The Experts below are selected from a list of 28707 Experts worldwide ranked by ideXlab platform
Dinesh K. Srivastava - One of the best experts on this subject based on the ideXlab platform.
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Net Baryon Density inAu+AuCollisions at the Relativistic Heavy Ion Collider
Physical Review Letters, 2003Co-Authors: Steffen A. Bass, Berndt Müller, Dinesh K. SrivastavaAbstract:We calculate the net-Baryon rapidity distribution in $\mathrm{A}\mathrm{u}+\mathrm{A}\mathrm{u}$ collisions at the Relativistic Heavy Ion Collider (RHIC) in the framework of the parton cascade model (PCM). Parton rescattering and fragmentation leads to a substantial increase in the net-Baryon Density at midrapidity over the Density produced by initial primary parton-parton scatterings. The PCM is able to describe the measured net-Baryon Density at RHIC.
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net Baryon Density in au au collisions at the relativistic heavy ion collider
Physical Review Letters, 2003Co-Authors: Steffen A. Bass, Berndt Müller, Dinesh K. SrivastavaAbstract:We calculate the net-Baryon rapidity distribution in $\mathrm{A}\mathrm{u}+\mathrm{A}\mathrm{u}$ collisions at the Relativistic Heavy Ion Collider (RHIC) in the framework of the parton cascade model (PCM). Parton rescattering and fragmentation leads to a substantial increase in the net-Baryon Density at midrapidity over the Density produced by initial primary parton-parton scatterings. The PCM is able to describe the measured net-Baryon Density at RHIC.
K G Klimenko - One of the best experts on this subject based on the ideXlab platform.
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pion condensation in electrically neutral cold matter with finite Baryon Density
European Physical Journal C, 2006Co-Authors: D Ebert, K G KlimenkoAbstract:The possibility of the pion condensation phenomenon in cold and electrically neutral dense Baryonic matter is investigated in β-equilibrium. For simplicity, the consideration is performed in the framework of a Nambu–Jona-Lasinio model with two quark flavors at zero current quark mass and for rather small values of the Baryon chemical potential, where the diquark condensation might be ignored. Two sets of model parameters are used. For the first, the pion condensed phase with finite Baryon Density is realized. In this phase both electrons and the pion condensate take part in the neutralization of the quark electric charge. For the second set of model parameters, the pion condensation is impossible if the neutrality condition is imposed. The behavior of meson masses vs. quark chemical potential has been studied in electrically neutral matter.
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pion condensation in quark matter with finite Baryon Density
Journal of Physics G, 2006Co-Authors: D Ebert, K G KlimenkoAbstract:The phase structure of the Nambu–Jona-Lasinio model at zero temperature and in the presence of Baryon and isospin chemical potentials is investigated. It is shown that in the chiral limit and for a wide range of model parameters, there exist two different phases with pion condensation. In the first, ordinary phase, the Baryon Density is zero and quarks are gapped particles. In the second, gapless pion condensation phase, there is no energy cost for creating only u or both u- and d-quarks, and the Density of Baryons is nonzero.
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Gapless pion condensation in quark matter with finite Baryon Density
Journal of Physics G, 2006Co-Authors: D Ebert, K G KlimenkoAbstract:The phase structure of the Nambu–Jona-Lasinio model at zero temperature and in the presence of Baryon and isospin chemical potentials is investigated. It is shown that in the chiral limit and for a wide range of model parameters, there exist two different phases with pion condensation. In the first, ordinary phase, the Baryon Density is zero and quarks are gapped particles. In the second, gapless pion condensation phase, there is no energy cost for creating only u or both u- and d-quarks, and the Density of Baryons is nonzero.
Rowan M Thomson - One of the best experts on this subject based on the ideXlab platform.
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holographic phase transitions at finite Baryon Density
Journal of High Energy Physics, 2007Co-Authors: Shinpei Kobayashi, David Mateos, Shunji Matsuura, Robert C Myers, Rowan M ThomsonAbstract:We use holographic techniques to study SU(Nc) super Yang-Mills theory coupled to Nf << Nc flavours of fundamental matter at finite temperature and Baryon Density. We focus on four dimensions, for which the dual description consists of Nf D7-branes in the background of Nc black D3-branes, but our results apply in other dimensions as well. A non-zero chemical potential μb or Baryon number Density nb is introduced via a nonvanishing worldvolume gauge field on the D7-branes. Ref. [1] identified a first order phase transition at zero Density associated with `melting' of the mesons. This extends to a line of phase transitions for small nb, which terminates at a critical point at finite nb. Investigation of the D7-branes' thermodynamics reveals that (∂μb/∂nb)T<0 in a small region of the phase diagram, indicating an instability. We comment on a possible new phase which may appear in this region.
D Ebert - One of the best experts on this subject based on the ideXlab platform.
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pion condensation in electrically neutral cold matter with finite Baryon Density
European Physical Journal C, 2006Co-Authors: D Ebert, K G KlimenkoAbstract:The possibility of the pion condensation phenomenon in cold and electrically neutral dense Baryonic matter is investigated in β-equilibrium. For simplicity, the consideration is performed in the framework of a Nambu–Jona-Lasinio model with two quark flavors at zero current quark mass and for rather small values of the Baryon chemical potential, where the diquark condensation might be ignored. Two sets of model parameters are used. For the first, the pion condensed phase with finite Baryon Density is realized. In this phase both electrons and the pion condensate take part in the neutralization of the quark electric charge. For the second set of model parameters, the pion condensation is impossible if the neutrality condition is imposed. The behavior of meson masses vs. quark chemical potential has been studied in electrically neutral matter.
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pion condensation in quark matter with finite Baryon Density
Journal of Physics G, 2006Co-Authors: D Ebert, K G KlimenkoAbstract:The phase structure of the Nambu–Jona-Lasinio model at zero temperature and in the presence of Baryon and isospin chemical potentials is investigated. It is shown that in the chiral limit and for a wide range of model parameters, there exist two different phases with pion condensation. In the first, ordinary phase, the Baryon Density is zero and quarks are gapped particles. In the second, gapless pion condensation phase, there is no energy cost for creating only u or both u- and d-quarks, and the Density of Baryons is nonzero.
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Gapless pion condensation in quark matter with finite Baryon Density
Journal of Physics G, 2006Co-Authors: D Ebert, K G KlimenkoAbstract:The phase structure of the Nambu–Jona-Lasinio model at zero temperature and in the presence of Baryon and isospin chemical potentials is investigated. It is shown that in the chiral limit and for a wide range of model parameters, there exist two different phases with pion condensation. In the first, ordinary phase, the Baryon Density is zero and quarks are gapped particles. In the second, gapless pion condensation phase, there is no energy cost for creating only u or both u- and d-quarks, and the Density of Baryons is nonzero.
Philippe De Forcrand - One of the best experts on this subject based on the ideXlab platform.
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the chiral critical line of nf 2 1 qcd at zero and non zero Baryon Density
Journal of High Energy Physics, 2007Co-Authors: Philippe De Forcrand, Owe PhilipsenAbstract:We present numerical results for the location of the chiral critical line at finite temperature and zero and non-zero Baryon Density for QCD with Nf = 2 + 1 flavours of staggered fermions on lattices with temporal extent Nt = 4. For degenerate quark masses, we compare our results obtained with the exact RHMC algorithm with earlier, inexact R-algorithm results and find a reduction of 25% in the critical quark mass, for which the first order phase transition changes to a smooth crossover. Extending our analysis to non-degenerate quark masses, we map out the chiral critical line up to the neighbourhood of the physical point, which we confirm to be in the crossover region. Our data are consistent with a tricritical point at (mu,d = 0,ms ∼500) MeV. We also investigate the shift of the critical line with finite Baryon Density, by simulating with an imaginary chemical potential for which there is no sign problem. We observe this shift to be very small or, conversely, the critical endpoint µ c (mu,d,ms) to be extremely quark mass sensitive. Moreover, the sign of this shift is opposite to standard expectations. If confirmed on a finer lattice, it implies the absence of a critical endpoint for physical QCD at small chemical potential, or another revision of the QCD phase diagram. We critically examine earlier lattice determinations of the QCD critical point, and find them to be in no contradiction with our conclusion. Hence we argue that finer lattices are required to settle even the qualitative features of the QCD phase diagram.
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qcd at zero Baryon Density and the polyakov loop paradox
Physical Review D, 2006Co-Authors: Slavo Kratochvila, Philippe De ForcrandAbstract:We compare the grand canonical partition function at fixed chemical potential µ with the canonical partition function at fixed Baryon number B, formally and by numerical simulations at µ = 0 and B = 0 with four flavours of staggered quarks. We verify that the free energy densities are equal in the thermodynamic limit, and show that they can be well described by the hadron resonance gas at T Tc. Small differences between the two ensembles, for thermodynamic observables characterising the deconfinement phase transition, vanish with increasing lattice size. These differences are solely caused by contributions of non-zero Baryon Density sectors, which are exponentially suppressed with increasing volume. The Polyakov loop shows a different behaviour: for all temperatures and volumes, its expectation value is exactly zero in the canonical formulation, whereas it is always non-zero in the commonly used grand-canonical formulation. We clarify this paradoxical difference, and show that the non-vanishing Polyakov loop expectation value is due to contributions of non-zero triality states, which are not physical, because they give zero contribution to the partition function.
