46 research outputs found
An effective scanning method of the NMSSM parameter space
The next-to-minimal supersymmetric standard model (NMSSM) naturally provides
a 125 GeV Higgs boson without the need for large loop corrections from
multi-TeV stop quarks. Furthermore, the NMSSM provides an electroweak scale
dark matter candidate consistent with all experimental data, like relic density
and non-observation of direct dark matter signals with the present experimental
sensitivity. However, more free parameters are introduced in the NMSSM, which
are strongly correlated. A simple parameter scan without knowing the
correlation matrix is not efficient and can miss significant regions of the
parameter space. We introduce a new technique to sample the NMSSM parameter
space, which takes into account the correlations. For this we project the 7D
NMSSM parameter space onto the 3D Higgs boson mass parameter space. The reduced
dimensionality allows for a non-random sampling and therefore a complete
coverage of the allowed NMSSM parameters. In addition, the parameter
correlations and possible deviations of the signal strengths of the observed
125 Higgs boson from the SM values are easily predicted.Comment: 15 pages, 5 figure
The impact of a 126 GeV Higgs on the neutralino mass
We highlight the differences of the dark matter sector between the
constrained minimal supersymmetric SM (CMSSM) and the next-to-minimal
supersymmetric SM (NMSSM) including the 126 GeV Higgs boson using GUT scale
parameters. In the dark matter sector the two models are quite orthogonal: in
the CMSSM the WIMP is largely a bino and requires large masses from the LHC
constraints. In the NMSSM the WIMP has a large singlino component and is
therefore independent of the LHC SUSY mass limits. The light NMSSM neutralino
mass range is of interest for the hints concerning light WIMPs in the Fermi
data. Such low mass WIMPs cannot be explained in the CMSSM. Furthermore,
prospects for discovery of XENON1T and LHC at 14 TeV are given.Comment: 18 pages, 5 figures, this version is accepted by PLB after
modifications including additional figure
Can we discover a light singlet-like NMSSM Higgs boson at the LHC?
In the next-to minimal supersymmetric standard model (NMSSM) one additional
singlet-like Higgs boson with small couplings to standard model (SM) particles
is introduced. Although the mass can be well below the discovered 125 GeV Higgs
boson mass its small couplings may make a discovery at the LHC difficult. We
use a novel scanning technique to efficiently scan the whole parameter space
and determine the range of cross sections and branching ratios for the light
singlet-like Higgs boson below 125 GeV. This allows to determine the
perspectives for the future discovery potential at the LHC. Specific LHC
benchmark points are selected representing the salient NMSSM features.Comment: 22 pages, 5 figures, this version is accepted by PLB after minor
modification
Perspectives of direct Detection of supersymmetric Dark Matter in the NMSSM
In the Next-to-Minimal-Supersymmetric-Standard-Model (NMSSM) the lightest
supersymmetric particle (LSP) is a candidate for the dark matter (DM) in the
universe. It is a mixture from the various gauginos and Higgsinos and can be
bino-, Higgsino- or singlino-dominated. Singlino-dominated LSPs can have very
low cross sections below the neutrino background from coherent neutrino
scattering which is limiting the sensitivity of future direct DM search
experiments. However, previous studies suggested that the combination of both,
the spin-dependent (SD) and spin-independent (SI) searches are sensitive in
complementary regions of parameter space, so considering both searches will
allow to explore practically the whole parameter space of the NMSSM. In this
letter, the different scenarios are investigated with a new scanning technique,
which reveals that significant regions of the NMSSM parameter space cannot be
explored, even if one considers both, SI and SD, searches.Comment: 22 pages, 3 figures, this version is accepted by PLB after minor
modification
Higgs Branching Ratios in Constrained Minimal and Next-to-Minimal Supersymmetry Scenarios Surveyed
In the CMSSM the heaviest scalar and pseudo-scalar Higgs bosons decay largely
into b-quarks and tau-leptons because of the large values favored
by the relic density. In the NMSSM the number of possible decay modes is much
richer. In addition to the CMSSM-like scenarios, the decay of the heavy Higgs
bosons is preferentially into top quark pairs (if kinematically allowed),
lighter Higgs bosons or neutralinos, leading to invisible decays. We provide a
scan over the NMSSM parameter space to project the 6D parameter space of the
Higgs sector on the 3D space of the Higgs masses to determine the range of
branching ratios as function of the Higgs boson mass for all Higgs bosons.
Specific LHC benchmark points are proposed, which represent the salient NMSSM
features.Comment: 24 pages, 3 figures, this version is accepted by PLB after minor
modification
Where is SUSY?
The direct searches for Superymmetry at colliders can be complemented by
direct searches for dark matter (DM) in underground experiments, if one assumes
the Lightest Supersymmetric Particle (LSP) provides the dark matter of the
universe. It will be shown that within the Constrained minimal Supersymmetric
Model (CMSSM) the direct searches for DM are complementary to direct LHC
searches for SUSY and Higgs particles using analytical formulae. A combined
excluded region from LHC, WMAP and XENON100 will be provided, showing that
within the CMSSM gluinos below 1 TeV and LSP masses below 160 GeV are excluded
(m_{1/2} > 400 GeV) independent of the squark masses.Comment: 16 pages, 10 figure
Perspectives of direct detection of supersymmetric dark matter in the MSSM and NMSSM
In the next to minimal supersymmetric standard model (NMSSM) the lightest supersymmetric particle (LSP) is a candidate for the dark matter (DM) in the universe. It is a mixture from the various gauginos and Higgsinos and can be bino-, Higgsino- or singlino-dominated. These different scenarios are investigated in detail and compared with the sensitivity of future direct DM experiments, where we use an efficient sampling technique of the parameter space. We find that LSPs with a significant amount of Higgsino and bino admixture will have cross sections in reach of future direct DM experiments, so the background from coherent neutrino scattering is not yet limiting the sensitivity. Both the spin-dependent (SD) and spinindependent (SI) searches are important, depending on the dominant admixture. If the predicted relic density is too low, additional DM candidates are needed, in which case the LSP direct DM searches loose sensitivity of the reduced LSP density. This is taken into account for expected sensitivity. The singlino-like LSP has regions of parameter space with cross sections below the “neutrino floor”. In this region the background from coherent neutrino scattering is expected to be too high, in which
case the NMSSM DM will evade discovery via direct detection experiments
Constraints on Supersymmetry from Relic Density compared with future Higgs Searches at the LHC
Among the theories beyond the Standard Model (SM) of particle physics
Supersymmetry (SUSY) provides an excellent dark matter (DM) candidate, the
neutralino. One clear prediction of cosmology is the annihilation cross section
of DM particles, assuming them to be a thermal relic from the early universe.
In most of the parameter space of Supersymmetry the annihilation cross section
is too small compared with the prediction of cosmology. However, for large
values of the tan beta parameter the annihilation through s-channel
pseudoscalar Higgs exchange yields the correct relic density in practically the
whole range of possible SUSY masses up to the few TeV range. The required
values of tan beta are typically around 50, i.e. of the order of top and bottom
mass ratio, which happens to be also the range allowing for Yukawa unification
in a Grand Unified Theory with gauge coupling unification. For such large
values of tan beta the associated production of the heavier Higgses, which is
enhanced by tan beta squared, becomes three orders of magnitude larger than the
production of a simlar SM-like Higgs and could be observable as one of the
first hints of new physics at the LHC.Comment: 12 pages, 5 figures, Published version in Phys. Lett. B with updated
references and minor correction
Constraints on Supersymmetry from LHC data on SUSY searches and Higgs bosons combined with cosmology and direct dark matter searches
The ATLAS and CMS experiments did not find evidence for Supersymmetry using
close to 5/fb of published LHC data at a center-of-mass energy of 7 TeV. We
combine these LHC data with data on B_s -> mu mu (LHCb experiment), the relic
density (WMAP and other cosmological data) and upper limits on the dark matter
scattering cross sections on nuclei (XENON100 data). The excluded regions in
the constrained Minimal Supersymmetric SM (CMSSM) lead to gluinos excluded
below 1270 GeV and dark matter candidates below 220 GeV for values of the
scalar masses (m_0) below 1500 GeV. For large m_0 values the limits of the
gluinos and the dark matter candidate are reduced to 970 GeV and 130 GeV,
respectively. If a Higgs mass of 125 GeV is imposed in the fit, the preferred
SUSY region is above this excluded region, but the size of the preferred region
is strongly dependent on the assumed theoretical error.Comment: 12 pages, 5 figures, Refs. updated, Published version in Eur. Phys.
J. C with updated references and minor corrections. arXiv admin note:
substantial text overlap with arXiv:1202.336