Search

We study the stability constraints on the parameter space of a triplet extension of the Minimal Supersymmetric Standard Model (MSSM). Existence of unbounded-from-below directions in the potential can spoil successful electroweak (EW) symmetry breaking by making the corresponding minimum unstable, and hence the model should be free from those directions. Avoiding those directions restricts the parameter space of the model. We derive four stability constraints, of which only three are independent from each other. After scanning the parameter space of the model for phenomenologically viable data points, we impose the stability constraints and find that only about a quarter of the data points features a stable EW minimum. At those data points featuring stability, p and the up Higgs soft mass turn out to be smaller than about a TeV in absolute value, which makes the mass of the lightest chargino and neutralino smaller than about 700 GeV. Two relevant phenomenological consequences of lifting the unbounded-frombelow directions are that the lightest Higgs boson decay rate to diphoton predicted by the triplet extension of MSSM generally features larger deviations from MSSM, and fine-tuning is actually higher than what each of the two would be without imposing stability constraints. [ABSTRACT FROM AUTHOR]

A positron excess up to energies of ~350 GeV has been observed by AMS-02, and it is consistent with the positron excess observed by PAMELA up to 100 GeV. There is no observed excess of antiprotons over the expected cosmic ray background. We propose a leptophilic dark matter with an U(1)Lμ-Lτ gauge extension of the minimal supersymmetric standard model. The dark matter is an admixture of the Lμ-Lτ gaugino and fermionic partners of the extra SU(2) singlet Higgs boson, which break the Lμ-Lτ symmetry. We construct the SM⊗U(1)Lμ-Lτ supersymmetry model which provides the correct relic density of dark matter and is consistent with the constraint on Z' from LHC. The large dark matter annihilation cross section into μ+μ- and τ+τ-, needed to explain PAMELA and AMS-02 results, is achieved by Breit-Wigner resonance. [ABSTRACT FROM AUTHOR]