Constraining Beam Systematics in the NOvA Sterile Search

The NOvA (NuMI Off-axis v_e Appearance) experiment measures neutrino oscillations in a nearly pure muon neutrino beam over a 810 km baseline. We look at neutral current (NC) interactions to search for evidence of Physics beyond the Standard Model as a deficit of NC interactions at the Far Detector would indicate oscillations to sterile neutrinos that do not couple to the Z boson. The NuMI beam line is capable of running in forward or reverse horn current modes, which creates a neutrino or antineutrino beam, respectively. Samples collected in forward horn current (FHC) or reverse horn current (RHC) modes are subject to beam optics uncertainties, in addition to cross section and hadron production uncertainties. We explore the possibility of using a sample collected with the focusing horns turned off, the zero horn current (ZHC) sample, to break the degeneracy between various uncertainty categories. Fitting the ZHC sample jointly with FHC and RHC samples would exclude the focusing uncertainties and factor out effects of various systematics in the sterile analysis. In this talk, we will show how the ZHC sample influence the NOvA sterile search sensitivity parameter spaces.