2021 Abstract from Arsh

A Statistical Analysis of Time-Dependent Signals from Neutrino Up-scattering

Student Researcher: Arsh Suri (Chattahooch High School)

Scientist Mentors: Ryan Plestid, Vedran Brdar

Solar neutrino up-scattering inside the Earth can source heavy neutral leptons (HNLs) that can reach terrestrial experiments and decay into photons within them. As HNLs are sourced through up-scattering inside the Earth, the photon deposition signal will modulate daily, reaching the peak during the night and its minimum during the day; where the distance traveled by the solar neutrinos is the longest and shortest, respectively. In this project, we represent this modulation as a sine wave with amplitude that depends on the mass of the HNLs, mN , and its dipole portal interaction strength, dN . Using Poisson-distributed backgrounds and the daynight asymmetry as the observable, we simulated a Borexino-like counting experiment in the 0.3 − 0.8 MeV range. Using this method, we can exclude, at a 98% CL, HNL dipole strengths of d_n & 10^−9.5MeV⁻¹ in the mass range of 2 − 3.2 MeV.