Search

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]

Motivated by the upcoming Higgs analyses, we investigate the importance of the complementarity of the Higgs boson chase on the low-mass weakly interacting massive particle (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 SU(3)C ⊗ SU(3)L ⊗ U(l)N. We obtain the relic abundance, thermal cross section, and the WIMP-nucleon cross section in the low-mass regime and network them with the branching ratios (BRs) 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 (MWIMP < 60 GeV) the BR(H→2 WIMPs) ≳90%. This scenario could explain the gamma-ray emission from the Galactic Center observed by the Fermi-LAT telescope through the b... channel with a WIMP in the mass range of 25-15 GeV, while still being consistent with the current limits from XENON 100 and CDMSII. However, after the recent LHC measurements concerning the Higgs, this window has been completely forfended, implying that MWIMP > MH/2 and, consequently, ruling out any attempt to explain the Fermi-LAT observations, although still offering a region of the parameter space consistent with the current bounds. Lastly, we show that our model has a Standard Model-like Higgs boson for the regime that MWIMP > MH/2, by computing the BRs into bb, γγ and ττ. [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]

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]

Recent simulation studies indicate that right-handed neutrinos may be discovered at future high luminosity LHC runs as long as a new neutral gauge boson, Z', have been discovered first. In this case, when Z' is resonantly produced at the LHC it, subsequently, decays into a pair of right-handed neutrinos with mass up to TeV scale. Then the decay of these neutrinos leave as signature trilepton final states and/or same-sign dimuon and a boost diboson. The prospect of discovering right-handed neutrinos through this mechanism has been developed within Abelian gauge extension of the standard model. In this work we study the processes involved in this discovery mechanism within the framework of a 3-3-1 model. [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]

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]

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]

The simplest non-Abelian gauge extension of the electroweak standard model, the SU(3)c ⊗ SU(3)L ⊗ U(1)N, known as the 3-3-1 model, has a minimal version which demands the least possible fermionic content to account for the whole established phenomenology for the well-known particles and interactions. Nevertheless, in its original form the minimal 3-3-1 model was proposed with a set of three scalar triplets and one sextet in order to yield the spontaneous breaking of the gauge symmetry and generate the observed fermion masses. Such a huge scalar sector turns the task of clearly identifying the physical scalar spectrum into a clumsy labor. It not only adds an obstacle for the development of its phenomenology, but implies a scalar potential plagued with new free coupling constants. In this work, we show that the framework of the minimal 3-3-1 model can be built with only two scalar triplets, but still triggering the desired pattern of spontaneous symmetry breaking and generating the correct fermion masses. We present the exact physical spectrum and also show all the interactions involving the scalars, obtaining a neat minimal 3-3-1 model far more suited for phenomenological studies at the current Large Hadron Collider. [ABSTRACT FROM AUTHOR]

We investigate the Higgs boson production through gluon fusion and its decay into two photons at the LHC in the context of the minimal 3-3-1 model and its alternative version with exotic leptons. The diphoton Higgs decay channel presents an enhanced signal in this model compared to the standard model due to the presence of an extra singly charged vector boson and a doubly charged one. Prospects for the Higgs boson detection at 7 TeV center-of-mass energy with up to 10 fb-1 are presented. Our results suggest that a Higgs boson from these 3-3-1 models can potentially explain the small excess for mH ≤ 145 GeV observed at the LHC. Otherwise, if this excess reveals to be only a statistical fluctuation of the standard model backgrounds, severe constraints can be put on these models. [ABSTRACT FROM AUTHOR]