Quarkonium dissociation in quark-gluon plasma via ionization in magnetic field

Abstract

We study the impact of magnetic fields generated in relativistic heavy ion collisions on the decay probability of quarkonium produced in the central rapidity region. The quark and anti-quark components are subject to mutually orthogonal electric and magnetic fields in the quarkonium comoving frame. In the presence of an electric field, quarkonium has finite dissociation probability. We use the WKB approximation to derive the dissociation probability. We found that quarkonium dissociation energy, i.e. the binding energy at which dissociation probability is of order unity, increases with the magnetic field strength. It also increases with quarkonium momentum in the laboratory frame due to Lorentz boost of electric field in the comoving frame. As a consequence, J/Psi in plasma dissociates at lower temperature then it would be in the absence of a magnetic field. We argue that J/Psi's produced in heavy-ion collisions at LHC with P_T>9GeV would dissociate even in vacuum. In plasma, J/Psi dissociation in magnetic field is much stronger due to decrease of its binding energy with temperature. We discuss the phenomenological implications of our results.