Diego Restrepo

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

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].

On the Connection of Gamma-Rays, Dark Matter and Higgs Searches at LHC

Motivated by the upcoming Higgs analyzes we investigate the importance of the complementarity of the Higgs boson chase on the low mass WIMP search in direct detection experiments and the gamma-ray emission from the Galactic Center measured by the Fermi-LAT telescope in the context of the

Models with radiative neutrino masses and viable dark matter candidates

SU(3)_c\otimes SU(3)_L\otimes U(1)_N

Collider signals of gravitino dark matter in bilinearly broken R-parity

. We obtain the relic abundance, thermal cross section, the WIMP-nucleon cross section in the low mass regime and network them with the branching ratios of the Higgs boson in the model. We conclude that the Higgs boson search has a profound connection to the dark matter problem in our model, in particular for the case that (

Gravitino dark matter and neutrino masses with bilinear R-parity violation

M_{WIMP} 60

Indirect detection of gravitino dark matter including its three-body decays

GeV, consequently ruling out any attempt to explain the Fermi-LAT observations.

Probing bilinear R-parity violating supergravity at the LHC

A bstractWe provide a list of particle physics models at the TeV-scale that are compatible with neutrino masses and dark matter. In these models, the Standard Model particle content is extended with a small number (≤ 4) of scalar and fermion fields transforming as singlets, doublets or triplets under SU(2), and neutrino masses are generated radiatively via 1-loop diagrams. The dark matter candidates are stabilized by a Z2 symmetry and are in general mixtures of the neutral components of such new multiplets. We describe the particle content of each of these models and determine the conditions under which they are consistent with current data. We find a total of 35 viable models, most of which have not been previously studied in the literature. There is a great potential to test these models at the LHC not only due to the TeV-scale masses of the new fields but also because about half of the viable models contain particles with exotic electric charges, which give rise to background-free signals. Our results should serve as a first step for detailed analysis of models that can simultaneously account for dark matter and neutrino masses.

Bounds on the tau and muon neutrino vector and axial vector charge radius

In models with gauge mediated supersymmetry breaking the gravitino is the lightest supersymmetric particle. If R-parity is violated the gravitino decays, but with a half-live far exceeding the age of the universe and thus is, in principle, a candidate for the dark matter. We consider the decays of the next-to-lightest supersymmetric particle, assumed to be the neutralino. We show that in models where the breaking of R-parity is bilinear, the condition that R-parity violation explains correctly the measured neutrino masses fixes the branching ratio of the decay 01 ? ? in the range (10-3?10-2), if the gravitino mass is in the range required to solve the dark matter problem, i.e. of the order (few) 100 eV. This scenario is therefore directly testable at the next generation of colliders.

Probing neutrino mass with displaced vertices at the Fermilab Tevatron

Bilinear

Leptonic Charged Higgs Decays in the Zee Model

R