725 research outputs found

### Next-to-leading order QCD corrections to Higgs production at a future lepton-proton collider

Crucial information on the coupling of the Higgs boson to bottom quarks is
expected from Higgs production in association with a forward tagging jet at a
future high-energy lepton-proton collider. In order to control the theoretical
uncertainties of the signal process, the impact of radiative corrections has to
be quantified. We present the full next-to-leading order QCD corrections to e-
p -> e- j H and e- p -> nu_e j H in the form of a flexible Monte-Carlo program
allowing for the calculation of cross sections and kinematic distributions
within experimentally feasible selection cuts. QCD corrections are found to be
very small for cross sections, while the shape distortion of distributions can
be as large as 20%. Residual scale uncertainties at next-to-leading order are
at the permille level.Comment: 15 pages, 14 figure

### SUSY parameter determination

The impact of the LHC, SLHC and the ILC on the precision of the determination
of supersymmetric parameters is investigated. In particular, in the point SPS1a
the measurements performed at the ILC will improve by an order of magnitude the
precision obtained by the LHC alone. The SLHC with respect to the LHC has the
potential to reduce the errors by a factor two.Comment: Invited talk at 2005 International Linear Collider Physics and
Detector Workshop and Second ILC Accelerator Workshop, Snowmass,
CO(Snowmass05) 3 pages, LaTe

### Probing the Higgs self-coupling at hadron colliders using rare decays

We investigate Higgs boson pair production at hadron colliders for Higgs
boson masses m_H\leq 140 GeV and rare decay of one of the two Higgs bosons.
While in the Standard Model the number of events is quite low at the LHC, a
first, albeit not very precise, measurement of the Higgs self-coupling is
possible in the gg -> HH -> b\bar{b}\gamma\gamma channel. A luminosity-upgraded
LHC could improve this measurement considerably. A 200 TeV VLHC could make a
measurement of the Higgs self-coupling competitive with a next-generation
linear collider. In the MSSM we find a significant region with observable Higgs
pair production in the small \tan\beta regime, where resonant production of two
light Higgs bosons might be the only hint at the LHC of an MSSM Higgs sector.Comment: Revtex, 23 pages, 4 tables, 7 figure

### Measuring CP Violating Phases at a Future Linear Collider

At a future Linear Collider one will be able to determine the masses of
charginos and neutralinos and their pair production cross sections to high
accuracies. We show how systematically including the cross sections into the
analysis improves the measurement of the underlying mass parameters, including
potential CP violating phases. In addition, we investigate how experimental
errors will affect the determination of these parameters. We present a first
estimate on the lower limit of observable small phases and on the accuracy in
determining large phases.Comment: 10 pages, 6 figures, RevTeX3.1, Version to be published in Physics
Letters B, physics setup improved, figures added, conclusions unchange

### Maximum Significance at the LHC and Higgs Decays to Muons

We present a new way to define and compute the maximum significance
achievable for signal and background processes at the LHC, using all available
phase space information. As an example, we show that a light Higgs boson
produced in weak--boson fusion with a subsequent decay into muons can be
extracted from the backgrounds. The method, aimed at phenomenological studies,
can be incorporated in parton--level event generators and accommodate
parametric descriptions of detector effects for selected observables.Comment: 7 pages, 2 figures, changes to wording and new references, published
versio

### SFitter: Reconstructing the MSSM Lagrangian from LHC data

Once supersymmetry is found at the LHC, the question arises what are the
fundamental parameters of the Lagrangian. The answer to this question should
thereby not be biased by assumptions on high-scale models. SFitter is a tool
designed for this task. Taking LHC (and possibly ILC) data as input it scans
the TeV-scale MSSM parameter space using its new weighted Markov chain
technique. Using this scan it determines a list of best-fitting parameter
points. Additionally a log-likelihood map is calculated, which can be reduced
to lower-dimensional Frequentist's profile likelihoods or Bayesian probability
maps.Comment: Submitted for the SUSY07 proceedings, 4 pages, LaTeX, 4 eps figure

### SUSY Particle Production at the Tevatron

The calculation of the next-to-leading order SUSY-QCD corrections to the
production of squarks, gluinos and gauginos at the Tevatron is reviewed. The
NLO corrections stabilize the theoretical predictions of the various production
cross sections significantly and lead to sizeable enhancements of the most
relevant cross sections for scales near the average mass of the produced
massive particles. We discuss the phenomenological consequences of the results
on present and future experimental analyses.Comment: 13 pages, latex, 9 figures, further extended versio

### Weak boson fusion production of supersymmetric particles at the LHC

We present a complete calculation of weak boson fusion production of
colorless supersymmetric particles at the LHC, using the new matrix element
generator SUSY-MadGraph. The cross sections are small, generally at the
attobarn level, with a few notable exceptions which might provide additional
supersymmetric parameter measurements. We discuss in detail how to consistently
define supersymmetric weak couplings to preserve unitarity of weak gauge boson
scattering amplitudes to fermions, and derive sum rules for weak supersymmetric
couplings.Comment: 24 p., 3 fig., 9 tab., published in PRD; numbers in Table IV
corrected to those with kinematic cuts cite

- â€¦