Speaker
Description
As the planning phases for a high-energy muon collider move into a new era, the issue of what new physics could be discovered becomes crucial. The discovery of neutrino oscillations has shown that neutrinos are massive and mixed, necessitating an extension of the Standard Model. In these extensions, neutrinos can acquire new interactions, namely neutrino non-standard interactions. On the other hand, several anomalies appear in the muon sector, beginning with muon $g-2$, neutrino short-baseline anomalies, $R_K(*)$, etc. Here, we examine whether a muon collider can cast light on these non-standard neutrino interactions $\epsilon_{\alpha \beta}^{\mu \mu}$ involving muonic forces. We show that the monophoton signal at a high energy muon collider, $\mu^+ \mu^- \rightarrow \nu \overline{\nu } \gamma$, is a sensitive probe of new physics. We consider the full set of four fermion contact interactions involving two muons and two neutrinos that contribute to this process at dimension six and discuss the complementarity of a muon collider and other experimental probes. Any UV-complete model of non-standard neutrino interactions is expected to provide a more extensive phenomenology; thus, for completeness, we consider a minimal $Z'$ model that interacts with both muons and neutrinos and discuss the phenomenology in depth.
Using centre-of-mass energies of 3, 10, and 30 TeV, we give projected sensitivities on the non-standard neutrino interaction strength $\epsilon_{\alpha \beta}^{\mu \mu}$ at 95$\%$CL and discuss the required luminosity for 5$\sigma$ discovery. We conclude with a comparison of the muon collider results to other future colliders.
| Collaboration / Activity | MPIK Heidelberg |
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