We calculate the quarkonium formation time in relativistic heavy-ion collisions from the space-time correlator of heavy quark vector currents in a hydrodynamic background with the initial nonequilibrium stage expanding only in the longitudinal direction. Using in-medium quarkonia properties determined with the heavy quark potential taken to be the free energy from lattice calculations and the fact that quarkonia can only be formed below their dissociation temperatures due to color screening, we find that Υ(1S), Υ(2S), Υ(3S), J/ψ, and ψ′ are formed, respectively, at 1.2, 6.6, 8.8, 5.8, and 11.0fm/c after the quark pair are produced in central Au+Au collisions at the top energy of the BNL Relativistic Heavy Ion Collider (RHIC), and these times become shorter in semicentral collisions. We further show, as an example, that including the effect of formation time enhances appreciably the survivability of Υ(1S) in the produced hot dense matter.
Bibliographical noteFunding Information:
This work was supported in part by the U.S. National Science Foundation under Grant No. PHY-1068572, the US Department of Energy under Contract No. DE-FG02-10ER41682 within the frame of the JET Collaboration, the Welch Foundation under Grant No. A-1358, the Korean Research Foundation under Grant Nos. KRF-2011-0020333 and KRF-2011-0030621, and the DFG.
© 2015 American Physical Society.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics