Tri-resonant leptogenesis in a non-holomorphic modular A₄ scotogenic model

We investigate low-scale baryogenesis via tri-resonant leptogenesis within the scotogenic model with a scalar dark matter embedded in non-holomorphic modular A₄ A 4 symmetry framework. The model naturally accommodates three nearly degenerate right-handed (RH) neutrinos when they are assigned to the triplet representation of A₄ A 4 . The near degeneracy originates from treating the symmetric contribution to the Majorana mass matrix, arising from the 3⊗ 3 3 ⊗ 3 decomposition of A₄ A 4 , as a small perturbation to the dominant singlet contribution. For inverted hierarchy (IH), the predicted 3σ 3 σ range of θ ₂₃ θ 23 lies in the lower octant close to maximal value while Dirac CP phase δ CP δ CP and the Majorana phase α ₂₁ α 21 are predicted to lie close to 0^∘ 0 ∘ or 360^∘ 360 ∘ . Also, in this case, predicted values of mₑₑ m ee and ∑ ᵢ mᵢ ∑ i m i can be tested and constrained by future neutrinoless double beta decay (0ν β β ) ( 0 ν β β ) experiments, as well as by cosmological observations, particularly DESI+CMB and Planck data. In fact DESI+CMB disallows IH in the model. We further show that successful baryogenesis can be achieved for both normal hierarchy (NH) and inverted hierarchy (IH) of light neutrino masses with RH neutrino masses as low as 537~GeV 537 GeV rendering this scenario experimentally testable. For NH, RH neutrino mass degeneracy of O(10⁻⁷\!-\!10⁻⁶)