Hadronic effects on charmonium elliptic flows in heavy-ion collisions

We study the effects of hadron phase on the collective flows of charmonia in heavy-ion collisions. In Pb-Pb collisions, charmonia with high transverse momentum $p_T$ are produced by the primordial hard process and then travel through the hot dense medium. In the semi-central centrality, the anisotropic energy density of quark-gluon plasma (QGP) in the transverse plane is transformed to the momentum anisotropy of the hadrons after the phase transition. Charmonia suffer different magnitudes of dissociation along different paths in QGP and then scatter with light hadrons in the hadron phase. We calculate both contributions and find that hadronic interactions can significantly enhance the elliptic flows of charmonia especially the excited states in the high $p_T$, which will increase the elliptic flows of prompt and inclusive $J/\psi$s with the decay process $\chi_c( \psi^\prime)\rightarrow J/\psi$ X.