Lepton Flavor Violating Non-Standard Interactions via Light Mediators

TL;DR

This paper explores light mediator models that induce lepton flavor violating neutral current interactions, affecting neutrino oscillations and potentially explaining hints of Higgs decay to mu-tau, with testable predictions for future experiments.

Contribution

It introduces new light mediator models for LFV NSIs, analyzes their phenomenological viability, and links them to observable signals in neutrino experiments and Higgs decays.

Findings

Predicts a lower bound on Br(H→μτ) measurable at DUNE and NOνA.

Shows current LHC hints for H→μτ can fit within the model.

Identifies parameter space constrained by τ→Z′μ and meson decay bounds.

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.