Muon production in low-energy electron-nucleon and electron-nucleus scattering

Abstract

Recently, muon production in electron-proton scattering has been suggested as a possible candidate reaction for the identification of lepton-flavor violation due to physics beyond the Standard Model. Here we point out that the Standard-Model processes $e^{-}p\to {\mu }^{-}p{\bar{\nu }}_{\mu }{\nu }_e$ and $e^{-}p\to e^{-}n{\mu }^{+}{\nu }_{\mu }$ can cloud potential beyond-the-Standard-Model signals in electron-proton collisions. We find that Standard-Model $ep\to \mu X$ cross sections exceed those from lepton-flavor-violating operators by several orders of magnitude. We also discuss the possibility of using a nuclear target to enhance the $ep\to \mu X$ signal.

Comments: 24 pages. Additional figure showing energy-dependence of total cross section, minor changes to text. Conclusions unaltered. This version to appear in Physical Review D