Implications of $\delta^{CP}_l\sim 270^\circ$ and $\theta_{23}\gtrsim 45^\circ$ for texture specific lepton mass matrices and $0\nu \beta \beta$ decay

TL;DR

This paper explores how recent neutrino experiment results influence the structure of lepton mass matrices, predicting specific neutrino mass ranges and implications for neutrinoless double beta decay detection.

Contribution

It introduces a framework linking recent experimental neutrino data to specific texture structures in lepton mass matrices, emphasizing deviations from parallel textures.

Findings

Hierarchical neutrino mass matrices are incompatible with zero neutrino mass.

Predicted neutrino masses are in the range of 0.1 to 52 meV.

Observation of neutrinoless double beta decay is challenging with current technology.

Abstract

We study the phenomenological consequences of recent results from atmospheric and accelerator neutrino experiments, favoring normal neutrino mass ordering $m_1 < m_2 < m_3$, a near maximal lepton Dirac CP phase $\delta_{l}\sim 270^\circ$ along with $\theta_{23}\gtrsim 45^\circ$, for possible realization of natural structure in the lepton mass matrices characterized by ${({M_{ij}})} \sim O(\sqrt {{m_i}{m_j}}) $ for $i,j=1,2,3$. It is observed that deviations from parallel texture structures for $M_{l}$ and $M_{\nu}$ are essential for realizing such structures. In particular, such hierarchical neutrino mass matrices are not supportive for a vanishing neutrino mass $m_{\nu 1}\rightarrow 0$ characterized by Det$M_{\nu}\ne 0$ and predict ${m_{\nu 1}} \simeq (0.1 - 8.0)$ $meV$ , ${m_{\nu 2}} \simeq (8.0 - 13.0)$ $meV$, ${m_{\nu 3}} \simeq (47.0 - 52.0)$ $meV$, $\Sigma \simeq (56.0 - 71.0)$ $meV$ and $\left\langle {{m_{ee}}} \right\rangle \simeq (0.01 - 10.0)$ $meV$, respectively, indicating that the task of observing a $0\nu \beta \beta$ decay may be rather challenging for near future experiments.