An experimental review of open heavy flavor and quarkonium production at RHIC

Open heavy flavors and quarkonia are unique probes of the hot–dense medium produced in heavy-ion collisions. Their production in p+p collisions also constitutes an important test of QCD. In this paper, we review selected results on the open heavy flavors and quarkonia generated in the p+p and heavy-ion collisions at the Relativistic Heavy Ion Collider. The physical implications are also discussed.

Extraction of inclusive photon production at mid-rapidity in p+p and Au+Au collisions at√SNN=200GeV

We present a comprehensive study on the individual sources of an inclusive photon production during high-energy hadronic collisions.The cross section and invariant yields of inclusive photons are obtained as a function of pT at mid-rapidity(|y|<0.5)in p+p and Au+Au collisions at√SNN=200GeVrespectively.These results provide crucial inputs to separate measurements of open bottom and charm hadron yield suppression in heavyion collisions,which are used to test the mass hierarchy of the parton energy loss in the quark gluon plasma created during these collisions.The procedure developed in this study can also be applied to other measurements of electrons from an open heavy-flavor hadron decay,such as the collective flow in the RHIC beam energy scan program.

Photoproduction of J/ψ in non-single-diffractive p+p collisions

Significant enhancements of J/ψ production at very low transverse momenta were recently observed by the ALICE and STAR collaborations in peripheral hadronic A+A collisions. The anomalous excess points to coherent photon-nucleus interactions in violent hadronic heavy-ion collisions, which were conventionally studied only in ultra-peripheral collisions. Assuming that the coherent photoproduction is the underlying mechanism responsible for the excess observed in peripheral A+A collisions, its contribution in p+p collisions with nuclear overlap, i.e. nonsingle-diffractive collisions, is of particular interest. In this paper, we perform a calculation of exclusive J/ψ photoproduction in non-single-diffractive p+p collisions at the RHIC and LHC energies based on the pQCD motivated parametrization using the world-wide experimental data, which could be further employed to improve the precision of the phenomenological calculations for photoproduction in A+A collisions. The differential rapidity and transverse momentum distributions of J/ψ from photoproduction are presented. In comparison with the J/ψ production from hadronic interactions, we find that the contribution of photoproduction is negligible.