Neutrino Mixing and Cosmological Constant above GUT Scale

TL;DR

This paper explores how quantum gravitational effects above the GUT scale influence neutrino mixing and contribute to the cosmological constant, especially in a nearly degenerate neutrino mass spectrum with bimaximal mixing.

Contribution

It introduces a model considering gravitational effects as perturbations to the neutrino mass matrix above the GUT scale, linking quantum gravity to neutrino properties and the cosmological constant.

Findings

Gravitational effects induce additional terms in the neutrino mass matrix.

These effects can lead to a non-zero cosmological constant.

Neutrino mixing is affected by Planck scale physics.

Abstract

Neutrino mixing lead to a non zero contribution to the cosmological constant. We consider non renormalization $1/M_{x}$ interaction term as a perturbation of the neutrino mass matrix. We find that for the degenerate neutrino mass spectrum. We assume that the neutrino masses and mixing arise through physics at a scale intermediate between Planck Scale and the electroweak scale. We also assume, above the electroweak breaking scale, neutrino masses are nearly degenerate and their mixing is bimaximal. Quantum gravitational (Planck scale )effects lead to an effective $SU(2)_{L}\times U(1)$ invariant dimension-5 Lagrangian involving neutrino and Higgs fields, which gives rise to additional terms in neutrino mass matrix. There additional term can be considered to be perturbation of the GUT scale bi-maximal neutrino mass matrix. We assume that the gravitational interaction is flavour blind and we study the neutrino mixing and cosmological constant due to physics above the GUT scale.