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

Abstract

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 (ν) with matter is one of such new physics scenarios that appears as a sub-dominant effect that can impact the ν-oscillations in matter. The presence of scalar NSI introduces an additional contribution directly to the ν-mass matrix in the interaction Hamiltonian and subsequently to the ν-oscillations. This indicates that scalar NSI may have a significant impact on measurements related to ν-oscillations e.g. leptonic CP phase (δCP), θ23 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 ν-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.