Eur. Phys. J. C (2016) 76: 662
https://doi.org/10.1140/epjc/s10052-016-4528-4

Regular Article - Theoretical Physics

Extended scaling and residual flavor symmetry in the neutrino Majorana mass matrix

¹ Astroparticle Physics and Cosmology Division, Saha Institute of Nuclear Physics, HBNI, Kolkata, 700064, India
² Center for Astroparticle Physics and Space Science, Bose Institute, Kolkata, 700091, India

^* e-mail: ambar.ghosal@saha.ac.in

Received: 26 July 2016
Accepted: 21 November 2016
Published online: 30 November 2016

Abstract

The residual symmetry approach, along with a complex extension for some flavor invariance, is a powerful tool to uncover the flavor structure of the 3 3 neutrino Majorana mass matrix toward gaining insights into neutrino mixing. We utilize this to propose a complex extension of the real scaling ansatz for which was introduced some years ago. Unlike the latter, our proposal allows a nonzero mass for each of the three light neutrinos as well as a nonvanishing . The generation of light neutrino masses via the type-I seesaw mechanism is also demonstrated. A major result of this scheme is that leptonic Dirac CP-violation must be maximal while atmospheric neutrino mixing does not need to be exactly maximal. Moreover, each of the two allowed Majorana phases, to be probed by the search for nuclear decay, has to be at one of its two CP-conserving values. There are other interesting consequences such as the allowed occurrence of a normal mass ordering which is not favored by the real scaling ansatz. Our predictions will be tested in ongoing and future neutrino oscillation experiments at T2K, NOA and DUNE.