# Connecting neutrino masses and dark matter by high-dimensional lepton number violation operator

Geng, Chao-Qiang (Chongqing University of Posts & Telecommunications, Chongqing, 400065, China) (Department of Physics, National Tsing Hua University, Hsinchu, 300, Taiwan) (Physics Division, National Center for Theoretical Sciences, Hsinchu, 300, Taiwan) ; Huang, Da (Department of Physics, National Tsing Hua University, Hsinchu, 300, Taiwan) ; Tsai, Lu-Hsing (Department of Physics, National Tsing Hua University, Hsinchu, 300, Taiwan) ; Wang, Qing (Department of Physics, Tsinghua University, Beijing, 100084, China) (Collaborative Innovation Center of Quantum Matter, Beijing, 100084, China)

03 September 2015

Abstract: We propose a new model with the Majorana neutrino masses generated at two-loop level, in which the lepton number violation (LNV) processes, such as neutrino-less double beta decays, are mainly induced by the dimension-7 LNV effective operator O 7 = l ¯ R c γ μ L L D μ Φ Φ Φ ${\mathcal{O}}_7={\overline{l}}_R^c{\gamma}^{\mu }{L}_L\left({D}_{\mu}\varPhi \right)\varPhi \varPhi$ . Note that it is necessary to impose an Z 2 symmetry in order that O 7 ${\mathcal{O}}_7$ dominates over the conventional dimension-5 Weinberg operator, which naturally results in a stable Z 2 -odd neutral particle to be the cold dark matter candidate. More interestingly, due to the non-trivial dependence of the charged lepton masses, the model predicts the neutrino mass matrix to be in the form of the normal hierarchy. We also focus on a specific parameter region of great phenomenological interests, such as electroweak precision tests, dark matter direct searches along with its relic abundance, and lepton flavor violation processes.

Published in: JHEP 1508 (2015) 141