Impact of scalar NSI on the neutrino mass ordering sensitivity at DUNE, HK and KNO

TL;DR

This paper investigates how scalar non-standard interactions (NSI) could influence neutrino mass ordering sensitivity at upcoming long-baseline experiments like DUNE, HK, and KNO, highlighting potential impacts on measurements and combined experimental sensitivities.

Contribution

It introduces the analysis of scalar NSI effects on neutrino mass ordering sensitivity in future long-baseline experiments, considering known NSI parameters and exploring experimental synergy.

Findings

Diagonal scalar NSI elements can significantly alter mass ordering sensitivities.

Combining data from DUNE, HK, and KNO enhances sensitivity and reveals experimental synergy.

Scalar NSI effects scale linearly with matter density, affecting oscillation measurements.

Abstract

The study of neutrino non-standard interactions (NSI) is a well-motivated phenomenological scenario to explore new physics beyond the Standard Model. The possible scalar coupling of neutrinos ($\nu$) with matter is one of such new physics scenarios that appears as a sub-dominant effect that can impact the $\nu$-oscillations in matter. The presence of scalar NSI introduces an additional contribution directly to the $\nu$-mass matrix in the interaction Hamiltonian and subsequently to the $\nu$-oscillations. This indicates that scalar NSI may have a significant impact on measurements related to $\nu$-oscillations e.g. leptonic CP phase $(\delta_{CP})$, $\theta_{23}$ octant and neutrino mass ordering (MO). The linear scaling of the effects of scalar NSI with matter density also motivates its exploration in long-baseline (LBL) experiments. In this paper, we study the impact of a scalar-mediated NSI on the MO sensitivity of DUNE, HK and HK+KNO, which are upcoming LBL experiments. We study the impact on MO sensitivities at these experiments assuming that scalar NSI parameters are present in nature and is known from other non-LBL experiments. We observe that the presence of diagonal scalar NSI elements can significantly affect the $\nu$-mass ordering sensitivities. We then also combine the data from DUNE with HK and HK+KNO to explore possible synergy among these experiments in a wider parameter space. We also observe a significant enhancement in the MO sensitivities for the combined analysis.