Lepton Flavor Violating Non-Standard Interactions via Light Mediators

Abstract: Non-Standard neutral current Interactions (NSIs) of neutrinos with matter can alter the pattern of neutrino oscillation due to the coherent forward scattering of neutrinos on the medium. This effect makes long-baseline neutrino experiments such as NO$\nu$A and DUNE a sensitive probe of beyond standard model (BSM) physics. We construct light mediator models that can give rise to both lepton flavor conserving as well as Lepton Flavor Violating (LFV) neutral current NSI. We outline the present phenomenological viability of these models and future prospects to test them. We predict a lower bound on Br$(H\to \mu \tau)$ in terms of the parameters that can be measured by DUNE and NO$\nu$A, and show that the hint for $H\to \mu \tau$ in current LHC data can be accommodated in our model. A large part of the parameter space of the model is already constrained by the bounds on Br$(\tau \to Z^\prime \mu)$ and rare meson decays and can in principle fully tested by improving these bounds.