3,766 research outputs found
Statistical Challenges of Global SUSY Fits
We present recent results aiming at assessing the coverage properties of Bayesian and frequentist inference methods, as applied to the reconstruction of supersymmetric parameters from simulated LHC data. We discuss the statistical challenges of the reconstruction procedure, and highlight the algorithmic difficulties of obtaining accurate profile likelihood estimates
Search for Higgs Bosons Decay Using Vector Boson Fusion
The sensitivity of the ATLAS experiment to low mass SM Higgs produced via
Vector Boson Fusion mechanism with is invest igated. A cut
based event selection has been chosen to optimize the expected signal
significance with this decay mode. A signal significance of 2. 2 may
be achieved for M_H=130 \gev with 30 fb of accumulated luminosity
A Coverage Study of the CMSSM Based on ATLAS Sensitivity Using Fast Neural Networks Techniques
We assess the coverage properties of confidence and credible intervals on the
CMSSM parameter space inferred from a Bayesian posterior and the profile
likelihood based on an ATLAS sensitivity study. In order to make those
calculations feasible, we introduce a new method based on neural networks to
approximate the mapping between CMSSM parameters and weak-scale particle
masses. Our method reduces the computational effort needed to sample the CMSSM
parameter space by a factor of ~ 10^4 with respect to conventional techniques.
We find that both the Bayesian posterior and the profile likelihood intervals
can significantly over-cover and identify the origin of this effect to physical
boundaries in the parameter space. Finally, we point out that the effects
intrinsic to the statistical procedure are conflated with simplifications to
the likelihood functions from the experiments themselves.Comment: Further checks about accuracy of neural network approximation, fixed
typos, added refs. Main results unchanged. Matches version accepted by JHE
Prospects for Higgs Searches via VBF at the LHC with the ATLAS Detector
We report on the potential for the discovery of a Standard Model Higgs boson
with the vector boson fusion mechanism in the mass range 115
with the ATLAS experiment at the LHC. Feasibility studies at hadron level
followed by a fast detector simulation have been performed for H\to
W^{(*)}W^{(*)}\to l^+l^-\sla{p_T}, and . The results obtained show a large discovery potential in the
range 115. Results obtained with multivariate techniques are
reported for a number of channels.Comment: 14 pages, 4 figures, contributed to 2003 Les Houches Workshop on
Physics at TeV Colliders. Incorporated comments from ATLAS referee
EventView - The Design Behind an Analysis Framework
The development of software used to process petabytes of data per year is an elaborate project. The complexity of the detector means components of very diverse nature are required to process the data and one needs well defined frameworks that are both flexible and maintainable. Modern programming architecture based on object-oriented component design supports desirable features of such frameworks. The principle has been applied in almost all sub-systems of ATLAS software and its robustness has benefited the collaboration. An implementation of such framework for physics analysis, however, did not exist before the work presented in this paper. As it turns out the realisation of object-oriented analysis framework is closely related to the design of the event data object. In this paper, we well review the design behind the analysis framework developed around a data class called ``EventView''. It is a highly integrated part of the ATLAS software framework and is now becoming a standard platform for physics analysis in the collaboration
Higgs Mass and Muon Anomalous Magnetic Moment in Supersymmetric Models with Vector-Like Matters
We study the muon anomalous magnetic moment (muon g-2) and the Higgs boson
mass in a simple extension of the minimal supersymmetric (SUSY) Standard Model
with extra vector-like matters, in the frameworks of gauge mediated SUSY
breaking (GMSB) models and gravity mediation (mSUGRA) models. It is shown that
the deviation of the muon g-2 and a relatively heavy Higgs boson can be
simultaneously explained in large tan-beta region. (i) In GMSB models, the
Higgs mass can be more than 135 GeV (130 GeV) in the region where muon g-2 is
consistent with the experimental value at the 2 sigma (1 sigma) level, while
maintaining the perturbative coupling unification. (ii) In the case of mSUGRA
models with universal soft masses, the Higgs mass can be as large as about 130
GeV when muon g-2 is consistent with the experimental value at the 2 sigma
level. In both cases, the Higgs mass can be above 140 GeV if the g-2 constraint
is not imposed.Comment: 26 pages; 7 figures; corrected typos; minor change
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