396 research outputs found

### Phenomenology of SUSY-models with spontaneously broken R-parity

We review the consequences of spontaneously broken R-parity in present and
planned lepton-lepton colliders. In the left-right models the R-parity,
$R=(-1)^{3(B-L)+2S}$, is preserved due to the gauge symmetry, but it must be
spontaneously broken in order to the scalar spectrum to be physically
consistent. The spontaneous breaking is generated via a non-vanishing VEV of at
least one of the sneutrinos, which necessarily means non-conservation of lepton
number $L$. The R-parity violating couplings are parametrized in terms of
mixing angles, whose values depend on model parameters. Combined with the
constraints derived from low-energy measurements this yields allowed ranges for
various R-parity breaking couplings. The R-parity breaking allows for the
processes in which a single chargino or neutralino is produced, subsequently
decaying at the interaction point to non-supersymmetric particles.Comment: 6 pages, Latex, talk given in Beyond the Standard Model V in Balholm,
Norwa

### Phenomenology of light Higgs bosons in supersymmetric left-right models

We carry out a detailed analysis of the light Higgs bosons in supersymmetric
left-right models (SLRM). This includes models with minimal particle content
and those with additional Higgs superfields. We also consider models with
non-renormalizable higher-dimensional terms. We obtain an upper bound on the
mass of the lightest CP-even neutral Higgs boson in these models. The upper
bound depends only on the gauge couplings, and the vacuum expectation values of
those neutral Higgs fields which control the spontaneous breakdown of the
$SU(2)_L \times U(1)_Y$ gauge symmetry. We calculate the one-loop radiative
corrections to this upper bound, and evaluate it numerically in the minimal
version of the supersymmetric left-right model. We consider the couplings of
this lightest CP-even Higgs boson to the fermions, and show that in a
phenomenologically viable model the branching ratios are similar to the
corresponding branching ratios in the minimal supersymmetric standard model
(MSSM). We then study the most promising particle for distinguishing the SLRM
from other models, namely the doubly charged Higgs boson. We obtain the mass of
this doubly charged Higgs boson in different types of supersymmetric left-right
models, and discuss its phenomenology.Comment: 29 pages, 4 figure

### Supersymmetric Models and CP violation in B decays

In this talk CP violation in the supersymmetric models, and especially in
B-decays is discussed. We review our analysis of the supersymmetric
contributions to the mixing CP asymmetries of $B\to \phi K_S$ and $B\to
\eta^{\prime} K_S$ processes. Both gluino and chargino exchanges are considered
in a model independent way by using the mass insertion approximation method.
The QCD factorization method is used, and parametrization of this method in
terms of Wilson coefficients is presented in both decay modes. Correlations
between the CP asymmetries of these processes and the direct CP asymmetry in
$b\to s \gamma$ decay are shown.Comment: 16 pages, 7 figures. Prepared for the proceedings of the 1st GUC
workshop on High Energy Physics, Cairo, Jan 9-13, 200

### Mass of the lightest Higgs Boson in Supersymmetric Left-Right Models

We consider the lightest Higgs boson in naturally R-parity conserving
supersymmetric left-right models. We obtain an upper bound on the tree level
mass of this lightest Higgs boson. This upper bound depends on the $SU(2)_L$
and $SU(2)_R$ gauge couplings, and the vacuum expectation values of bidoublet
Higgs fields, which are needed to break $SU(2)_L\times U(1)_Y$. The upper bound
does not depend on either the $SU(2)_R$ breaking scale or the supersymmetry
breaking scale. We evaluate the bound numerically by assuming that the theory
remains perturbative upto some scale $\Lambda$. We find that the bound can be
considerably larger than in MSSM. The dominant radiative corrections to the
upper bound due to top-stop and bottom-sbottom systems are of the same form as
in the minimal supersymmetric standard model.Comment: 14 pages including 2 figures, LaTe

### Chargino contributions to the CP asymmetry in B -> Phi K(S) decay

We perform a model independent analysis of the chargino contributions to the
CP asymmetry in B -> Phi K(S) process. We use the mass insertion approximation
method generalized by including the possibility of a light right-stop. We find
that the dominant effect is given by the contributions of the mass insertions
deltaU_LL(32) and deltaU_RL(32) to the Wilson coefficient of the chromomagnetic
operator. By considering both these contributions simultaneously, the CP
asymmetry in B -> Phi K(S) process is significantly reduced and negative
values, which are within the 1-sigma experimental range and satisfy the b -> s
gamma constraints, can be obtained.Comment: 14 pages, LaTeX, 3.eps Figure

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