Systematic Uncertainties and Cross-Checks for the NOvA Joint $ν_μ$+$ν_e$ Analysis
The physics goals of NOvA are the constraints of neutrino oscillation parameters such as the octant of $θ_{23}$, $δ_{\rm{CP}}$, and the neutrino mass hierarchy via a joint fit to $ν_μ$ and $ν_{e}$ oscillation spectrum. We do this by propagating $ν_μ$ from the world's most intense neutrino beam at Fermilab, over a baseline of 810 km to northern Minnesota, USA, and measure the $ν_μ$ to $ν_{e}$ 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: $Δm^2_{32}=2.51^{+0.12}_{-0.08}\times 10^{-3} \mathrm{eV}^2$, $\mathrm{sin}^2θ_{23} = 0.58 \pm 0.03$ (upper octant), and $δ_{\rm{CP}}=0.17π$ 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.