Low scale leptogenesis and TM1 mixing in neutrinophilic two Higgs doublet model (ν2HDM) with S4 flavor symmetry

Abstract

We study a modified version of the Standard Model that includes a scalar doublet and two right-handed neutrinos, forming the neutrinophillic two higgs doublet ($\nu \text{2HDM}$) framework. For the two Higgs-doublet vacuum expectation values satisfying ${\text{v}}_2<<{\text{v}}_1$, this model operates at a TeV scale, bringing the RHNs within experimental reach. To further enhance its predictive power, we introduce an $S_4\times Z_4$ flavor symmetry with five flavons, resulting in mass matrices that realize the so-called Trimaximal ${\text{TM}}_1$ mixing scheme. The model effectively explains lepton masses and flavor mixing under the normal ordering of neutrino masses, predicting that the effective neutrino mass in 0$\nu \beta \beta$ decay lies between [4 - 5] meV, significantly lower than the sensitivity limits of current experiments. We also investigate how this framework could support low-scale leptogenesis as a natural way to explain the observed imbalance between matter and antimatter in the Universe. This work explores how neutrino physics, flavor symmetry and baryon asymmetry are connected, providing a clear framework that links theoretical predictions with experimental possibilities.