Coherent J/ψ photoproduction in peripheral heavy-ion collisions

In 2015, the ALICE Collaboration reported the first measurement of an excess in the yield of at very low transverse momentum ( ) in the forward rapidity region (2.5 <  y  < 4) in peripheral lead-lead (Pb-Pb) collisions at at the CERN LHC. The coherent photoproduction was proposed as the potential underlying physics mechanism. This is known to be the main production mechanism for low- production in ultra-peripheral collisions, which are dominated by electromagnetic interactions. However, the observation of a large effect in more central collisions that are dominated by the hadronic interactions was quite surprising. This article represents a proceeding contribution on the preliminary results from Pb-Pb collisions at shown in a poster during the National Congress of the French Physics Society in July 2019.