69 research outputs found
Higgs Production in Neutralino Decays in the MSSM - The LHC and a Future e+e- Collider
The search for the production of weakly-interacting SUSY particles at the LHC
is crucial for testing supersymmetry in relation to dark matter. Decays of
neutralinos into Higgs bosons occur over some significant part of the SUSY
parameter space and represent the most important source of boson production
in SUSY decay chains in the MSSM. We study h production in neutralino decays
using scans of the phenomenological MSSM. Whilst in constrained MSSM scenarios
the decay chi^0_2 -> h chi^0_1 is the dominant channel, this does not hold in
more general MSSM scenarios. On the other hand, the chi^0_2,3 -> h chi^0_1
decays remain important and are highly complementary to multi-lepton final
states in the LHC searches. The perspectives for the LHC analyses at 8 and 14
TeV as well as the reach of an e+e- collider at 0.5, 1, 1.5 and 3 TeV are
discussed.Comment: 11 pages, 13 figure
Supersymmetry with Light Dark Matter confronting the recent CDMS and LHC Results
We revisit MSSM scenarios with light neutralino as a dark matter candidate in
view of the latest LHC and dark matter direct and indirect detection
experiments. We show that scenarios with a very light neutralino (~ 10 GeV) and
a scalar bottom quark close in mass, can satisfy all the available constraints
from LEP, Tevatron, LHC, flavour and low energy experiments and provide
solutions in agreement with the bulk of dark matter direct detection
experiments, and in particular with the recent CDMS results.Comment: v2: 11 pages, 9 figures; extended study of mono-jet constraints,
revised references. Two benchmark SLHA files provide
The correlation matrix of Higgs rates at the LHC
The imperfect knowledge of the Higgs boson decay rates and cross sections at
the LHC constitutes a critical systematic uncertainty in the study of the Higgs
boson properties. We show that the full covariance matrix between the Higgs
rates can be determined from the most elementary sources of uncertainty by a
direct application of probability theory. We evaluate the error magnitudes and
full correlation matrix on the set of Higgs cross sections and branching ratios
at , , and TeV, which are provided in ancillary files.
The impact of this correlation matrix on the global fits is illustrated with
the latest + TeV Higgs dataset.Comment: 25 pages, 1 figure. Complete covariance matrix is available in C,
Fortran, Mathematica, PDF, TeX and text formats in ancillary file
One-loop quantum corrections to cosmological scalar field potentials
We study the loop corrections to potentials of complex or coupled real scalar
fields used in cosmology to account for dark energy, dark matter or dark fluid.
We show that the SUGRA quintessence and dark matter scalar field potentials are
stable against the quantum fluctuations, and we propose solutions to the
instability of the potentials of coupled quintessence and dark fluid scalar
fields. We also find that a coupling to fermions is very restricted, unless
this coupling has a structure which already exists in the scalar field
potential or which can be compensated by higher order corrections. Finally, we
study the influence of the curvature and kinetic term corrections.Comment: 11 pages, 1 figure, accepted for publication in Phys. Rev.
Supersymmetric Heavy Higgs Bosons at the LHC
The search for heavy Higgs bosons is an essential step in the exploration of
the Higgs sector and in probing the Supersymmetric parameter space. This paper
discusses the constraints on the M(A) and tan beta parameters derived from the
bounds on the different decay channels of the neutral H and A bosons accessible
at the LHC, in the framework of the phenomenological MSSM. The implications
from the present LHC results and the expected sensitivity of the 14 TeV data
are discussed in terms of the coverage of the [M(A) - tan beta] plane. New
channels becoming important at 13 and 14 TeV for low values of tan beta are
characterised in terms of their kinematics and the reconstruction strategies.
The effect of QCD systematics, SUSY loop effects and decays into pairs of SUSY
particles on these constraints are discussed in details.Comment: 12 pages, 18 figure
Anomaly mediated SUSY breaking scenarios in the light of cosmology and in the dark (matter)
Anomaly mediation is a popular and well motivated supersymmetry breaking
scenario. Different possible detailed realisations of this set-up are studied
and actively searched for at colliders. Apart from limits coming from flavour,
low energy physics and direct collider searches, these models are usually
constrained by the requirement of reproducing the observations on dark matter
density in the universe. We reanalyse these bounds and in particular we focus
on the dark matter bounds both considering the standard cosmological model and
alternative cosmological scenarios. These scenarios do not change the
observable cosmology but relic dark matter density bounds strongly depend on
them. We consider few benchmark points excluded by standard cosmology dark
matter bounds and suggest that loosening the dark matter constraints is
necessary in order to avoid a too strong (cosmological) model dependence in the
limits that are obtained for these models. We also discuss briefly the
implications for phenomenology and in particular at the Large Hadron Collider.Comment: 37 pages, 20 figures, 1 tabl
Cosmological constraints on quintessential halos
A complex scalar field has recently been suggested to bind galaxies and
flatten the rotation curves of spirals. Its cosmological behavior is thoroughly
investigated here. Such a field is shown to be a potential candidate for the
cosmological dark matter that fills up a fraction Omega_cdm = 0.3 of the
Universe. However, problems arise when the limits from galactic dynamics and
some cosmological constraints are taken simultaneously into account. A free
complex field, associated to a very small mass m = 10^{-23} eV, has a correct
cosmological behavior in the early Universe, but behaves today mostly as a real
axion, with a problematic value of its conserved quantum number. On the other
hand, an interacting field with quartic coupling lambda = 0.1 has a more
realistic mass m = 1 eV and carries a quantum number close to the photon number
density. Unlike a free field, it would be spinning today in the complex plane -
like the so-called ``spintessence''. Unfortunately, the cosmological evolution
of such field in the early Universe is hardly compatible with constraints from
nucleosynthesis and structure formation.Comment: 13 pages, 3 figures. Some minor changes, version accepted in PR
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