Testing Non-Standard Interactions Between Solar Neutrinos and Quarks with Super-Kamiokande

TL;DR

This study investigates non-standard neutrino interactions with quarks using Super-Kamiokande data, finding mild evidence for such interactions, especially with down quarks, and combining results from other detectors to enhance significance.

Contribution

First analysis to search for NSI between solar neutrinos and quarks using Super-Kamiokande data, providing new constraints and evidence for these interactions.

Findings

Evidence for NSI with down quarks at 1.8σ

Evidence for NSI with up quarks at 1.6σ

Combined data increases significance slightly

Abstract

Non-Standard Interactions (NSI) between neutrinos and matter affect the neutrino flavor oscillations. Due to the high matter density in the core of the Sun, solar neutrinos are suited to probe these interactions. Using the $277$ kton-yr exposure of Super-Kamiokande to $^{8}$B solar neutrinos, we search for the presence of NSI. Our data favors the presence of NSI with down quarks at 1.8$\sigma$, and with up quarks at 1.6$\sigma$, with the best fit NSI parameters being ($\epsilon_{11}^{d},\epsilon_{12}^{d}$) = (-3.3, -3.1) for $d$-quarks and ($\epsilon_{11}^{u},\epsilon_{12}^{u}$) = (-2.5, -3.1) for $u$-quarks. After combining with data from the Sudbury Neutrino Observatory and Borexino, the significance increases by 0.1$\sigma$.