Pair invariant mass spectrum and polarization asymmetry in the event generation of gamma-ray conversions

Abstract

We examine the dielectron invariant mass spectrum and the variation of the polarization asymmetry as a function of that mass in the event generator of the five-dimensional Bethe-Heitler differential cross section of the conversion of linearly polarized photons that we have implemented recently as a Geant4 Physics Model. We compare the results obtained with simulated samples to analytical expressions. Studies of $b\to s\gamma$ decays at LHC and Belle II experiments could provide hints of physics beyond the standard model in flavor-changing neutral current processes; issues have been reported in the simulation of the properties of the background induced by genuine $\gamma$-ray conversions in their detectors. Our results demonstrate that using the five-dimensional model would help solve these issues.

Comments: v2 : complemented [7] with most recent LHCb result