Two-to-two processes at an electron-muon collider

Abstract

Based on a recent proposal to build an electron-muon collider, we study two-to-two production processes e − µ + → f f , γγ that originate from dimension 6 and 8 operators. We compare the sensitivity to those effective couplings obtained at the collider with that of low energy measurements of µ → eγ, µ → eēe and µ → e conversion that have recently been reported in the literature. Whereas for the production of first family fermions the sensitivity of the collider processes is much weaker, for the second and third familiy fermions it is similar or stronger than that of low-energy processes. In the case of e − µ + → γγ, the sensitivity to a dimension 8 contact operator turns out to be the strongest in comparison.