Bottomonium Production at √ S N N =200 Gev and √ S N N =5.5 Tev

Properties of bottomonia (Υ, χb and Υ ′) in the Quark-Gluon Plasma (QGP) are investigated by assessing inelastic reaction rates and their interplay with open-bottom states (b quarks or B mesons) and color-screening. The latter leads to vanishing quarkonium-binding energies at sufficiently high temperatures (close to the dissolution point), which, in particular, renders standard gluodissociation, g+Υ → b+ b̄, inefficient due to a substantial reduction in final-state phase space. This problem is overcome by invoking a “quasifree” destruction mechanism, g, q, q̄ +Υ → g, q, q̄ + b+ b̄, as previously introduced for charmonia. The pertinent reaction rates are implemented into a kinetic theory framework to evaluate the time evolution of bottomonia in heavy-ion reactions at RHIC and LHC within an expanding fireball model. While bottom quarks are assumed to be exclusively produced in primordial nucleon-nucleon collisions, their thermal relaxation times in the QGP, which importantly figure into Υ-formation rates, are estimated according to a recent Fokker-Planck treatment. Predictions for the centrality dependence of Υ production are given for upcoming experiments at RHIC and LHC. At both energies, Υ suppression turns out to be the prevalent effect.