Impact of cross-section uncertainties on supernova neutrino spectral parameter fitting in the Deep Underground Neutrino Experiment

International audience ; A primary goal of the upcoming Deep Underground Neutrino Experiment (DUNE) is to measure the O ( 10 ) MeV neutrinos produced by a Galactic core-collapse supernova if one should occur during the lifetime of the experiment. The liquid-argon-based detectors planned for DUNE are expected to be uniquely sensitive to the ν e component of the supernova flux, enabling a wide variety of physics and astrophysics measurements. A key requirement for a correct interpretation of these measurements is a good understanding of the energy-dependent total cross section σ ( E ν ) for charged-current ν e absorption on argon. In the context of a simulated extraction of supernova ν e spectral parameters from a toy analysis, we investigate the impact of σ ( E ν ) modeling uncertainties on DUNE’s supernova neutrino physics sensitivity for the first time. We find that the currently large theoretical uncertainties on σ ( E ν ) must be substantially reduced before the ν e flux parameters can be extracted reliably; in the absence of external constraints, a measurement of the integrated neutrino luminosity with less than 10% bias with DUNE requires σ ( E ν ) to be known to about 5%. The neutrino spectral shape parameters can be known to better than 10% for a 20% uncertainty on the cross-section scale, although they will be sensitive to uncertainties on the shape of σ ( E ν ) . A direct measurement of low-energy ν e -argon scattering would be invaluable for improving the theoretical precision to the needed level.