Heavy quarkonium photoproduction in ultrarelativistic heavy ion collisions

摘要

Based on the factorization formalism of nonrelativistic quantum chromodynamics (NRQCD), we calculate the production cross section for the charmonium [J/ψ, ψ(2S), χ_(cJ) , η_c, and h_c] and the bottomonium [γ(nS), χ_(bJ) , η_b, and h_b] produced by the hard photoproduction processes and fragmentation processes in relativistic heavy ion collisions. It is shown that the existing experimental data on heavy quarkonium production at the Large Hadron Collider (LHC) can be described in the framework of the NRQCD formalism, and the phenomenological values of matrix elements for color-singlet and color-octet components give the main contribution. The numerical results of photoproduction processes and fragmentation processes for the heavy quarkonium production become prominent in p-p collisions and Pb-Pb collisions at LHC energies.