The production of J/ψ originating from photoproduction processes in pp and PbPb collisions at leading order is calculated.We use the color singlet and color octet mechanisms for heavy quarkonium production to deal wi...The production of J/ψ originating from photoproduction processes in pp and PbPb collisions at leading order is calculated.We use the color singlet and color octet mechanisms for heavy quarkonium production to deal with the direct photon processes,and consider fragmentation processes.The shadowing and iso-spin of the nucleus are also considered in our calculation.The numerical results show that the modification of photoproduction processes for J/ψ production becomes obvious in the large pT region at LHC energy.展开更多
Using the photon spectrum of a high energy charged patton, we investigate the J/ψ production via the two photon interaction mechanism in ultra-peripheral pp collisions. It is shown that the contributions from the dir...Using the photon spectrum of a high energy charged patton, we investigate the J/ψ production via the two photon interaction mechanism in ultra-peripheral pp collisions. It is shown that the contributions from the direct electromagnetic and the corresponding fragmentation processes are meaningful for the J/ψ productions in ultra-peripheral pp collisions at LHC energy.展开更多
The thermal widths for heavy quarkonia are calculated for both Coulomb gauge (CG) and Feynman gauge (FG), and the comparisons between these results with the hard thermal loop (HTL) approximation ones are illustr...The thermal widths for heavy quarkonia are calculated for both Coulomb gauge (CG) and Feynman gauge (FG), and the comparisons between these results with the hard thermal loop (HTL) approximation ones are illustrated. The dissociation temperatures of heavy quarkonia in thermal medium are also discussed for CG, FG and HTL cases. It is shown that the thermal widths, derived from the HTL approximation and used in many research studies, cause some errors in the practical calculations at the temperature range accessible in the present experiment, and the problem of gauge dependence cannot be avoided when the complete self energy is used in the derivation of potential.展开更多
The contribution of the quark loop to the gluon damping rate at zero momentum is calculated using the effective perturbative expansion technique developed by Braaten and Pisarski. It is shown that in the temperature r...The contribution of the quark loop to the gluon damping rate at zero momentum is calculated using the effective perturbative expansion technique developed by Braaten and Pisarski. It is shown that in the temperature range accessible in the present heavy-ion experiments, the contribution of the quark loop can not be ignored. The numerical results show that the quark loop provides ~n apparent contribution to the gluon damping rate at temperatures of experimental interest.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10665003 and 11065010.
文摘The production of J/ψ originating from photoproduction processes in pp and PbPb collisions at leading order is calculated.We use the color singlet and color octet mechanisms for heavy quarkonium production to deal with the direct photon processes,and consider fragmentation processes.The shadowing and iso-spin of the nucleus are also considered in our calculation.The numerical results show that the modification of photoproduction processes for J/ψ production becomes obvious in the large pT region at LHC energy.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11465021 and 11065010.
文摘Using the photon spectrum of a high energy charged patton, we investigate the J/ψ production via the two photon interaction mechanism in ultra-peripheral pp collisions. It is shown that the contributions from the direct electromagnetic and the corresponding fragmentation processes are meaningful for the J/ψ productions in ultra-peripheral pp collisions at LHC energy.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11065010 and 11465021
文摘The thermal widths for heavy quarkonia are calculated for both Coulomb gauge (CG) and Feynman gauge (FG), and the comparisons between these results with the hard thermal loop (HTL) approximation ones are illustrated. The dissociation temperatures of heavy quarkonia in thermal medium are also discussed for CG, FG and HTL cases. It is shown that the thermal widths, derived from the HTL approximation and used in many research studies, cause some errors in the practical calculations at the temperature range accessible in the present experiment, and the problem of gauge dependence cannot be avoided when the complete self energy is used in the derivation of potential.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11465021 and 11065010
文摘The contribution of the quark loop to the gluon damping rate at zero momentum is calculated using the effective perturbative expansion technique developed by Braaten and Pisarski. It is shown that in the temperature range accessible in the present heavy-ion experiments, the contribution of the quark loop can not be ignored. The numerical results show that the quark loop provides ~n apparent contribution to the gluon damping rate at temperatures of experimental interest.