Radiative seesaw model: Warm dark matter, collider signatures, and lepton flavor violating signals

Abstract

INTRODUCTION: Solar [1], atmospheric [2], and reactor [3] neutrino experiments have demonstrated that neutrinos have mass and nonzero mixing angles among the different generations. On the other hand, observations of the cosmic microwave background, primordial abundances of light elements, and large scale structure formation have firmly established that most of the mass of the Universe consists of dark matter (DM) [4]. These experimental results are at present the most important evidences for physics beyond the standard model. There are several ways in which neutrino masses can be generated. Certainly the best-known mechanism to generate small Majorana neutrino masses is the seesaw [5]. However, a large variety of models exists in which lepton number is broken near or at the electroweak scale. Examples are supersymmetric models with explicit or spontaneous breaking of R parity [6,7], models with Higgs triplets [8], pure radiative models at one-loop [9] or at two-loop [10] order, and models in which neutrino masses are induced by leptoquark interactions [11].