IceCube DeepCore's sensitivity to Non-Standard neutrino Interactions in the Earth

TL;DR

The paper investigates whether non-standard neutrino interactions (NSI) in Earth matter can modify atmospheric neutrino oscillations and potentially explain the T2K–NOvA $\delta_{\text{CP}}$ tension. It uses IceCube DeepCore data with a model-independent GMP NSI parameterization and a modified chi-square sensitivity approach to analyze 9.28 years of data. The study finds a substantial improvement over previous NSI analyses, delivering leading constraints on GMP parameters ($\varepsilon$, $\varphi_{12}$, $\varphi_{13}$) and on $\varepsilon_{e\mu}$ and $\varepsilon_{e\tau}$, including explicit 1σ and 2σ bounds. These constraints enable strong statements about whether NSI could resolve the T2K–NOvA $\delta_{\text{CP}}$ tension and demonstrate IceCube DeepCore’s role in testing NSI models.

Abstract

Neutrino oscillations continue to provide one of the most promising avenues for uncovering physics beyond the Standard Model. In particular, beyond-standard-model neutrino matter interactions may perturb neutrino oscillations in matter, leading to an observable signal in long baseline oscillation experiments. Moreover, such interactions can be a possible explanation of the rising tension between T2K and NOvA's $δ_{\text{CP}}$ measurements. We examine IceCube DeepCore's sensitivity to these Non-Standard Interactions (NSI) by employing a model-independent NSI parameterization, and examine IceCube DeepCore's ability to comment on NSI being the cause of the T2K-NOvA $δ_{\text{CP}}$ tension.

Figures (2)

• Figure 1: Sensitivities to the SI hypothesis ($\varepsilon = 1, \varphi_{12} = \varphi_{13} = 0$) for each individual GMP parameter are shown in red. For comparison, the sensitivities for the previous 3 year DeepCore analysis dragon are shown in blue.
• Figure 2: Our sensitivities to $\varepsilon_{e\mu}$ and $\varepsilon_{e\tau}$ are shown in panels (a) and (b) respectively. We indicate the best-fit value of each parameter for resolving the T2K-NOvA tension with an x. The projections of the TS profile on to the magnitude and phase of each NSI parameter are shown as well.