J/ψ production at low transverse momentum in p+p and d + Au collisions at sNN =200 GeV

Abstract

We report on the measurement of J/ψ production in the dielectron channel at midrapidity (|y|<1) in p+p and d+Au collisions at sNN=200GeV from the STAR experiment at the Relativistic Heavy Ion Collider. The transverse momentum pT spectra in p+p for pT<4GeV/c and d+Au collisions for pT<3GeV/c are presented. These measurements extend the STAR coverage for J/ψ production in p+p collisions to low pT. The (pT2) from the measured J/ψ invariant cross section in p+p and d+Au collisions are evaluated and compared to similar measurements at other collision energies. The nuclear modification factor for J/ψ is extracted as a function of pT and collision centrality in d+Au and compared to model calculations using the modified nuclear parton distribution function and a final-state J/ψ nuclear absorption cross section.