3,972 research outputs found
A General MSSM Parameter Scan
The excluded tan(beta) range and Higgs boson mass regions in the framework of
the Minimal Supersymmetric extension of the Standard Model (MSSM) depend on
several parameters. The Higgs boson masses, cross-sections and branching
fractions have been determined including two-loop diagrammatic calculations.
The limits obtained with a more general scan over the parameter space of the
MSSM are compared with those in the so-called benchmark scenario. The
combination of the searches for Higgs particles in the 1999 data collected by
the DELPHI collaboration at center-of-mass energies between 191.6 and 201.7 GeV
allows stringent limits to be set in combination with previous DELPHI results.
In addition, an interpretation in the framework of the general MSSM scan of the
2000 LEP data at the hightest energies between 201.7 and 209.0 GeV is given. We
show that the current data for the HZ and hA production can be comfortably
accommodated in the MSSM.Comment: 3 pages, 3 figure
Search for New Particles at LEP
The latest preliminary results of the searches for Higgs bosons and
Supersymmetric particles at LEP are reviewed. The results include the
data-taking in 1999 up to center-of-mass energies of 196 GeV. The combination
of the results from the four LEP experiments leads to a significant increase of
the detection sensitivity. No indication of a signal has been observed. In the
Standard Model (SM) a lower limit of 102.6 GeV on the mass of the Higgs boson
is set at 95% CL. In extended models, stringent limits are also set on the HZZ
coupling. Interpretations in the Minimal extension of the Supersymmetric
Standard Model (MSSM) are given and the importance of general MSSM parameter
scans is emphasized. In general scans, the limit on the mass of the lightest
scalar Higgs boson is about 7 GeV lower in comparison with benchmark results.
The data also constrains charged Higgs bosons of a general two-doublet model
and Supersymmetric partners of the SM particles.Comment: 16 pages, 38 figure
Complete LEP Data: Status of Higgs Boson Searches
The LEP experiments completed data-taking in November 2000. New preliminary
combined results of the four LEP experiments ALEPH, DELPHI, L3 and OPAL are
presented for various Higgs boson searches.Comment: 9 pages, 12 figures. Proc. Third Int.Conference on Non-Accelerator
New Physics, NANP-01, Moscow, 200
Status of Higgs Boson Searches at the Tevatron
Over the last years the Tevatron Run-II has extended several limits on Higgs
boson masses and coupling which were pioneered during the LEP accelerator
operation between 1989 and 2000. Higgs boson searches will also be at the
forefront of research at the LHC. This review concisely discusses the
experimental constraints set by the CDF and D0 collaborations in winter
2008/2009 at the beginning of the LHC era. Model-independent and
model-dependent limits on Higgs boson masses and couplings have been set and
interpretations are discussed both in the Standard Model and in extended
models. Recently, for the first time the Tevatron excludes a SM Higgs boson
mass range (160-170 GeV) beyond the LEP limit at 95% CL. The experimental
sensitivities are estimated for the completion of the Tevatron programme.Comment: Presented at WONP'09, 18 pages, 38 figure
A Comparison of Mixed-Higgs Scenarios In the NMSSM and the MSSM
We study scenarios in the minimal and next-to minimal supersymmetric models
in which the lightest CP-even Higgs boson can have mass below the 114 GeV
standard model LEP limit by virtue of reduced ZZ coupling due to substantial
mixing among the Higgs bosons. We pay particular attention to the size of
corrections from superpartners needed for these scenarios to be viable and
point to boundary conditions at large scales which lead to these scenarios
while at the same time keeping electroweak fine tuning modest in size. We find
that naturalness of electroweak symmetry breaking in the mixed-Higgs scenarios
of both models points to the same region of soft supersymmetry breaking terms,
namely those leading to large mixing in the stop sector at the electroweak
scale, especially if we also require that the lightest CP-even Higgs explains
the Higgs-like LEP events at about 98 GeV.Comment: 14 pages, 19 figure
Alignment of the Central D-Zero Detector
The alignment procedure of the Silicon Microstrip Tracker, SMT, and the
Central Fiber Tracker, CFT, is described. Alignment uncertainties and resulting
systematic errors in physics analyses are addressed.Comment: 20 pages, 33 figures, presented at workshop on Tracking In high
Multiplicity Environments (TIME'05) Zurich, October 3-7, 2005. Proceedings
Nucl. Inst. Methods
Charge Transfer Inefficiency Studies for CCD Vertex Detectors at a LC
The Linear Collider Flavour Identification (LCFI) collaboration studies CCD
detectors for quark flavour identification in the framework of a future linear
e+e- collider. The flavour identification is based on precision reconstruction
of charged tracks very close to the interaction point. Therefore, this detector
will be exposed to a high level of radiation and thus an important aspect of
the vertex detector development are radiation hardness studies. Results of
detailed simulations of the charged transport properties of a CCD prototype
chip are reported and compared with initial measurements. The simulation
program allows to study the effect of radiation damage after the exposure of
the detector to a realistic radiation dose, which is expected in the
environment of detector operation at a future LC.Comment: 6 pages, 10 figures, Proceedings 2005 International Linear Collider
Workshop - Stanford, U.S.
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