153 research outputs found
Precision Studies of the Higgs Boson Profile at the e+e- Linear Collider
This paper reviews the potential of a high luminosity e+e- linear collider
(LC) in the precision study of the Higgs boson profile. The complementarity of
the linear collider data with that from the LHC is also discussed together with
a comparison with a muon collider.Comment: 20 pages 11 figures, to appear in the Proceedings of the 5th Int.
Linear Collider Workshop LCWS2000, Fermilab, October 200
Extracting SUSY parameters from LHC measurements using Fittino
We show that presently available precision data are in good agreement with
supersymmetry at a mass scale below 1 TeV. Using a SUSY point close to the best
fit to present data, we give a projection of the capabilities of the LHC to
constrain SUSY models and their parameters as function of the accumulated
luminosity.Comment: 4 pages, contribution to the proceedings of the 17th International
Conference on Supersymmetry and the Unification of Fundamental Interactions
(SUSY09), Northeastern University, Boston, MA, USA, June 200
Using an InGrid Detector to Search for Solar Chameleons with CAST
We report on the construction, operation experience, and preliminary
background measurements of an InGrid detector, i.e. a MicroMegas detector with
CMOS pixel readout. The detector was mounted in the focal plane of the Abrixas
X-Ray telescope at the CAST experiment at CERN. The detector is sensitive to
soft X-Rays in a broad energy range (0.3--10 keV) and thus enables the search
for solar chameleons. Smooth detector operation during CAST data taking in
autumn 2014 has been achieved. Preliminary analysis of background data
indicates a background rate of above 2 keV and
around
1 keV. An expected limit of on the
chameleon photon coupling is estimated in case of absence of an excess in solar
tracking data. We also discuss the prospects for future operation of the
detector.Comment: Contributed to the 11th Patras Workshop on Axions, WIMPs and WISPs,
Zaragoza, June 22 to 26, 201
Supersymmetry Parameter Analysis with Fittino
We present the results of a realistic global fit of the Lagrangian parameters
of the Minimal Supersymmetric Standard Model to simulated data from ILC and LHC
with realistic estimates of the observable uncertainties. Higher order
radiative corrections are accounted for where ever possible to date. Results
are obtained for a modified SPS1a MSSM benchmark scenario but they were checked
not to depend critically on this assumption. Exploiting a simulated annealing
algorithm, a stable result is obtained without any a priori assumptions on the
fit parameters. Most of the Lagrangian parameters can be extracted at the
percent level or better if theoretical uncertainties are neglected. Neither LHC
nor ILC measurements alone will be sufficient to obtain a stable result. The
effects of theoretical uncertainties arising from unknown higher-order
corrections and parametric uncertainties are examined qualitatively. They
appear to be relevant and the result motivates further precision calculations.Comment: 6 pages, 2 figures, presented at the Linear Collider Workshop 2005,
Stanfor
Physics at Future Linear Colliders
This article summarises the physics at future linear colliders. It will be
shown that in all studied physics scenarios a 1 TeV linear collider in addition
to the LHC will enhance our knowledge significantly and helps to reconstruct
the model of new physics nature has chosen.Comment: Invited talk at the Lepton Photon Symposium 2005, Upsala, Sweden,
July 2005, V2: minor improvement
An InGrid based Low Energy X-ray Detector
An X-ray detector based on the combination of an integrated Micromegas stage
with a pixel chip has been built in order to be installed at the CERN Axion
Solar Telescope. Due to its high granularity and spatial resolution this
detector allows for a topological background suppression along with a detection
threshold below . Tests at the CAST Detector Lab show the
detector's ability to detect X-ray photons down to an energy as low as
. The first background data taken after the installation at the
CAST experiment underline the detector's performance with an average background
rate of between 2 and
when using a lead shielding.Comment: 4 pages, 5 figures, Contributed to the 10th Patras Workshop on
Axions, WIMPs and WISPs, CERN, June 29 to July 4, 201
Killing the cMSSM softly
We investigate the constrained Minimal Supersymmetric Standard Model (cMSSM)
in the light of constraining experimental and observational data from precision
measurements, astrophysics, direct supersymmetry searches at the LHC and
measurements of the properties of the Higgs boson, by means of a global fit
using the program Fittino. As in previous studies, we find rather poor
agreement of the best fit point with the global data. We also investigate the
stability of the electro-weak vacuum in the preferred region of parameter space
around the best fit point. We find that the vacuum is metastable, with a
lifetime significantly longer than the age of the Universe. For the first time
in a global fit of supersymmetry, we employ a consistent methodology to
evaluate the goodness-of-fit of the cMSSM in a frequentist approach by deriving
p-values from large sets of toy experiments. We analyse analytically and
quantitatively the impact of the choice of the observable set on the p-value,
and in particular its dilution when confronting the model with a large number
of barely constraining measurements. Finally, for the preferred sets of
observables, we obtain p-values for the cMSSM below 10%, i.e. we exclude the
cMSSM as a model at the 90% confidence level.Comment: 22 pages, 16 figures, to be submitted to EPJ
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