English

Direct virtual photon production in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

Nuclear Experiment 2017-05-01 v2 High Energy Physics - Experiment High Energy Physics - Phenomenology Nuclear Theory

Abstract

We report the direct virtual photon invariant yields in the transverse momentum ranges 1 ⁣< ⁣pT ⁣< ⁣31\!<\!p_{T}\!<\!3 GeV/cc and 5 ⁣< ⁣pT ⁣< ⁣105\!<\!p_T\!<\!10 GeV/cc at mid-rapidity derived from the dielectron invariant mass continuum region 0.10<Mee<0.280.10<M_{ee}<0.28 GeV/c2c^{2} for 0-80\% minimum-bias Au+Au collisions at sNN=200\sqrt{s_{NN}}=200 GeV. A clear excess in the invariant yield compared to the number-of-binary-collisions (NbinN_{bin}) scaled p+pp+p reference is observed in the pTp_T range 1 ⁣< ⁣pT ⁣< ⁣31\!<\!p_{T}\!<\!3 GeV/cc. For pT ⁣>6p_T\!>6 GeV/cc the production follows NbinN_{bin} scaling. Model calculations with contributions from thermal radiation and initial hard parton scattering are consistent within uncertainties with the direct virtual photon invariant yield.

Keywords

Cite

@article{arxiv.1607.01447,
  title  = {Direct virtual photon production in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV},
  author = {STAR Collaboration},
  journal= {arXiv preprint arXiv:1607.01447},
  year   = {2017}
}

Comments

9 pages, 6 figures