Expanding quark-gluon plasmas: Transverse flow, chemical equilibration, and electromagnetic radiation

Journal Article · Fri Aug 01 04:00:00 EDT 1997 · Physical Review, C

DOI:https://doi.org/10.1103/PhysRevC.56.1064· OSTI ID:528186

Srivastava, D K; Mustafa, M G ^[1]; Mueller, B ^[2]

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1. Variable Energy Cyclotron center, 1/AF Bidhan Nagar, Calcutta 700 064 (India)
2. Department of Physics, Duke University, Durham, North Carolina 27708-0305 (United States)

We investigate the chemical equilibration of the parton distributions in collisions of two heavy nuclei. We use initial conditions obtained from a self-screened parton cascade calculation and, for comparison, from the HIJING model. We consider a one-dimensional as well as a three-dimensional expansion of the parton plasma and find that the onset of the transverse expansion impedes the chemical equilibration. At energies of 100 GeV/nucleon, the results for one-dimensional and three-dimensional expansions are quite similar except at large values of the transverse radius. At energies of several TeV/nucleon, the plasma initially approaches chemical equilibrium, but then is driven away from it, when the transverse velocity gradients develop. We find that the total parton multiplicity density remains essentially unaffected by the flow, but the individual concentrations of quarks, antiquarks, and gluons are sensitive to the transverse flow. The consequences of the flow are also discernible in the transverse momenta of the partons and in the lepton pair spectra, where the flow causes a violation of the so-called M{sub T} scaling. {copyright} {ital 1997} {ital The American Physical Society}

• DOE Contract Number: FG02-96ER40945
• OSTI ID: 528186
• Journal Information: Physical Review, C, Journal Name: Physical Review, C Journal Issue: 2 Vol. 56; ISSN PRVCAN; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CASCADE THEORY
DISTRIBUTION
ELECTROMAGNETIC RADIATION
EXPANSION
FLOW MODELS
GLUONS
HEAVY ION REACTIONS
LEPTONS
MULTIPLICITY
PAIR PRODUCTION
PARTON MODEL
PARTONS
PLASMA
QUARK MATTER
QUARKS
SCALING
TRANSVERSE MOMENTUM