Non-Standard Neutrino Interactions at a Muon Collider Neutrino Detector

In addition to their broad physics reach enabled by their high energies and precision, future multi-TeV muon colliders will also be the world's most intense sources of neutrinos. This offers the opportunity to search for new non-standard neutrino interactions, possible by installing a dedicated forward neutrino detector in the straight sections of the collision ring, which is then used to measure reactions initiated by neutrinos from the decaying beam muons. In this paper, we show that these searches can exceed current and upcoming bounds on non-standard neutrino interactions from low-energy precision experiments and the LHC. This is achieved by the large flux of high-energetic neutrinos, the precise knowledge of the neutrino flavor composition on each side of the interaction point and the chirality of the neutrinos. We further discuss the technical requirements of the proposed forward neutrino detector, \FASERmuC, to maximally exploit this physics potential.