Complementary Signals of Lepton Flavor Violation at a High-Energy Muon Collider

TL;DR

A high-energy muon collider can effectively probe lepton flavor violation, complementing low-energy experiments, by discovering sleptons, measuring their properties, and providing insights into new physics beyond the Standard Model.

Contribution

This paper demonstrates the collider's potential to detect flavor-violating sleptons and measure their properties, offering a complementary approach to low-energy precision experiments in exploring new physics.

Findings

Collider can discover sleptons and measure masses precisely

Collider reach overlaps with future $$ conversion and EDM experiments

Collider can directly shed light on the nature of flavor-violating new physics

Abstract

A muon collider would be a powerful probe of flavor violation in new physics. There is a strong complementary case for collider measurements and precision low-energy probes of lepton flavor violation (as well as CP violation). We illustrate this by studying the collider reach in a supersymmetric scenario with flavor-violating slepton mixing. We find that the collider could discover sleptons and measure the slepton and neutralino masses with high precision, enabling event reconstruction that could cleanly separate flavor-violating new physics signals from Standard Model backgrounds. The discovery reach of a high-energy muon collider would cover a comparably large, and overlapping, range of parameter space to future $\mu \to e$ conversion and electron EDM experiments, and unlike precision experiments could immediately shed light on the nature of new physics responsible for flavor violation. This complementarity strengthens the case that a muon collider could be an ideal energy-frontier laboratory in the search for physics beyond the Standard Model.