2,040 research outputs found
Sfermion decays into singlets and singlinos in the NMSSM
We investigate how the addition of the singlet Higgs field in the NMSSM
changes the sfermion branching ratios as compared to the MSSM. We concentrate
in particular on the third generation, discussing decays of the heavier stop,
sbottom or stau into the lighter mass eigenstate plus a scalar or pseudoscalar
singlet Higgs. We also analyse stop, sbottom and stau decays into singlinos. It
turns out that the branching ratios of these decays can be large, markedly
influencing the sfermion phenomenology in the NMSSM. Moreover, we consider
decays of first and second generation sfermions into singlinos.Comment: 10 pages, 4 figures; a few additional remarks on the model, version
to be publishe
Yukawa Induced Radiative Corrections to the Lightest Higgs Boson Mass in the NMSSM
We compute the leading logarithmic radiative corrections to the lightest
Higgs mass in the NMSSM involving the electroweak gauge couplings and in the
NMSSM specific Yukawa couplings lambda and kappa (including all mixed
combinations), which are induced by chargino, neutralino and Higgs boson loops.
The effect of the NMSSM specific Yukawa couplings lambda and kappa is to
increase the upper bound on the lightest Higgs mass by up to ~2 GeV, but they
can also decrease the lightest Higgs mass by up to ~-20 GeV.Comment: 12 pages, 3 figs, improved (generalized) treatment of CP odd loop
contributions; the possibility to get large negative contributions to the
lightest Higgs mass is clarified in a third figure; typos correcte
Cosmological evolution in compactified Horava-Witten theory induced by matter on the branes
The combined Einstein equations and scalar equation of motion in the
Horava-Witten scenario of the strongly coupled heterotic string compactified on
a Calabi-Yau manifold are solved in the presence of additional matter densities
on the branes. We take into account the universal Calabi-Yau modulus phi with
potentials in the 5-d bulk and on the 3-branes, and allow for an arbitrary
coupling of the additional matter to phi and an arbitrary equation of state. No
ad hoc stabilization of the five dimensional radius is assumed. The matter
densities are assumed to be small compared to the potential for phi on the
branes; in this approximation we find solutions in the bulk which are exact in
y and t. Depending on the coupling of the matter to phi and its equation of
state, various solutions for the metric on the branes and in the 5-d bulk are
obtained: Solutions corresponding to a ``rolling radius'', and solutions with a
static 5-d radius, which reproduce the standard cosmological evolution.Comment: 20 pages (LaTeX2e), no figs. References added and comments rectifie
The Cosmological Constant
Various contributions to the cosmological constant are discussed and
confronted with its recent measurement. We briefly review different scenarious
-- and their difficulties -- for a solution of the cosmological constant
problem.Comment: Lecture given at the XIV Workshop "Beyond the Standard Model", Bad
Honnef, 11-14 March 200
Testing the higgsino-singlino sector of the NMSSM with trileptons at the LHC
We propose a simplified light higgsino-singlino scenario in the NMSSM, in
which the masses of the chargino and the lightest neutralino determine the
masses and couplings of all 3 lightest neutralinos. This scenario is
complementary to the simplified wino-like chargino/neutralino scenario used
conventionally for the interpretation of results from trilepton searches, and
motivated by lower bounds on the gluino mass in the case of GUT relations
between the wino and gluino masses. We present all masses and mixing angles
necessary for the determination of production cross sections of the chargino
and the 3 neutralinos in the form of Tables in the M_{neutralino_1} -
M_{chargino_1} plane, assuming Higgs mass motivated values for tan(beta)=2 and
lambda=0.6. We show that this scenario leads to considerable signal rates, and
present constraints in this plane from recent searches for trileptons at the
LHC.Comment: 16 pages, 1 Figure, 8 Table
Gradient flows for functions via multi-scale renormalization group equations
Renormalization schemes and cutoff schemes allow for the introduction of
various distinct renormalization scales for distinct couplings. We consider the
coupled renormalization group flow of several marginal couplings which depend
on just as many renormalization scales. The usual functions describing
the flow with respect to a common global scale are assumed to be given. Within
this framework one can always construct a metric and a potential in the space
of couplings such that the functions can be expressed as gradients of
the potential. Moreover the potential itself can be derived explicitly from a
prepotential which, in turn, determines the metric. Some examples of
renormalization group flows are considered, and the metric and the potential
are compared to expressions obtained elsewhere.Comment: 8 page
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