We study a radiative inverse seesaw model with local B-L symmetry, in which we extend the neutrino mass structure that is generated through a kind of inverse seesaw framework to the more generic one than our previous work. We focus on a real part of bosonic particle as a dark matter and investigate the features in O(1-80) GeV mass range, reported by the experiments such as CoGeNT and XENON (2012).
The singlet majoron model of seesaw neutrino mass is appended by one dark Majorana fermion singlet $chi$ with $L=2$ and one dark complex scalar singlet $zeta$ with $L=1$. This simple setup allows $chi$ to obtain a small radiative mass anchored by the same heavy right-handed neutrinos, whereas the one-loop decay of the standard-model Higgs boson to $chi chi + bar{chi} bar{chi}$ provides the freeze-in mechanism for $chi$ to be the light dark matter of the Universe.
The Inverse Seesaw scenario relates the smallness of the neutrino masses to a small $B-L$ breaking parameter. We investigate a possible dynamical generation of the Inverse Seesaw neutrino mass mechanism from the spontaneous breaking of a gauged $U(1)_{B-L}$. To obtain an anomaly free theory we need to introduce additional fermions which exhibit an interesting phenomenology. Additionally, we predict a $Z$ boson associated to the broken $B-L$ which preferentially interacts with the dark sector formed by the extra fermions making it particularly elusive.
We discuss radiative seesaw models, in which an exact $Z_2times Z_2$ symmetry is imposed. Due to the exact $Z_2times Z_2$ symmetry, neutrino masses are generated at a two-loop level and at least two extra stable electrically neutral particles are predicted. We consider two models: one has a multi-component dark matter system and the other one has a dark radiation in addition to a dark matter. In the multi-component dark matter system, non-standard dark matter annihilation processes exist. We find that they play important roles in determining the relic abundance and also responsible for the monochromatic neutrino lines resulting from the dark matter annihilation process. In the model with the dark radiation, the structure of the Yukawa coupling is considerably constrained and gives an interesting relationship among cosmology, lepton flavor violating decay of the charged leptons and the decay of the inert Higgs bosons.
We study phenomenological implications of a radiative inverse seesaw dark matter model. In this model, because neutrino masses are generated at two loop level with inverse seesaw, the new physics mass scale can be as low as a few hundred GeV and the model also naturally contain dark matter candidate. The Yukawa couplings linking the SM leptons and new particles can be large. This can lead to large lepton flavor violating effects. We find that future experimental data on $mu to e gamma$ and $mu - e$ conversion can further test the model. The new charged particles can affect significantly the $h to gamma gamma$ branching ratio in the SM. The model is able to explain the deviation between the SM prediction and the LHC data. We also study some LHC signatures of the new particles in the model.
We discuss a classically conformal radiative neutrino model with gauged B$-$L symmetry, in which the B$-$L symmetry breaking can occur through the Coleman-Weinberg mechanism. As a result, Majorana mass term is generated and EW symmetry breaking also occurs. We show some allowed parameters to satisfy several theoretical and experimental constraints. Theoretical constraints are inert conditions and Coleman-Weinberg condition. Experimental bounds are lepton flavor violation(especially mu -> e gamma), the current bound on the $Z$ mass at LHC, in additions to the neutrino oscillations.