Constraining the NuMI neutrino flux using inverse muon decay reactions in MINERvA

Abstract

Inverse muon decay, ${\ensuremath{\nu}}_{\ensuremath{\mu}}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ensuremath{-}}{\ensuremath{\nu}}_{e}$, is a reaction whose cross section can be predicted with very small uncertainties. It has a neutrino energy threshold of $\ensuremath{\approx}11\text{ }\text{ }\mathrm{GeV}$ and can be used to constrain the high-energy part of the flux in the NuMI neutrino beam. This reaction is the dominant source of events which only contain high-energy muons nearly parallel to the direction of the neutrino beam. We have isolated a sample of hundreds of such events in neutrino and antineutrino enhanced beams, and have constrained the predicted high-energy flux.