Neutrino symmetries from high to low scales

TL;DR

This paper investigates how certain neutrino symmetry relations established at high energy scales can be preserved during their evolution to low energies by constraining Majorana phases, with implications for future experiments.

Contribution

It demonstrates that neutrino symmetry relations like QLC and TBM can be maintained through RG evolution by constraining Majorana phases, providing explicit examples within the MSSM.

Findings

Majorana phases can preserve symmetry relations during RG evolution.

Preference for Majorana phase b1_2 b1 d b1 b2 d d b1 b2 d d b1 b2 d d b1 b2 d d b1 b2 d d in each case.

Future measurements of b8_{13} can discriminate among the models.

Abstract

Proposed symmetry relations, e.g., quark-lepton complementarity (QLC) or tribimaximal mixing (TBM), need to be imposed at a high scale $\wedge \sim 10^{12}$ GeV characterising the large masses of right-handed neutrinos required to implement the seesaw mechanism. RG evolution down to the laboratory scale $\lambda \sim 10^3$ GeV, generically prone to spoil these relations and their predicted neutrino mixing patterns, can be made to preserve them by appropriately constraining the Majorana phases $\alpha_{2,3}$. This is explicitly demonstrated in the MSSM for two versions of QLC and two versions of TBM. A preference for $\alpha_2 \simeq \pi$ (i.e. $m_1 \simeq - m_2$) emerges in each case. Discrimination among the four cases is shown to be possible by future measurements of $\theta_{13}$.