Measuring the rate of electron antineutrino charged-current interactions in the NOvA near detector with NuMI neutrino- and antineutrino-mode data*

The NOvA near detector (ND) is exposed to a large flux of (anti)neutrinos delivered by the NuMI beam when operating in (anti)neutrino mode. While most of the beam is composed of muon (anti)neutrinos, a small electron (anti)neutrino component is incident at the ND originating from the decay of muons, kaons, and pions resulting from the initial proton collision. The charged-current inclusive interaction rate of these intrinsic electron neutrinos in the NOvA detector has been recently measured with a sample of data observed during neutrino-mode run periods of NuMI. We now aim to measure the charged-current inclusive interaction rate of electron antineutrinos with data from NuMI antineutrino run periods.

 

A significant challenge of this measurement comes from the relatively large electron neutrino background due to similar topologies and its large cross section compared to the electron antineutrino. We present a data-driven template fit approach to signal estimation and a simultaneous fit to neutrino and antineutrino beam-mode data to constrain the electron neutrino background. This approach enables the measurement of the charged-current inclusive interaction rate of the electron antineutrino, and the ratio of measured electron neutrino and antineutrino interaction rates.