Probing strange-sector flavor-changing neutral currents at DUNE-like facilities

Abstract

We investigate the sensitivity of DUNE-like facilities to flavor-changing neutral-current interactions between down and strange quarks through inclusive deep-inelastic neutrino scattering. In the framework of a general low-energy effective Lagrangian for Dirac and Majorana neutrinos, we evaluate projected sensitivities for CP- and $\tau$-optimized beam configurations. The strongest bounds on the dimensionless Wilson coefficients, defined relative to the Fermi constant $G_F$, reach $\mathcal{O}(10^{-3})\text{--}\mathcal{O}(10^{-2})$ at the near detector, whereas far-detector limits are roughly one order of magnitude weaker. When systematic uncertainties are included, the near-detector sensitivity is dominated by the background-rate uncertainty, while the far-detector sensitivity is limited primarily by the signal-rate uncertainty. At the far detector, the dependence of the projected bounds on the neutrino mass ordering and the Dirac CP-violating phase $\delta_{\mathrm{CP}}$ is largely confined to coefficients involving the electron flavor.