Search

We show that the simplest supersymmetric scenario where a large Higgs mass can be attained at tree level for any ratio of the Higgs vacuum expectation values corresponds to the case where the neutrino masses are generated through the type II seesaw mechanism. This allows a standard model-like Higgs with mass around 125 GeV without assuming a heavy spectrum for the top squarks. We show that our results are consistent with the bounds coming from perturbativity up to the grand unified scale and discuss gauge coupling unification and possible signals at the Large Hadron Collider. [ABSTRACT FROM AUTHOR]

Baryon number violating interactions could modify the signatures of supersymmetric models at the Large Hadron Collider. In this article we investigate the predictions for the Higgs mass and the Higgs decays in a simple extension of the minimal supersymmetric standard model where the local baryon and lepton numbers are spontaneously broken at the TeV scale. This theory predicts baryon number violation at the low scale that can change the current LHC bounds on the supersymmetric spectrum. Using the ATLAS and CMS bounds on the Higgs mass we show the constraints on the sfermion masses and show the subsequent predictions for the radiative Higgs decays. We found that the Higgs decay into two photons is suppressed due to the existence of new light leptons. In this theory the stops can be very light in agreement with all experimental bounds, and we make a brief discussion of the possible signals at the LHC. [ABSTRACT FROM AUTHOR]

The fate of R-parity in the context of the minimal supersymmetric standard model is a central issue which has profound implications for particle physics and cosmology. In this article, we discuss the possibility of testing the mechanism responsible for the stability of the lightest supersymmetric particle at the Large Hadron Collider (LHC). The simplest theoretical framework where R-parity conservation can be explained dynamically allows for two types of B-L models. In the first scenario the new Higgses decay mainly into two right-handed neutrinos, giving rise to exotic lepton number violating signals together with displaced vertices. In the second model, one could have peculiar channels with multileptons and/or multiphotons in the final state. In both cases, the local B-L gauge symmetry is broken at the TeV scale and the discovery of the new Higgs bosons may be possible at the LHC. We investigate in detail the production mechanisms for the Higgs bosons relevant for the LHC and the key decays which would shed light on how R-parity is conserved. These results may help to understand the link between the cold dark matter of the universe and the missing energy that could be observed at the LHC if supersymmetry is realized in nature. [ABSTRACT FROM AUTHOR]

The possible origin of the R-parity-violating interactions in the minimal supersymmetric standard model and its connection to the radiative symmetry-breaking mechanism is investigated in the context of the simplest model where the radiative symmetry-breaking mechanism can be implemented. We find that, in the majority of the parameter space, R parity is spontaneously broken at the low scale. These results hint that R-parity-violating processes could be observed at the Large Hadron Collider, if supersymmetry is realized in nature. [ABSTRACT FROM AUTHOR]

We investigate in detail the predictions coming from the d = 4 operators for proton decay. We find the most general constraints for the R-parity violating couplings coming from proton decay, taking into account all fermion mixing and in different supersymmetric scenarios.

We investigate the predictions of anomaly-free dark matter models for direct and indirect detection experiments. We focus on gauge theories where the existence of a fermionic dark matter candidate is predicted by anomaly cancellation, its mass is defined by the new symmetry breaking scale, and its stability is guaranteed by a remnant symmetry after the breaking of the gauge symmetry. We find an upper bound on the symmetry breaking scale by applying the relic density and perturbative constraints. The anomaly-free property of the theories allows us to perform a full study of the gamma lines from dark matter annihilation. We investigate the correlation between predictions for final-state radiation processes and gamma lines. Furthermore, we demonstrate that the latter can be distinguished from the continuum gamma-ray spectrum. [ABSTRACT FROM AUTHOR]

We discuss the possible connection between the scale for baryon number violation and the cosmological bound on the dark matter relic density. A simple gauge theory for baryon number which predicts the existence of a leptophobic cold dark matter particle candidate is investigated. In this context, the dark matter candidate is a Dirac fermion with mass defined by the new symmetry breaking scale. Using the cosmological bounds on the dark matter relic density we find the upper bound on the symmetry breaking scale around 200 TeV. The properties of the leptophobic dark matter candidate are investigated in great detail and we show the prospects to test this theory at current and future experiments. We discuss the main implications for the mechanisms to explain the matter and antimatter asymmetry in the Universe. [ABSTRACT FROM AUTHOR]