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This work deals with the right-handed sneutrino as thermal cold dark matter candidate. This scalar emerges in a supersymmetric version of the SU(3)c⊗SU(3)L⊗U(1)X gauge model where right-handed neutrinos are a natural component of leptonic chiral scalar supermultiplets. We first consider the issue of a 125 GeV Higgs boson mass in this model, showing that constraints on the stop mass and trilinear soft coupling are considerably alleviated compared to the minimal supersymmetric standard model. Then, we investigate the region of parameter space that is consistent with right-handed sneutrino as thermal cold dark matter, under the light of Planck results on the relic abundance and direct detection from the LUX experiment. This sneutrino mainly annihilates through an extra neutral gauge boson, Z′, and Higgs exchange so that the physics of dark matter is somewhat related to the parameters determining Higgs and Z′ masses. We then obtain that the right-handed sneutrino in this model must be heavier than 400 GeV to conform with Planck and LUX, simultaneously constraining the Z′ mass to be above 2400 GeV, which is in perfect agreement with LHC searches in a nonsupersymmetric version of this model. [ABSTRACT FROM AUTHOR]

A supersymmetric version of the recently proposed reduced minimal 331 model is considered and its Higgs sector is investigated. We focus on the mass spectrum of the lightest scalars of the model. We show that the Higgs mass of 125 GeV requires substantial radiative corrections. However, stops may develop small mixing and must have a mass around TeV. Moreover, some soft supersymmetry breaking terms may lie at the electroweak scale, which alleviates some tension concerning the fine-tuning of the related parameters. The lightest doubly charged scalar may have a mass of around a few hundreds of GeV, which can be probed at the LHC, while the remaining scalars of the model have masses at the TeV scale. [ABSTRACT FROM AUTHOR]

Differently from the canonical seesaw mechanism, which is grounded in grand unified theories, the inverse seesaw mechanism lacks a special framework that realizes it naturally. In this work we advocate that the 3-3-1 model with right-handed neutrinos has such an appropriate framework to accommodate the inverse seesaw mechanism. We also discuss the smallness of the lepton number violating mass and estimate the branching ratio for the rare lepton flavor violation process μ → eγ. [ABSTRACT FROM AUTHOR]

The minimal 3-3-1 model is perturbative until energies around 4-5 TeV, posing a challenge to generate neutrino masses at eV scale, mainly if one aims to take advantage of the seesaw mechanism. As a means to circumvent this problem, we propose a modification of the model such that it accommodates the type I and type II seesaw mechanisms altogether. We show that the conjunction of both mechanisms yield a neutrino mass expression suppressed by a high power of the cutoff scale, M5, in its denominator. With such a suppression term, we naturally obtain neutrino masses at eV scale when M is around few TeV. We also investigate the size of lepton flavor violation through the process µ → ey. [ABSTRACT FROM AUTHOR]

In this work we build a gauge model based on the SU(3)c ⊗ SU(3)L ⊗ U(l)N symmetry with heavy neutrinos and show that we can have two wealdy interacting cold dark matter candidates in its spectrum. This is achieved by noticing that a global U(1) symmetry can be imposed on the model in such a way that the stability of the dark matter is guaranteed. We obtain their relic abundance and analyze their compatibility with recent direct detection experiments, also exploring the possibility of explaining the two events reported by CDMSII. An interesting outcome of this 3-3-1 model, concerning direct detection of these WIMPs, is a strong bound on the symmetry breaking scale, which imposes it to be above 3 TeV. [ABSTRACT FROM AUTHOR]

It is a longstanding desire of cosmologists, and particle physicists as well, to connect inflation to low energy physics, culminating, for instance, in what is known as Higgs inflation. The condition for the standard Higgs boson playing the role of the inflaton, and driving sucessfully inflation, is that it couples nonminimally with gravity. Nevertheless, cosmological constraints impose that the nonminimal coupling be large. This causes the loss of perturbative unitarity in a scale of energy far below the Planck one. Our aim in this work is to point out that inflaton potential containing a particular type of trilinear coupling involving the inflaton may circumvent this problem by realizing Higgs inflation with tiny nonminimal coupling of the inflaton with gravity. We then develop the idea within a toy model and implement it in the inverse type-II seesaw mechanism for small neutrinos masses. [ABSTRACT FROM AUTHOR]