Vacuum misalignment corrections to tri-bimaximal mixing and form dominance

TL;DR

This paper derives approximate analytic expressions for deviations from tri-bimaximal neutrino mixing caused by vacuum misalignment in see-saw models, and relates these deviations to departures from form dominance affecting leptogenesis.

Contribution

It provides a novel analytic framework connecting vacuum misalignment to neutrino mixing deviations and leptogenesis, highlighting their uncorrelated nature.

Findings

Deviations depend on vacuum misalignment pattern

Corrections to mixing and form dominance are uncorrelated

Analytic expressions quantify the impact of misalignment

Abstract

Tri-bimaximal neutrino mixing may arise from see-saw models based on family symmetry which is spontaneously broken by flavons with particular vacuum alignments. However recent analyses hint that tri-bimaximal mixing may be insensitive to the precise form of vacuum alignment. In this paper we derive approximate analytic results which express the deviations from tri-bimaximal neutrino mixing due to vacuum misalignment. We also relate vacuum misalignment to departures from form dominance, corresponding to deviations from the real orthogonal $R$ matrix, where such corrections are necessary to allow for successful leptogenesis. The analytic results show that the corrections to tri-bimaximal mixing and form dominance depend on the pattern of the vacuum misalignment, with the two effects being uncorrelated.