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Title: Specific heat in hadronic matter and in quark-gluon matter

Abstract

A parton and hadron cascade model, PACIAE, is applied to follow the particle transport in partonic and the hadronic stages in 0-5% most central Au+Au collisions at energies from SPS to RHIC. We have determined the specific heat of hadron matter ({pi}{sup +}+{pi}{sup -}) in the hadronic final state and the specific heat of quark-gluon matter (u+d+g) in the partonic initial state in Au+Au collisions as a function of the reaction energy (excitation function). It turns out that the quark-gluon matter (QGM) specific heat is hard to survive the hadronization and there is not a peak structure in the specific heat excitation functions in studied energy region.

Authors:
 [1];  [2];  [3];  [2]; ; ; ;  [1];  [4]
  1. China Institute of Atomic Energy, P. O. Box 275 (18), Beijing 102413 (China)
  2. (China)
  3. (World Laboratory), P. O. Box 8730 Beijing 100080 (China)
  4. Institute of Particle Physics, Huazhong Normal University, Wuhan 430079 (China)
Publication Date:
OSTI Identifier:
20995316
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 5; Other Information: DOI: 10.1103/PhysRevC.75.054912; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; COLLISIONS; EXCITATION FUNCTIONS; GOLD; HEAVY ION REACTIONS; MASS NUMBER; NUCLEI; PARTICLES; PEAKS; PIONS MINUS; QUARK MATTER; QUARK-GLUON INTERACTIONS; SPECIFIC HEAT

Citation Formats

Sa Benhao, Institute of Particle Physics, Huazhong Normal University, Wuhan 430079, CCAST, Institute of Theoretical Physics, Academy Sciences, Beijing 100080, Li Xiaomei, Hu Shouyang, Li Shouping, Feng Jing, and Zhou Daimei. Specific heat in hadronic matter and in quark-gluon matter. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.054912.
Sa Benhao, Institute of Particle Physics, Huazhong Normal University, Wuhan 430079, CCAST, Institute of Theoretical Physics, Academy Sciences, Beijing 100080, Li Xiaomei, Hu Shouyang, Li Shouping, Feng Jing, & Zhou Daimei. Specific heat in hadronic matter and in quark-gluon matter. United States. doi:10.1103/PHYSREVC.75.054912.
Sa Benhao, Institute of Particle Physics, Huazhong Normal University, Wuhan 430079, CCAST, Institute of Theoretical Physics, Academy Sciences, Beijing 100080, Li Xiaomei, Hu Shouyang, Li Shouping, Feng Jing, and Zhou Daimei. Tue . "Specific heat in hadronic matter and in quark-gluon matter". United States. doi:10.1103/PHYSREVC.75.054912.
@article{osti_20995316,
title = {Specific heat in hadronic matter and in quark-gluon matter},
author = {Sa Benhao and Institute of Particle Physics, Huazhong Normal University, Wuhan 430079 and CCAST and Institute of Theoretical Physics, Academy Sciences, Beijing 100080 and Li Xiaomei and Hu Shouyang and Li Shouping and Feng Jing and Zhou Daimei},
abstractNote = {A parton and hadron cascade model, PACIAE, is applied to follow the particle transport in partonic and the hadronic stages in 0-5% most central Au+Au collisions at energies from SPS to RHIC. We have determined the specific heat of hadron matter ({pi}{sup +}+{pi}{sup -}) in the hadronic final state and the specific heat of quark-gluon matter (u+d+g) in the partonic initial state in Au+Au collisions as a function of the reaction energy (excitation function). It turns out that the quark-gluon matter (QGM) specific heat is hard to survive the hadronization and there is not a peak structure in the specific heat excitation functions in studied energy region.},
doi = {10.1103/PHYSREVC.75.054912},
journal = {Physical Review. C, Nuclear Physics},
number = 5,
volume = 75,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • The energy densities achieved during central collisions of large nuclei at Brookhaven's AGS may be high enough to allow the formation of quark-gluon plasma. Calculations based on relativistic nucleation theory suggest that rare events, perhaps one in every 10[sup 2] or 10[sup 3], undergo the phase transition. Experimental ramifications may include an enhancement in the ratio of pions to baryons, a reduction in the ratio of deuterons to protons, and a larger source size as seen by hadron interferometry.
  • The density of the number of states of colorless quark-gluon bags is determined. This result is used to calculate the partition function of a gas of bags with van der Waals exclusion of their proper volumes. It is shown that the requirement that the bags be colorless has a decisive influence on the thermodynamic properties of this system and leads to a first-order phase transition between hadronic and quark-gluon matter.
  • The emission of high-energy photons from an expanding quark-gluon plasma (QGP), which undergoes a first-order phase transition to a hot hadronic gas before freeze-out, is evaluated. Compton and annihilation processes in the quark-gluon plasma and an exhaustive array of {ital hh}{r arrow}{ital h}{gamma} reactions as wel l as decays in hot hadronic matter are considered. We find that, if the initial temperature of the QGP is more than twice the critical temperature, then, beyond a transverse momentum of about 2--3 GeV, the photons from the QGP outshine those having their origin in hadronic matter. We further note that the increasemore » in degrees of freedom in the hot hadronic matter reduces the lifetime of the mixed phase.« less
  • We introduce a combined macroscopic-microscopic transport approach employing relativistic hydrodynamics for the early, dense, deconfined stage of the reaction and a microscopic nonequilibrium model for the later hadronic stage where the equilibrium assumptions are not valid anymore. Within this approach we study the dynamics of hot, bulk QCD matter, which is expected to be created in ultrarelativistic heavy-ion collisions at the Super Proton Synchrotron, the Relativistic Heavy Ion Collider, and the Large Hadron Collider. Our approach is capable of self-consistently calculating the freeze-out of the hadronic system, while accounting for the collective flow on the hadronization hypersurface generated by themore » QGP expansion. In particular, we perform a detailed analysis of the reaction dynamics, hadronic freeze-out, and transverse flow. (c) 2000 The American Physical Society.« less
  • The specific heat, mean hadronic mass excited and its fluctuation are connected to particle production yields and properties of baryon and electric charge chemical potentials (value, slope and curvature). A possible divergence of the specific heat as 1/(T{sub 0}-T){sup 2} is discussed. A Hagedorn model with {rho}{approx}m{sup -{tau}}exp({beta}{sub h}m) is studied and restriction on {tau} are analyzed. Limitations imposed by a Q-g transition are mentioned.