1,024 research outputs found
Charged TGC from 1999 DELPHI data
No full textMeasurements of the trilinear gauge boson couplings WW gamma and WWZ are presented from data taken by DELPHI in 1999 at an energy ranging from 192 to 202 GeV. Values are extracted with respect to Delta g/sub 1//sup z/ and Delta kappa /sub gamma /, the differences of the WWZ charge coupling and of the WW gamma dipole coupling from their standard model values, and lambda /sub gamma /, the WW gamma quadrupole coupling. The study uses data from the final states jjl nu , jjjj, lX, jjX and gamma X, where j represents a quark jet, l an identified lepton and X missing four-momentum. The observations are consistent with the standard model predictions. (5 refs)
Search for non-Standard-Model Higgs at the LHC with ATLAS
No full textThe discovery prospects of non Standard Model Higgs bosons with the ATLAS detector are presented. Due to the high branching ratio, results on decay channels that include tau leptons are presented both for the search of the neutral and the charged MSSM Higgs bosons. For the neutral Higgs bosons results on the muon pair final state are also reported. Furthermore, decay scenarios that include SUSY particle cascades are investigated. Finally, in the absence of light Higgs bosons, processes of vector boson scattering at high mass are discussed, in the context of studying the mechanism of electroweak symmetry breaking. All the studies presented are based on the analysis of Monte Carlo signal and background data simulated in detail through the experimental apparatu
Higgs Physics in ATLAS
No full textA brief description of the numerous studies perfromed by ATLAS on Run-1 data in the context of Higgs physics will be presented. First a brief summary of the key incredients for Higgs physics of detector performance will be presented. Next, the major study channels , the discovery of the new boson along with its properties will be discussed. Finally the searches for additional Higgs-like bosons will be briefly presented
Searches for W'/Z' and W*/Z* and new contact interactions in di-lepton final states with ATLAS
No full textA search for high mass resonances decaying to leptons is performed using pp collisions at √7 = 7 TeV at LHC. The data, which correspond to an integrated luminosity of ~40 pb-1, were collected with the ATLAS detector during 2010. No statistical significant deviations from the Standard Model expectations are observed and therefore 95% CL limits on the cross section times branching ratio of such resonances as a function of their mass. Lower mass limits are imposed on sequential standard model W’ and Z’, on chiral bosons W* and Z*, as well as on E6 motivated Z’ bosons. The dimuon mass spectrum is interpreted in terms of contact interactions and limits are set on their energy scale in the framework of the left-left isoscalar compositeness model
Higgs @ LHC
No full textIn this talk an overview of Higgs searches at LHC is presented. Emphasis is put on the different channels that exploit the discovery potential of the two large multipurpose experiments of the LHC, ATLAS and CMS. The combination of these channels cover the whole of the allowed mass region of the SM higgs. A couple of specific MSSM Higgs channels are also presented, together with a summary of the expectations for the estimation of the Higgs parameters
The Inspiring Science Education project and the resources for HEP analysis by university students
No full textThe Inspiring Science Education outreach project has been miming for more than two years, creating a large number of inquiry based educational resources for high-school teachers and students. Its goal is the promotion of science education in schools though new methods built on the inquiry based education techniques, involving large consortia of European partners and implementation of large-scale pilots in schools. Recent hands-on activities, developing and testing the above mentioned innovative applications are reviewed. In general, there is a lack for educational scenaria and laboratory courses earmarked for more advanced, namely university, students. At the University of Athens for the last four years, the HYPATIA on-line event analysis tool has been used as a lab course for fourth year undergraduate physics students, majoring in HEP. Up to now, the course was limited to visual inspection of a few tens of ATLAS events. Recently the course was enriched with additional analysis exercises, which involve large samples of events. The students through a user friendly interface can analyse the samples and optimize the cut selection in order to search for new physics. The implementation of this analysis is described
HEP in Greek Classes
No full textThe HEP Inquiry learning resources created over the last four years by the European outreach projects are reviewed. The resources are mostly addressed to high school students and the purpose is to ignite their interest on science. In addition, at the University of Athens for the last four years we have been using the HYPATIA on-line event analysis tool as a lab course for fourth year undergraduate physics students, majoring in HEP. Each year 40-50 students highly appreciated the course, since they get a direct involvement in the actual top-level research. Up to now, the course was limited to visual inspection of a few tens of ATLAS events. Recently we have enriched the course with additional analysis exercises, which involve large samples of events. The students, through a user friendly interface can analyze the samples (both signal and background ones) and optimize the cut selection in order to search for the Higgs decay H ((sic)) 4 leptons. Recently ATLAS released 1/fb of data, so starting now the students analyse real data
The Estimation of the Effective Centre of Mass Energy in Events from DELPHI
No full textThe photon radiation in the initial state lowers the energy available for the ee collisions; this effect is particularly important at LEP2 energies (above the mass of the Z boson). Being aligned to the beam direction, such initial state radiation is mostly undetected. This article describes the procedure used by the DELPHI experiment at LEP to estimate the effective centre-of-mass energy in hadronic events collected at energies above the Z peak. Typical resolutions ranging from 2 to 3 GeV on the effective center-of-mass energy are achieved, depending on the event topology.The photon radiation in the initial state lowers the energy available for the ee collisions; this effect is particularly important at LEP2 energies (above the mass of the Z boson). Being aligned to the beam direction, such initial state radiation is mostly undetected. This article describes the procedure used by the DELPHI experiment at LEP to estimate the effective centre-of-mass energy in hadronic events collected at energies above the Z peak. Typical resolutions ranging from 2 to 3 GeV on the effective center-of-mass energy are achieved, depending on the event topology
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