750 research outputs found
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
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
Understanding Jet Scaling and Jet Vetos in Higgs Searches
Jet counting and jet vetos are crucial analysis tools for many LHC searches.
We can understand their properties from the distribution of the exclusive
number of jets. LHC processes tend to show either a distinct staircase scaling
or a Poisson scaling, depending on kinematic cuts. We illustrate our approach
in a detailed study of jets in weak boson fusion Higgs production.Comment: 5 pages, 4 figures, 1 table. Text clarified to reflect that we
applied forward-backward tagging jet selectio
Better Higgs-CP Tests Through Information Geometry
Measuring the CP symmetry in the Higgs sector is one of the key tasks of the
LHC and a crucial ingredient for precision studies, for example in the language
of effective Lagrangians. We systematically analyze which LHC signatures offer
dedicated CP measurements in the Higgs-gauge sector, and discuss the nature of
the information they provide. Based on the Fisher information measure, we
compare the maximal reach for CP-violating effects in weak boson fusion,
associated ZH production, and Higgs decays into four leptons. We find a subtle
balance between more theory-independent approaches and more powerful analysis
channels, indicating that rigorous evidence for CP violation in the Higgs-gauge
sector will likely require a multi-step process.Comment: 27 pages, 8 figure
Precision Measurements of Higgs Couplings: Implications for New Physics Scales
The measured properties of the recently discovered Higgs boson are in good
agreement with predictions from the Standard Model. However, small deviations
in the Higgs couplings may manifest themselves once the currently large
uncertainties will be improved as part of the LHC program and at a future Higgs
factory. We review typical new physics scenarios that lead to observable
modifications of the Higgs interactions. They can be divided into two broad
categories: mixing effects as in portal models or extended Higgs sectors, and
vertex loop effects from new matter or gauge fields. In each model we relate
coupling deviations to their effective new physics scale. It turns out that
with percent level precision the Higgs couplings will be sensitive to the
multi-TeV regime.Comment: Invited review for Journal of Physics G, 33pp; v2: references added
and improved discussion of operator basis in section 2.
Signatures of gravitational fixed points at the LHC
We study quantum-gravitational signatures at the CERN Large Hadron Collider (LHC) in the context of theories with extra spatial dimensions and a low fundamental Planck scale in the TeV range. Implications of a gravitational fixed point at high energies are worked out using WilsonÂżs renormalization group. We find that relevant cross sections involving virtual gravitons become finite. Based on gravitational lepton pair production we conclude that the LHC is sensitive to a fundamental Planck scale of up to 6 TeV
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