Abstract We introduce a lepton mass generation and flavor mixing model, realized through a (2, 3) inverse seesaw structure based on modular S₄ S 4 symmetry. The model employs modular forms to construct the lepton Yukawa couplings, significantly simplifying the framework by reducing redundant parameters. A detailed numerical analysis demonstrates consistency with current neutrino oscillation data, yielding specific outputs for the mixing angles and CP-violating phases. The Dirac CP phase is predicted to lie near ₂ 90^ δ CP ≈ ± 90 ∘, corresponding to near-maximal leptonic CP violation. The total neutrino mass lies within m_ 0. 0587 --0. 0924 ∑ m ν ≈ 0. 0587 -- 0. 0924 eV, and the effective Majorana mass |m₄₄| (0. 002 --0. 02) | m ee | ≈ (0. 002 -- 0. 02) eV, within reach of upcoming neutrinoless double beta decay experiments such as nEXO and AMoRE-II. The model also remains consistent with current bounds on charged lepton flavor violating processes from MEG and BaBar. We further explore resonant leptogenesis enabled by quasi-degenerate heavy neutrino states and show that the observed baryon asymmetry of the universe can be successfully generated in this scenario. The combined treatment of low-energy observables and high-scale baryogenesis demonstrates the predictivity and testability of the modular S₄ S 4 -based ISS (2, 3) framework.
Abhishek et al. (Thu,) studied this question.