Measurement of Muon Antineutrino Quasi-Elastic Scattering on a Hydrocarbon Target at E_{\nu} ~ 3.5 GeV

TL;DR

This study measures muon antineutrino quasi-elastic scattering on hydrocarbon at around 3.5 GeV, comparing results to models and finding good agreement with a modified vector form factor approach.

Contribution

It provides the first flux-averaged differential cross-section measurement for muon antineutrino quasi-elastic interactions at this energy, testing and supporting specific theoretical models.

Findings

Good agreement with a model using M_A=0.99 GeV/c^2 and modified vector form factors.

Data at higher Q^2 favor the modified vector form factor interpretation.

Results constrain theoretical models of neutrino-nucleus interactions.

Abstract

We have isolated muon anti-neutrino charged-current quasi-elastic interactions occurring in the segmented scintillator tracking region of the MINERvA detector running in the NuMI neutrino beam at Fermilab. We measure the flux-averaged differential cross-section, d{\sigma}/dQ^2, and compare to several theoretical models of quasi-elastic scattering. Good agreement is obtained with a model where the nucleon axial mass, M_A, is set to 0.99 GeV/c^2 but the nucleon vector form factors are modified to account for the observed enhancement, relative to the free nucleon case, of the cross-section for the exchange of transversely polarized photons in electron-nucleus scattering. Our data at higher Q^2 favor this interpretation over an alternative in which the axial mass is increased.