Predictions of effective Majorana neutrino mass under radiative corrections to $μ-τ$ reflection symmetry

TL;DR

This work analyzes how radiative corrections to a $μ$-$τ$ reflection-symmetric neutrino mass structure, within the MSSM, shape the low-energy effective Majorana mass $|m_{ee}|$ relevant for neutrinoless double beta decay. By evolving high-scale inputs at $Λ_{μτ}=10^{14}$ GeV down to $Λ_{EW}$ using one-loop RGEs across several SUSY-breaking scales $Λ_s$ and $tanβ$ values, the authors extract updated neutrino masses, mixings, and CP phases, then compute $|m_{ee}|$ and compare it to the KamLAND-Zen bound $|m_{ee}|<(0.028-0.122)$ eV. They find that the resulting $|m_{ee}|$ values are consistent with current limits for both normal and inverted ordering, with inverted ordering predicting larger $|m_{ee}|$ and the dependence on $Λ_s$ differing between hierarchies. These results provide testable predictions for upcoming $0νββ$ experiments and illuminate how RG effects can modify Majorana mass observables in $μ$-$τ$ symmetric frameworks.

Abstract

The search for neutrinoless double beta decay ($0νββ$) is currently one of the key objectives in neutrino physics research. The decay rate of $0νββ$ decay depends on the effective Majorana neutrino mass $|\langle m \rangle_{ee}|$. In this work we study the numerical prediction of $|\langle m \rangle_{ee}|$ in the scenario of deviation from the $μ$-$τ$ reflection symmetry due to radiative corrections, as an extension of our earlier work \cite{pegu}. In \cite{pegu}, we consider an exact $μ$-$τ$ reflection symmetry in the light effective Majorana neutrino mass matrix and in the corresponding lepton mixing matrix as well at the seesaw scale. We choose numerical values of all the mixing parameters and neutrino mass eigenvalues at the seesaw scale as inputs and estimate the values of mass eigenvalues and mixing parameters at the electroweak scale due to radiative corrections. We find these low energy predictions consistent with global $3σ$ oscillation data. In the present work, we compute the effective Majorana neutrino mass $|\langle m \rangle_{ee}|$ using these low energy values at the electroweak scale. We find that the low energy predictions of $|\langle m \rangle_{ee}|$ are consistent with the latest upper bound $|\langle m \rangle_{ee}|<(0.028-0.122)\ eV$ provided by KamLAND-Zen Collaboration.