3,957 research outputs found

    A Method to include Detector Effects in Estimators sensitive to the Trilinear Gauge Couplings

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    This paper describes the use of weighted Monte Carlo events to accurately approximate integrals of functions of the experimentally measured kinematical vectors and their dependence on physical parameters. This technique is demonstrated in estimating the evolution of cross sections, efficiencies, measured kinematical distributions and mean values as functions of the Trilinear Gauge Couplings.Comment: 20 pages, 10 figures, Late

    Accurate Estimation of the Trilinear Gauge Couplings Using Optimal Observables Including Detector Effects

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    This paper describes the definition of maximum likelihood equivalent estimators of the Trilinear Gauge Couplings which include detector effects. The asymptotic properties of these estimators as well as their unbiasedness and efficiency when dealing with finite statistical samples are demonstrated by Monte Carlo experimentation, using simulated events corresponding to the production of q qbar lepton neutrino in e+ e- collisions at 172 GeV. Emphasis is given to the determination of the expected efficiencies in extracting the aWphi, aW and aBphi couplings from LEPII data, which in this particular case found to be close to the maximum possible.Comment: 32 pages, 12 figures, Late

    The ATLAS Student Event Challenge

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    The ASEC (ATLAS Student Event Challenge) is an educational project which allows the students to learn about the elementary particles by studying "events", the products of beam collisions at the LHC. The events are collected by the ATLAS detector and displayed graphically using the ATLANTIS package. The students are given the means to select and analyse the events on-line, and subsequently present the results and draw conclusions

    Extended Modified Observable Technique for a Multi-Parametric Trilinear Gauge Coupling Estimation at LEP II

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    This paper describes the extension of the Modified Observables technique in estimating simultaneously more than one Trilinear Gauge Couplings. The optimal properties, unbiasedness and consistent error estimation of this method are demonstrated by Monte Carlo experimentation using ‚ĄďőĹjj\ell \nu jj four-fermion final state topologies. Emphasis is given in the determination of the expected sensitivities in estimating the őĽő≥‚ąíőĒg1z\lambda_{\gamma} - \Delta g_{1}^{z} and őĒkő≥‚ąíőĒg1z\Delta k_{\gamma} - \Delta g_{1}^{z} pair of couplings with data from the 183 GeV LEPII run.Comment: (17 pages, 8 figures

    Muon Energy Loss Upsteam of the Muon Spectrometer

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    A method for the estimation of the muon energy loss downstream of the Muons Spectrometer is presented. The method provides an improved and updated parametrization of the muon energy loss in ATLAS, along with an estimation based on the actual energy deposition in the calorimeters. The latter aims to account, on an event-by-event basis, for the statistical fluctuations of the energy loss. The final implementation of the presented method combines both the energy loss parametrization and the calorimeter information. This hybrid method provides on average a 5% improvement on the muon stand-alone momentum resolution, reaching 10% for , and reduces the non-gaussian tails. The method is implemented inside the ATHENA framework, in the MuidCaloEnergyTools package

    Multidimensional Binning Techniques for a Two Parameter Trilinear Gauge Coupling Estimation at LEP II

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    This paper describes two generalization schemes of the Optimal Variables technique in estimating simultaneously two Trilinear Gauge Couplings. The first is an iterative procedure to perform a 2-dimensional fit using the linear terms of the expansion of the probability density function with respect to the corresponding couplings, whilst the second is a clustering method of probability distribution representation in five dimensions. The pair production of W's at 183 GeV center of mass energy, where one W decays leptonically and the other hadronically, was used to demonstrate the optimal properties of the proposed estimation techniques.Comment: (25 pages, 11 figures

    Higgs @ LHC

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    In 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 Estimation of the Effective Centre of Mass Energy in q-qbar-gamma Events from DELPHI

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    The photon radiation in the initial state lowers the energy available for the e+^+e‚ąí^- 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.Comment: 12 pages, 6 figure

    A PMT-Block test bench

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    The front-end electronics of the ATLAS hadronic calorimeter (Tile Cal) is housed in a unit, called {\it PMT-Block}. The PMT-Block is a compact instrument comprising a light mixer, a PMT together with its divider and a {\it 3-in-1} card, which provides shaping, amplification and integration for the signals. This instrument needs to be qualified before being assembled on the detector. A PMT-Block test bench has been developed for this purpose. This test bench is a system which allows fast, albeit accurate enough, measurements of the main properties of a complete PMT-Block. The system, both hardware and software, and the protocol used for the PMT-Blocks characterisation are described in detail in this report. The results obtained in the test of about 10000 PMT-Blocks needed for the instrumentation of the ATLAS (LHC-CERN) hadronic Tile Calorimeter are also reported.Comment: 23 pages, 10 figure
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