ψ′ production and B decay in heavy ion collisions at LHC

In comparison with J/ψ, the excited charmonium state ψ′ is loosely bounded and its yield is dominantly from the B-hadron decay. Based on the transport approach, we study the double ratio of N(ψ′)/N(J/ψ) from A+A collisions to that from p+p collisions at LHC energy. We found that the primordial production in the initial stage and the regeneration in the hot medium are not significant for ψ′ production in heavy ion collisions at LHC and the double ratio in semi-central and central collisions is controlled by the B decay.