J/ψproduction at low transverse momentum inp+pandd+ Au collisions at

Abstract

We report on the measurement of J/ψ production in the dielectron channel at mid-rapidity (|y| < 1) in p+p and d+Au collisions at √ sNN = 200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider. The transverse momentum pT spectra in p+p for pT < 4 GeV/c and d+Au collisions for pT < 3 GeV/c are presented. These measurements extend the STAR coverage for J/ψ production in p+p collisions to low pT . The p 2 T 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.

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

“…Figure 9 shows the inclusive J/ψ production cross-section at mid-rapidity (|y| < 1) as a function of p T in non-singlediffractive p+p collisions at √ s = 200 GeV measured by the STAR Collaboration [70] via the di-electron decay channel by combining the events from minimum-bias trigger and triggered by the electromagnetic calorimeter with various thresholds, taken in 2012. The results are found to be consistent with STAR previously published results [71,72] and PHENIX published results (|y| < 0.35) [73] but with improved precision at p T > 2 GeV/c. The decay branching ratio is not corrected for.…”

“…9. Top panels: Inclusive J/ψ production cross section times decay branching ratio as a function of p T at mid-rapidity in non-single diffractive p+p collisions at √ s = 200GeV measured by the STAR [70][71][72] and PHENIX [73] Collaborations. The bars and boxes on the data points depict statistical and systematical uncertainties, respectively.…”

Quarkonium propagation in the quark–gluon plasma

“…Excited states of quarkonia can feed-down to the lower energy states after formation. CNM effects (see [160][161][162][163][164][165][166][167][168][169][170][171][172][173][174][175] for experimental constraints) modify the initial production rates in AA collisions.…”

Measurement of $ψ(2S)$ nuclear modification at backward and forward rapidity in $p$$+$$p$, $p$$+$Al, and $p$$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV

“…At backward and forward rapidity 1.2 < |y| < 2.2, PHENIX has published J/ψ nuclear modification in p+Al, p+Au, and 3 He+Au collisions [30]. The J/ψ nuclear modification in d+Au collisions was measured by the STAR collaboration at rapidity |y| < 1 [31]. The ψ(2S) nuclearmodification factor was also measured by PHENIX in d+Au collisions at rapidity |y| < 0.35 [8], and the ψ(2S) to J/ψ ratio for the centrality-integrated case was measured in p+p, p+Al, p+Au, and 3 He+Au collisions at rapidity 1.2 < |y| < 2.2 [32].…”