$J/\psi$ dissociation by pions in QCD

Abstract

We compute the $J/\psi \pi \to charmedmesons$ cross section using QCD sum rules. This cross section is important to distinguish the suppression in the production of $J/\psi$ through the dissociation by comoving pions and through the formation of quark-gluon plasma. Our sum rules for the $J/\psi \pi \to \bar{D}{D}^{\ast }$, $D{\bar{D}}^{\ast }$, ${\bar{D}}^{\ast }{D}^{\ast }$ and $\bar{D}D$ hadronic matrix elements are constructed by using vaccum-pion correlation functions, and we work up to twist-4 in the soft-pion limit. After doing a thermal average we get $<{\sigma }^{\pi J/\psi }v>\sim 0.2-0.4$ mb at $T=150\text{MeV}$

Comments: revised version to be published in Phys. Lett. B