Neutrino trident process at a muon collider

Abstract

A TeV-scale muon collider enables the production of a highly collimated high-energy neutrino flux by muon decay in the straight sections of the collider ring. Recent studies have demonstrated that these neutrinos can be used for high-precision measurements in neutrino physics with a dedicated far-forward neutrino detector. In this study, we investigate the potentiality of the muon collider to discover the rare neutrino trident process, which is characterized by the fusion between a weak boson from the neutrino and a photon from the Coulomb field of the nucleus target. Our results indicate large neutrino trident rates per year [$\mathcal{O}(10^3)$] in a baseline 10 kg neutrino detector for a configuration of different flavour pairs of charged leptons in the final state, which will allow high-precision tests of the Standard Model and searches for New Physics. As a first example, we investigate the impact of the a new gauge boson $Z'$, as predicted by the $L_\mu - L_\tau$ model, and derive the projected sensitivity to this new gauge boson. Our findings show that a neutrino detector at a muon collider will significantly extend the current excluded regions of the parameter space.