Trimaximal Mixing and Extended Magic Symmetry in a Model of Neutrino Mass Matrix

Abstract

The trimaximal mixing schemes (TM 1 /TM 2 ) result in "magic" neutrino mass matrix (M ν ) which is known to accommodate neutrino oscillation data. In this paper, we propose a phenomenological ansatz for M ν by extending the magic symmetry that leads to further reduction in the number of free parameters, thereby, increasing the predictability of the model. The neutrino mixing parameters, effective Majorana mass m ee and CP invariants (J CP , I 1 , I 2 ) are found to exhibit strong correlations for both TM 1 and TM 2 mixing paradigms. One of the generic feature of the model is the requirement of non-maximal θ 23 for possible CP violation measurable in neutrino oscillation experiments. The inverted hierarchy in TM 1 mixing scheme is disallowed by the low energy neutrino phenomenology. The observables m ee and sum of neutrino masses ( m i ) have imperative implications for yet unknown neutrino mass hierarchy. The lower bounds on m ee predicted by the model, especially, in TM 2 (with inverted hierarchy) and TM 1 (with normal hierarchy) mixing schemes, are found to be well with in the sensitivity reach of the 0νββ decay experiments. However, cosmological bound of 0.12 eV on m i , at 95% CL, refutes inverted and normal hierarchy in TM 2 and TM 1 mixing scenarios, respectively, implying TM 2 with normal hierarchy as the only viable possibility in the model. We have, also, illustrated a scenario wherein such a construction of the neutrino mass matrix can be realized using ∆(54) symmetry in the framework of Type-I+II seesaw mechanism.

Is the magic texture of Majorana neutrinos immanent in Dirac nature?

“…In this study, we focus on magic texture, which is a known successful texture of the Majorana flavor neutrino mass matrix [1][2][3][4][5][6][7][8]. Accordingly, we investigate the relationship between the Dirac flavor neutrino mass and Majorana flavor neutrino mass matrices.…”