2009/02/06 by Rupa Chatterjee, Dinesh Kumar Srivastava, Dinesh K. Srivastava +1 · 1 citation
Physics and Astronomy · #Elliptic flow #Factorization #Hadron #High-Energy Particle Collisions Research #Large Hadron Collider #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Photon #Physics #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #Quark #Quark–gluon plasma #Super Proton Synchrotron #Yield (engineering) #hep-ph #nucl-ex #nucl-th
paper · pdf · doi:10.1103/physrevc.79.034906
published as Phys.Rev.C79:034906,2009 · 10 pages, 13 figures
arxiv created 2009/02/06 · openalex publication_date 2009/03/18 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present a reanalysis of single photon production from a relativistic collision of lead nuclei at CERN SPS measured by the WA98 experiment. The refinements include use of isospin and shadowing corrected NLO pQCD treatment for prompt photon production using an optimized scale for factorization, renormalization, and fragmentation and use of hydrodynamics suited for noncentral collisions along with a well tested equation of state admitting a quark-hadron phase transition. A quantitative explanation of the data requires a large initial temperature (at a small formation time of about 0.2 fm/c) and a moderate increase in the prompt yield which could perhaps be attributed to the Cronin effect in nuclei. The data can also be explained using a moderate initial temperature (at a formation time of about 1 fm/c) with a very large K-factor multiplying the prompt yield. We show that different initial times give rise to different values for the elliptic flow parameter v2 for thermal photons. We also argue that a measurement of v2 for thermal photons could also distinguish between the scenarios with or without a phase transition.