full heavy-quark loop dependence, matched to a parton shower. We consider a Higgs with standard model couplings as well as models where the Higgs has enhanced couplings to bottom quarks (b-philic). We study the most relevant kinematic distributions, such as jet and Higgs pT spectra and find that matched samples provide an accurate description of the final state. For the SM Higgs, we confirm the excellent accuracy of the large heavy-quark-mass approximation also in differential distributions over all phase space, with significant effects arising only at large pT. For a b-philic Higgs however, the loops have a dramatic impact on the kinematics of the Higgs as well as of the jets and need to be accounted for exactly to achieve reliable event simulations.

Johan Alwall, Qiang Li, and Fabio Maltoni

2012-01-26T23:59:59.000Z

199

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

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

1983-01-01T23:59:59.000Z

200

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

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

Carlos G. Granados; Misak M. Sargsian

2009-07-29T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

201

Top Quark Condensate Revisited

Science Journals Connector (OSTI)

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

Koichi Yamawaki

1996-02-01T23:59:59.000Z

202

Phenomenology of infrared finite gluon propagator and coupling constant

We report on some recent solutions of the Dyson-Schwinger equations for the infrared behavior of the gluon propagator and coupling constant, discussing their differences and proposing that these different behaviors can be tested through hadronic phenomenology. We discuss which kind of phenomenological tests can be applied to the gluon propagator and coupling constant, how sensitive they are to the infrared region of momenta and what specific solution is preferred by the experimental data.

A. A. Natale

2006-10-23T23:59:59.000Z

203

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

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

204

Holographic Accelerated Heavy Quark-Anti-Quark Pair

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

Veronika E. Hubeny; Gordon W. Semenoff

2014-10-05T23:59:59.000Z

205

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

Potamianos, Karolos

2011-12-01T23:59:59.000Z

206

Top Quark Current Experimental Status

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

A. Juste

2006-03-04T23:59:59.000Z

207

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

Heavy quark three-body collisional energy loss in quark-gluon plasma... III-1 C. M. Ko and Wei Liu Elliptic flow of deuterons in relativistic heavy ion...

208

Cold quark matter in compact stars

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

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

2013-03-25T23:59:59.000Z

209

Heavy quark production in photon-Pomeron interactions at high energies

The diffractive heavy quark cross sections are estimated considering photon-Pomeron interactions in hadron - hadron at RHIC, Tevatron, and CERN LHC energies. We assume the validity of the hard diffractive factorization and calculate the charm and bottom total cross sections and rapidity distributions using the diffractive parton distribution functions of the Pomeron obtained by the H1 Collaboration at DESY-HERA. Such processes are sensitive to the gluon content of the Pomeron at high energies and are a good place to constrain the behavior of this distribution. We also compare our predictions with those obtained using the dipole model, and verify that these processes are a good test of the different mechanisms for heavy quarks diffractive production at hadron colliders.

Machado, M. M. [Instituto Federal de Ciencia, Educacao e Tecnologia Farroupilha, Campus Sao Borja, Rua Otaviano Castilho Mendes, 355, CEP 97670-000, Sao Borja, RS (Brazil); Goncalves, V. P. [Instituto de Fisica e Matematica - IFM, Universidade Federal de Pelotas, Caixa Postal 354, CEP 96010-900, RS (Brazil)

2013-03-25T23:59:59.000Z

210

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

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

211

Shear Viscosity of Quark Matter

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

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

2007-07-30T23:59:59.000Z

212

Dissipative force on an external quark in heavy quark cloud

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

Shankhadeep Chakrabortty

2011-10-01T23:59:59.000Z

213

Top quark studies at hadron colliders

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

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

1997-01-01T23:59:59.000Z

214

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

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

2006-09-25T23:59:59.000Z

215

Symmetries of Quarks and Leptons

Science Journals Connector (OSTI)

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

F. Gürsey

1979-01-01T23:59:59.000Z

216

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

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

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

2015-01-01T23:59:59.000Z

217

The threshold region for Higgs production in gluon fusion

We provide a quantitative determination of the effective center of mass energy of the partonic subprocess for Higgs production in gluon fusion in terms of the collider energy at the LHC. We use the result to assess, as a function of the Higgs mass, whether the large top mass approximation is adequate and whether Sudakov resummation is advantageous. We argue that our results hold to all perturbative orders.

Bonvini, Marco; Ridolfi, Giovanni

2012-01-01T23:59:59.000Z

218

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

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

David d'Enterria; Krisztian Krajczar; Hannu Paukkunen

2015-01-23T23:59:59.000Z

219

The origin of plasma turbulence from currents and spatial gradients in plasmas is described and shown to lead to the dominant transport mechanism in many plasma regimes. A wide variety of turbulent transport mechanism exists in plasmas. In this survey the authors summarize some of the universally observed plasma transport rates.

Horton, W. [Univ. of Texas, Austin, TX (United States). Inst. for Fusion Studies; Hu, G. [Globalstar LP, San Jose, CA (United States)

1998-07-01T23:59:59.000Z

220

Charm -- a thermometer of the mixed phase

A charmed quark experiences drag and diffusion in the quark-gluon plasma, as well as strong interaction with the plasma surface. Our simulations indicate that charmed quarks created in heavy ion collisions will be trapped in the mixed phase and will come to equilibrium in it. Their momentum distribution will thus reflect the temperature at the confinement phase transition.

Benjamin Svetitsky; Asher Uziel

1997-09-03T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

221

Top quark production at ATLAS and CMS

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

Luca Lista; on behalf of the ATLAS; CMS collaborations

2014-05-20T23:59:59.000Z

222

Heavy quarks in effective field theories

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

Jain, Ambar

2009-01-01T23:59:59.000Z

223

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 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...

224

Top Quark Production at the LHC

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

Francesco Spanò; for the ATLAS; CMS collaborations

2011-12-16T23:59:59.000Z

225

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

Werner Bernreuther

2008-05-09T23:59:59.000Z

226

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

Schwarz, Thomas A.; /Michigan U.

2006-01-01T23:59:59.000Z

227

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

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

228

Flavordynamics of quarks and leptons

Science Journals Connector (OSTI)

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

H. Fritzsch; P. Minkowski

1981-01-01T23:59:59.000Z

229

"Probing the Matter Created at RHIC." Mioduszewski discusses the results from RHIC's experimental collaborations and how researchers hope to create a form of matter in which the basic building blocks of matter -- quarks and gluons -- interact freely in what is called quark gluon plasma.

Saskia Mioduszewski

2010-09-01T23:59:59.000Z

230

Vortices and Other Topological Solitons in Dense Quark Matter

In this review, we discuss various properties of topological solitons in dense QCD matter, with a particular emphasis on the CFL phase exhibiting superfluidity and superconductivity, and their phenomenological implications in terms of the effective field theories such as the Ginzburg-Landau theory, the chiral Lagrangian, or the Bogoliubov--de Gennes equation. The most fundamental topological excitations are non-Abelian vortices, which are 1/3 quantized superfluid vortices and color magnetic flux tubes. They are created at a phase transition or a rotation such compact stars. The intervortex-interaction is repulsive and consequently a vortex lattice is formed. Bosonic and fermionic zero-energy modes are trapped in the vortex core and propagate along it as gapless excitations. The former consists of translational zero modes (a Kelvin mode) with a quadratic dispersion and CP(2) Nambu-Goldstone gapless modes with a linear dispersion, while the latter is the triplet Majorana fermion zero modes. The low-energy effective theory of the bosonic zero modes is a non-relativistic free complex scalar field and a CP(2) model in 1+1 dimensions. The effects of strange quark mass, electromagnetic interactions and non-perturbative quantum corrections are taken into account. Colorful boojums at the CFL interface, quantum color magnetic monopole confined by vortices, which supports the notion of quark-hadron duality, and Yang-Mills instantons inside a vortex as lumps are discussed. The interactions between a vortex and quasi-particles such as phonons, gluons, mesons, and photons are studied. A vortex lattice is shown to behave as a cosmic polarizer. Non-Abelian vortices are shown to behave as a novel kind of non-Abelian anyons. For the chiral symmetry breaking, we discuss fractional and integer axial domain walls, Abelian and non-Abelian axial vortices, axial wall-vortex composites, and Skyrmions.

Minoru Eto; Yuji Hirono; Muneto Nitta; Shigehiro Yasui

2013-08-07T23:59:59.000Z

231

A relativistic constituent quark model

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

Schlumpf, F.

1993-08-01T23:59:59.000Z

232

DOE R&D Accomplishments [OSTI]

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

Kim, S. B.

1995-08-00T23:59:59.000Z

233

Quark confinement mechanism for baryons

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

Yu. P. Goncharov

2013-12-14T23:59:59.000Z

234

Fully differential heavy quark contributions to the photon structure functions in deeply inelastic scattering are computed in next-to-leading order QCD, including both the direct and resolved contributions. A variety of distributions are presented and discussed. Several of the distributions show marked differences between the resolved and direct cases due primarily to the presense of the gluon distribution in the former and lack thereof in the later.

B. W. Harris; J. F. Owens

1996-03-13T23:59:59.000Z

235

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

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

Neumann, Tobias

2014-01-01T23:59:59.000Z

236

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

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

d'Enterria, David; Paukkunen, Hannu

2015-01-01T23:59:59.000Z

237

On relevance of triple gluon fusion in $J/\\psi$ hadroproduction

A contribution to $J/\\psi$ hadroproduction is analyzed in which the meson production is mediated by three-gluon partonic state, with two gluons coming from the target and one gluon from the projectile. This mechanism involves double gluon density in one of the protons, hence this contribution enters at a non-leading twist. It is, however, relevant due to an enhancement factor coming from large double gluon density at small~$x$. We calculate the three-gluon contribution to $J/\\psi$ hadroproduction within perturbative QCD in the $k_T$-factorization framework. Results are obtained for differential $p_T$-dependent cross-sections for all $J/\\psi$ polarizations and for the sum over the polarization components. The rescattering contribution is found to provide a significant correction to the standard leading twist cross-section at the energies of the Tevatron or the LHC at moderate $p_T$. We suggest $J/\\psi$ production in proton-nucleus collision as a possible probe of the triple gluon mechanism.

Motyka, Leszek

2015-01-01T23:59:59.000Z

238

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

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

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

2007-11-07T23:59:59.000Z

239

Top Quark Production at the Tevatron

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

Mietlicki, David J.

2011-12-01T23:59:59.000Z

240

Nonperturbative gluon and ghost propagators for d=3 Yang-Mills theory

Science Journals Connector (OSTI)

We study a manifestly gauge-invariant set of Schwinger-Dyson equations to determine the nonperturbative dynamics of the gluon and ghost propagators in d=3 Yang-Mills theory. The use of the well-known Schwinger mechanism, in the Landau gauge leads to the dynamical generation of a mass for the gauge boson (gluon in d=3), which, in turn, gives rise to an infrared finite gluon propagator and ghost dressing function. The propagators obtained from the numerical solution of these nonperturbative equations are in very good agreement with the results of SU(2) lattice simulations.

A. C. Aguilar; D. Binosi; J. Papavassiliou

2010-06-25T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

241

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

Science Journals Connector (OSTI)

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

Masahiro Imachi; Shoichiro Otsuki; Fumihiko Toyoda

2008-10-01T23:59:59.000Z

242

Comment on ``Success of collinear expansion in the calculation of induced gluon emission''

We show that the arguments against our recent paper on the failure of the collinear expansion in the calculation of the induced gluon emission raised by X.N. Wang are either incorrect or irrelevant.

P. Aurenche; B. G. Zakharov; H. Zaraket

2008-06-01T23:59:59.000Z

243

What if dark matter gamma-ray lines come with gluon lines?

Science Journals Connector (OSTI)

In dark matter (DM) models, the production of a ? line (or of a “box-shaped” ?-ray spectrum) from DM annihilation proceeds in general from a loop diagram involving a heavy charged particle. If the charged particle in the loop carries also a color charge, this leads inevitably to DM annihilation to gluons, with a naturally larger rate. We consider a scenario in which DM candidates annihilate dominantly into gluon pairs, and determine (as far as possible, model-independent) constraints from a variety of observables: (a) the dark matter relic density, (b) the production of antiprotons, (c) DM direct detection and (d) gluon-gluon fusion processes at LHC. Among other things, we show that this scenario together with the recent claim for a possible ? line from the Galactic center in the Fermi-LAT data, leads to a relic abundance of DM that may be naturally close to the cosmological observations.

Xiaoyong Chu; Thomas Hambye; Tiziana Scarna; Michel H. G. Tytgat

2012-10-10T23:59:59.000Z

244

Towards the continuum limit of the lattice Landau gauge gluon propagator

The infrared behaviour of the lattice Landau gauge gluon propagator is discussed, combining results from simulations with different volumes and lattice spacings. In particular, the Cucchieri-Mendes bounds are computed and their implications for D(0) discussed.

Oliveira, O. [Centro de Fisica Computacional, Rua Larga, Universidade de Coimbra, P-3004-516 Coimbra (Portugal); Departamento de Fisica, Instituto Tecnologico de Aeronautica, 12.228-900, Sao Jose dos Campos, SP (Brazil); Silva, P. J. [Centro de Fisica Computacional, Rua Larga, Universidade de Coimbra, P-3004-516 Coimbra (Portugal)

2011-05-23T23:59:59.000Z

245

The inclusive hadronic production of $\\eta_Q$($\\eta_c$ or $\\eta_b$) pair is proposed to extract the transverse momentum dependent(TMD) gluon distribution functions. We use nonrelativistic QCD(NRQCD) for the production of $\\eta_Q$. Under nonrelativistic limit TMD factorization for this process is assumed to make a lowest order calculation. For unpolarized initial hadrons, unpolarized and linearly polarized gluon distributions can be extracted by studying different angular distributions.

Guang-Peng Zhang

2014-06-20T23:59:59.000Z

246

CP violation in top-quark physics

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

German Valencia

2010-07-27T23:59:59.000Z

247

Review of Top Quark Physics Results

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

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

2007-12-01T23:59:59.000Z

248

Recent advances in heavy quark theory

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

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

1997-01-01T23:59:59.000Z

249

Heavy quark thermodynamics in full QCD

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

Konstantin Petrov; RBC-Bielefeld Collaboration

2007-01-22T23:59:59.000Z

250

The Top Quark, QCD, And New Physics.

DOE R&D Accomplishments [OSTI]

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

Dawson, S.

2002-06-00T23:59:59.000Z

251

Top quark physics expectations at the LHC

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

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

2008-10-22T23:59:59.000Z

252

Excited quark production at the CERN LHC

Science Journals Connector (OSTI)

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

O. Çak?r and R. Mehdiyev

1999-06-22T23:59:59.000Z

253

Viscosity and jet quenching from holographic model

We consider the backreaction of the fundamental flavor degrees of freedom on the AdS$_5$-Schwarz background, and calculate their contributions to the shear viscosity and jet-quenching parameter of the thermal quark-gluon plasma.

Yi-hong Gao; Wei-shui Xu; Ding-fang Zeng

2007-07-05T23:59:59.000Z

254

QGP viscosity at RHIC and the LHC - a 2012 status report

In this article, we briefly review the recent progress related to extracting the quark-gluon plasma (QGP) specific shear viscosity from the flow data measured at Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC).

Huichao Song

2012-10-21T23:59:59.000Z

255

(Nuclear theory). [Research in nuclear physics

This report discusses research in nuclear physics. Topics covered in this paper are: symmetry principles; nuclear astrophysics; nuclear structure; quark-gluon plasma; quantum chromodynamics; symmetry breaking; nuclear deformation; and cold fusion. (LSP)

Haxton, W.

1990-01-01T23:59:59.000Z

256

Science Journals Connector (OSTI)

......Phase Transition and Particle Distribution in High Energy Nuclear Collisions Youichi Akase Masashi Mizutani Shin Muroya...quark-gluon plasma fluid possibly produced in high energy nuclear collisions. The temperature dependences of thermodynamical......

Youichi Akase; Masashi Mizutani; Shin Muroya; Mikita Yasuda

1991-02-01T23:59:59.000Z

257

Jet Quenching Parameter Via Soft Collinear Effective Theory (SCET)

We analyze the transverse momentum broadening in the absence of radiation of an energetic parton propagating through quark-gluon plasma via Soft Collinear Effective Theory (SCET). We show that the probability for picking ...

D'Eramo, Francesco

258

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

R. Rapp, EMMI Rapid Reaction Task Force on "Direct-Photon Flow Puzzle", GSI, Darmstadt, Germany (February 2014). VI-7 Quarkonia in the quark-gluon plasma, R. Rapp, Invited...

259

Production and decay of heavy top quarks

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

Kauffman, R.P.

1989-08-01T23:59:59.000Z

260

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

of light years can emerge from the frenetic motion of plasmas. A team of Lawrence Livermore researchers has discovered that supersonic counter-streaming (directed at each...

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

261

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

first active year) first active year) QuarkNet Home - Information - Calendar - Contacts - Projects - Forms: EoI - Teachers Institution Contact e-mail Year Brown, Northeastern & Brandeis Universities Richard Dower - rick.dower@roxburylatin.org 1999 Fermilab & University of Chicago Chris Stoughton - stoughto@fnal.gov 1999 Florida State University Horst Wahl - wahl@hep.fsu.edu 1999 Indiana University Rick Van Kooten - rickv@paoli.physics.indiana.edu 1999 University of California - Santa Cruz Steve Ritz - ritz@scipp.ucsc.edu 1999 University of Notre Dame Dan Karmgard - Karmgard.1@nd.edu 1999 University of Oklahoma Michael Strauss - strauss@mail.nhn.ou.edu 1999 University of Rochester Kevin McFarland - ksmcf@pas.rochester.edu 1999

262

This report covers preliminary measurements from SLD on heavy quark production at the Z{sup 0}, using 150,000 hadronic Z{sup 0} decays accumulated during the 1993-1995 runs. A measurement of R{sub b} with a lifetime double tag is presented. The high electron beam polarization of the SLC is employed in the direct measurement of the parity-violating parameters A{sub b} and A{sub c} by use of the left-right forward-backward asymmetry. The lifetimes of B{sup +} and B{sup 0} mesons have been measured by two analyses. The first identifies semileptonic decays of B mesons with high (p,p{sub t}) leptons; the second analysis isolates a sample of B meson decays with a two-dimensional impact parameter tag and reconstructs the decay length and charge using a topological vertex reconstruction method.

Messner, R. [Stanford Univ., CA (United States)

1997-01-01T23:59:59.000Z

263

Plasma jets and plasma bullets

Science Journals Connector (OSTI)

Plasma plumes, or plasma jets, belong to a large family of gas discharges whereby the discharge plasma is extended beyond the plasma generation region into the surrounding ambience, either by a field (e.g. electromagnetic, convective gas flow, or shock wave) or a gradient of a directionless physical quantity (e.g. particle density, pressure, or temperature). This physical extension of a plasma plume gives rise to a strong interaction with its surrounding environment, and the interaction alters the properties of both the plasma and the environment, often in a nonlinear and dynamic fashion. The plasma is therefore not confined by defined physical walls, thus extending opportunities for material treatment applications as well as bringing in new challenges in science and technology associated with complex open-boundary problems. Some of the most common examples may be found in dense plasmas with very high dissipation of externally supplied energy (e.g. in electrical, optical or thermal forms) and often in or close to thermal equilibrium. For these dense plasmas, their characteristics are determined predominantly by strong physical forces of different fields, such as electrical, magnetic, thermal, shock wave, and their nonlinear interactions [1]. Common to these dense plasma plumes are significant macroscopic plasma movement and considerable decomposition of solid materials (e.g. vaporization). Their applications are numerous and include detection of elemental traces, synthesis of high-temperature materials and welding, laser--plasma interactions, and relativistic jets in particle accelerators and in space [2]–[4]. Scientific challenges in the understanding of plasma jets are exciting and multidisciplinary, involving interweaving transitions of all four states of matter, and their technological applications are wide-ranging and growing rapidly. Using the Web of Science database, a search for journal papers on non-fusion plasma jets reveals that a long initial phase up to 1990 with only 31 papers per year on average, and a total of some 1300 papers, precedes a considerable growth of some 35–50% in research activity every five years, over the last 20 years or so. As shown in the table, the annual dissemination of the field is more than 1600 papers and the total number of papers is in excess of 20000. This upwards trajectory is typical of a strong and growing subject area in physical science, with considerable capacity in both fundamental science and applications. PeriodNumber of papersPapers per annum 1948–1990130031 1991–19952279456 1996–20003447689 2001–20054571914 2006–201066401328 2011 1658 In many of the dense plasma jets discussed above, strong physical forces generated by the plasma are often desired and this favours plasma generation at elevated gas pressure, including atmospheric pressure, which favours a high level of gas ionization. Historically it has been challenging to reduce and control the strong physical forces in high-pressure plasmas for applications where these are unwanted, for example, surface modification of polymeric sheets [5]. Indeed, there is a real need for a vast range of material processing applications at temperatures below 100oC (or below 400 K) and this favours atmospheric-pressure plasma jets sustained far from thermal equilibrium with the dissipated electrical energy largely used not in heat generation but in unleashing non-equilibrium chemical reactions. The long-standing difficulty of effectively controlling the level of gas ionization at atmospheric pressure was overcome by the technological breakthrough of achieving atmospheric-pressure glow discharges in the late 1980s [6]. A related challenge stemming from high collisionality of atmospheric-pressure plasmas (v >> ?0) means that large-area plasmas sustained between parallel-plate electrodes are very susceptible to strong plasma instabilities when molecular gases are introduced for processing applications. This led to an effective technological solution in the early to late 1990s of confining atmospheric plasmas in a small v

M G Kong; B N Ganguly; R F Hicks

2012-01-01T23:59:59.000Z

264

Science Journals Connector (OSTI)

... JUST over ten years ago the first book on plasma physics as a subject in its own right appeared; in a gradually swelling stream ... been surprisingly few monographs. One topic which has had scant coverage in any form is plasma radiation (except for spectral-line radiation which has been dealt with very fully in ...

T. J. M. BOYD

1967-07-01T23:59:59.000Z

265

Five-quark components in baryons

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

B. S. Zou

2010-01-07T23:59:59.000Z

266

Fractional electric charge and quark confinement

Owing to their fractional electric charges, quarks are blind to transformations that combine a color center phase with an appropriate electromagnetic one. Such transformations are part of a global $Z_6$-like center symmetry of the Standard Model that is lost when quantum chromodynamics (QCD) is treated as an isolated theory. This symmetry and the corresponding topological defects may be relevant to non-perturbative phenomena such as quark confinement, much like center symmetry and ordinary center vortices are in pure SU($N$) gauge theories. Here we report on our investigations of an analogous symmetry in a 2-color model with dynamical Wilson quarks carrying half-integer electric charge.

Sam R. Edwards; André Sternbeck; Lorenz von Smekal

2012-02-07T23:59:59.000Z

267

Press Pass - Press Release - Single top quark

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

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

268

Accelerator probes for new stable quarks

The nonbaryonic dark matter of the Universe can consist of new stable double charged particles $O^{--}$, bound with primordial helium in heavy neutral O-helium (OHe)"atoms" by ordinary Coulomb interaction. O-helium dark atoms can play the role of specific nuclear interacting dark matter and provide solution for the puzzles of dark matter searches. The successful development of composite dark matter scenarios appeals to experimental search for the charged constituents of dark atoms. If $O^{--}$ is a "heavy quark cluster" $\\bar U \\bar U \\bar U$, its production at accelerators is virtually impossible and the strategy of heavy quark search is reduced to search for heavy stable hadrons, containing only single heavy quark (or antiquark). Estimates of production cross section of such particles at LHC are presented and the experimental signatures for new stable quarks are outlined.

Konstantin M. Belostky; Maxim Yu. Khlopov; Konstantin I. Shibaev

2011-11-15T23:59:59.000Z

269

Theory of top quark production and decay

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

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

1997-01-01T23:59:59.000Z

270

Evidence for production of single top quarks

Science Journals Connector (OSTI)

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

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

2008-07-14T23:59:59.000Z

271

Shear viscosity of the quark matter

We discuss shear viscosity of the quark matter by using Kubo formula. The shear viscosity is calculated in the framework of the quasi-particle RPA for the Nambu-Jona-Lasinio model. We obtain a formula that the shear viscosity is expressed by the quadratic form of the quark spectral function in the chiral symmetric phase. The magnitude of the shear viscosity is discussed assuming the Breit-Wigner type for the spectral function.

Masaharu Iwasaki; Hiromasa Ohnishi; Takahiko Fukutome

2007-03-26T23:59:59.000Z

272

Magnetism and superconductivity in quark matter

Magnetic properties of quark matter and its relation to the microscopic origin of the magnetic field observed in compact stars are studied. Spontaneous spin polarization appears in high-density region due to the Fock exchange term, which may provide a scenario for the behaviors of magnetars. On the other hand, quark matter becomes unstable to form spin density wave in the moderate density region, where restoration of chiral symmetry plays an important role. Coexistence of magnetism and color superconductivity is also discussed.

T. Tatsumi; E. Nakano; K. Nawa

2005-06-01T23:59:59.000Z

273

We present a measurement of the ratio of the tt? production cross section via gluon-gluon fusion to the total tt? production cross section in pp? collisions at ?s=1.96??TeV at the Tevatron. Using a data sample with an ...

Xie, Si

274

Baryons with strangeness and charm in a quark model with chromodynamics

Science Journals Connector (OSTI)

The low-lying spectrum of baryons containing a charmed quark and one or two strange quarks is calculated in a a quark model with chromodynamics.

Kim Maltman and Nathan Isgur

1980-10-01T23:59:59.000Z

275

The Temperature Dependence of the SU(N) Gluon Condensate from Lattice Gauge Theory

An analysis of the temperature dependence of the leading contributions to the gluon condensate for SU(N) lattice gauge theory is presented using the data from recent Monte Carlo simulations. The gluon condensate is calculated directly from the new lattice calculations of the interaction measure. It is shown how these computations provide a simple picture for the melting of the condensate around the deconfinement temperature, and the fact that it is negative, and increases in magnitude, above Tc. We close with a discussion of the implications for full QCD of recent results from simulations including fermions.

Graham Boyd; David E. Miller

1996-08-29T23:59:59.000Z

276

We present a measurement of the ratio of the tt production cross section via gluon-gluon fusion to the total tt production cross section in pp collisions at {radical}(s)=1.96 TeV at the Tevatron. Using a data sample with an integrated luminosity of 955 pb{sup -1} recorded by the CDF II detector at Fermilab, we select events based on the tt decay to lepton+jets. Using an artificial neural network technique we discriminate between tt events produced via qq annihilation and gg fusion, and find G{sub f}={sigma}(gg{yields}tt)/{sigma}(pp{yields}tt)<0.33 at the 68% confidence level. This result is combined with a previous measurement to obtain the most stringent measurement of this quantity by CDF to date, G{sub f}=0.07{sub -0.07}{sup +0.15}.

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

2009-02-01T23:59:59.000Z

277

We explore intensity correlations for thermal photons having K{sub T}{<=}2 GeV/c for central collisions of heavy nuclei at Relativistic Heavy Ion Collider and Large Hadron Collider energies. These photons get competing contributions from the quark and hadronic phases. This competition gives rise to a unique structure, especially in the outward correlation function, owing to the interference between the photons from the two sources. The temporal separation of the two sources provides the lifetime of the system and their strengths provide the relative contribution of the two phases. The results are found to be quite sensitive to the quark-hadron phase transition temperature and the formation time of the plasma.

Srivastava, Dinesh Kumar; Chatterjee, Rupa [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700 064 (India)

2009-11-15T23:59:59.000Z

278

Measurements of top quark properties at the Tevatron collider

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

Margaroli, Fabrizio

2011-05-01T23:59:59.000Z

279

Free magnetized knots of parity-violating deconfined matter in heavy-ion collisions

We show that the local parity violation in the quark-gluon plasma supports existence of free (meta)stable knots of deconfined hot quark matter stabilized by superstrong magnetic fields. The magnetic field in the knots resembles the spheromak plasma state of the magnetic confinement approach to nuclear fusion. The size of the knot is quantized, being inversely proportional to the chiral conductivity of the quark-gluon plasma. The parity symmetry is broken inside the knot. Particles produced in the decays of the knots have unusual azimuthal distribution and specific flavor content. We argue that these knots may be created in noncentral heavy-ion collisions.

M. N. Chernodub

2010-02-07T23:59:59.000Z

280

Free magnetized knots of parity-violating deconfined matter in heavy-ion collisions

We show that the local parity violation in the quark-gluon plasma supports existence of free (meta)stable knots of deconfined hot quark matter stabilized by superstrong magnetic fields. The magnetic field in the knots resembles the spheromak plasma state of the magnetic confinement approach to nuclear fusion. The size of the knot is quantized, being inversely proportional to the chiral conductivity of the quark-gluon plasma. The parity symmetry is broken inside the knot. Particles produced in the decays of the knots have unusual azimuthal distribution and specific flavor content. We argue that these knots may be created in noncentral heavy-ion collisions.

Chernodub, M N

2010-01-01T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

281

Baryon Dissociation in a Strongly Coupled Plasma

Using the dual string theory, we study a circular baryonic configuration in a wind of strongly coupled N=4 Yang-Mills plasma blowing in the plane of the baryon, before and after a quark has dissociated from it. A simple enough model that captures many interesting features is when there are four quarks in the baryon. As a step towards phenomenology, we compare representative dissociated configurations, and make some comments about their energetics and other properties. Related results that we find include the observation that the screening length formula L_s T ~ (1-v^2)^{1/4} obtained previously for other color singlet configurations, is robust for circular baryons as well.

Chethan Krishnan

2008-09-30T23:59:59.000Z

282

Baryon Dissociation in a Strongly Coupled Plasma

Using the dual string theory, we study a circular baryonic configuration in a wind of strongly coupled N=4 Yang-Mills plasma blowing in the plane of the baryon, before and after a quark has dissociated from it. A simple enough model that captures many interesting features is when there are four quarks in the baryon. As a step towards phenomenology, we compare representative dissociated configurations, and make some comments about their energetics and other properties. Related results that we find include the observation that the screening length formula L_s T ~ (1-v^2)^{1/4} obtained previously for other color singlet configurations, is robust for circular baryons as well.

Krishnan, Chethan

2008-01-01T23:59:59.000Z

283

We compute power-suppressed corrections to the {eta}{gamma} and {eta}{sup '}{gamma} transition form factors Q{sup 2}F{sub {eta}}{sub ({eta}}{sub {sup '}}{sub {gamma}}(Q{sup 2}) arising from the end point regions x{yields}0,1 by employing the infrared-renormalon approach. The contribution to the form factors from the quark and gluon content of the {eta},{eta}{sup '} mesons is taken into account using for the {eta}-{eta}{sup '} mixing the SU{sub f}(3) singlet {eta}{sub 1} and octet {eta}{sub 8} basis. The theoretical predictions obtained this way are compared with the corresponding CLEO data and restrictions on the input parameters (Gegenbauer coefficients) B{sub 2}{sup q}({eta}{sub 1}), B{sub 2}{sup g}({eta}{sub 1}), and B{sub 2}{sup q}({eta}{sub 8}) in the distribution amplitudes for the {eta}{sub 1},{eta}{sub 8} states with one nonasymptotic term are deduced. Comparison is made with the results from QCD perturbation theory.

Agaev, S.S.; Stefanis, N.G. [High Energy Physics Laboratory, Baku State University, Z. Khalilov Street 23, 370148 Baku (Azerbaijan); Institut fuer Theoretische Physik II, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

2004-09-01T23:59:59.000Z

284

Questions and Answers - What is the charge of an up quark and the charge of

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

What kinds of quarks are inprotons and neutrons? What kinds of quarks are in<br>protons and neutrons? Previous Question (What kinds of quarks are in protons and neutrons?) Questions and Answers Main Index Next Question (Are quarks confineable for study?) Are quarks confineable for study? What is the charge of an up quark and the charge of a down quark? How many quarks make up a proton and a neutron? Protons and neutrons are each composed of three quarks. Protons are made up of two 'up' quarks and one 'down' quark while neutrons are made up of two 'down' quarks and one 'up' quark. Quarks carry fractional electrical charges. An 'up' quark has a charge of +2/3 and a 'down' quark has a charge of -1/3. Is this consistent with what we know about protons and neutrons? Remember that protons carry an electrical charge of +1 while neutrons carry no electrical charge. We said

285

QCD effective charge from the three-gluon vertex of the background-field method

Science Journals Connector (OSTI)

In this article we study in detail the prospects of determining the infrared finite QCD effective charge from a special kinematic limit of the vertex function corresponding to three background gluons. This particular Green’s function satisfies a QED-like Ward identity, relating it to the gluon propagator, with no reference to the ghost sector. Consequently, its longitudinal form factors may be expressed entirely in terms of the corresponding gluon wave function, whose inverse is proportional to the effective charge. After reviewing certain important theoretical properties, we consider a typical lattice quantity involving this vertex, and derive its exact dependence on the various form factors, for arbitrary momenta. We then focus on the particular momentum configuration that eliminates any dependence on the (unknown) transverse form factors, projecting out only the desired quantity. A preliminary numerical analysis indicates that the effective charge is relatively insensitive to the numerical uncertainties that may afflict future simulations of the aforementioned lattice quantity. The numerical difficulties associated with a parallel determination of the dynamical gluon mass are briefly discussed.

D. Binosi; D. Ibañez; J. Papavassiliou

2013-06-17T23:59:59.000Z

286

A polarized version of the CCFM equation for gluons Martin Maul

interest [6,7] due to the pos- sibility that one may access the region of x future projects of the unpolarized gluon distribution function at small momentum fractions has been intensively discussed over; h hphe depends in the high energy limit on the helicity state of the electron h e and the helicity

Lunds Universitet,

287

Calculation of Massive 2-Loop Operator Matrix Elements with Outer Gluon Lines

Massive on-shell operator matrix elements and self-energy diagrams with outer gluon lines are calculated analytically at $O(\\alpha_s^2)$, using Mellin-Barnes integrals and representations through generalized hypergeometric functions. This method allows for a direct evaluation without decomposing the integrals using the integration-by-parts method.

I. Bierenbaum; J. Blümlein; S. Klein

2007-02-26T23:59:59.000Z

288

Anisotropy of the semi-classical gluon field of a large nucleus at high energy

The McLerran-Venugopalan model describes a highly boosted hadron/nucleus as a sheet of random color charges which source soft classical Weizs\\"acker-Williams gluon fields. We show that due to fluctuations, individual configurations are azimuthally anisotropic. We compute the first four azimuthal Fourier amplitudes of the S-matrix of a fundamental dipole in such background fields.

Dumitru, Adrian

2014-01-01T23:59:59.000Z

289

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

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

290

The NJL Model for Quark Fragmentation Functions

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

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

2009-10-01T23:59:59.000Z

291

Essence of the Vacuum Quark Condensate

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

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

2010-08-25T23:59:59.000Z

292

Bulk viscosity in nuclear and quark matter: A short review

The history and recent progresses in the study of bulk viscosity in nuclear and quark matter are reviewed. The constraints from baryon number conservation and electric neutrality in quark matter on particle densities and fluid velocity divergences are discussed.

Hui Dong; Nan Su; Qun Wang

2007-02-07T23:59:59.000Z

293

Phenomenological applications of non-perturbative heavy quark effective theory

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

Mauro Papinutto

2007-10-11T23:59:59.000Z

294

Top quark pair cross section prospects in ATLAS

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

Andrei Gaponenko; for the ATLAS Collaboration

2009-10-20T23:59:59.000Z

295

Down Type Isosinglet Quarks in ATLAS

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

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

2007-11-07T23:59:59.000Z

296

Top Quark Mass Measurements at the Tevatron

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

Ye, Zhenyu; /Fermilab

2011-07-01T23:59:59.000Z

297

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

Akira Shibata

2008-07-31T23:59:59.000Z

298

Heavy-quark correlations in deep inelastic scattering

We discuss results for heavy quark correlations in next-to-leading order QCD in deep inelastic electroproduction.

J. Smith; B. W. Harris

1996-05-20T23:59:59.000Z

299

Cold quark matter, quadratic corrections, and gauge/string duality

Science Journals Connector (OSTI)

We make an estimate of the quadratic correction in the pressure of cold quark matter using gauge/string duality.

Oleg Andreev

2010-04-05T23:59:59.000Z

300

Review of recent top-quark LHC combinations

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

Cortiana, Giorgio

2014-01-01T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

301

Bestimmung des ep{Wirkungsquerschnittes von Beauty-Quarks

Bestimmung des ep{Wirkungsquerschnittes von Beauty-Quarks durch ihren semileptonischen Zerfall in Myonen mit dem H1-Detektor bei HERA Determination of the ep Cross Section for Beauty Quarks via werden die sichtbaren ep-Wirkungsquerschnitte fur schwere Quarks in dem kinematischen Bereich Q2

302

Phase transition from quark-meson coupling hyperonic matter to deconfined quark matter

We investigate the possibility and consequences of phase transitions from an equation of state (EOS) describing nucleons and hyperons interacting via mean fields of {sigma}, {omega}, and {rho} mesons in the recently improved quark-meson coupling (QMC) model to an EOS describing a Fermi gas of quarks in an MIT bag. The transition to a mixed phase of baryons and deconfined quarks, and subsequently to a pure deconfined quark phase, is described using the method of Glendenning. The overall EOS for the three phases is calculated for various scenarios and used to calculate stellar solutions using the Tolman-Oppenheimer-Volkoff equations. The results are compared with recent experimental data, and the validity of each case is discussed with consequences for determining the species content of the interior of neutron stars.

Carroll, J. D.; Leinweber, D. B.; Williams, A. G.; Thomas, A. W. [Centre for the Subatomic Structure of Matter (CSSM), Department of Physics, University of Adelaide, SA 5005 (Australia); Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, Virginia 23606 (United States); College of William and Mary, Williamsburg, Virginia 23187 (United States) and Centre for the Subatomic Structure of Matter (CSSM), Department of Physics, University of Adelaide, SA 5005 (Australia)

2009-04-15T23:59:59.000Z

303

In this paper we apply the equation of state (EOS) of QCD at finite chemical potential and zero temperature proposed in H. S. Zong and W. M. Sun [Int. J. Mod. Phys. A 23, 3591 (2008)] to the study of properties of quark star. This EOS contains only one adjustable parameter m{sub D} which sets the scale of chiral symmetry breaking (in our calculation we have chosen two values of m{sub D}: m{sub D}=244 MeV and m{sub D}=239 MeV, which is fitted from the value of f{sub {pi}} and determined by e{sup +}e{sup -} annihilation experiment, respectively). From this EOS a model of quark star is established by applying the Tolman-Oppenheimer-Volkoff equation under two conditions: with the P({mu}=0) term and without the P({mu}=0) term. Our results show clearly that the P({mu}=0) term is an important quantity in the study of quark star. A comparison between our model and other models of quark star is made. In particular, we have compared our results with the most recent observational data measured using Shapiro delay reported in P. B. Demorest et al.[Nature (London) 467, 1081 (2010)].

Li Hua; Jiang Yu [Department of Physics, Nanjing University, Nanjing 210093 (China); Luo Xinlian [Department of Astronomy, Nanjing University, Nanjing 210093 (China); Zong Hongshi [Department of Physics, Nanjing University, Nanjing 210093 (China); Joint Center for Particle, Nuclear Physics and Cosmology, Nanjing 210093 (China)

2011-01-15T23:59:59.000Z

304

Electroproduction of heavy quarks at NLO

A new next-to-leading order Monte Carlo program for the calculation of fully differential heavy quark cross sections in electroproduction is described. A comparison between the theoretical predictions and the latest charm production data from H1 and ZEUS at HERA is presented.

B. W. Harris

1996-08-20T23:59:59.000Z

305

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

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

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

2012-06-15T23:59:59.000Z

306

Search for Single Top Quark Production at HERA

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

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

2009-01-01T23:59:59.000Z

307

Stable quarks of the 4th family?

Existence of metastable quarks of new generation can be embedded into phenomenology of heterotic string together with new long range interaction, which only this new generation possesses. We discuss primordial quark production in the early Universe, their successive cosmological evolution and astrophysical effects, as well as possible production in present or future accelerators. In case of a charge symmetry of 4th generation quarks in Universe, they can be stored in neutral mesons, doubly positively charged baryons, while all the doubly negatively charged "baryons" are combined with He-4 into neutral nucleus-size atom-like states. The existence of all these anomalous stable particles may escape present experimental limits, being close to present and future experimental test. Due to the nuclear binding with He-4 primordial lightest baryons of the 4th generation with charge +1 can also escape the experimental upper limits on anomalous isotopes of hydrogen, being compatible with upper limits on anomalous lithium. While 4th quark hadrons are rare, their presence may be nearly detectable in cosmic rays, muon and neutrino fluxes and cosmic electromagnetic spectra. In case of charge asymmetry, a nontrivial solution for the problem of dark matter (DM) can be provided by excessive (meta)stable anti-up quarks of 4th generation, bound with He-4 in specific nuclear-interacting form of dark matter. Such candidate to DM is surprisingly close to Warm Dark Matter by its role in large scale structure formation. It catalyzes primordial heavy element production in Big Bang Nucleosynthesis and new types of nuclear transformations around us.

K. Belotsky; M. Khlopov; K. Shibaev

2008-06-05T23:59:59.000Z

308

Questions and Answers - Are quarks confineable for study?

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

is the charge of an up quarkand of down quark? is the charge of an up quark<br>and of down quark? Previous Question (What is the charge of an up quark and of down quark?) Questions and Answers Main Index Next Question (Is vacuum matter? What are ten things that are not matter? ) Is vacuum matter? What are tenthings that are not matter? Are quarks confineable for study? Quarks we study at Jefferson Lab are confined to each other by nature's laws. We shine our electrons on them to observe their behavior in their confined state. This is not so different from turning on a light to see a gold fish swimming in a glass bowl. Author: Nathan Isgur, Theory Group Leader (Other answers by Nathan Isgur) Related Pages: All About Atoms What is the smallest particle of matter known? Could there be anything smaller inside of an electron or inside of a

309

Anomalous dimension of the gluon operator in pure Yang-Mills theory

We present new one loop calculations that confirm the theorems of Joglekar and Lee on the renormalization of composite operators. We do this by considering physical matrix elements with the operators inserted at non-zero momentum. The resulting IR singularities are regulated dimensionally. We show that the physical matrix element of the BRST exact gauge variant operator which appears in the energy- momentum tensor is zero. We then show that the physical matrix elements of the classical energy-momentum tensor and the gauge invariant twist two gluon operator are independent of the gauge fixing parameter. A Sudakov factor appears in the latter cases. The universality of this factor and the UV finiteness of the energy-momentum tensor provide another method of finding the anomalous dimension of the gluon operator. We conjecture that this method applies to higher loops and takes full advantage of the triangularity of the mixing matrix.

B. W. Harris; J. Smith

1994-09-24T23:59:59.000Z

310

By means of two different parametrizations of quark energy loss and the nuclear parton distributions determined only with lepton-nuclear deep inelastic scattering experimental data, a leading order phenomenological analysis is performed on the nuclear Drell-Yan differential cross section ratios as a function of the quark momentum fraction in the beam proton and target nuclei for E772 experimental data. It is shown that there is the quark energy loss effect in nuclear Drell-Yan process apart from the nuclear effects on the parton distribution as in deep inelastic scattering. The uncertainties due to quark energy loss effect is quantified on determining nuclear sea quark distribution by using nuclear Drell-Yan data. It is found that the quark energy loss effect on nuclear Drell-Yan cross section ratios make greater with the increase of quark momentum fraction in the target nuclei. The uncertainties from quark energy loss become bigger as the nucleus A come to be heavier. The Drell-Yan data on proton incident middle and heavy nuclei versus deuterium would result in an overestimate for nuclear modifications on sea quark distribution functions with neglecting the quark energy loss. Our results are hoped to provide good directional information on the magnitude and form of nuclear modifications on sea quark distribution functions by means of the nuclear Drell-Yan experimental data.

C. G. Duan; N. Liu; G. L. Li

2008-11-05T23:59:59.000Z

311

Science Journals Connector (OSTI)

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

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

2009-04-16T23:59:59.000Z

312

Screenings of the quark-gluon plasma in electric and magnetic sectors are studied on the basis of generalized Polyakov-line correlation functions in lattice QCD simulations with two flavors of improved Wilson quarks. Using the Euclidean-time reflection ($\\R$) and the charge conjugation ($\\Ca$), electric and magnetic screening masses are extracted in a gauge invariant manner. Long distance behavior of the standard Polyakov-line correlation in the quark-gluon plasma is found to be dictated by the magnetic screening. Also, ratio of the two screening masses agrees with that obtained from the dimensionally-reduced effective field theory and the ${\\cal N}=4$ supersymmetric Yang-Mills theory.

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

2010-05-11T23:59:59.000Z

313

RHIC | Why Does Quark Matter Matter?

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

Why Does Quark Matter 'Matter'? Why Does Quark Matter 'Matter'? The history of modern technological development can be viewed as a series of investigations, with ever increasing resolution, into the microscopic structure of matter. Since the days of the early Greek philosophers, science has been on a continual quest to find the smallest piece - the most fundamental building block - forming the substance of the universe. STAR researchers During that journey, many beautiful and exotic properties of the subatomic world have been discovered: particles with wave-like properties the ultimate position of which can never be known; "particles" of light that deliver a fixed amount of energy when they strike the atoms of a material's surface; particles in some types of electrical conductors that

314

The Bonn nuclear quark model revisited

We present the exact solutions to the equations of the lowest energy states of the colored and color-symmetric sectors of the Bonn quark model, which is SU(3) symmetric and is defined in terms of an effective pairing force with su(4) algebraic structure. We show that the groundstate of the model is not color symmetrical except for a narrow interval in the range of possible quark numbers. We also study the performance of the Glauber coherent state, as well as of superconducting states of the BCS type, with respect to the description, not only of the absolute (colored) groundstate, but also of the minimum energy state of the color-symmetrical sector, finding that it is remarkably good. We use the model to discuss, in a schematic context, some controversial aspects of the conventional treatment of color superconductivity.

Providencia, Constanca [Departamento de Fi sica, Universidade de Coimbra, Rua Larga, P-3004-516 Coimbra (Portugal); Providencia, Joao da [Departamento de Fi sica, Universidade de Coimbra, Rua Larga, P-3004-516 Coimbra (Portugal)], E-mail: providencia@teor.fis.uc.pt; Cordeiro, Flavio [Departamento de Fi sica, Universidade de Coimbra, Rua Larga, P-3004-516 Coimbra (Portugal); Yamamura, Masatoshi [Department of Pure and Applied Physics, Faculty of Engineering Science, Kansai University, Suita 564-8680 (Japan); Tsue, Yasuhiko; Nishiyama, Seiya [Physics Division, Faculty of Science, Kochi University, Kochi 780-8520 (Japan)

2009-08-15T23:59:59.000Z

315

The Surface Tension of Magnetized Quark Matter

The surface tension of quark matter plays a crucial role for the possibility of quark matter nucleation during the formation of compact stellar objects and also for the existence of a mixed phase within hybrid stars. However, despite its importance, this quantity does not have a well established numerical value. Some early estimates have predicted that, at zero temperature, the value falls within the wide range $\\gamma_0\\approx10-300{\\rm\\ MeV/fm^2}$ but, very recently, different model applications have reduced these numerical values to fall within the range $\\gamma_0\\approx5-30{\\rm\\ MeV/fm^2}$ which would favor the phase conversion process as well as the appearance of a mixed phase in hybrid stars. In magnetars one should also account for the presence of very high magnetic fields which may reach up to about $ eB\\approx 3-30\\, m_\\pi^2$ ($B \\approx 10^{19}-10^{20} \\,G$) at the core of the star so that it may also be important to analyze how the presence of a magnetic field affects the surface tension. With this aim we consider magnetized two flavor quark matter, described by the Nambu--Jona-Lasinio model. We show that although the surface tension oscillates around its B=0 value, when $0 surface tension value drops by about 30% while for $eB \\gtrsim 10\\, m_\\pi^2$ it quickly raises with the field intensity so that the phase conversion and the presence of a mixed phase should be suppressed if extremely high fields are present. We also investigate how thermal effects influence the surface tension for magnetized quark matter.

A. F. Garcia; M. B. Pinto

2013-06-13T23:59:59.000Z

316

Domain wall QCD with physical quark masses

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

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

2014-11-25T23:59:59.000Z

317

Flavor Physics in the Quark Sector

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

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

2009-07-29T23:59:59.000Z

318

Properties of Nonneutral Plasma

Science Journals Connector (OSTI)

We describe an apparatus for producing a magnetized column of nonneutral electron plasma which is many Debye lengths in radius. The plasma exhibits the linear and nonlinear electron-wave effects observed in neutralized plasmas.

J. H. Malmberg and J. S. deGrassie

1975-09-01T23:59:59.000Z

319

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

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

Adomeit, Stefanie

2014-01-01T23:59:59.000Z

320

The Onset of Quark-Hadron Duality in Pion Electroproduction

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

T. Navasardyan

2006-08-18T23:59:59.000Z

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321

The Onset of Quark-Hadron Duality in Pion Electroproduction

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

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

2006-08-29T23:59:59.000Z

322

Covariant nonlocal chiral quark models with separable interactions

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

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

2006-09-01T23:59:59.000Z

323

QCD Thermodynamics with an almost realistic quark mass spectrum

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

C. Schmidt

2006-01-25T23:59:59.000Z

324

Decuplet baryon magnetic moments in the chiral quark model

Science Journals Connector (OSTI)

We present calculations of the decuplet baryon magnetic moments in the chiral quark model. As input we use parameters obtained in qualitatively accurate fits to the octet baryon magnetic moments studied previously. The values found for the magnetic moments of ?++ and ?- are in good agreement with experiments. We finally calculate the total quark spin polarizations of the decuplet baryons and find that they are considerably smaller than what is expected from the non-relativistic quark model.

Johan Linde; Tommy Ohlsson; Håkan Snellman

1998-05-01T23:59:59.000Z

325

Report of the Quark Flavor Physics Working Group

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

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

2013-01-01T23:59:59.000Z

326

Dynamical electroweak symmetry breaking and the top quark

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

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

1997-01-01T23:59:59.000Z

327

Top quark charge asymmetry measurements with ATLAS detector

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

U. De Sanctis; for the ATLAS Collaboration

2014-11-13T23:59:59.000Z

328

Top quark charge asymmetry measurements with ATLAS detector

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

De Sanctis, Umberto; The ATLAS collaboration

2014-01-01T23:59:59.000Z

329

Search for Excited Quarks in ep Collisions at HERA

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

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

2009-01-01T23:59:59.000Z

330

Thermodynamics of two-flavor QCD at finite temperature and density is studied on a $16^3 \\times 4$ lattice, using a renormalization group improved gauge action and the clover improved Wilson quark action. In the simulations along lines of constant $m_{\\rm PS}/m_{\\rm V}$, we calculate the Taylor expansion coefficients of the heavy-quark free energy with respect to the quark chemical potential ($\\mu_q$) up to the second order. By comparing the expansion coefficients of the free energies between quark($Q$)and antiquark($\\bar{Q}$), and between $Q$ and $Q$, we find a characteristic difference at finite $\\mu_q$ due to the first order coefficient of the Taylor expansion. We also calculate the quark number and isospin susceptibilities, and find that the second order coefficient of the quark number susceptibility shows enhancement around the pseudo-critical temperature.

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

2007-10-04T23:59:59.000Z

331

Velocity Dependence of Baryon Screening in a Hot Strongly Coupled Plasma

The L-dependence of the static potential between Nc quarks arranged in a circle of radius L (a "baryon") immersed in the hot plasma of a gauge theory with Nc colors defines a screening length Ls. We use the AdS/CFT correspondence to compute this screening length for the case of heavy quarks in the plasma of strongly coupled N=4 super Yang-Mills theory moving with velocity v relative to the baryon. We find that in the v -> 1 limit, Ls \\propto (1-v^2)^{1/4}/T, and find that corrections to this velocity dependence are small at lower velocities. This result provides evidence for the robustness of the analogous behavior of the screening length defined by the static quark-antiquark pair, which has been computed previously and in QCD is relevant to quarkonium physics in heavy ion collisions. Our results also show that as long as the hot wind is not blowing precisely perpendicular to the plane of the baryon configuration that we analyze, the Nc different quarks are not all affected by the wind velocity to the same degree, with those quarks lying perpendicular to the wind direction screened most effectively.

Christiana Athanasiou; Hong Liu; Krishna Rajagopal

2008-01-07T23:59:59.000Z

332

Nathaniel J Fisch | Princeton Plasma Physics Lab

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

His professional interests include: plasma physics with applications to nuclear fusion, astrophysics, plasma-based pulse compression, plasma thrusters, plasma...

333

Higgs boson gluon-fusion production beyond threshold in N3LO QCD

In this article, we compute the gluon fusion Higgs boson cross-section at N3LO through the second term in the threshold expansion. This calculation constitutes a major milestone towards the full N3LO cross section. Our result has the best formal accuracy in the threshold expansion currently available, and includes contributions from collinear regions besides subleading corrections from soft and hard regions, as well as certain logarithmically enhanced contributions for general kinematics. We use our results to perform a critical appraisal of the validity of the threshold approximation at N3LO in perturbative QCD.

Anastasiou, Charalampos; Dulat, Falko; Furlan, Elisabetta; Gehrmann, Thomas; Herzog, Franz; Mistlberger, Bernhard

2014-01-01T23:59:59.000Z

334

Photon emission from bare quark stars

We investigate the photon emission from the electrosphere of a quark star. It is shown that at temperatures T\\sim 0.1-1 MeV the dominating mechanism is the bremsstrahlung due to bending of electron trajectories in the mean Coulomb field of the electrosphere. The radiated energy for this mechanism is much larger than that for the Bethe-Heitler bremsstrahlung. The energy flux from the mean field bremsstrahlung exceeds the one from the tunnel e^{+}e^{-} pair creation as well. We demonstrate that the LPM suppression of the photon emission is negligible.

B. G. Zakharov

2010-08-16T23:59:59.000Z

335

Seismic Search for Strange Quark Nuggets

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

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

2005-05-29T23:59:59.000Z

336

Communication through plasma sheaths

We wish to transmit messages to and from a hypersonic vehicle around which a plasma sheath has formed. For long distance transmission, the signal carrying these messages must be necessarily low frequency, typically 2 GHz, to which the plasma sheath is opaque. The idea is to use the plasma properties to make the plasma sheath appear transparent.

Korotkevich, A. O.; Newell, A. C.; Zakharov, V. E. [Landau Institute for Theoretical Physics RAS, 2, Kosygin Str., Moscow, 119334 (Russian Federation); Department of Mathematics, University of Arizona, 617 N. Santa Rita Ave., Tucson, Arizona 85721 (United States); Department of Mathematics, University of Arizona, 617 N. Santa Rita Ave., Tucson, Arizona 85721 (United States); Lebedev Physical Institute RAS, 53, Leninsky Prosp., GSP-1 Moscow, 119991 (Russian Federation); Landau Institute for Theoretical Physics RAS, 2, Kosygin Str., Moscow, 119334 (Russian Federation) and Waves and Solitons LLC, 918 W. Windsong Dr., Phoenix, Arizona 85045 (United States)

2007-10-15T23:59:59.000Z

337

Anomalous radial transport in tokamak edge plasma

Transport in tokamak plasma . . . . . . . . . . . . . . .Numerical simulations of tokamak plasma . . . . . . . . .of blobs in tokamak edge plasmas . . . . . . . . . . . . . .

Bodi, Vasudeva Raghavendra Kowsik

2010-01-01T23:59:59.000Z

338

Plasma Physics PART Al: INTRODUCTION TO PLASMA SCIENCE

Plasma Physics PART Al: INTRODUCTION TO PLASMA SCIENCE I. What is a plasma? 1 II. Plasma fundamentals 3 1. Quasineutrality and Debye length 2. Plasma frequency and acoustic velocity 3. Larmor radius; magnetic buckets Cross section data 21 PART A3: PLASMA SOURCES I IV. Introduction to plasma sources 25 1

Chen, Francis F.

339

Heavy quark impact factor for the LHC phenomenology

We comment on the calculation of the finite part of the heavy quark impact factor at next-to-leading logarithmic (NLx) accuracy. The result is presented in a form suitable for phenomenological studies such as the calculation of the cross-section for single heavy quark production at the LHC within the kT-factorization scheme.

Grigorios Chachamis; Michal Deak; German Rodrigo

2013-10-29T23:59:59.000Z

340

Search for baryon number violation in top-quark decays

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

CMS Collaboration

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

341

The Top Quark, Its Discovery, and Subsequent Research

Office of Scientific and Technical Information (OSTI)

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

342

Diquark condensation effects on hot quark star configurations

The equation of state for quark matter is derived for a nonlocal, chiral quark model within the mean field approximation. We investigate the effects of a variation of the form factors of the interaction on the phase diagram of quark matter under the condition of beta-equilibrium and charge neutrality. Special emphasis is on the occurrence of a diquark condensate which signals a phase transition to color superconductivity and its effects on the equation of state. We calculate the quark star configurations by solving the Tolman- Oppenheimer- Volkoff equations and obtain for the transition from a hot, normal quark matter core of a protoneutron star to a cool diquark condensed one a release of binding energy of the order of Delta M c^2 ~ 10^{53} erg. We discuss the claim that this energy could serve as an engine for explosive phenomena.

Blaschke, David B; Grigorian, H

2004-01-01T23:59:59.000Z

343

We study the evolution of a gluon system under conditions of density and temperature similar to those explored in the early stage of ultra-relativistic heavy-ion collisions. We first describe the implementation of Relativistic Boltzmann-Nordheim (RBN) transport approach that includes in the collision integral the quantum effects of Bose-Einstein Statistics. Then, we describe the evolution of a spatially uniform gluon system in a box under elastic collisions solving the RBN for various initial conditions. We discuss the critical phase-space density that leads to the onset of a Bose-Einstein condensate (BEC) and the time scale for this process to occur. In particular, thanks to the fact that RBN allows to relax the small angle approximation, we study the effect at both small and large screening mass $ m_{D} $. For small $ m_{D}\\ll T $ we see that our solution of RBN is in agreement with the recent extensive studies within a Fokker-Planck scheme in small angle approximation. For the same total cross section but with large $ m_{D}\\simeq 2\\, T $ (large angle scatterings), we see a significant time speed-up of the onset of BEC respect to small $m_{D}\\ll T$. This further strengthen the possibility that at least a transient BEC is formed in the early stage of ultra-relativistic heavy-ion collisions.

F. Scardina; D. Perricone; S. Plumari; M. Ruggieri; V. Greco

2014-08-06T23:59:59.000Z

344

By means of two typical kinds of quark energy loss parametrization and the nuclear parton distributions determined only with lepton-nuclear deep inelastic scattering experimental data, a leading order analysis are performed on the proton-induced Drell-Yan differential cross section ratios of tungsten versus deuterium as a function of the quark momentum fraction in the beam proton and target nuclei. It is found that the theoretical results with quark energy loss are in good agreement with the experimental data. The quark energy loss effect produce approximately 3% to 11% suppression on the Drell-Yan differential cross section ratios $R_{W/D}$ in the range $0.05\\leq x_2\\leq0.3$. The application of nuclear Drell-Yan data with heavy targets is remarkably subject to difficulty in the constraints of the nuclear sea-quark distribution.

Duan Chun-Gui; Liu Na

2008-09-28T23:59:59.000Z

345

Theoretical & Computational Plasma Physicist | Princeton Plasma...

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

Research Requisition Number: 1400777 PPPLTheory Department has an opening at the rank of Research Physicist in theoretical and computational plasma physics in the area of...

346

Plasma Astrophysics | Princeton Plasma Physics Lab

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

Plasma Astrophysics One of the most common but least understood phenomena in the universe is an explosive process called magnetic reconnection. PPPL's Magnetic Reconnection...

347

Interdisciplinary plasma theory workshop | Princeton Plasma Physics...

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

Science sponsored the week-long event with additional support from the Max Planck-Princeton Center for Plasma Physics, whose members include PPPL and the Princeton...

348

Nonlinear plasma wave in magnetized plasmas

Nonlinear axisymmetric cylindrical plasma oscillations in magnetized collisionless plasmas are a model for the electron fluid collapse on the axis behind an ultrashort relativisically intense laser pulse exciting a plasma wake wave. We present an analytical description of the strongly nonlinear oscillations showing that the magnetic field prevents closing of the cavity formed behind the laser pulse. This effect is demonstrated with 3D PIC simulations of the laser-plasma interaction. An analysis of the betatron oscillations of fast electrons in the presence of the magnetic field reveals a characteristic “Four-Ray Star” pattern.

Bulanov, Sergei V. [Kansai Photon Science Institute, JAEA, Kizugawa, Kyoto 619-0215 (Japan) [Kansai Photon Science Institute, JAEA, Kizugawa, Kyoto 619-0215 (Japan); Prokhorov Institute of General Physics, Russian Academy of Sciences, Moscow 119991 (Russian Federation); Moscow Institute of Physics and Technology, Dolgoprudny, Moscow region 141700 (Russian Federation); Esirkepov, Timur Zh.; Kando, Masaki; Koga, James K. [Kansai Photon Science Institute, JAEA, Kizugawa, Kyoto 619-0215 (Japan)] [Kansai Photon Science Institute, JAEA, Kizugawa, Kyoto 619-0215 (Japan); Hosokai, Tomonao; Zhidkov, Alexei G. [Photon Pioneers Center, Osaka University, 2-8 Yamadaoka, Suita, Osaka 565-0871 (Japan) [Photon Pioneers Center, Osaka University, 2-8 Yamadaoka, Suita, Osaka 565-0871 (Japan); Japan Science and Technology Agency, CREST, 2-1, Yamadaoka, Suita, Osaka 565-0871 (Japan); Kodama, Ryosuke [Photon Pioneers Center, Osaka University, 2-8 Yamadaoka, Suita, Osaka 565-0871 (Japan) [Photon Pioneers Center, Osaka University, 2-8 Yamadaoka, Suita, Osaka 565-0871 (Japan); Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

2013-08-15T23:59:59.000Z

349

Brane Viscous Cosmology in the Plasma Era

We consider how the five-dimensional Randall-Sundrum (one-brane) theory becomes modified when account is taken of the bulk viscosity of the cosmic fluid on the brane. We focus on the plasma era between $10^{12}$K (muon pair annihilation) to about $5\\times 10^9$K (electron-positron annihilation), which includes the first order quark-hadron transition beginning at an energy density of about $5\\times 10^9\\rm MeV^4$. Various possibilities are examined for modeling the bulk viscosity, preference being at the end given to the results calculated from relativistic kinetic theory. According to this, the viscosity is negligible at the highest temperatures, but may amount to a few per cent corrections in the later stages of the plasma era. We also briefly consider anisotropic universes where the shear viscosity comes into play, and show that in the case of the Kasner model the influences from bulk viscosity and shear viscosity become comparable when the anisotropy parameter of the universe is of order $A \\sim 10^{-11} $ in the beginning of the plasma era, and $A \\sim 10^{-2}$ in its later region.

Iver Brevik

2014-10-08T23:59:59.000Z

350

Toward parton equilibration with improved parton interaction matrix elements

The Quark-Gluon Plasma can be produced in high energy heavy ion collisions and how it equilibrates is important for the extraction of the properties of strongly interacting matter. A radiative transport model can be used to reveal interesting characteristics of Quark-Gluon Plasma thermalization. For example, screened parton interactions always lead to partial pressure isotropization. Systems with different initial pressure anisotropies evolve toward the same asymptotic evolution. In particular, radiative processes are crucial for the chemical equilibration of the system. Matrix elements under the soft and collinear approximation for these processes, as first derived by Gunion and Bertsch, are widely used. A different approach is to start with the exact matrix elements for the two to three and its inverse processes. General features of this approach will be reviewed and the results will be compared with the Gunion-Bertsch results. We will comment on the possible implications of the exact matrix element approach on Quark-Gluon Plasma thermalization.

Bin Zhang

2012-08-06T23:59:59.000Z

351

Science Journals Connector (OSTI)

This study deals with the boundary between a normal plasma of ions and electrons, and an adjacent complex plasma of ions, electrons, and microparticles, as found in innumerable examples in nature. Here we show that the matching between the two plasmas involve electrostatic double layers. These double layers explain the sharp boundaries observed in the laboratory and in astrophysics. A modified theory is derived for the double layers that form at the discontinuity between two different complex plasmas and at the point of contact of three complex plasmas. The theory is applied to the first measurements from the Plasma Kristall Experiment (PKE) Nefedov Laboratory in the International Space Station.

B. M. Annaratone; S. A. Khrapak; P. Bryant; G. E. Morfill; H. Rothermel; H. M. Thomas; M. Zuzic; V. E. Fortov; V. I. Molotkov; A. P. Nefedov; S. Krikalev; Yu. P. Semenov

2002-11-26T23:59:59.000Z

352

Combined search for the quarks of a sequential fourth generation

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

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

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

2012-12-01T23:59:59.000Z

353

Combined search for the quarks of a sequential fourth generation

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

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

2012-01-01T23:59:59.000Z

354

Four-Quark Hadrons: an Updated Review

The past decade witnessed a remarkable proliferation of exotic charmonium-like resonances discovered at accelerators. In particular, the recently observed charged states are clearly not interpretable as q-qbar mesons. Notwithstanding the considerable advances on the experimental side, conflicting theoretical descriptions do not seem to provide a definitive picture about the nature of the so-called XYZ particles. We present here a comprehensive review about this intriguing topic, discussing both those experimental and theoretical aspects which we consider relevant to make further progress in the field. At this state of progress, XYZ phenomenology speaks in favour of the existence of compact four-quark particles (tetraquarks) and we believe that realizing this instructs us in the quest for a firm theoretical framework.

Angelo Esposito; Andrea L. Guerrieri; Fulvio Piccinini; Alessandro Pilloni; Antonio D. Polosa

2014-12-29T23:59:59.000Z

355

Four-Quark Hadrons: an Updated Review

The past decade witnessed a remarkable proliferation of exotic charmonium-like resonances discovered at accelerators. In particular, the recently observed charged states are clearly not interpretable as q-qbar mesons. Notwithstanding the considerable advances on the experimental side, conflicting theoretical descriptions do not seem to provide a definitive picture about the nature of the so-called XYZ particles. We present here a comprehensive review about this intriguing topic, discussing both those experimental and theoretical aspects which we consider relevant to make further progress in the field. At this state of progress, XYZ phenomenology speaks in favour of the existence of compact four-quark particles (tetraquarks) and we believe that realizing this instructs us in the quest for a firm theoretical framework.

Esposito, Angelo; Piccinini, Fulvio; Pilloni, Alessandro; Polosa, Antonio D

2014-01-01T23:59:59.000Z

356

Congeniality bounds on quark masses from nucleosynthesis

Science Journals Connector (OSTI)

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

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

2013-08-02T23:59:59.000Z

357

Joint resummation for heavy quark production.

ar X iv :h ep -p h/ 05 10 14 9v 1 1 2 O ct 2 00 5 February 2, 2008 4:14 WSPC/INSTRUCTION FILE jr International Journal of Modern Physics A c© World Scientific Publishing Company JOINT RESUMMATION FOR HEAVY QUARK PRODUCTION ANDREA BANFI Cavendish... to corrections O(1/p2T ), the observable may at any order 12 be written in the following factorized form d?AB?Q+X dpT = ? a,b ? 1 0 d?ad?b ?a/A(?a, µ)?b/B(?b, µ) d?ˆab?Q+X dpT (?a, ?b, ?s(µ), pT ) , (1) with d?ˆab?Q+X/dpT the partonic differential cross...

Banfi, Andrea; Laenen, Eric

358

Quark contact interactions at the LHC

Science Journals Connector (OSTI)

Quark contact interactions are an important signal of new physics. We introduce a model in which the presence of a symmetry protects these new interactions from giving large corrections in flavor changing processes at low energies. This minimal model provides the basic set of operators which must be considered to contribute to the high-energy processes. To discuss their experimental signature in jet pairs produced in proton-proton collisions, we simplify the number of possible operators down to two. We show (for a representative integrated luminosity of 200??pb-1 at s=7??TeV) how the presence of two operators significantly modifies the bound on the characteristic energy scale of the contact interactions, which is obtained by keeping a single operator.

F. Bazzocchi; U. De Sanctis; M. Fabbrichesi; A. Tonero

2012-06-01T23:59:59.000Z

359

Science Journals Connector (OSTI)

If the quark-hadron transition is first order, hadron bubbles nucleate with a radius Rnuc and grow into the quark sea. Baryon number prefers to reside in the quark phase and must diffuse away from the interface in order for the phase transition to proceed. This slowly diffusing excess baryon number that forms on the surface of the bubble wall may drive a shape instability of the bubble wall. This instability to non-spherical structure occurs when the bubbles have grown to a critical size of (7-1000)Rnuc, a much shorter length scale than the instabilities studied previously; this effect can thus be important for heavy-ion collisions. The stability of the bubbles depends very sensitively on the ratio ?=nhnq of baryon number in the two phases (in local thermodynamic equilibrium). For the expected values of the parameters, bubbles of the hadronic phase are likely to be stable in the early Universe and unstable in heavy-ion collisions. The phenomenology of heavy-ion collisions could be altered by the instability of the hadron bubbles, although future work that takes into account mutual heating effects of the bubbles and the expansion of the hot underlying plasma will be required to confirm this.

Fred C. Adams; Katherine Freese; J. S. Langer

1993-05-15T23:59:59.000Z

360

Plasma window characterization

Parameters of an arc Ar plasma discharge used as a plasma window with a discharge current of {approx}50 A and a voltage of {approx}58 V are presented. It is shown that this arc discharge allows one to decrease the pressure at the low pressure end of the plasma window almost 380 times using relatively low pumping at the low pressure end of the plasma window. Calculations of the plasma parameters and their spatial distribution using a simple wall-stabilized arc model showed a satisfactory agreement with the experimentally obtained data. It is shown that a significant decrease in gas flow through the plasma window occurs due to the increase in plasma viscosity. An improvement of the plasma window ignition and some of its design aspects are described as well.

Krasik, Ya. E.; Gleizer, S.; Gurovich, V.; Kronhaus, I.; Hershcovitch, A.; Nozar, P.; Taliani, C. [Physics Department, Technion, 32000 Haifa (Israel); Brookhaven National Laboratory, New York 11973-5000 (United States); Istituto per lo Studio dei Materiali Nanostrutturati, 40 129 Bologna (Italy)

2007-03-01T23:59:59.000Z

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they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

361

What's up with IR gluon and ghost propagators in Landau gauge? A puzzling answer from huge lattices

Several analytic approaches predict for SU(N_c) Yang-Mills theories in Landau gauge an enhanced ghost propagator G(p^2) and a suppressed gluon propagator D(p^2) at small momenta. This prediction applies to two, three and four space-time dimensions. Moreover, the gluon propagator is predicted to be null at p = 0. Numerical studies by several groups indeed support an enhanced ghost propagator when compared to the tree-level behavior $1/p^2$ and a finite infrared gluon propagator. However, the agreement between analytic and numerical studies is only at the qualitative level in three and in four dimensions. In particular, the infrared exponent of the ghost propagator seems to be smaller than the one predicted analytically and the gluon propagator seems to display a (finite) nonzero value at zero momentum. It has been argued that this discrepancy might go away once simulations are done on much larger lattice sizes than the ones used up to now. Here we present data in three and four space-time dimensions using huge lattices in the scaling region, i.e. up to 320^3 at beta = 3.0 and up to 128^4 at beta = 2.2, corresponding to V \\approx (85 fm)^3 and V \\approx (27 fm)^4. Simulations have been done on the IBM supercomputer at the University of Sao Paulo

Attilio Cucchieri; Tereza Mendes

2007-10-02T23:59:59.000Z

362

The sigma term and the quark number operator in QCD

We discuss the relationship of the forward matrix element of the operator $\\bar\\psi\\psi$, related to the so-called sigma term, to the quark number. We show that in the naive quark model in the canonical formalism these quantities coincide in the limit of small average quark momenta. In the QCD parton model defined through light-front quantization this result is preserved at leading perturbative order but it receives radiative corrections. We analyze the theoretical and phenomenological consequences of this result, which provides a bridge between a current algebra quantity, the sigma term, and a deep-inelastic quantity, the parton number.

Mauro Anselmino; Stefano Forte

1993-05-03T23:59:59.000Z

363

Heavy-quark correlations in deep-inelastic electroproduction

We have completed the next-to-leading order perturbative QCD corrections to the virtual-photon exclusive differential cross sections for heavy quark production in deep-inelastic electron-proton scattering, i.e. $e + P \\rightarrow Q + \\overline{Q} + X$. Using these results, we have computed distributions which are sensitive to correlations among the heavy quark, the heavy antiquark, and the associated jet. Some predictions for charm and bottom heavy quark production at the electron-proton collider HERA are presented.

B. W. Harris; J. Smith

1995-03-31T23:59:59.000Z

364

Nucleosynthesis in neutron-rich ejecta from quark-novae

We explore heavy-element nucleosynthesis by rapid neutron capture (r-process) in the decompressing ejecta from the surface of a neutron star. The decompression is triggered by a violent phase transition to strange quark matter (quark-nova scenario). The presence of neutron-rich large Z nuclei (40,95) solar abundance pattern of r-process elements. We highlight the distinguishing features of quark-novae by contrasting it with conventional nucleosynthetic sites such as type II supernovae and neutron star mergers, especially in the context of heavy-element compositions of extremely metal-deficient stars.

Prashanth Jaikumar; Bradley S. Meyer; Kaori Otsuki; Rachid Ouyed

2006-10-04T23:59:59.000Z

365

Science Journals Connector (OSTI)

...W.D., BEAM-PLASMA DISCHARGE - BUILDUP...DURING ELECTRON BEAM-PLASMA INTERACTIONS, GEOPHYSICAL...ELECTRON-BEAM IN THE ATMOSPHERE, PLANETARY AND SPACE...1980 ). Space plasma physics: electron...regula' occurred at large pitch angles. Note...in quite different areas. (i) There is...

KLAUS WILHELM; WOLFGANG STÜDEMANN; WILLIBALD RIEDLER

1984-07-13T23:59:59.000Z

366

Science Journals Connector (OSTI)

...po-tential, the local plasma potential mea-sured...Wave instabilities. The plasma wave activity is measured...analyzer (0.1 to 11.4 MHz) in a time-sharing...direct measure of the plasma frequencyfp (Eq. 1...cm3) = 0.0121fp2 (kHz) (2) Here fc is the...

C. BEGHIN; J. P. LEBRETON; B. N. MAEHLUM; J. TROIM; P. INGSOY; J. L. M?CHAU

1984-07-13T23:59:59.000Z

367

Thermionic energy conversion plasmas

In this paper the history, application options, and ideal basic performance of the thermionic energy converter are outlined. The basic plasma types associated with various modes of converter operation are described, with emphasis on identification and semi-quantitative characterization of the dominant physical processes and utility of each plasma type. The frontier plasma science issues in thermionic converter applications are briefly summarized.

Rasor, N.S. (Rasor Associates, Inc., Sunnyvale, CA (United States))

1991-12-01T23:59:59.000Z

368

The Particle Adventure | What is the world made of? | The naming of quarks

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

The naming of quarks The naming of quarks The naming of quarks The naming of quarks... ...began when, in 1964, Murray Gell-Mann and George Zweig suggested that hundreds of the particles known at the time could be explained as combinations of just three fundamental particles. Gell-Mann chose the name "quarks," pronounced "kworks," for these three particles, a nonsense word used by James Joyce in the novel Finnegan's Wake: "Three quarks for Muster Mark!" In order to make their calculations work, the quarks had to be assigned fractional electrical charges of 2/3 and -1/3. Such charges had never been observed before. Quarks are never observed by themselves, and so initially these quarks were regarded as mathematical fiction. Experiments have since convinced physicists that not only do quarks exist, but there are six of them, not three.

369

Constraining CP-violating Higgs Sectors at the LHC using gluon fusion

We investigate the constraints that the LHC can set on a 126 GeV Higgs boson that is an admixture of CP eigenstates. Traditional analyses rely on Higgs couplings to massive vector bosons, which are suppressed for CP-odd couplings, so that these analyses have limited sensitivity. Instead we focus on Higgs production in gluon fusion, which occurs at the same order in the strong coupling for both CP-even and -odd couplings. We study the Higgs plus two jet final state followed by Higgs decay into a pair of tau leptons. We show that using the 8 TeV dataset it is possible to rule out the pure CP-odd hypothesis in this channel alone at nearly 95\\% C.L, assuming that the Higgs is CP-even. We also provide projected limits for the 14 TeV LHC run.

Matthew J. Dolan; Philip Harris; Martin Jankowiak; Michael Spannowsky

2014-06-12T23:59:59.000Z

370

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

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

2009-11-02T23:59:59.000Z

371

Science Journals Connector (OSTI)

In a previous paper, we have shown that a double phi peak structure appears in the dilepton invariant mass spectrum if a first order QCD phase transition occurs in ultrarelativistic heavy-ion collisions. Furthermore, the transition temperature can be determined from the transverse momentum distribution of the low mass phi peak. In this work, we extend the study to the case that a smooth crossover occurs in the quark-gluon plasma to the hadronic matter transition. We find that the double phi peak structure still exists in the dilepton spectrum and thus remains a viable signal for the formation of the quark-gluon plasma in ultrarelativistic heavy-ion collisions.

M. Asakawa and C. M. Ko

1994-12-01T23:59:59.000Z

372

Reading Comprehension - Looking for Quarks Inside the Atom

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

Looking for Quarks Inside the Atom Looking for Quarks Inside the Atom In the late 1960's, three scientists ran some accelerator experiments to study the nucleus at the _________ outside edge center perimeter of the atom. They ran the experiments because they wanted to know more about the structure of the _________ nucleus accelerator electromagnet spectrometer . They found that the protons and neutrons in the nucleus are made of quarks. The discovery of _________ alpha quarks nuclei electron raised new questions about the nucleus. The three scientists are Richard Taylor, Henry Kendall and Jerome Friedman. They did their experiments from 1967 to 1973 in California at the Stanford Linear Accelerator Center, called SLAC for short. These scientists won the 1990 Nobel Prize in Physics, one of the world's greatest honors for

373

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

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

Notre Dame were two of the initial QuarkNet centers. Marge Bardeen, head of the Fermilab Education Office, started the Fermilab center 15 years ago. Her vision was to inspire and...

374

Phase Transition from QMC Hyperonic Matter to Deconfined Quark Matter

We investigate the possibility and consequences of phase transitions from an equation of state (EoS) describing nucleons and hyperons interacting via mean-fields of sigma, omega, and rho mesons in the recently improved Quark-Meson Coupling (QMC) model to an EoS describing a Fermi gas of quarks in an MIT bag. The transition to a mixed phase of baryons and deconfined quarks, and subsequently to a pure deconfined quark phase is described using the method of Glendenning. The overall EoS for the three phases is calculated for various scenarios and these are used to calculate stellar solutions using the Tolman-Oppenheimer-Volkoff equations. The results are compared to recent experimental data and the validity of each case is discussed with consequences for determining the species content of the interior of neutron stars.

Carroll, Jonathan; Leinweber, Derek; Thomas, Anthony; Williams, Anthony

2008-01-01T23:59:59.000Z

375

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 NEWPORT NEWS, VA., Sept. 11, 2008 - New theory work at the U.S. Department of Energy's Thomas Jefferson National Accelerator Facility...

376

Measurement of Heavy Quark cross-sections at CDF

The measurement of heavy quark cross-sections provides important tests of the QCD theory. This paper reviews recent measurements of single b-quark and correlated b-quark cross-sections at CDF. Two new measurements of the single b-quark production at CDF agree with the first result from CDF Run II. This clarifies the experimental situation and confirms the recent agreement of theoretical prediction with data. A new measurement of the correlated $b\\bar{b}$ cross-section with dimuon events at CDF is presented. It agrees with theory and it does not confirm the anomalously large $b\\bar{b}$ cross-section seen in Run I by CDF and D${\

A. Annovi

2007-09-28T23:59:59.000Z

377

Statistical quark models for the nucleon structure functions

We consider some existing relativistic models for the nucleon structure functions, relying on statistical approaches instead of perturbative ones. These models are based on the Fermi-Dirac distribution for the confined quarks, where a density of energy levels is obtained from an effective confining potential. In this context, it is presented some results obtained with a recent statistical quark model for the sea-quark asymmetry in the nucleon. It is shown, within this model, that experimental available observables, such as the ratio and difference between proton and neutron structure functions, are quite well reproduced with just three parameters: two chemical potentials used to reproduce the valence up and down quark numbers in the nucleon, and a temperature that is being used to reproduce the Gottfried sum rule violation.

Mirez, Carlos [Instituto de Fisica Teorica, Universidade Estadual Paulista, Rua Dr. Bento Teobaldo Ferraz, 271, Barra-Funda, 01140-070, Sao Paulo, SP (Brazil); Tomio, Lauro [Instituto de Fisica Teorica, Universidade Estadual Paulista, Rua Dr. Bento Teobaldo Ferraz, 271, Barra-Funda, 01140-070, Sao Paulo, SP (Brazil); Instituto de Fisica, Universidade Federal Fluminense, 24210-346, Niteroi, RJ (Brazil)

2010-11-12T23:59:59.000Z

378

Eight-quark interactions as a chiral thermometer

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

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

2008-06-02T23:59:59.000Z

379

Plasma Diagnostics and Plasma-Surface Interactions in Inductively Coupled Plasmas

discharge. The atmospheric plasma is generated between theatmospheric dielectric barrier discharge. 6.2 Introduction Low temperature plasmas

Titus, Monica Joy

2010-01-01T23:59:59.000Z

380

Observation of $t$-channel electroweak top quark production

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

Triplett, Nathan; /Iowa State U.

2011-04-01T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

381

Quark Phase Transition Parameters and $?$-Meson Field in RMF Theory

The deconfinement phase transition from hadronic matter to quark matter in the interior of compact stars is investigated. The hadronic phase is described in the framework of relativistic mean-field (RMF) theory, when also the scalar- isovector $\\delta$-meson effective field is taken into account. To describe a quark phase the MIT bag model is used. The changes of the mixed phase threshold parameters caused by the presence of $\\delta$-meson field are investigated.

G. B. Alaverdyan

2009-07-23T23:59:59.000Z

382

Shear viscosity and spectral function of the quark matter

We discuss the shear viscosity of the quark matter by using the Kubo-Mori formula. It is found that the shear viscosity is expressed in terms of the quark spectral function. If the spectral function is approximated by a modified Bright-Wigner type, the viscosity decreases as the width of the spectral function increases. We also discuss dependence of the shear viscosity on the temperature and the density.

Masaharu Iwasaki; Hiromasa Ohnishi; Takahiko Fukutome

2006-06-19T23:59:59.000Z

383

Testing ETC Generation of the Top Quark Mass

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

L. Randall

1992-10-13T23:59:59.000Z

384

Velocity Dependence of Baryon Screening in a Hot Strongly Coupled Plasma

The L-dependence of the static potential between Nc quarks arranged in a circle of radius L (a "baryon") immersed in the hot plasma of a gauge theory with Nc colors defines a screening length Ls. We use the AdS/CFT correspondence to compute this screening length for the case of heavy quarks in the plasma of strongly coupled N=4 super Yang-Mills theory moving with velocity v relative to the baryon. We find that in the v -> 1 limit, Ls \\propto (1-v^2)^{1/4}/T, and find that corrections to this velocity dependence are small at lower velocities. This result provides evidence for the robustness of the analogous behavior of the screening length defined by the static quark-antiquark pair, which has been computed previously and in QCD is relevant to quarkonium physics in heavy ion collisions. Our results also show that as long as the hot wind is not blowing precisely perpendicular to the plane of the baryon configuration that we analyze, the Nc different quarks are not all affected by the wind velocity to the same de...

Athanasiou, Christiana; Rajagopal, Krishna

2008-01-01T23:59:59.000Z

385

Revisting the boiling of quark nuggets at nonzero chemical potential

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

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

2013-12-13T23:59:59.000Z

386

Observation of the top quark with the DO detector

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

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

1997-01-01T23:59:59.000Z

387

Plasma Camp | Princeton Plasma Physics Lab

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

Plasma Camp December 12, 2013 Due to unforeseen budget cuts, this program has been cancelled for 2014. We are very sorry we cannot offer the program and apologize for the late...

388

QuarkNet Workshop: Beyond Human Error

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

Human Error Human Error QuarkNet Workshop for High School Science Teachers 8:30 am to 4:00 pm, August 1 -3, 2012 at Fermi National Accelerator Laboratory This was a three-day workshop for high school science teachers. Measurement and error are key ingredients for all science applications. Both align with the Next Generation Science Standards, but many high school students struggle to understand the importance of error analysis and prevention. Over the three days we examined multiple experiments going on at Fermilab and discussed the ways that scientists take measurements and reduce error on these projects. Participants met and worked with scientists from Fermilab and University of Chicago to look at how error analysis takes place at Fermilab and bridged those ideas into high school classes. Teachers discussed lesson plans available at Fermilab and their own methods of teaching error analysis. Additionally, participants heard from high school students who participated in summer research as they presented their findings and linked students' learning back to the teachers' understanding of error recognition and analysis.

389

Triton burnup in plasma focus plasmas

Science Journals Connector (OSTI)

Pure deuterium plasma discharge from plasma focus breeds 1.01 MeV tritons via the D(d p)T fusion branch which has the same cross section as the D(d n)3He (E n =2.45 MeV) fusion branch. Tritons are trapped in and collide with the background deuterium plasma producing 14.1 MeV neutrons via the D(t n)4He reaction. The paper presents published in preliminary form as well as unpublished experimental data and theoretical studies of the neutron yield ratio R=Y n (14.1 MeV)/Y n (2.45 MeV). The experimental data were obtained from 1 MJ Frascati plasma focus operated at W=490 kJ with pure deuterium plasma (in the early 1980s). Neutrons were monitored using the nuclear activation method and nuclear emulsions. The present theoretical analysis of the experimental data is based on an exact adaptation of the binary encounter theory developed by Gryzinski. It is found that the experimentally defined value 1?10?3plasma domains of very high density (n?1021 cm?3) high temperature (kT?1 keV) and short trapping time (t 0?20 ns). These domains are known as efficient traps of MeV ions but are not the main source of D(d n)3He fusion.

Jan S. Brzosko; Jan R. Brzosko Jr.; Benjamin V. Robouch; Luigi Ingrosso

1995-01-01T23:59:59.000Z

390

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

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

Robert M. Harris

1995-06-15T23:59:59.000Z

391

Plasma atomic layer etching using conventional plasma equipment Ankur Agarwala

Plasma atomic layer etching using conventional plasma equipment Ankur Agarwala Department plasma etching processes having atomic layer resolution. The basis of plasma atomic layer etching PALE will be discussed with the goal of demonstrating the potential of using conventional plasma etching equipment having

Kushner, Mark

392

Plasma abatement of perfluorocompounds in inductively coupled plasma reactors

Plasma abatement of perfluorocompounds in inductively coupled plasma reactors Xudong ``Peter'' Xu PFCs , gases which have large global warming potentials, are widely used in plasma processing, the effluents from plasma tools using these gases typically have large mole fractions of PFCs. The use of plasma

Kushner, Mark

393

Plasma Materials Interaction Issues For Burning Plasma Experiments

Plasma Materials Interaction Issues For Burning Plasma Experiments M. Ulrickson Presented Â· Introduction to Burning Plasmas Â· Plasma Materials Interaction Phenomena Â· Materials Issues Â· Summary #12;MAU 4 Â Resistance to neutron damage #12;MAU 5 11/15/2001 The FIRE Burning Plasma Device Â· A compact high field

394

Plasma-Therm Workshop: Fundamentals of Plasma Processing (Etching & Deposition)

Plasma-Therm Workshop: Fundamentals of Plasma Processing (Etching & Deposition) Nanofabrication The workshop will focus on the fundamentals of plasma etching and deposition. Lectures will include an introduction to vacuum technology, the basics of plasma and plasma reactors and an overview of mechanisms

Martin, Jan M.L.

395

Brane Viscous Cosmology in the Plasma Era

We consider how the five-dimensional Randall-Sundrum (one-brane) theory becomes modified when account is taken of the bulk viscosity of the cosmic fluid on the brane. We focus on the plasma era between $10^{12}$K (muon pair annihilation) to about $5\\times 10^9$K (electron-positron annihilation), which includes the first order quark-hadron transition beginning at an energy density of about $5\\times 10^9\\rm MeV^4$. Various possibilities are examined for modeling the bulk viscosity, preference being at the end given to the results calculated from relativistic kinetic theory. According to this, the viscosity is negligible at the highest temperatures, but may amount to a few per cent corrections in the later stages of the plasma era. We also briefly consider anisotropic universes where the shear viscosity comes into play, and show that in the case of the Kasner model the influences from bulk viscosity and shear viscosity become comparable when the anisotropy parameter of the universe is of order $A \\sim 10^{-11} $...

Brevik, Iver

2014-01-01T23:59:59.000Z

396

Science Journals Connector (OSTI)

The plasma analog of an adiabatic lapse rate (or temperature variation with height) in atmospheric physics is obtained. A new source of plasma temperature gradient in a binary ion species mixture is found that is proportional to the concentration gradient ??? and difference in average ionization states Z2-Z1. Application to inertial-confinement-fusion implosions indicates a potentially strong effect in plastic (CH) ablators that is not modeled with mainline (single-fluid) simulations. An associated plasma thermodiffusion coefficient is derived, and charge-state diffusion in a single-species plasma is also predicted.

Peter Amendt; Claudio Bellei; Scott Wilks

2012-08-16T23:59:59.000Z

397

Michigan Institute Plasma Science

Michigan Institute Plasma Science and Engineering Seminar Neutral Atom Imaging of the Terrestrial re- search includes ion heating in the solar corona, electric double layers, magne- tosphere neutral

Shyy, Wei

398

Applications of Atmospheric Plasmas.

??Surface modification techniques using plasmas have generally been completed in a low pressure environment due to Pd (pressure x gap distance) considerations influencing the behavior… (more)

Oldham, Christopher John

2009-01-01T23:59:59.000Z

399

Plasma Processing Of Hydrocarbon

The Idaho National Laboratory (INL) developed several patented plasma technologies for hydrocarbon processing. The INL patents include nonthermal and thermal plasma technologies for direct natural gas to liquid conversion, upgrading low value heavy oil to synthetic light crude, and to convert refinery bottom heavy streams directly to transportation fuel products. Proof of concepts has been demonstrated with bench scale plasma processes and systems to convert heavy and light hydrocarbons to higher market value products. This paper provides an overview of three selected INL patented plasma technologies for hydrocarbon conversion or upgrade.

Grandy, Jon D; Peter C. Kong; Brent A. Detering; Larry D. Zuck

2007-05-01T23:59:59.000Z

400

Michigan Institute for Plasma Sci-

This talk will focus on the achievements of the Drexel Plasma Institute in direct application of plasmasMichigan Institute for Plasma Sci- ence and Engi- neering Seminar Plasma Medicine: Mechanisms of Direct Non-Thermal Plasma Interaction with Living Tissue Prof. Alexander Fridman Drexel University

Shyy, Wei

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

401

Plasma Synthesis of Hydrogen Peroxide | Princeton Plasma Physics...

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

Plasma Synthesis of Hydrogen Peroxide In the past, there has been interest in synthesis of certain chemicals in plasma. One chemical that has been synthesized in a plasma on an...

402

Investigation of Plasma Facing Components in Plasma Focus Operation

Science Journals Connector (OSTI)

Both aspects of the plasma–wall interactions, counter effect of plasma and materials, have been considered in our experiments. The AEOI plasma focus, Dena, has Filippov-type electrodes. The...

M. V. Roshan; A. R. Babazadeh; S. M. Sadat Kiai; H. Habibi…

2007-09-01T23:59:59.000Z

403

Diquark condensation effects on hot quark star configurations

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

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

2004-02-07T23:59:59.000Z

404

Top quark mass measurement using the template method at CDF

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

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

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

2011-06-03T23:59:59.000Z

405

Top Quark Properties from Top Pair Events and Decays

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

Ivanov, A.; /UC, Davis

2008-11-01T23:59:59.000Z

406

Fundamentals of Plasma Physics

Fundamentals of Plasma Physics James D. Callen University of Wisconsin, Madison June 28, 2006 #12;PREFACE Plasma physics is a relatively new branch of physics that became a mature science over the last half of the 20th century. It builds on the fundamental areas of classical physics: mechanics

Callen, James D.

407

Diamagnetism of rotating plasma

Diamagnetism and magnetic measurements of a supersonically rotating plasma in a shaped magnetic field demonstrate confinement of plasma pressure along the magnetic field resulting from centrifugal force. The Grad-Shafranov equation of ideal magnetohydrodynamic force balance, including supersonic rotation, is solved to confirm that the predicted angular velocity is in agreement with spectroscopic measurements of the Doppler shifts.

Young, W. C.; Hassam, A. B.; Romero-Talamas, C. A.; Ellis, R. F.; Teodorescu, C. [IREAP, University of Maryland, College Park, Maryland 20742 (United States)

2011-11-15T23:59:59.000Z

408

Triggered plasma opening switch

A triggerable opening switch for a very high voltage and current pulse includes a transmission line extending from a source to a load and having an intermediate switch section including a plasma for conducting electrons between transmission line conductors and a magnetic field for breaking the plasma conduction path and magnetically insulating the electrons when it is desired to open the switch.

Mendel, Clifford W. (Albuquerque, NM)

1988-01-01T23:59:59.000Z

409

Octet Baryon Electromagnetic Form Factors in a Relativistic Quark Model

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

Gilberto Ramalho, Kazuo Tsushima

2011-09-01T23:59:59.000Z

410

NJL-jet model for quark fragmentation functions

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

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

2009-10-01T23:59:59.000Z

411

Hybrid stars within a covariant, nonlocal chiral quark model

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

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

2007-06-15T23:59:59.000Z

412

Quark Stars as inner engines for Gamma Ray Bursts?

A model for Gamma ray bursts inner engine based on quark stars (speculated to exist in nature) is presented. We describe how and why these objects might constitute new candidates for GRB inner engines. At the heart of the model is the onset of exotic phases of quark matter at the surface of such stars, in particular the 2-flavor color superconductivity. A novel feature of such a phase is the generation of particles which are unstable to photon decay providing a natural mechanism for a fireball generation; an approach which is fundamentally different from models where the fireball is generated during collapse or conversion of neutron star to quark star processes. The model is capable of reproducing crucial features of Gamma ray bursts, such as the episodic activity of the engine (multiple and random shell emission) and the two distinct categories of the bursts (two regimes are isolated in the model with \\sim 2 s and \\sim 81 s burst total duration).

R. Ouyed; F. Sannino

2001-03-01T23:59:59.000Z

413

Reconstruction of stop quark mass at the LHC

Science Journals Connector (OSTI)

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

Diego Casadei; Rostislav Konoplich; Rashid Djilkibaev

2010-10-15T23:59:59.000Z

414

Relating quarks and leptons with the T7 flavour group

In this letter we present a model for quarks and leptons based on T7 as flavour symmetry, predicting a canonical mass relation between charged leptons and down-type quarks proposed earlier. Neutrino masses are generated through a Type-I seesaw mechanism, with predicted correlations between the atmospheric mixing angle and neutrino masses. Compatibility with oscillation results lead to lower bounds for the lightest neutrino mass as well as for the neutrinoless double beta decay rates, even for normal neutrino mass hierarchy.

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

2014-11-18T23:59:59.000Z

415

CP violation in the six-quark model

Science Journals Connector (OSTI)

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

Sandip Pakvasa and Hirotaka Sugawara

1976-07-01T23:59:59.000Z

416

Compatibility of various approaches to heavy-quark fragmentation

We find that the definition of the heavy-quark fragmentation function given by Jaffe and Randall differs by a factor of the longitudinal-momentum fraction z from the standard Collins-Soper definition. Once this factor is taken into account, the explicit calculation of Braaten et al. is found to be in agreement with the general analysis of Jaffe and Randall. We also examine the model of Peterson et al. for heavy-quark fragmentation and find that the quoted values of the width and of the value of $z$ at the maximum are in error. The corrected values are in agreement with the analysis of Jaffe and Randall.

G. T. Bodwin; B. W. Harris

2000-12-05T23:59:59.000Z

417

Chiral and Heavy Quark Symmetry Violation in B Decays

The most general Lagrangian consistent with chiral, heavy quark, and strong interaction symmetries to order $1/M$ and to linear order in the SU(3) vector and axial currents is presented. Two new dimensionful and five dimensionless couplings arise at this order. The heavy to light flavor changing current is derived to the same order, giving rise to two additional dimensionful constants and six dimensionless ones. The dimensionless parameters are shown to be irrelevant at \\ord. The leading nonanalytic heavy quark and chiral symmetry violating corrections to heavy meson decay constants are computed, and implications to B decays are discussed; measurements of the experimentally accessible form factors for $D \\to \\pi l \

C. G. Boyd; B. Grinstein

1994-02-22T23:59:59.000Z

418

Relating quarks and leptons with the T7 flavour group

In this letter we present a model for quarks and leptons based on T7 as flavour symmetry, predicting a canonical mass relation between charged leptons and down-type quarks proposed earlier. Neutrino masses are generated through a Type-I seesaw mechanism, with predicted correlations between the atmospheric mixing angle and neutrino masses. Compatibility with oscillation results lead to lower bounds for the lightest neutrino mass as well as for the neutrinoless double beta decay rates, even for normal neutrino mass hierarchy.

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

2014-01-01T23:59:59.000Z

419

ITER | Princeton Plasma Physics Lab

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

pioneering plasma physicist whose contributions to the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) ranged from seminal advances in fusion energy...

420

Stellarators | Princeton Plasma Physics Lab

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

in stellarators By John Greenwald Researchers at the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) and the Max Planck Institute of Plasma Physics...

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

421

Plasma Diagnostics and Plasma-Surface Interactions in Inductively Coupled Plasmas

intensities for pure Ar plasmas focus on the dominant 104.8emitted from pure A r plasmas focus on the intensities ofdissertation work focuses on plasma and wafer diagnostics as

Titus, Monica Joy

2010-01-01T23:59:59.000Z

422

Quarks and the Strong Force Summary/Review Spring 2009 Compton Lecture Series

groups: one with non-zero quark number and the other with zero quark number Â The non-zero quark number particles are all either spin 1/2 or spin 3/2. The zero quark number particles are all either spin 0 or spin exchange is a residual effect from the color structure of baryons which have no net color Â Protons

423

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

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

B. W. Harris; J. Smith

1997-06-11T23:59:59.000Z

424

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

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

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

2010-11-12T23:59:59.000Z

425

Science Journals Connector (OSTI)

The air plasma spraying is characterized by using of a compressed air as a plasma forming gas. Here is shown the application of benefits of the present technology compared with other spraying process. The creation of the present process was possible due to a reliable plasma torch and certain condition of heating and deposition of powder materials on a work. Plasma torch develops a power up to 50 kW and can work during 14 hours without replacement of a cathode and during 25 hours as for an anode what is acceptable for industrial application. When spraying of coatings a minimum waste of alloying elements is attained with slight increase of oxygen in coating which is comparable with argon plasma spraying in the open. In certain cases the air plasma spraying allows to obtain more perfect coatings and at high performance. The present method finds large application at restoration and strengthening of machine parts, at forming of components etc. The air plasma spraying provides high quality coatings at low cost of components.

Valery S. Klubnikin

1993-01-01T23:59:59.000Z

426

Science Journals Connector (OSTI)

A new concept for spinning unmagnetized plasma is demonstrated experimentally. Plasma is confined by an axisymmetric multicusp magnetic field and biased cathodes are used to drive currents and impart a torque in the magnetized edge. Measurements show that flow viscously couples momentum from the magnetized edge (where the plasma viscosity is small) into the unmagnetized core (where the viscosity is large) and that the core rotates as a solid body. To be effective, collisional viscosity must overcome the ion-neutral drag due to charge-exchange collisions.

C. Collins; N. Katz; J. Wallace; J. Jara-Almonte; I. Reese; E. Zweibel; C. B. Forest

2012-03-12T23:59:59.000Z

427

Influence of pions on the hadron-quark phase transition

In this work we present the features of the hadron-quark phase transition diagrams in which the pions are included in the system. To construct such diagrams we use two different models in the description of the hadronic and quark sectors. At the quark level, we consider two distinct parametrizations of the Polyakov-Nambu-Jona-Lasinio (PNJL) models. In the hadronic side, we use a well known relativistic mean-field (RMF) nonlinear Walecka model. We show that the effect of the pions on the hadron-quark phase diagrams is to move the critical end point (CEP) of the transitions lines. Such an effect also depends on the value of the critical temperature (T{sub 0}) in the pure gauge sector used to parametrize the PNJL models. Here we treat the phase transitions using two values for T{sub 0}, namely, T{sub 0}= 270 MeV and T{sub 0}= 190 MeV. The last value is used to reproduce lattice QCD data for the transition temperature at zero chemical potential.

Lourenco, O.; Dutra, M.; Frederico, T.; Malheiro, M. [Departamento de Fisica, Instituto Tecnologico de Aeronautica-CTA, 12228-900, Sao Jose dos Campos (Brazil); Delfino, A. [Instituto de Fisica, Universidade Federal Fluminense, Av. Litoranea s/n, 24210-150, Boa Viagem, Niteroi RJ (Brazil)

2013-05-06T23:59:59.000Z

428

Solar Energy without Neutrinos: Fusion Catalysis by Quarks

Science Journals Connector (OSTI)

... some features of fusion catalysis by quarks and the consequences relating to release of stellar energy. In particular, the recent non-observation8 of ... . In particular, the recent non-observation8 of solar neutrinos which rules out9-12 the carbon cycle as the main mechanism for ...

L. MARSHALL LIBBY; F. J. THOMAS

1969-06-28T23:59:59.000Z

429

Precision Top-Quark Mass Measurements at CDF

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

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

2012-07-01T23:59:59.000Z

430

Proton Sea Quark Flavour Asymmetry and Roper Resonance

We study the proton and the Roper resonance together with the meson cloud model, by constructing a Hamiltonian matrix and solving the eigenvalue equation. The proton sea quark flavour asymmetry and some properties of the Roper resonance are thus reproduced in one scheme.

Yong-Jun Zhang; Bin Zhang

2010-05-25T23:59:59.000Z

431

Baryon production and the charmed-quark fragmentation function

Science Journals Connector (OSTI)

The fragmentation function for a charmed quark into a charmed baryon should peak at large x like its fragmentation function for charmed mesons. With model assumptions the decay of these fast baryons can account for as much as 20 to 40% of the ?'s observed at large x in e+e- annihilation at Ec.m.=30 GeV.

Thomas A. DeGrand

1982-12-01T23:59:59.000Z

432

Nucleosynthesis in neutron-rich ejecta from Quark-Novae.

We explore heavy-element nucleosynthesis by rapid neutron capture (r-process) in the decompressing ejecta from the surface of a neutron star. The decompression is triggered by a violent phase transition to strange quark matter (quark-nova scenario). The presence of neutron-rich large Z nuclei (40,95) < (Z,A) < (70,177), the large neutron-to-seed ratio, and the low electron fraction Y{sub e} {approx} 0.03 in the decompressing ejecta present favorable conditions for the r-process. We perform network calculations that are adapted to the quark-nova conditions, and which mimic usual (n-{gamma}) equilibrium r-process calculations during the initially cold decompression phase. They match to dynamical r-process calculations at densities below neutron drip (4 x 10{sup 11} g cm{sup -3}). We present results for the final element abundance distribution with and without heating from nuclear reactions, and compare to the solar abundance pattern of r-process elements. We highlight the distinguishing features of quark-novae by contrasting it with conventional nucleosynthetic sites such as type II supernovae and neutron star mergers, especially in the context of heavy-element compositions of extremely metal-deficient stars.

Jaikumar, P.; Ouyed, R.; Otsuki, K.; Meyer, B. S.; Physics; Univ. of Calgary; Univ. of Chicago; Clemson Univ.

2007-01-01T23:59:59.000Z

433

Phase transitions in quark matter under strong magnetic fields

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

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

2013-03-25T23:59:59.000Z

434

Hypercentral Constituent Quark Model with a Meson Cloud

The results for the elastic nucleon form factors and the electromagnetic transition amplitudes to the Delta(1232) resonance, obtained with the Hypercentral Constituent Quark Model with the inclusion of a meson cloud correction are briefly presented. The pion cloud effects are explicitly discussed.

D. Y. Chen; Y. B. Dong; M. M. Giannini; E. Santopinto

2006-11-07T23:59:59.000Z

435

A Precision Measurement of the Mass of the Top Quark

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

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

2004-01-01T23:59:59.000Z

436

Weak interactions of quarks and leptons: experimental status

The present experimental status of weak interactions is discussed with emphasis on the problems and questions and on the possible lines of future investigations. Major topics include; (1) the quark mixing matrix, (2) CP violation, (3) rare decays, (4) the lepton sector, and (5) right handed currents. 118 references. (WHK)

Wojcicki, S.

1984-09-01T23:59:59.000Z

437

Gamma-Ray Bursts and Dark Matter - a joint origin?

A scenario is presented where large quark-gluon plasma (QGP) objects escaping the quark-hadron transition in the early Universe account for the baryonic dark matter as well as act as the sources for gamma-ray bursts. Two basic assumptions are made. Firstly, we assume that a QGP consisting of u,d and s quarks is the absolute ground state of QCD and secondly, that the quark-hadron transition in the early Universe was of first order. Both particle physics and astrophysics constraints are discussed, mainly from an observational point of view.

Daniel Enstrom

1998-10-13T23:59:59.000Z

438

$\\gamma$-Ray Bursts and Dark Matter a joint origin?

A scenario is presented where large quark-gluon plasma (QGP) objects escaping the quark-hadron transition in the early Universe account for the baryonic dark matter as well as act as the sources for gamma-ray bursts. Two basic assumptions are made. Firstly, we assume that a QGP consisting of u,d and s quarks is the absolute ground state of QCD and secondly, that the quark-hadron transition in the early Universe was of first order. Both particle physics and astrophysics constraints are discussed, mainly from an observational point of view.

Enström, D; Hansson, J; Nicolaidis, A; Ekelin, S

1998-01-01T23:59:59.000Z

439

Hydrodynamic Modeling and the QGP Shear Viscosity

In this article, we will briefly review the recent progress on hydrodynamic modeling and the extraction of the quark-gluon plasma (QGP) specific shear viscosity with an emphasis on results obtained from the hybrid model VISHNU that couples viscous hydrodynamics for the macroscopic expansion of the QGP to the hadron cascade model for the microscopic evolution of the late hadronic stage.

Huichao Song

2012-07-10T23:59:59.000Z

440

STAR Highlights on Heavy Ion Physics

RHIC-STAR is a mid-rapidity collider experiment for studying high energy nuclear collisions. The main physics goals of STAR experiment are 1) studying the properties of the strongly coupled Quark Gluon Plasma, 2) explore the QCD phase diagram structure. In these proceedings, we will review the recent results of heavy ion physics at STAR.

Shusu Shi

2014-09-30T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

441

Anisotropic flow from hard partons in ultra-relativistic nuclear collisions

Anisotropies of hadronic distribution in nuclear collisions are used for determination of properties of the nuclear matter. At the LHC it is important to account for the contribution to the flow due to momentum transferred from hard partons to the quark-gluon plasma.

Tomasik, Boris

2014-01-01T23:59:59.000Z

442

by high baryon density and low temperature, and in the other by zero net baryon density and temperatures be pointed out that while the phase transition to the quark--gluon plasma with zero net baryon density has in a solid. QCD lattice calculations confirm the existence of a well defined phase transition signaling

443

of China E-mail: ruan@bnl.gov Received 30 April 2009 Published 17 July 2009 Online at stacks the critical values predicted by lattice QCD for formation of a quarkÂgluon plasma (QGP); (2) opacity to jets

Llope, William J.

444

Reentrant behavior of the spinodal curve in a nonequilibrium ferromagnet P. I. Hurtado

system in which a generic type of microscopic disorder induces nonequilibrium steady states is studied in liquids and glasses [3], quark/gluon plasmas [4], globular proteins [5], cosmological phase transitions [6 ensemble theory [1]. Consequently, a lot of activity still focuses on very simple cases, particularly

Garrido, Pedro L.

445

[Nuclear theory: Annual report

This report discusses topics on : nuclear structure models; algebraic models of hadronic structure; nuclear reactions; hot rotating nuclei; chaos in nuclei; signatures of the quark-gluon plasma; hadronic spectroscopy; octupole collectivity in nuclei; finite-temperature methods for the many-body problem; and classical limit of algebraic hamiltonians. (LSP)

Iachello, F.; Alhassid, Y.; Kusnezov, D.

1991-12-31T23:59:59.000Z

446

(Nuclear theory: Annual report)

This report discusses topics on : nuclear structure models; algebraic models of hadronic structure; nuclear reactions; hot rotating nuclei; chaos in nuclei; signatures of the quark-gluon plasma; hadronic spectroscopy; octupole collectivity in nuclei; finite-temperature methods for the many-body problem; and classical limit of algebraic hamiltonians. (LSP)

Iachello, F.; Alhassid, Y.; Kusnezov, D.

1991-01-01T23:59:59.000Z

447

Event by event fluctuations in heavy ion collisions

The authors discuss the physics underlying event-by-event fluctuations in relativistic heavy ion collisions. We will argue that the fluctuations of the ratio of positively over negatively charged particles may serve as a unique signature for the Quark Gluon Plasma.

Koch, Volker

2001-01-01T23:59:59.000Z

448

In a lecture titled "Hotter, Denser, Faster, Smaller...and Nearly Perfect: What's the Matter at RHIC?", Steinberg discusses the basic physics of the quark-gluon plasma and BNL's Relativistic Heavy Ion Collider, with a focus on several intriguing results from RHIC's recently ended PHOBOS experiment.

Peter Steinberg

2010-09-01T23:59:59.000Z

449

Plasma-Current Multipole Experiments

Science Journals Connector (OSTI)

The magnetohydrodynamic equilibrium and stability of the plasma-current multipole configuration have been demonstrated experimentally.

T. Ohkawa and H. G. Voorhies

1969-06-16T23:59:59.000Z

450

Basic concepts in plasma accelerators

Science Journals Connector (OSTI)

...plasma accelerators. Plasma accelerators are ideal...2. Relativistic plasma wave acceleration The...electric field at the focus of high-power short-pulse...Diffraction limits the depth of focus to the Rayleigh length...stimulated Brillouin and plasma modulational instabilities...

2006-01-01T23:59:59.000Z

451

Michigan Institute for Plasma Science

of the Program in Plasma Physics and Professor of Astrophysical Sciences at Princeton University. He also serves as Associate Director for Academic Affairs at the Princeton Plasma Physics Laboratory. DrMichigan Institute for Plasma Science and Engineering Seminar Compressing Waves in Plasma

Shyy, Wei

452

Cathodic Arc Plasma Deposition

Office of Scientific and Technical Information (OSTI)

Cathodic Arc Plasma Deposition Cathodic Arc Plasma Deposition AndrÃ© Anders Lawrence Berkeley National Laboratory, University of California, 1 Cyclotron Road, Mailstop 53, Berkeley, California 94720 aanders@lbl.gov Abstract Cathodic arc plasma deposition is one of oldest coatings technologies. Over the last two decades it has become the technology of choice for hard, wear resistant coatings on cutting and forming tools, corrosion resistant and decorative coatings on door knobs, shower heads, jewelry, and many other substrates. The history, basic physics of cathodic arc operation, the infamous macroparticle problem and common filter solutions are reviewed. Cathodic arc plasmas stand out due to their high degree of ionization, with important consequences for film nucleation, growth, and efficient utilization of substrate bias. The

453

Science Journals Connector (OSTI)

29 June 1987 research-article Plasma Magnetic Insulation B. B. Kadomtsev Theoretically the strong magnetic field of a tokamak should confine electrons and ions in a high-temperature...

1987-01-01T23:59:59.000Z

454

The upcoming ITER experiment (www.iter.org) represents the next major milestone in realizing the promise of using nuclear fusion as a commercial energy source, by moving into the ?burning plasma? regime where the dominant heat source is the internal fusion reactions. As part of its support for the ITER mission, the US fusion community is actively developing validated predictive models of the behavior of magnetically confined plasmas. In this talk, I will describe how the plasma community is using the latest high performance computing facilities to develop and refine our models of the nonlinear, multiscale plasma dynamics, and how recent advances in experimental diagnostics are allowing us to directly test and validate these models at an unprecedented level.

Chris Holland

2010-01-08T23:59:59.000Z

455

Phase structure of cold magnetized quark matter within the SU(3) NJL model

The possible different phases of cold quark matter in the presence of a finite magnetic field and chemical potential are obtained within the SU(3) NJL model for two parameter sets often used in the literature. Although the general pattern is the same in both cases, the number of intermediate phases is parameter dependent. The chiral susceptibilities, as usually defined, are different not only for the s-quark as compared with the two light quarks, but also for the u and d-quarks, yielding non identical crossover lines for the light quark sector.

A. G. Grunfeld; D. P. Menezes; M. B. Pinto; N. N. Scoccola

2014-02-19T23:59:59.000Z

456

Uncovering the single top: observation of electroweak top quark production

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

Benitez, Jorge Armando; /Michigan State U.

2009-08-01T23:59:59.000Z

457

Electrostatics of moving plasma

The stability of charge distribution over the surface of a conducting body in moving plasma is analyzed. Using a finite-width plate streamlined by a cold neutralized electron flow as an example, it is shown that an electrically neutral body can be unstable against the development of spontaneous polarization. The plasma parameters at which such instability takes place, as well as the frequency and growth rate of the fundamental mode of instability, are determined.

Ignatov, A. M. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation)] [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation)

2013-07-15T23:59:59.000Z

458

Research | Princeton Plasma Physics Lab

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

Overview Experimental Fusion Research Theoretical Fusion Research Basic Plasma Science Plasma Astrophysics Other Physics and Engineering Research PPPL Technical Reports Education Organization Contact Us Overview Experimental Fusion Research Theoretical Fusion Research Basic Plasma Science Plasma Astrophysics Other Physics and Engineering Research PPPL Technical Reports Research The U.S. Department of Energy's Princeton Plasma Physics Laboratory is dedicated to developing fusion as a clean and abundant source of energy and to advancing the frontiers of plasma science. The Laboratory pursues these goals through experiments and computer simulations of the behavior of plasma, the hot electrically charged gas that fuels fusion reactions and has a wide range of practical applications.

459

Chiral Magnetic Effect from Q-balls

We apply a generic framework of linear sigma models for revealing a mechanism of the mysterious phenomenon, the chiral magnetic effect, in quark-gluon plasma. An electric current arises along a background magnetic field, which is given rise to by Q-balls (non-topological solitons) of the linear sigma model with axial anomaly. We find additional alternating current due to quark mass terms. The hadronic Q-balls, baby boson stars, may be created in heavy-ion collisions.

Minoru Eto; Koji Hashimoto; Hideaki Iida; Akitsugu Miwa

2010-12-15T23:59:59.000Z

460

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

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

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

While these samples are representative of the content of NLE

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to obtain the most current and comprehensive results.

461

We illustrate the role of repulsive interactions in a hadron-resonance gas at freeze-out and in a gas of quark-gluon bags. Taking into account non-zero size of particles in hadron gas leads to a significant decrease and shift of the net-baryon density maximum. The transition point from baryon to meson dominated matter depends on the difference between baryon and meson radii. We also show that depending on the properties of the quark-gluon bags one may obtain any type of the phase transition from hadron gas to quark-gluon plasma: the first or second order, as well as four types of the crossover.

V. V. Begun

2014-11-13T23:59:59.000Z

462

Microsoft Word - QuarkNet Friday Flyer.docx

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

Flyer, March 15, 2013 SPECIAL EDITION Flyer, March 15, 2013 SPECIAL EDITION QuarkNet Workshops Since 1999, QuarkNet has introduced teachers to inquiry-based investigations using particle physics data. Select workshops from this menu for your center programs. Contacts can answer your questions and schedule a workshop. Teaching and Learning Workshop (2-3 days) - Contact Tom: jordant@fnal.gov This workshop introduces teachers to inquiry-based resources that incorporate particle physics content. We tailor this workshop to the needs and interests of the center and provide teachers with investigations that can be used in a high school classroom. The following workshops prepare teachers to facilitate data analysis for students, from scaffolding to investigation and reporting using different datasets.

463

Search for electroweak single top quark production with CDF

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

Kemp, Y.; /Karlsruhe U.

2005-01-01T23:59:59.000Z

464

NLO evolution of 3-quark Wilson loop operator

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

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 the next-to-leading order (NLO) and present a quasi-conformal evolution equation for a composite 3-Wilson-lines operator. We also obtain the linearized version of that evolution equation describing the amplitude of the odderon exchange at high energies.

Balitsky, Ian [ODU, JLAB; Grabovsky, A V [Novosibirsk

2015-01-01T23:59:59.000Z

465

Quark-lepton symmetric model at the LHC

Science Journals Connector (OSTI)

We investigate the quark-lepton symmetric model of Foot and Lew in the context of the Large Hadron Collider (LHC). In this “bottom-up” extension to the standard model, quark-lepton symmetry is achieved by introducing a gauged “leptonic color” symmetry which is spontaneously broken above the electroweak scale. If this breaking occurs at the TeV scale, then we expect new physics to be discovered at the LHC. We examine three areas of interest: the Z? heavy neutral gauge boson, charge ±1/2 exotic leptons, and a color triplet scalar diquark. We find that the LHC has already explored and/or will explore new parameter space for these particles over the course of its lifetime.

Jackson D. Clarke; Robert Foot; Raymond R. Volkas

2012-04-10T23:59:59.000Z

466

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

Contacts Hours Online Access Directions Contacts Hours Online Access Directions QuickFind Main Catalog Databases PPPL Publications & Reports/PPLcat Plasma Physics E-Journals clear Click arrows to scroll for more clear Plasma Physics Colloquia The Global Carbon Cycle and Earth's Climate - January 15, 2014 Addressing Big Data Challenges in Simulation-based Science - January 22, 2014 "The Usefulness of Useless Knowledge?: The History of the Institute for Advanced Study - January 29, 2014 PM-S-1 PDF PM-S-2 PDF PM-S-3 PDF PM-S-4 PDF PM-S-5 PDF PM-S-6 PDF See All Library History Intro 950 1960-1970 1980 1990 2000 Quick Order Article Express Borrow Direct Interlibrary Loan PPL Book Request More Resources and Services Search & Find Articles & Databases - Plasma Physics, Physics, Engineering & Technology,

467

Wounded quarks and diquarks in heavy ion collisions

A model in which the soft collisions of the nucleon are described in terms of interactions of its two constituents (a quark and a diquark) is proposed. When adjusted to describe precisely the elastic proton-proton scattering data and supplemented with the idea of wounded constituents, the model accounts rather well for the centrality dependence of particle production in the central rapidity region at RHIC energies.

A. Bialas; A. Bzdak

2006-11-23T23:59:59.000Z

468

On the conversion of neutron stars into quark stars

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

Giuseppe Pagliara

2013-12-04T23:59:59.000Z

469

Measurement of the Top Quark Mass With 2012 CMS Data

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

Richard Nally

2014-09-01T23:59:59.000Z

470

QCD and Top Quark Physics at the LHC

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

Frank-Peter Schilling

2009-01-30T23:59:59.000Z

471

COLLOQUIUM: Excitement at the Plasma Boundary" | Princeton Plasma...

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

Presentation: WC16JAN2013RGoldston.pdf We now know how to heat plasmas to thermonuclear temperatures, and even how to confine the resulting hot plasmas to produce immense...

472

Many others in the fusion energy and advanced scientific computing communities participated in the development of this plan. The core planning team is grateful for their important contributions. This summary is meant as a quick overview the Fusion Simulation Program's (FSP's) purpose and intentions. There are several additional documents referenced within this one and all are supplemental or flow down from this Program Plan. The overall science goal of the DOE Office of Fusion Energy Sciences (FES) Fusion Simulation Program (FSP) is to develop predictive simulation capability for magnetically confined fusion plasmas at an unprecedented level of integration and fidelity. This will directly support and enable effective U.S. participation in International Thermonuclear Experimental Reactor (ITER) research and the overall mission of delivering practical fusion energy. The FSP will address a rich set of scientific issues together with experimental programs, producing validated integrated physics results. This is very well aligned with the mission of the ITER Organization to coordinate with its members the integrated modeling and control of fusion plasmas, including benchmarking and validation activities. [1]. Initial FSP research will focus on two critical Integrated Science Application (ISA) areas: ISA1, the plasma edge; and ISA2, whole device modeling (WDM) including disruption avoidance. The first of these problems involves the narrow plasma boundary layer and its complex interactions with the plasma core and the surrounding material wall. The second requires development of a computationally tractable, but comprehensive model that describes all equilibrium and dynamic processes at a sufficient level of detail to provide useful prediction of the temporal evolution of fusion plasma experiments. The initial driver for the whole device model will be prediction and avoidance of discharge-terminating disruptions, especially at high performance, which are a critical impediment to successful operation of machines like ITER. If disruptions prove unable to be avoided, their associated dynamics and effects will be addressed in the next phase of the FSP.

Greenwald, Martin

2011-10-04T23:59:59.000Z

473

The Surface Tension of Quark Matter in a Geometrical Approach

The surface tension of quark matter plays a crucial role for the possibility of quark matter nucleation during the formation of compact stellar objects, because it determines the nucleation rate and the associated critical size. However, this quantity is not well known and the theoretical estimates fall within a wide range, $\\gamma_0 \\approx 5-300 MeV/fm^2$. We show here that once the equation of state is available one may use a geometrical approach to obtain a numerical value for the surface tension that is consistent with the model approximations adopted. We illustrate this method within the two-flavor linear \\sigma model and the Nambu--Jona-Lasinio model with two and three flavors. Treating these models in the mean-field approximation, we find $\\gamma_0 \\approx 7-30 MeV/fm^2$. Such a relatively small surface tension would favor the formation of quark stars and may thus have significant astrophysical implications. We also investigate how the surface tension decreases towards zero as the temperature is raised from zero to its critical value.

Marcus B. Pinto; Volker Koch; Jorgen Randrup

2012-07-21T23:59:59.000Z

474

Discovery Mass Reach for Excited Quarks at Hadron Colliders

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

Robert M. Harris

1996-09-11T23:59:59.000Z

475

Ultra-high energy cosmic rays from Quark Novae

We explore acceleration of ions in the Quark Nova (QN) scenario, where a neutron star experiences an explosive phase transition into a quark star (born in the propeller regime). In this picture, two cosmic ray components are isolated: one related to the randomized pulsar wind and the other to the propelled wind, both boosted by the ultra-relativistic Quark Nova shock. The latter component acquires energies $10^{15} {\\rm eV}wind, achieves ultra-high energies $E> 10^{18.6}$ eV. The composition is dominated by ions present in the pulsar wind in the energy range above $10^{18.6}$ eV, while at energies below $10^{18}$ eV the propelled ejecta, consisting of the fall-back neutron star crust material from the explosion, is the dominant one. Added to these two components, the propeller injects relativistic particles with Lorentz factors $\\Gamma_{\\rm prop.} \\sim 1-1000$, later to be accelerated by galactic supernova shocks. The QN model appears to be able to account for the extragalactic cosmic rays above the ankle and to contribute a few percent of the galactic cosmic rays below the ankle. We predict few hundred ultra-high energy cosmic ray events above $10^{19}$ eV for the Pierre Auger detector per distant QN, while some thousands are predicted for the proposed EUSO and OWL detectors.

R. Ouyed; P. Keränen; J. Maalampi

2003-01-29T23:59:59.000Z

476

Science Journals Connector (OSTI)

The propagation of high-velocity shock waves in an axial magnetic field generated by single-turn coils connected in parallel to a condenser bank is investigated. Time-resolved photographs show that the plasma behind the shock front is driven away from the tube walls by the magnetic pressure. This compression heats the ionized gas and maintains a high shock velocity during the transit of the front through the coil. The compressed plasma appears to be stable and undergoes radial oscillations that follow the current oscillations. The interpretation and significance of these observations in controlled thermonuclear fusion research are discussed.

A. C. Kolb

1958-10-15T23:59:59.000Z

477

Reflectivity of nonideal plasmas

Science Journals Connector (OSTI)

New results on optical reflectance measurements of shock-compressed dense xenon plasma at wavelengths ? = 532 nm and ? = 694 nm are reported. The investigations have been performed for nonideal plasma (? = 0.87–2.0) at densities ? = 0.27–3.84 g cm?3 and pressures P = 1.6–17 GPa. The obtained high optical reflectance values are characteristic of a metallic fluid and are evidence for a conducting state in the shocked xenon. Reflectance measurements at different wavelengths provide information about the density profile of the shock wave front.

Yu Zaporoghets; V Mintsev; V Gryaznov; V Fortov; H Reinholz; T Raitza; G Röpke

2006-01-01T23:59:59.000Z

478

The objective of our theoretical research under this grant over the past 3 years was to develop new understanding in a range of topics in the physics of dust-plasma interactions, with application to space and the laboratory. We conducted studies related to the physical properties of dust, waves and instabilities in both weakly coupled and strongly coupled dusty plasmas, and innovative possible applications. A major consideration in our choice of topics was to compare theory with experiments or observations, and to motivate new experiments, which we believe is important for developing this relatively new field. Our research is summarized, with reference to our list of journal publications.

Dr. M. Rosenberg

2010-01-05T23:59:59.000Z

479

The Shape and Flow of Heavy Ion Collisions (490th Brookhaven Lecture)

The sun can’t do it, but colossal machines like the Relativistic Heavy Ion Collider (RHIC) at Brookhaven Lab and Large Hadron Collider (LHC) in Europe sure can. Quarks and gluons make up protons and neutrons found in the nucleus of every atom in the universe. At heavy ion colliders like RHIC and the LHC, scientists can create matter more than 100,000 times hotter than the center of the sun—so hot that protons and neutrons melt into a plasma of quarks and gluons. The particle collisions and emerging quark-gluon plasma hold keys to understanding how these fundamental particles interact with each other, which helps explain how everything is held together—from atomic nuclei to human beings to the biggest stars—how all matter has mass, and what the universe looked like microseconds after the Big Bang. Dr. Schenke discusses theory that details the shape and structure of heavy ion collisions. He will also explain how this theory and data from experiments at RHIC and the LHC are being used to determine properties of the quark-gluon plasma.

Schenke, Bjoern [BNL Physics Department

2014-12-18T23:59:59.000Z

480

Recent results for plasma antennas

Plasma antennas are just as effective as metal antennas. They can transmit, receive, and reflect radio waves just as well as metal antennas. In addition, plasma generated noise does not appear to be a problem.

Alexeff, Igor; Anderson, Ted; Farshi, Esmaeil; Karnam, Naresh; Pulasani, Nanditha Reddy [Department of Electrical Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States)

2008-05-15T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

481

Gas lens laser produced plasma

Science Journals Connector (OSTI)

A gas lens is used to focus a megawatt ruby laser beam on to a target to create a plasma. By using focal plane photographs and Faraday cup plasma diagnostics, the focusing ability of a...

Notcutt, Mark; Waltham, J A; Michaelis, M M; Cunningham, P F; Cazalet, R S

1989-01-01T23:59:59.000Z

482

Atmospheric Plasma Effect on Cotton Nonwovens

Science Journals Connector (OSTI)

Atmospheric Plasma Effect on Cotton Nonwovens ... (22) Plasma II is more effective than Plasma I with the ability to develop homogeneous plasmas and eliminate boundary-layer air effects. ...

Sudheer Jinka; Uday Turaga; Vinitkumar Singh; Rachel L. Behrens; Cenk Gumeci; Carol Korzeniewski; Todd Anderson; Rory Wolf; Seshadri Ramkumar

2014-07-22T23:59:59.000Z

483

Proposal for PLASMA LENS EXPERIMENT AT

.....................................................................................3 1.1 Plasma Focusing ......................................................................3 1

484

Directory | Princeton Plasma Physics Lab

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

Procurement Division Technology Transfer Furth Plasma Physics Library Contact Us Lab Leadership Directory Careers Human Resources Environment, Safety & Health Procurement...

485

Experiments on Cryogenic Complex Plasma

Experiments on a cryogenic complex plasma have been performed. Preliminary experiments include production of a plasma in a liquid helium or in a cryogenic helium gas by a pulsed discharge. The extended production of a plasma has been realized in a vapor of liquid helium or in a cryogenic helium gas by rf discharge. The charge of dust particles injected in such a plasma has been studied in detail.

Ishihara, O.; Sekine, W.; Kubota, J.; Uotani, N.; Chikasue, M.; Shindo, M. [Faculty of Engineering, Yokohama National University Yokohama, 240-8501 (Japan)

2009-11-10T23:59:59.000Z

486

Fusion Plasmas Martin Greenwald

. Despite the cold war, which raged for a