Upcgen: a Monte Carlo simulation program for dilepton pair production in ultra-peripheral collisions of heavy ions

Abstract

Ultra-peripheral collisions (UPCs) of heavy ions can be used as a clean environment to study two-photon induced interactions such as dilepton pair photoproduction. Recently, precise data on lepton pair production in UPCs were obtained by the ATLAS experiment at the LHC where significant deviations, of up to 20%, from available theoretical predictions were observed. In this work, we present a Monte Carlo event generator, Upcgen, that implements an improved treatment of nuclear form factors in the photon flux calculation allowing us to reproduce experimental measurements. Besides, the new generator offers a possibility to set arbitrary values of the lepton anomalous magnetic moment that can be used in the future studies of tau g − 2 via ditau production measurements in UPCs.