Modeling supernova neutrino interactions in argon with MARLEY
Core-collapse supernovae, the death throes of stars larger than about eight solar masses, are sources of incredible numbers of neutrinos. Since the first observation of one of these events via its neutrinos in 1987, there has been a growing effort to make a high-statistics measurement of neutrinos from the next galactic or nearby extragalactic core-collapse supernova. The successful detection of many neutrinos from this supernova would represent a significant scientific achievement, allowing us to better understand supernova dynamics and nucleosynthesis, to search for exotic physics beyond the Standard Model, and to provide an early warning signal for later observations of the explosion using conventional telescopes. Unlike most of the existing neutrino detectors that would be sensitive to a nearby supernova, which use water or liquid scintillator as the target material, the liquid-argon-based Deep Underground Neutrino Experiment (DUNE) would primarily observe charged current interactions of electron neutrinos. This sensitivity to electron neutrinos would allow DUNE to provide unique information about a supernova event, such as a measurement of the neutronization burst. However, unlike the relatively simple antineutrino captures on protons that dominate in oil- and water-based detectors, supernova neutrino reactions on argon are strongly affected by nuclear structure and can lead to numerous final states. Detector simulations can in principle allow future DUNE analyses to account for this complexity, but a more detailed model of neutrino-argon scattering than is currently available in standard high-energy neutrino event generators is needed. In an effort to understand supernova neutrino signals in DUNE, we have developed a detailed low-energy model of charged current electron neutrino scattering on argon, including event-by-event nuclear de-excitation products. This model has been implemented in a new neutrino event generator called MARLEY (Model of Argon Reaction Low Energy Yields). In this talk, we present our model, its implementation in MARLEY, and some MARLEY-based calculations of expected supernova signals in DUNE.