Forward J/ψ production in U + U collisions at √sNN =193 GeV

Adare, A. and Aidala, C. and Ajitanand, N. N. and Akiba, Y. and Akimoto, R. and Csanád, Máté and Csörgő, Tamás and Varga-Kőfaragó, Mónika and Nagy, Márton and Novák, Tamás and Ster, András and Sziklai, János István and Vargyas, Márton and Vértesi, Róbert (2016) Forward J/ψ production in U + U collisions at √sNN =193 GeV. PHYSICAL REVIEW C, 93 (3). ISSN 2469-9985

Preview

Text 1509.05380.pdf Available under License Creative Commons Attribution. Download (1MB) | Preview

Abstract

The invariant yields for $J/\psi$ production at forward rapidity $(1.2<|y|<2.2)$ in U$+$U collisions at $\sqrt{s_{_{NN}}}$=193 GeV have been measured as a function of collision centrality. The invariant yields and nuclear-modification factor $R_{AA}$ are presented and compared with those from Au$+$Au collisions in the same rapidity range. Additionally, the direct ratio of the invariant yields from U$+$U and Au$+$Au collisions within the same centrality class is presented, and used to investigate the role of $c\bar{c}$ coalescence. Two different parameterizations of the deformed Woods-Saxon distribution were used in Glauber calculations to determine the values of the number of nucleon-nucleon collisions in each centrality class, $N_{\rm coll}$, and these were found to give significantly different $N_{\rm coll}$ values. Results using $N_{\rm coll}$ values from both deformed Woods-Saxon distributions are presented. The measured ratios show that the $J/\psi$ suppression, relative to binary collision scaling, is similar in U$+$U and Au$+$Au for peripheral and midcentral collisions, but that $J/\psi$ show less suppression for the most central U$+$U collisions. The results are consistent with a picture in which, for central collisions, increase in the $J/\psi$ yield due to $c\bar{c}$ coalescence becomes more important than the decrease in yield due to increased energy density. For midcentral collisions, the conclusions about the balance between $c\bar{c}$ coalescence and suppression depend on which deformed Woods-Saxon distribution is used to determine $N_{\rm coll}$.

Actions (login required)

Edit Item