Gluo-dissociation of heavy quarkonium in the quark-gluon plasma reexamined

Abstract

Using an effective Hamiltonian derived from the QCD multipole expansion, we calculate the cross sections of gluo-dissociation of heavy quarkonia in the quark-gluon plasma, by including both the chromo-electric dipole (E 1 ) as well as the chromo-magnetic dipole (M 1 ) transition mechanisms. While the former allows to reproduce the results from operator-product-expansion calculations in the Coulomb approximation, the latter as a novel contribution is shown to be significant at low energies close to the threshold. Using thus obtained cross sections, we further carry out a full calculation of the gluo-dissociation rates for various charmonia and bottomonia within a non-relativitic in-medium potential model. The M 1 contribution turns out to be most prominent for the J/ψ and accounts for ∼ 10% − 25% of the total (E1 + M 1) dissociation rate at temperatures close to the transition temperature.

Dissociation of Quarkonium in Hot and Dense Media in an Anisotropic Plasma in the Nonrelativistic Quark Model

“…[2][3][4][5][6][7][8][9][10][11][12], and the disassociation temperature has been studied in Refs. [13][14][15][16][17]. In addition, ultrarelativistic heavy-ion collisions (URHIC) are used to explore the quark-gluon plasma (QGP) media as in [18][19][20].…”

Suppression of quarkonia in PbPb collisions at $\sqrt{{s}_{{NN}}}$ = 5.02 TeV

“…In that work, the gluon dissociation cross section has been adopted from the calculations of Bhanot and Peskin [36] where the gluon dissociation rate has been estimated from operator product expansion in the Coulomb approximation. Recently, Chen and He have revisited the gluon dissociation using QCD multipole expansion for various quarkonia in QGP [37]. They reproduced the result of Bhanot and Peskin as the colour-electric dipole (E1) transition.…”

“…where 0 is the quarkonia binding energy and m q is the charm/bottom quark mass and a 0 = 1/ √ m q 0 . Using the same procedure, the M1 transition cross-section of gluon dissociation can be calculated as [37] The total dissociation cross section is given as…”

“…For the excited states of bottomonia, the dissociation cross sections are used from Ref. [37,43]. Figure 1 shows the gluon dissociation cross sections of J/ψ and Υ(1S) as a function of gluon energy for both color-electric and color-magnetic dipole transitions.…”

“…The color screening of qq potential inside the QGP [34,35] was the first approach to study the suppression of quarkonia in heavy ion collisions. In a complementary way to this static approach, J/ψ suppression can also be understood as a result of dynamical interactions with the surrounding gluons [36,37,26]. One of the ways to calculate the regeneration is to use the principle of detailed balance [23].…”