Prediction of h→γZh\to\gamma Z from h→γγh\to\gamma\gamma at LHC for the IMDS3_3 Model

We consider the decays $h\to\gamma\gamma,\gamma Z$ in the context of an extension of the standard model with two inert doublets and an additional $S_3$ symmetry. This model has contributions for these processes through new charged scalar-loops. Comparing our $h\to\gamma\gamma$ with the more precise available experimental data we can predict the behaviour of $h\to\gamma Z$ due that they depend on the same parameters, our estimation for this channel is 1.05 times the standard model value, but can be up to 1.16 if consider the $+1\sigma$ uncertainty from the $h\to\gamma\gamma$ data, and down to 0.96 if consider $-1\sigma$.Comment: 14 pages, and 5 figures, new title, new phenomenological analysis, updated experimental data, new references, new Appendix and discussion adde

Skew-Flavored Dark Matter

We explore a novel flavor structure in the interactions of dark matter with the Standard Model. We consider theories in which both the dark matter candidate, and the particles that mediate its interactions with the Standard Model fields, carry flavor quantum numbers. The interactions are skewed in flavor space, so that a dark matter particle does not directly couple to the Standard Model matter fields of the same flavor, but only to the other two flavors. This framework respects Minimal Flavor Violation, and is therefore naturally consistent with flavor constraints. We study the phenomenology of a benchmark model in which dark matter couples to right-handed charged leptons. In large regions of parameter space the dark matter can emerge as a thermal relic, while remaining consistent with the constraints from direct and indirect detection. The collider signatures of this scenario include events with multiple leptons and missing energy. These events exhibit a characteristic flavor pattern that may allow this class of models to be distinguished from other theories of dark matter.Comment: 10 pages, 7 figures. v2: Discussion of collider signatures expanded, added new section on alternative flavor structures, other minor changes. Matches published versio

Semitauonic B Decay Anomaly

The anomalously large experimentally measured ratios of the semitauonic decay $B\rightarrow D^{(*)} +\tau+\nu$ and the corresponding semileptonic B\rightarrow D^{*} +\l+\bar{\nu}_l disagree with the predictions of the standard E.W + QCD model(S.M). We briefly comment on this disagreement and on possible new physics explanations which are rather constrained and difficult to implement.Comment: Version published in PR

Low Mass Pseudoscalar Dark Matter in an Extended B - L Model

We study an extended B-L model, which has in its structure four neutral scalars. In this model, a representative set of parameters enable us to conclude that one of these scalars is a promising candidate for low-mass dark matter. We introduce an Z_2 symmetry, which ensure the stability of the dark matter. The dominant annihilation process will be through $s$-channel exchange of a scalar in $b\overline{b}$. So, this is also a Higgs portal dark matter model, but the Higgs decay to dark matter is suppressed and meets the constraints from invisible decays of Higgs boson. The model is also in agreement with the constraints established by XENON100, CoGeNT and CDMS experiments, maching the relic abundance and the cross section with nucleon.Comment: Version submitted and accepted for publication in PR

Tunable Double Negative Band Structure from Non-Magnetic Coated Rods

A system of periodic poly-disperse coated nano-rods is considered. Both the coated nano-rods and host material are non-magnetic. The exterior nano-coating has a frequency dependent dielectric constant and the rod has a high dielectric constant. A negative effective magnetic permeability is generated near the Mie resonances of the rods while the coating generates a negative permittivity through a field resonance controlled by the plasma frequency of the coating and the geometry of the crystal. The explicit band structure for the system is calculated in the sub-wavelength limit. Tunable pass bands exhibiting negative group velocity are generated and correspond to simultaneously negative effective dielectric permittivity and magnetic permeability. These can be explicitly controlled by adjusting the distance between rods, the coating thickness, and rod diameters