J/psi production at low transverse momentum in p plus p and d plus Au collisions at root s(NN)=200 GeV
We report on the measurement of J/psi production in the dielectron channel at midrapidity (vertical bar y vertical bar < 1) in p + p and d + Au collisions at root s(NN) = 200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider. The transverse momentum p(T) spectra in p + p for pT < 4 GeV/c and d + Au collisions for p(T) < 3 GeV/c are presented. These measurements extend the STAR coverage for J/psi production in p + p collisions to low p(T). The < p(T)(2)> from the measured J/psi 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/psi 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/psi nuclear absorption cross section.
Drachenberg, J L.; Gibson, A; Grosnick, D; Koetke, D D.; Stanislaus, T D.; and STAR Collaboration, "J/psi production at low transverse momentum in p plus p and d plus Au collisions at root s(NN)=200 GeV" (2016). Physics and Astronomy Faculty Publications. 150.