Coherent photo-produced J/ψ and dielectron yields in isobaric collisions

Abstract

Recently, significant enhancements of J/ψ and e+e− pair production at very low transverse momenta were observed by the STAR and ALICE collaborations in peripheral hadronic A + A collisions. The anomalous excesses point to evidence of coherent photon–nucleus and photon–photon interactions in violent hadronic heavy-ion collisions, which were conventionally studied only in ultra-peripheral collisions. The isobaric collisions performed at RHIC provides a unique opportunity to test the existence of coherent photon products in hadronic heavy-ion collisions. The idea is that the possible production of coherent photon products is significantly different in different collision systems due to the variations in their charge and nuclear density distributions. In this letter, we focus on the peripheral collisions and provide theoretical predictions for coherent production of J/ψ and dielectron in isobaric collisions. We show that the expected yields differ significantly to perform the experimental test.