R-Parity Violation and Family Symmetry

In this talk, we investigate the implications of R-parity violating (RPV) operators in a model with family symmetry. Family symmetry can determine the form of RPV operators as well as the Yukawa matrices. We consider a concrete model with non-abelian discrete symmetry Q_6, which has only three RPV trilinear operators with no baryon number violating terms. We find that ratios of decay rates of the lepton flavor violating processes are fixed thanks to the family symmetry, predicting BR(tau to 3e)/BR(tau to 3mu) ~ 4 m_{mu}^2/m_{tau}^2.Comment: 11pages, 2 figures. Talk given at CTP symposium on Supersymmetry at LHC: Theoretical and Experimental Perspectives, The British University in Egypt, Cairo, Egypt, 11-14 March 200

Electron/Muon Specific Two Higgs Doublet Model

We discuss two Higgs doublet models with a softly-broken discrete $\mathbb{S}_3$ symmery, where the mass matrix for charged-leptons is predicted as the diagonal form in the weak eigenbasis of lepton fields. Similar to an introduction of $\mathbb{Z}_2$ symmetry, the tree level flavor changing neutral current can be forbidden by imposing the $\mathbb{S}_3$ symmetry to the model. Under the $\mathbb{S}_3$ symmetry, there are four types of Yukawa interactions depending on the $\mathbb{S}_3$ charge assignment to right-handed fermions. We find that extra Higgs bosons can be muon and electron specific in one of four types of the Yukawa interaction. This property does not appear in any other two Higgs doublet models with a softly-broken ${\mathbb Z}_2$ symmetry. We discuss the phenomenology of the muon and electron specific Higgs bosons at the Large Hadron Collider; namely we evaluate allowed parameter regions from the current Higgs boson search data and discovery potential of such a Higgs boson at the 14 TeV run.Comment: 17 pages, 5 figures, 6 tables; version published in Nuclear Physics

Light Dark Matter Candidate in B-L Gauged Radiative Inverse Seesaw

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).Comment: 10 pages, 1 table, 3 figures; version accepted for publication in European Physical Journal

The SUSY Flavor Problem, Proton Decay and Discrete Family Symmetry

We consider a supersymmetric extension of the standard model, which possess a family symmetry based on a binary dihedral group Q6, and investigate the consequences of the family symmetry on the mixing of fermions, FCNCs and the stability of proton.Comment: 5 pages, 1 figure, to appear in Proceedings of SUSY06, the 14th International Conference on Supersymmetry and the Unification of Fundamental Interactions, UC Irvine, California, 12-17 June 200