313 research outputs found
Leptogenesis as an origin of dark matter and baryon asymmetries in the E6 inspired SUSY models
We explore leptogenesis within the E6 inspired U(1) extension of the MSSM in
which exact custodial symmetry forbids tree-level flavour-changing transitions
and the most dangerous baryon and lepton number violating operators. This
supersymmetric (SUSY) model involves extra exotic matter beyond the MSSM. In
the simplest phenomenologically viable scenarios the lightest exotic fermions
are neutral and stable. These states should be substantially lighter than 1 eV
forming hot dark matter in the Universe. The low-energy effective Lagrangian of
the SUSY model under consideration possesses an approximate global U(1)_E
symmetry associated with the exotic states. The U(1)_E symmetry is explicitly
broken because of the interactions between the right-handed neutrino
superfields and exotic matter supermultiplets. As a consequence the decays of
the lightest right-handed neutrino/sneutrino give rise to both U(1)_E and
U(1)_{B-L} asymmetries. When all right-handed neutrino/sneutrino are relatively
light \sim 10^6-10^7 GeV the appropriate amount of the baryon asymmetry can be
induced via these decays if the Yukawa couplings of the lightest right-handed
neutrino superfields to the exotic matter supermultiplets vary between
10^{-4}-10^{-3}.Comment: 17 pages, 1 figur
Exotic Higgs decays in the E6 inspired SUSY models
We study the decays of the SM-like Higgs state within the E6 inspired
supersymmetric (SUSY) models with exact custodial symmetry that forbids
tree-level flavor-changing transitions and the most dangerous baryon and lepton
number violating operators. In these models there are two states which are
absolutely stable and can contribute to the dark matter density. One of them is
the lightest SUSY particle (LSP) which is expected to be lighter than 1 eV
forming hot dark matter in the Universe. The presence of another stable neutral
state allows to account for the observed cold dark matter density. In the
considered SUSY models next-to-lightest SUSY particle (NLSP) also tend to be
light. We argue that the NLSP with GeV scale mass can result in the substantial
branching ratio of the nonstadard decays of the lightest Higgs boson.Comment: 15 pages, minor changes to the text. arXiv admin note: text overlap
with arXiv:1201.5488 by other author
750 GeV Diphoton Resonance from Singlets in an Exceptional Supersymmetric Standard Model
The 750-760 GeV diphoton resonance may be identified as one or two scalars
and/or one or two pseudoscalars contained in the two singlet superfields
S_{1,2} arising from the three 27-dimensional representations of E_6 . The
three 27s also contain three copies of colour-triplet charge \mp 1/3
vector-like fermions D,\bar{D} and two copies of charged inert Higgsinos
\tilde{H}^{+},\tilde{H}^{-} to which the singlets S_{1,2} may couple. We
propose a variant of the E_6SSM where the third singlet S_3 breaks a gauged
U(1)_N above the TeV scale, predicting Z'_N, D,\bar{D},
\tilde{H}^{+},\tilde{H}^{-} at LHC Run 2, leaving the two lighter singlets
S_{1,2} with masses around 750 GeV. We calculate the branching ratios and
cross-sections for the two scalar and two pseudoscalar states associated with
the S_{1,2} singlets, including possible degeneracies and maximal mixing,
subject to the constraint that their couplings remain perturbative up to the
unification scale.Comment: 22 pages, 4 figures, some minor changes to the text, references adde
Approximate solutions for the Higgs masses and couplings in the NMSSM
We find the approximate solutions for the Higgs masses and couplings in the
NMSSM with exact and softly broken PQ--symmetry. The obtained solutions
indicate that there exists a mass hierarchy in the Higgs spectrum which is
caused by the stability of the physical vacuum.Comment: To appear in the proceedings of International Workshop on What Comes
Beyond the Standard Model?, Bled, Slovenia, 19-30 Jul 200
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