Luminosity measurement at muon collider

Abstract

The precise determination of the luminosity in a collider is of crucial importance for any physics cross sections measurement since it directly translates to the precision of the cross section determination. In a muon collider high intensity beams are necessary to achieve the target luminosity, and due to the muon decay they generate very high fluxes of particles that arrive to the detector. Ad-hoc shielding structure has been designed to mitigate the effect of the beam-induced background on the detector located in the backward and forward regions. Therefore, the instrumentation for the measurement of the luminosity can not be placed, as in the LHC experiments, in these regions. In this paper an alternative way to determine such a fundamental parameter is proposed, taking inspiration from flavour factories such as Belle2 and BESIII, where the luminosity is measured by counting $e^+$ $e^-$ $\rightarrow$ $e^+$ $e^-$ Bhabha events, whose cross section is theoretically known with high precision. At muon collider the large angle muon Bhabha ($\mu^+$ $\mu^-$ $\rightarrow$ $\mu^+$ $\mu^-$) events are used, and here the first results on the precision obtained at 1.5 TeV center of mass energy by using full detector simulation, taking into account the beam-induced background effects, are presented.