Elliptic flow as a probe for $\psi (2S)$ production mechanism in relativistic heavy ion collisions

Abstract

I discuss the elliptic flows of $\psi (2S)$ with different production mechanisms in $\sqrt{s_{NN}}=2.76$ TeV Pb-Pb collisions. If the final $\psi (2S)$s are mainly from the recombination of uncorrelated charm and anticharm quarks at $T\approx T_c$, charm and anticharm quarks will carry large collective flows of the bulk medium, which will be inherited by the regenerated $\psi (2S)$s. This indicates a larger elliptic flow of $\psi (2S)$ than that of $J/\psi$ which can be regenerated at $T\ge T_c$, $v_2^{\psi (2S)}>v_2^{J/\psi }$. However, if the final $\psi (2S)$s are mainly from the transitions of $J/\psi \to \psi (2S)$ caused by the color screening of QGP, its elliptic flow should be close to the elliptic flow of $J/\psi$, $v_2^{\psi (2S)}\sim v_2^{J/\psi }$. Therefore, $\psi (2S)$ elliptic flow is a sensitive probe for its production mechanisms in relativistic heavy ion collisions.

Comments: 6 pages, 4 figures. (implements of Wigner function for regeneration, and other discussions.)