Exploring New-Physics Effects of Scalar NSI at DUNE, T2HK and T2HKK

The Non-Standard Interactions (NSIs) are subdominant effects due to unknown couplings, often appearing in various extensions of SM, which may impact the neutrino oscillations through matter. It is important and interesting to explore the impact of NSIs in the ongoing and upcoming precise neutrino oscillations experiments. In this work, we have probed the imprints of a scalar-mediated NSI in three upcoming long-baseline (LBL) experiments (DUNE, T2HK and T2HKK). The effects of scalar NSI appear as a medium-dependent correction to the neutrino mass term. Its contribution scales linearly with matter density, making LBL experiments a suitable candidate to probe its effects. We show that the scalar NSI may significantly impact the oscillation probabilities, event rates at the detectors and the \(\chi ^2\) -sensitivities of \(\delta _{CP}\) measurements. We present the results of a combined analysis involving the LBL experiments (DUNE+T2HK, DUNE+T2HKK, DUNE+T2HK+T2HKK) which offer a better capability of constraining the scalar NSI parameters as well as an improved sensitivity towards CP-violation.