Muonic Force and Neutrino Non-Standard Interactions at Muon Colliders

Abstract: The discovery of neutrino oscillations implies that neutrinos are massive and mixed, necessitating an extension of the Standard Model, which may require the introduction of non-standard neutrino interactions (NSI). We investigate the potential of a high-energy muon collider to probe such NSIs with muons, specifically focusing on muonic forces. By analyzing the monophoton signal from the process $\mu^+ \mu^- \rightarrow \nu \overline{\nu } \gamma$, we explore four-fermion contact interactions involving two muons and two neutrinos. Moreover, we examine minimal models that generate scalar and vector-mediated NSIs and study their phenomenology. Projected sensitivities for the strength of NSIs, $\epsilon_{\alpha \beta}^{\mu \mu}$, are presented at a 95$\%$ confidence level for a center-of-mass energy of 3 TeV and integrated luminosities of $\mathcal{L} = 1$ and $10~\mathrm{ab}^{-1}$, showcasing the complementarity between a muon collider and other experimental probes.