Search for Nonstandard Neutrino Interactions with IceCube DeepCore

TL;DR

This paper uses IceCube-DeepCore atmospheric neutrino data to set the most stringent limits to date on nonstandard neutrino interactions in the mu-tau sector, constraining new physics beyond the Standard Model.

Contribution

It provides the most restrictive experimental bounds on the nonstandard interaction parameter $\epsilon_{\mu au}$ using three years of IceCube-DeepCore data, improving upon previous limits.

Findings

Best fit for $\epsilon_{\mu au}$ is -0.0005.

90\% confidence level range is -0.0067 to 0.0081.

Results are more restrictive than recent limits from other experiments.

Abstract

As atmospheric neutrinos propagate through the Earth, vacuum-like oscillations are modified by Standard-Model neutral- and charged-current interactions with electrons. Theories beyond the Standard Model introduce heavy, TeV-scale bosons that can produce nonstandard neutrino interactions. These additional interactions may modify the Standard Model matter effect producing a measurable deviation from the prediction for atmospheric neutrino oscillations. The result described in this paper constrains nonstandard interaction parameters, building upon a previous analysis of atmospheric muon-neutrino disappearance with three years of IceCube-DeepCore data. The best fit for the muon to tau flavor changing term is $\epsilon_{\mu \tau}=-0.0005$, with a 90\% C.L. allowed range of $-0.0067 <\epsilon_{\mu \tau}< 0.0081$. This result is more restrictive than recent limits from other experiments for $\epsilon_{\mu \tau}$. Furthermore, our result is complementary to a recent constraint on $\epsilon_{\mu \tau}$ using another publicly available IceCube high-energy event selection. Together, they constitute the world's best limits on nonstandard interactions in the $\mu-\tau$ sector.