Minimally Allowed Neutrinoless Double Beta Decay Rates From Approximate Flavor Symmetries

Abstract

Neutrinoless double beta decay ($\beta \beta 0\nu$) is among the only realistic probes of Majorana neutrinos. In the standard scenario, dominated by light neutrino exchange, the process amplitude is proportional to $m_{ee}$, the $e-e$ element of the Majorana mass matrix. Naively, current data allows for vanishing $m_{ee}$, but this should be protected by an appropriate flavor symmetry. All such symmetries lead to mass matrices inconsistent with oscillation phenomenology. I perform a spurion analysis to break all possible Abelian symmetries that guarantee vanishing $\beta \beta 0\nu$ rates and search for minimally allowed values. I survey 230 broken structures to yield $m_{ee}$ values and current phenomenological constraints under a variety of scenarios. This analysis also extracts predictions for both neutrino oscillation parameters and kinematic quantities. Assuming reasonable tuning levels, I find that $m_{ee}>4\times 10^{-6}$ eV at 99% confidence. Bounds below this value might indicate the Dirac neutrino nature or the existence of new light (eV-MeV scale) degrees of freedom that can potentially be probed elsewhere.

19 Pages, 4 .eps Figures, 3 Tables

References in corpus (10)

• Precision Measurement of Neutrino Oscillation Parameters with KamLAND
• Three-flavour neutrino oscillation update
• Disassembling the Nuclear Matrix Elements of the Neutrinoless double beta Decay
• Erratum: Assessment of uncertainties in QRPA $0\nu \beta \beta$-decay nuclear matrix elements [Nucl. Phys. A 766, 107 (2006)]
• A Survey of Lepton Number Violation Via Effective Operators
• Rephasing Invariants of Quark and Lepton Mixing Matrices
• Extended Black Box Theorem for Lepton Number and Flavor Violating processes
• The smallest neutrino mass
• The Physical Range of Majorana Neutrino Mixing Parameters
• Minimally Allowed Neutrinoless Double Beta Decay Rates Within an Anarchical Framework

Cited by in corpus (4)

• Probing the Weinberg Operator at Colliders
• Neutrino masses in the Standard Model effective field theory
• A Survey of Neutrino Flavor Models and the Neutrinoless Double Beta Decay Funnel
• Minimally Allowed Neutrinoless Double Beta Decay Rates Within an Anarchical Framework