Bounds on Non-Standard Neutrino Interactions Using PINGU

TL;DR

This paper assesses how the proposed PINGU experiment can improve constraints on non-standard neutrino interactions by analyzing atmospheric neutrino data, providing tighter bounds than previous experiments.

Contribution

It introduces analytical formulas for neutrino survival probabilities with NSIs and performs a statistical analysis showing PINGU's improved bounds on NSI parameters.

Findings

PINGU bounds on NSI parameters improve by an order of magnitude.

Analytical formulas for muon neutrino survival probability with NSIs.

No significant correlation between $\varepsilon_{\mu au}$ and $\varepsilon_{\tau au}$.

Abstract

We investigate the impact of non-standard neutrino interactions (NSIs) on atmospheric neutrinos using the proposed PINGU experiment. In particular, we focus on the matter NSI parameters $\varepsilon_{\mu\tau}$ and $|\varepsilon_{\tau\tau} - \varepsilon_{\mu\mu}|$ that have previously been constrained by the Super-Kamiokande experiment. First, we present approximate analytical formulas for the difference of the muon neutrino survival probability with and without the above-mentioned NSI parameters. Second, we calculate the atmospheric neutrino events at PINGU in the energy range (2-100) GeV, which follow the trend outlined on probability level. Finally, we perform a statistical analysis of PINGU. Using three years of data, we obtain bounds from PINGU given by $-0.0043~(-0.0048) < \varepsilon_{\mu\tau} < 0.0047~(0.0046)$ and $-0.03~(-0.016) < \varepsilon_{\tau\tau} < 0.017~(0.032)$ at 90 % confidence level for normal (inverted) neutrino mass hierarchy, which improve the Super-Kamiokande bounds by one order of magnitude. In addition, we show the expected allowed contour region in the $\varepsilon_{\mu\tau}$-$\varepsilon_{\tau\tau}$ plane if NSIs exist in Nature and the result suggests that there is basically no correlation between $\varepsilon_{\mu\tau}$ and $\varepsilon_{\tau\tau}$.