Littlest modular seesaw

We present the first complete model of Littlest Modular Seesaw, based on two right-handed neutrinos, within framework multiple modular symmetries, justifying use moduli fields which take their values at 3 specific stabilizers $\Gamma_4 \simeq S_4$, including a new phenomenological possibility. Using semi-analytical approach, we perform $\chi^2$ analysis each case and show that good agreement with neutrino oscillation data is obtained, predictive relations between leptonic mixing angles ratio light masses, non-trivially agree experimental values. It noteworthy in this very setup, models fit global fits remarkably well, both without Super-Kamiokande atmospheric data, for choices stabilizers. By extending to include weighton double cover group $\Gamma'_4 S'_4$, are able also account hierarchy charged leptons using altering predictions.