3,893 research outputs found
Boosting Higgs decays into gamma and a Z in the NMSSM
In this work we present the computation of the Higgs decay into a photon and
a boson at one-loop level in the framework of the Next-to-Minimal
Supersymmetric Standard Model (NMSSM). The numerical evaluation of this decay
width was performed within the framework of the SloopS code, orginally
developped for the Minimal Supersymmetric Standard Model (MSSM) but which was
recently extended to deal with the NMSSM. Thanks to the high level of
automation of SloopS all contributions from the various sector of the NMSSM are
consistently taken into account, in particular the non-diagonal chargino and
sfermion contributions. We then explored the NMSSM parameter space, using
HiggsBounds and HiggsSignals, to investigate to which extent these signal can
be enhanced.Comment: 14 pages, 3 figures, typos fixed, matches the public version, results
and conclusions unchange
One-loop renormalisation of the NMSSM in SloopS : 1. the neutralino-chargino and sfermion sectors
We have completed the one-loop renormalisation of the Next-to-Minimal
Supersymmetric Standard Model (NMSSM) allowing for and comparing between
different renormalisation schemes. A special attention is paid to on-shell
schemes. We study a variety of these schemes based on alternative choices of
the physical input parameters. In this paper we present our approach to the
renormalisation of the NMSSM and report on our results for the
neutralino-chargino and sfermion sectors. We will borrow some results from our
study of the Higgs sector whose full discussion is left for a separate
publication. We have implemented the set up for all the sectors of the NMSSM
within \sloops, a code for the automatic computation of one-loop corrections
initially developed for the standard model and the MSSM. Among the many
applications that allows the code, we present here the one-loop corrections to
neutralino masses and to partial widths of neutralinos and charginos into final
states with one gauge boson. One-loop electroweak and QCD corrections to the
partial widths of third generation sfermions into a fermion and a chargino or a
neutralino are also computed.Comment: 44 page
Precision measurements, dark matter direct detection and LHC Higgs searches in a constrained NMSSM
We reexamine the constrained version of the Next-to-Minimal Supersymmetric
Standard Model with semi universal parameters at the GUT scale (CNMSSM). We
include constraints from collider searches for Higgs and SUSY particles, upper
bound on the relic density of dark matter, measurements of the muon anomalous
magnetic moment and of B-physics observables as well as direct searches for
dark matter. We then study the prospects for direct detection of dark matter in
large scale detectors and comment on the prospects for discovery of heavy Higgs
states at the LHC.Comment: 22 pages, 8 figures. Note added and references adde
Higgs decays in supersymmetric models with light neutralinos
In the Minimal Supersymmetric Standard Model, neutralinos lighter than 50 GeV
are compatible with all accelerator, precision, and cosmological bounds. Such
neutralinos might constitute a relevant decay channel for the Higgs boson,
modifying its expected signatures at hadron colliders. We study the branching
ratio h --> \chi\chi and determine the region in the supersymmetric parameter
space where it is sizable. We have found that, in fact, the Higgs may
dominantly decay into neutralino pairs. Besides, as a result of this new
channel, the branching ratio into visible modes, such as h --> \gamma\gamma,
gets suppressed.Comment: 9 pages, 5 figure
The top squark-mediated annihilation scenario and direct detection of dark matter in compressed supersymmetry
Top squark-mediated annihilation of bino-like neutralinos to top-antitop
pairs can play the dominant role in obtaining a thermal relic dark matter
abundance in agreement with observations. In a previous paper, it was argued
that this can occur naturally in models of compressed supersymmetry, which
feature a running gluino mass parameter that is substantially smaller than the
wino mass parameter at the scale of apparent gauge coupling unification. Here I
study in some more detail the parameter space in which this is viable, and
compare to other scenarios for obtaining the observed dark matter density. I
then study the possibility of detecting the dark matter directly in future
experiments. The prospects are consistently very promising for a wide variety
of model parameters within this scenario.Comment: 17 pages. v2: additions to figures 4 and
micrOMEGAs : a tool for dark matter studies
micrOMEGAs is a tool for cold dark matter (DM) studies in generic extensions
of the standard model with a R-parity like discrete symmetry that guarantees
the stability of the lightest odd particle. The code computes the DM relic
density, the elastic scattering cross sections of DM on nuclei relevant for
direct detection, and the spectra of positrons, anti-protons and photons
originating from DM annihilation including porpagation of charged cosmic rays.
The cross sections and decay properties of new particles relevant for collider
studies are included as well as constraints from the flavour sector on the
parameter space of supersymmetric models.Comment: 10 pages, Proceedings of LC09, e+e- Physics at the TeV scale and the
Dark Matter connection, Perugia, Italy, 21-24 sept. 200
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