Measurements of Hadronic Asymmetries in e+e- Collisions

High precision experimental new electroweak results measured at the four LEP experiments and the SLD collaboration are discussed. Heavy quark (b b-bar and c c-bar) forward-backward asymmetries measured at LEP are presented along with polarized forward-backward and left-right asymmetries measured at SLD. The results are compared, and the combined averages are used to evaluate the Standard Model parameters.Comment: 8 Pages, 5 eps files, Presented at the International Europhysics Conference on High Energy Physics, August 1997, Jerusalem, Israe

Experimental Studies of Electroweak Physics

Some experimental new Electroweak physics results measured at the LEP/SLD and the TEVATRON are discussed. The excellent accuracy achieved by the experiments still yield no significant evidence for deviation from the Standard Model predictions, or signal to physics beyond the Standard Model. The Higgs particle still has not been discovered and a low bound is given to its mass.Comment: 10 pages, 5 figures, Invited talk at "Fundemental Particles and Interactions", Vanderbilt University, Nashville, Tennessee, May 199

B Physics and Quarkonia studies with early ATLAS data

Quarkonia and B-Physics are among the first areas to be investigated with the first data collected by ATLAS. The ATLAS detector at CERN's LHC is preparing to take data from proton-proton collisions expected to start by the end of 2009. Investigation of the decay of B-hadrons represents a complementary approach to direct searches for Physics beyond the Standard Model. Early B-physics data will provide valuable information on the detector performance, as well as allow calibration studies in support of new Physics searches. Meaningful quarkonia studies performed with early data are expected to have the reach to make authoritative statements about the underlying production mechanism and provide cross-sections in this new energy regime. We review various aspects of prompt quarkonium production at the LHC: the accessible ranges in transverse momentum and pseudo-rapidity, spin alignment of vector states, separation of color octet and color singlet production mechanism and feasibility of observing radiative chi_c decaysComment: Proceedings of the Fourth High-Energy Physics International Conference HEP-MAD 09, Antananarivo, Madagascar, August 21-28, 200

Analysis of the Tau Polarization and its Forward-Backward Asymmetry on the Z0

This thesis describes a new a measurement of the tau lepton polarization and its forward-backward asymmetry at the Z resonance using the OPAL detector. This measurement is based on analyses of the tau->electron, muon and pion (Kaon) decays from a sample of 30663 tau-pair events collected in the polar angle range of Abs(cos(theta)) <0.68 during the 1990-1992 data taking period. Taking then the Standard Model with the V-A structure of the tau lepton decay, we measure the average tau polarization to be =(-13.5+/-2.9+/-2.2)% and the tau polarization forward-backward asymmetry to be AFBpol=(-11.0+/-3.5+/-0.5)% where the first error is statistical and the second systematic. Combining these figures with the OPAL and AFBpol measured with the tau->rho channel we get an average tau polarization, =(-14.9+/-1.9+/-1.3)% and for the asymmetry in the polarization, AFBpol=(-8.9+/-2.2+/-0.9)% . These results are consistent with lepton universality. Combining the two results we obtain for the electroweak mixing angle the value sin^2(theta_W)=0.2331+/-0.0023 within the context of the Standard Model, where the error includes both statistical and systematic uncertainties.Comment: PhD Thesis, Tel Aviv Universit

Momentum Reconstruction and Triggering in the ATLAS Detector

A neural network solution for a complicated experimental High Energy Physics problem is described. The method is used to reconstruct the momentum and charge of muons produced in collisions of particle in the ATLAS detector. The information used for the reconstruction is limited to the output of the outer layer of the detector, after the muons went through strong and inhomogeneous magnetic field that have bent their trajectory. It is demonstrated that neural network solution is efficient in performing this task. It is shown that this mechanism can be efficient in rapid classification as required in triggering systems of the future particle accelerators. The parallel processing nature of the network makes it relevant for hardware realization in the ATLAS triggering system.A neural network solution for a complicated experimental High Energy Physics problem is described. The method is used to reconstruct the momentum and charge of muons produced in collisions of particle in the ATLAS detector. The information used for the reconstruction is limited to the output of the outer layer of the detector, after the muons went through strong and inhomogeneous magnetic field that have bent their trajectory. It is demonstrated that neural network solution is efficient in performing this task. It is shown that this mechanism can be efficient in rapid classification as required in triggering systems of the future particle accelerators. The parallel processing nature of the network makes it relevant for hardware realization in the ATLAS triggering system.A neural network solution for a complicated experimental High Energy Physics problem is described. The method is used to reconstruct the momentum and charge of muons produced in collision of particles in the ATLAS detector. The information used for the reconstruction is limited to the output of the outer layer of the detector, after the muons went through strong and inhomogeneous magnetic field that have bent their trajectory. It is demonstrated that neural network solution is efficient in performing this task. It is shown that this mechanism can be efficient in rapid classification as required in triggering systems of the future particle accelerators. The parallel processing nature of the network makes it relevant for hardware realization in the ATLAS triggering system

ATLAS reach for Quarkonium production and polarization measurements

The ATLAS detector at CERN's LHC is preparing to take data from the first proton-proton collisions expected in the next few months. We report on the analysis of simulated data samples for production of heavy Quarkonium states J/psi and Upsilon, corresponding to an integrated luminosity of 10 pb^-1 with center of mass energy of 14 TeV expected at the early ATLAS data. We review various aspects of prompt Quarkonium production at LHC: the accessible ranges in transverse momentum and pseudorapidity, spin alignment of vector states, separation of color octet and color singlet production mechanism and feasibility of observing radiative decays Xi_c and Xi_b decays. Strategies of various measurements are outlined and methods of separating promptly produced J/psi and Upsilon mesons from various backgrounds are discussed

Vertex Reconstructing Neural Network at the ZEUS Central Tracking Detector

An unconventional solution for finding the location of event creation is presented. It is based on two feed-forward neural networks with fixed architecture, whose parameters are chosen so as to reach a high accuracy. The interaction point location is a parameter that can be used to select events of interest from the very high rate of events created at the current experiments in High Energy Physics. The system suggested here is tested on simulated data sets of the ZEUS Central Tracking Detector, and is shown to perform better than conventional algorithms.Comment: Presentes at ACAT 2000, FermiLab, Chicago, October 200

The use of cluster quality for track fitting in the CSC detector

The new particle accelerators and its experiments create a challenging data processing environment, characterized by large amount of data where only small portion of it carry the expected new scientific information. Modern detectors, such as the Cathode Strip Chamber (CSC), achieve high accuracy of coordinate measurements (between 50 to 70 microns). However, heavy physical backgrounds can decrease the accuracy significantly. In the presence of such background, the charge induced over adjacent CSC strips (cluster) is different from the ideal Matheison distribution. The traditional least squares method which takes the same ideal position error for all clusters loses its optimal properties on contaminated data. A new technique that calculates the cluster quality and uses it to improve the track fitting results is suggested. The algorithm is applied on test beam data, and its performance is compared to other fitting methods. It is shown that the suggested algorithm improves the fitting performance significantly.Comment: Proceedings of 2006 IEEE NSS, San Diego, California, USA, November 200