Measurements of charmonium production in p+p, p+Au, and Au+Au collisions at [formula omitted] with the STAR experiment

Abstract

We present the first results from the STAR MTD of mid-rapidity charmonium measurements via the di-muon decay channel in p+p, p+Au, and Au+Au collisions at sNN=200 GeV at RHIC. The inclusive J/ψ production cross section in p+p collisions can be described by the Non-Relativistic QCD (NRQCD) formalism coupled with the color glass condensate effective theory (CGC) at low transverse momentum (pT) and next-to-leading order NRQCD at high pT. The nuclear modification factor in p+Au collisions for inclusive J/ψ is below unity at low pT and consistent with unity at high pT, which can be described by calculations including both nuclear PDF and nuclear absorption effects. The double ratio of inclusive J/ψ and ψ(2S) production rates for 0 <pT < 10 GeV/c at mid-rapidity between p+p and p+Au collisions is measured to be 1.37 ± 0.42 ± 0.19. The nuclear modification factor in Au+Au collisions for inclusive J/ψ shows significant J/ψ suppression at high pT in central collisions and can be qualitatively described by transport models including dissociation and regeneration contributions.