The Atmosphere as a Sandbox for BSM Solutions to Short-Baseline Anomalies

This research advances the simulation of neutrino oscillations in the atmosphere as a method for investigating Beyond the Standard Model (BSM) theories. The continuously varying density profile of the atmosphere (~0–0.0012 g/cm3) along with the large energy range of atmospheric neutrinos presents an ideal medium for observing the Mikheyev-Smirnov-Wolfenstein (MSW) matter effects of BSM theories on neutrino oscillations as it allows phenomenological access to a wide range of energies at which the theories become relevant. Through this work, enhancements made to the neutrino Simple Quantum Integro-Differential Solver (nuSQuIDS) now allow for the simultaneous modeling of production and oscillation of neutrinos in the atmosphere, a capability previously absent across neutrino propagation simulators. This development is important in the context of the short-baseline anomalies observed at MiniBooNE and LSND. At MiniBooNE, the relevant baseline density (~2 g/cm3) and the energy range (200–1250 MeV) of the anomalous ?e appearance correspond to an equivalent MSW effect at the surface atmospheric density of 0.0012 g/cm3 and at energies of 333 GeV–2 TeV, well within the range of atmospheric neutrinos produced from cosmic rays. We use the work of Daniele S. M. Alves et al. on the short baseline anomaly as a model theory to motivate the use of atmospheric neutrinos as a natural laboratory for exploring novel neutrino physics.