Neutrino Mass and its Impact on Gravitational Waves from Domain Wall Collision

Abstract

The $A_{4} \times Z_{4}$ symmetry models are constructed to study neutrino masses and mixings, as well as the gravitational-wave spectrum from domain-wall annihilation. The first neutrino mass model is constructed with the flavon's vacuum expectation value and alignment obtained from the self-interacting potential terms, while the second model uses a new vacuum expectation value arising from a potential containing both self-interaction and mixed terms. The resulting neutrino mixing patterns for both models are in good agreement with current neutrino oscillation data with different mixing values. Further, the flavon mixing terms lift the vacua degeneracy that often shows in the spontaneous symmetry breaking of the discrete symmetry. These mixing terms and the modified neutrino mass matrix of the second model are considered to produce the necessary bias for analysing the gravitational waves spectrum. The spectrum predicted by the model could be detected by current and near-future experiments when the flavons have the vacuum expectation value of $10^4$ TeV.