Indirect Probe of Electroweak-Interacting Particles at $\mu$TRISTAN $\mu^+\mu^+$ Collider

Abstract

Recently, a novel collider, called $\mu$TRISTAN, has been proposed, offering the capability to achieve high-energy collisions of anti-muons. This high-energy collider presents an exceptional opportunity for the discovery of electroweak-interacting massive particles (EWIMPs), which are predicted by various new physics models. In a lepton collider like $\mu$TRISTAN, the potential for discovering EWIMPs extends beyond their direct production. Quantum corrections arising from EWIMP loops can significantly enhance our prospects for discovery by precise measurement of Standard Model processes. This study focuses on the indirect detection method within the $\mu$TRISTAN experiment, with a specific emphasis on TeV-scale EWIMP dark matter scenarios that yield the correct thermal relic density. At collision energies for $ \sqrt{s} = O(1-10)$ TeV, these EWIMPs introduce noticeable effects, typically in the range of $O(0.1-1)$\%. Our findings indicate that at $\sqrt{s} = 2\, (10)$ TeV, with an integrated luminosity of 10 ab$^{-1}$, the $\mu$TRISTAN can detect Higgsino at a mass of 1.3 (3.0) TeV and Wino at a mass of 1.9 (4.4) TeV, assuming an optimistic level of systematic uncertainty in the observation of the Standard Model processes.