Same-sign single dilepton productions at the LHC

We examine the same-sign single dilepton productions of $\ell_i^{\pm}\ell_j^{\pm} (\ell_{i,j}=e,\mu)$ in high-energy proton-proton collisions at the Large Hadron Collider (LHC) in models with doubly charged Higgs scalars as well as heavy Majorana neutrinos. We demonstrate that these spectacular productions can be detected at the LHC for a class model in which the doubly charged Higgs scalars couple only to the right-handed charged leptons. The ranges of the possible doubly charged Higgs masses and mixings to observe the processes at the LHC are discussed.Comment: 10 pages, 5 figure

ATIC/PAMELA anomaly from fermionic decaying Dark Matter

We demonstrate that an economical two Higgs doublet model can explain the electron and positron excesses in the recent ATIC and PAMELA experiments by the three body decays of the dark matter (DM) fermions without requiring the fine turning of the couplings and degeneracy of masses. We also show that the mass and lifetime of the decaying DM particle may not be fixed to be around 1 TeV and 10^{26} sec, respectively. Moreover, we note that this model includes a stable dark matter candidate as well.Comment: 8 pages, 4 figures; references added, typos corrected. The version to appear in PL

New Solution for Neutrino Masses and Leptogenesis in Adjoint SU(5)

We investigate baryogenesis via leptogenesis and generation of neutrino masses and mixings through the Type I plus Type III seesaw plus an one-loop mechanism in the context of Renormalizable Adjoint SU(5) theory. One light neutrino remains massless, because the contributions of three heavy Majorana fermions \rho_0, \rho_3 and \rho_8 to the neutrino mass matrix are not linearly independent. However none of these heavy fermions is decoupled from the generation of neutrino masses. This opens a new range in parameter space for successful leptogenesis, in particular, allows for inverted hierarchy of the neutrino masses.Comment: 16 pages, 4 figures; references added and typos fixe

Resolving Fermi, PAMELA and ATIC anomalies in split supersymmetry without R-parity

A long-lived decaying dark matter as a resolution to Fermi, PAMELA and ATIC anomalies is investigated in the framework of split supersymmetry (SUSY) without R-parity, where the neutralino is regarded as the dark matter and the extreme fine-tuned couplings for the long-lived neutralino are naturally evaded in the usual approach.Comment: 14 pages, 6 figures. Erroneous results concerning the cascade processes removed. Main results unchange

Searching for doubly charged Higgs bosons in M\"{o}ller scattering by resonance effects at linear e−e−e^-e^- collider

We discuss the parity-violating left-right asymmetries (LRAs) in M\"{o}ller scattering at the International Linear Collider (ILC) induced by doubly charged Higgs bosons in models with $SU(2)_L$ triplet and singlet scalar bosons, which couple to the left- and right-handed charged leptons, respectively. These bosons are important in the scenarios for the generation of the neutrino mass. We demonstrate that the contributions to the LRAs from the triplet and singlet bosons are opposite to each other. In particular, we show that the doubly charged Higgs boson from the singlet scalar can be tested at the ILC by using the resonance effect.Comment: 12 pages, 5 figures; version published in Eur.Phys.J.C60:119-124,200