Study of Non-Standard Neutrino Interactions with Atmospheric Neutrino Data in Super-Kamiokande I and II

TL;DR

This study investigates non-standard neutrino interactions using atmospheric neutrino data from Super-Kamiokande I and II, setting limits on flavor-changing and non-universal effects, with no evidence found for such interactions.

Contribution

First comprehensive analysis of non-standard neutrino interactions with atmospheric data from Super-Kamiokande I and II, constraining FCNC and NU parameters.

Findings

Set upper limit on FCNC coupling |varepsilon_{mu tau}|<1.1 x 10^{-2}

No evidence of non-standard neutrino interactions detected

Provided constraints on FCNC and NU parameters as functions of each other

Abstract

In this paper we study non-standard neutrino interactions as an example of physics beyond the standard model using atmospheric neutrino data collected during the Super-Kamiokande I(1996-2001) and II(2003-2005) periods. We focus on flavor-changing-neutral-currents (FCNC), which allow neutrino flavor transitions via neutral current interactions, and effects which violate lepton non-universality (NU) and give rise to different neutral-current interaction-amplitudes for different neutrino flavors. We obtain a limit on the FCNC coupling parameter, varepsilon_{mu tau}, |varepsilon_{mu tau}|<1.1 x 10^{-2} at 90%C.L. and various constraints on other FCNC parameters as a function of the NU coupling, varepsilon_{e e}. We find no evidence of non-standard neutrino interactions in the Super-Kamiokande atmospheric data.