Systematic Uncertainties and Cross-Checks for the NOvA Joint $\nu_\mu$+$\nu_e$ Analysis

Abstract

The physics goals of NOvA are the constraints of neutrino oscillation parameters such as the octant of $\theta_{23}$, $\delta_{\rm{CP}}$, and the neutrino mass hierarchy via a joint fit to $\nu_{\mu}$ and $\nu_{e}$ oscillation spectrum. We do this by propagating $\nu_{\mu}$ from the world's most intense neutrino beam at Fermilab, over a baseline of 810 km to northern Minnesota, USA, and measure the $\nu_{\mu}$ to $\nu_{e}$ oscillation probability. NOvA announced its latest oscillation results, based on 8.85$\times10^{20}$ (6.9$\times10^{20}$) protons on target neutrino (antineutrino) data. Preliminary results for the allowed values of oscillation parameters are: $\Delta m^2_{32}=2.51^{+0.12}_{-0.08}\times 10^{-3} \mathrm{eV}^2$, $\mathrm{sin}^2\theta_{23} = 0.58 \pm 0.03$ (upper octant), and $\delta_{\rm{CP}}=0.17\pi$ with preference to the normal hierarchy. Reliable constraints on these oscillation parameters require a rigorous treatment of systematic uncertainties and thorough cross-checks. In this paper, we present an overview of the treatment of systematic uncertainties as well as cross-checks using muon removed simulations and cosmic muon bremsstrahlung showers.