We demonstrate that measurements of coherent elastic neutrino-nucleus scattering at spallation sources are valuable probes of muon-decay physics. Using COHERENT data we derive the first direct constraint on the Michel parameters governing the ν¯μ energy distribution. We also discuss future sensitivities, the implications for the Lorentz structure of the interactions mediating muon decay, and the application to other neutrino-production mechanisms like pion decay.
Bresó-Pla et al. (Mon,) studied this question.