Abstract
A
bstract
We study a realization of neutrino masses and mixing phenomena within a linear seesaw mechanism based on non-holomorphic modular
A
4
symmetry, which extends modular-invariant flavor models beyond the conventional holomorphic framework. The model is constructed in a non-supersymmetric setting and involves six heavy
SU
(2)
L
singlet fermions,
N
Ri
and
S
Li
, together with a single flavon field, thereby significantly reducing the field content compared to conventional
A
4
flavor models that typically require multiple flavon fields as well as supersymmetric (holomorphic) modular frameworks involving additional superfields. The modular transformation properties of the Yukawa couplings under
A
4
symmetry lead to a highly constrained neutrino mass matrix with a distinctive flavor structure. After presenting the general theoretical framework, we perform a systematic numerical analysis of neutrino phenomenology by restricting the modulus parameter
τ
to the fundamental domain and scanning the allowed parameter space. We identify regions consistent with current neutrino oscillation data at the 3
σ
level and obtain predictions for currently unknown observables, including the absolute neutrino mass scale and leptonic CP-violating phases. We further examine the implications for neutrinoless double beta decay, highlighting testable signatures in the upcoming precision oscillation as well as rare-process experiments. These results demonstrate the phenomenological viability and predictive power of non-holomorphic modular symmetry in linear seesaw neutrino mass models.