Trimaximal mixing and extended magic symmetry in a model of neutrino mass matrix

The trimaximal mixing scheme (TM2) results in magic neutrino mass matrix (M & nu;) which is known to accommodate neutrino oscillation data. In this paper, we propose a phenomenological ansatz for M & nu; by extending the magic symmetry that leads to further reduc-tion in the number of free parameters, thereby increasing the predictability of the model. The neutrino mixing parameters, effective Majorana mass mee and CP invariants (JCP, I1 , I2) are found to exhibit strong correlations for TM2 mixing paradigm. One of the generic feature of the model is the requirement of non-maximal & theta;23 for possible CP violation measurable in neu-trino oscillation experiments. The observables mee and sum of neutrino masses (E mi) have imperative implications for yet unknown neutrino mass hierarchy. For inverted hierarchy, the lower bound on mee > 0.02 eV, predicted by the model, is found to be within the sensitivity reach of the 0 & nu;& beta;& beta; decay experiments. Also, cosmological bound of 0.12 eV on E mi , at 95% CL, refutes inverted hierarchy implying TM2 with normal hierarchy as the only viable possibility in the model. We have, also, illustrated a scenario wherein such a construction of the neu-trino mass matrix can be realized using & UDelta;(54) symmetry in the framework of Type-I+II seesaw mechanism.Copyright & COPY; 2023 EPLA

Automated summary

In this paper, a phenomenological ansatz for the magic neutrino mass matrix (M & nu;) is proposed by extending the magic symmetry, which leads to a reduction in the number of free parameters and increases the predictability of the model. The correlations between the neutrino mixing parameters, effective Majorana mass mee, and CP invariants (JCP, I1 , I2) are found to be strong for the trimaximal mixing scheme (TM2). The findings have important implications for the neutrino mass hierarchy and CP violation measurements.