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Title: Measuring the isotropization time of quark-gluon plasma from direct photons at energies available at the BNL Relativistic Heavy Ion Collider (RHIC)

Abstract

We calculate transverse momentum distribution of direct photons from various sources by taking into account the initial state momentum anisotropy of quark-gluon plasma (QGP) and late stage transverse flow effects. To evaluate the photon yield from hadronic matter we include the contributions from baryon-meson reactions. The total photon yield, calculated for various combinations of initial conditions and transition temperatures, is then compared with the recent measurement of photon transverse momentum distribution by the PHENIX Collaboration. It is shown that because of the initial state anisotropy the photon yield from the QGP is larger by a factor of 8-10 than that of the isotropic case in the intermediate p{sub T} regime. It is also demonstrated that the presence of such an anisotropy can describe the PHENIX photon data better than the isotropic case in the present model. We show that the isotropization time thus extracted lies within the range 1.5{>=}{tau}{sub iso}{>=}0.5 fm/c for the initial conditions used here.

Authors:
;  [1]
  1. Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India)
Publication Date:
OSTI Identifier:
21286971
Resource Type:
Journal Article
Journal Name:
Physical Review. C, Nuclear Physics
Additional Journal Information:
Journal Volume: 79; Journal Issue: 5; Other Information: DOI: 10.1103/PhysRevC.79.054910; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0556-2813
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ANISOTROPY; BNL; BROOKHAVEN RHIC; COMPUTERIZED SIMULATION; DISTRIBUTION; HADRONS; MESON-BARYON INTERACTIONS; PHOTONS; QUARK MATTER; TRANSITION TEMPERATURE; TRANSVERSE MOMENTUM

Citation Formats

Bhattacharya, Lusaka, and Roy, Pradip. Measuring the isotropization time of quark-gluon plasma from direct photons at energies available at the BNL Relativistic Heavy Ion Collider (RHIC). United States: N. p., 2009. Web. doi:10.1103/PHYSREVC.79.054910.
Bhattacharya, Lusaka, & Roy, Pradip. Measuring the isotropization time of quark-gluon plasma from direct photons at energies available at the BNL Relativistic Heavy Ion Collider (RHIC). United States. doi:10.1103/PHYSREVC.79.054910.
Bhattacharya, Lusaka, and Roy, Pradip. Fri . "Measuring the isotropization time of quark-gluon plasma from direct photons at energies available at the BNL Relativistic Heavy Ion Collider (RHIC)". United States. doi:10.1103/PHYSREVC.79.054910.
@article{osti_21286971,
title = {Measuring the isotropization time of quark-gluon plasma from direct photons at energies available at the BNL Relativistic Heavy Ion Collider (RHIC)},
author = {Bhattacharya, Lusaka and Roy, Pradip},
abstractNote = {We calculate transverse momentum distribution of direct photons from various sources by taking into account the initial state momentum anisotropy of quark-gluon plasma (QGP) and late stage transverse flow effects. To evaluate the photon yield from hadronic matter we include the contributions from baryon-meson reactions. The total photon yield, calculated for various combinations of initial conditions and transition temperatures, is then compared with the recent measurement of photon transverse momentum distribution by the PHENIX Collaboration. It is shown that because of the initial state anisotropy the photon yield from the QGP is larger by a factor of 8-10 than that of the isotropic case in the intermediate p{sub T} regime. It is also demonstrated that the presence of such an anisotropy can describe the PHENIX photon data better than the isotropic case in the present model. We show that the isotropization time thus extracted lies within the range 1.5{>=}{tau}{sub iso}{>=}0.5 fm/c for the initial conditions used here.},
doi = {10.1103/PHYSREVC.79.054910},
journal = {Physical Review. C, Nuclear Physics},
issn = {0556-2813},
number = 5,
volume = 79,
place = {United States},
year = {2009},
month = {5}
}