Limits on Neutrinophilic Two-Higgs-Doublet Models from Flavor Physics

TL;DR

This paper establishes new constraints on neutrinophilic two-Higgs-doublet models using low-energy flavor observables, especially lepton flavor violating decays, significantly narrowing the parameter space for the charged Higgs mass and scalar vacuum expectation value.

Contribution

It provides the first comprehensive limits on the model parameters from flavor physics, especially highlighting the importance of loop-induced lepton flavor violation.

Findings

Current bounds imply charged Higgs mass > 250 GeV for very small v2.

Future experiments could improve these limits by a factor of 100.

Lepton flavor conserving decays do not constrain the model effectively.

Abstract

We derive stringent limits on neutrinophilic two-Higgs-doublet models from low-energy observables after the discovery of the Higgs boson and of the mixing angle $\theta_{13}$. These decays can constrain the plane spanned by $m_{H^\pm}$, the mass of the new charged Higgs, and $v_2$, the vacuum expectation value of the new neutrinophilic scalar doublet. Lepton flavor conserving decays are not able to set meaningful bounds, since they depend strongly on the unknown neutrino absolute mass scale. On the other hand, loop induced lepton flavor violating decays, such as $\mu \to e \gamma$, $\mu \to 3 e $ or $\mu \to e$ in nuclei are currently responsable for the best limits today. If $v_2 \lesssim 1 \, (0.1)$ eV we get $m_{H^\pm} \gtrsim 250 \, (2500)$ GeV at 90% CL. In the foreseen future these limits can improve by at least a factor of 100.