The Construction of the CMS Silicon Strip Tracker

The CMS Silicon Strip tracker is a very large scale tracker entirely based on silicon strip detectors technology. The integration of modules, electronics, mechanics and services has been completed within the last eighteen months; first large standalone sub-structures (shells, disks, rods, petals depending on the tracker subdetector) have been integrated and verified; then they have been brought together into the final configuration. The CMS silicon tracker design and its construction is reviewed with particular emphasis on the procedures and quality checks deployed to successfully assembly several silicon strip modules and all ancillary components into these large sub-structures. An overview of the results and the lesson learned from the tracker integration are given, also in terms of failure and damage rates.Comment: 2 pages, 5 figures, submitted to Hadron Collider Physics Symposium 2007 - La Biodola (Elba) May 200

An Unexpected Effect in ALEPH: Long-Term Displacements of the Silicon Vertex Detector

The ALEPH Silicon Vertex Detector for LEP2 featured a laser survey system to monitor its mechanical stability. The analysis of laser system data from 1997 to 2000 showed that VDET suffered a time-dependent displacement. It resulted to be compatible with a deformation of the support structure that made the device to slowly rotate during the data-taking. A maximal local displacement of ~20 microns was observed, corresponding to a rotation of ~10E-4 rad. The implementation of a time-dependent correction on the alignment by using the laser system data led to sizeable improvements on the ALEPH data quality.Comment: 4 pages, 8 figures. To be published in Proceedings of 'XXXVII Rencontres de Moriond, QCD and Hadronic Interactions', March 2002, Les Arcs, Franc

The CMS Si-strip Tracker

The Compact Muon Solenoid (CMS) experiment at LHC features the largest Silicon Strip Tracker (SST) ever build. This device is immersed in a 4T magnetic field and, in conjunction with a Pixel system, it allows the momentum of the charged particles to be measured and the heavy-flavour final states to be tagged despite the hostile radiation environment. The impact of operating conditions and physics requirements on the SST layout and design choices is discussed and the expected performances are reviewed. The SST collaboration is now facing the production of the ~15000 modules and their assembly into the SST substructures. A status is given.Comment: 6 pages, 9 figures, to be published in proceedings of "8th ICATPP Conference on Astroparticle, Particle, Space Physics, Detectors and Medical Physics Applications" Como (Italy), October 200

Higgs and Beyond Standard Model Searches at LEP

Extensive searches for Higgs bosons and other new phenomena predicted by extensions of the Standard Model have been performed at LEP. A summary is given reviewing the principal aspects and presenting a selection of results.Comment: 10 pages, 7 figures, talk presented at Hadron Structure 2004, Smolenice Castle, Slovaki

The topologies of Supersymmetry signals at LEP

The topologies arising from the production of supersymmetric particles at the LEP collider are briefly reviewed recalling detector requirements, simulation and other experimental issues.Comment: 4 pages, 3 figures. To be published in Proceedings of 'XIV IFAE - Incontri sulla Fisica delle Alte Energie (Meetings on High Energy Physics)', 3-5 April 2002, Parm

SUSY Particles Searches at LEP and Interpretations within the MSSM

Searches for R-parity conserving supersymmetric particles have been performed in e+e- data collected by LEP detectors, at centre-of-mass energies up to 209GeV, corresponding to an integrated luminosity of 3.1fb-1. The results and their interpretation in the context of MSSM frameworks are briefly reviewed.Comment: 4 pages, 5 figures. To be published in Proceedings of 'ICHEP02 - 31st International Conference on High Energy Physics', 24-31 July 2002, Amsterda

CMS Inner Tracker Detector Modules

The production of silicon detector modules that will instrument the CMS Inner Tracker has nowadays reached 1300 units out of the approximately 3700 needed in total, with an overall yield close to 96%. A description of the module design, the assembly procedures and the qualification tests is given. The results of the quality assurance are presented and the experience gained is discussed.Comment: 5 pages, 3 figures, talk presented at RESMDD04, 5th International Conference on Radiation Effects on Semiconductor Materials Detectors and Devices, October 2004, Florence, Ital

Scalar Quark searches with the ALEPH Experiment at LEP2

The description of the strong, weak and electromagnetic interactions within matter, the Standard Model theory, has been shown to be very consistent with experimental data up to explored energy scale even if the Higgs boson, the visible remnant of mechanism responsible of the gauge symmetry breaking and of the fermion mass hierarchy, is not yet discovered. Despite this success it is common opinion that Standard Model is a lower energy effective theory of a larger and more fundamental framework not suffering the several problems that occur as soon as one tries to extend the Standard Model to higher energies (typically the Planck scale). Supersymmetry (SUSY) is one of the most elegant theory that provides such a solid framework. Supersymmetry enlarges the elementary particle spectra predicting the existence of new particles. The supersymmetric particles have the same couplings as the Standard Model particles. Therefore the LEP e+e- collider is almost ideal to confirm or exclude their presence. In particular the supersymmetric scalar partners of top and bottom quarks could be enough light; thus they are a natural target of an experimental search of SUSY existence. In this report the extensive scalar quark ( squarks) search performed at LEP2 with the ALEPH experiment will be described. The obtainable results are complementary to the ones from similar searches performed at the TEVATRON collider since the LEP experiments have the possibility of testing for squarks domains left unexplored by the TEVATRON experiments. The results presented here are based on ALEPH data sample collected at energies up to 202GeV. The report is organised as follows: the chapter 1 is a short introduction to Supersymme- try and its motivations compared with weak aspects of the Standard Model. In chapter 2 some detail about the squark sector phenomenology is given. In chapter 3 the ALEPH experiment and the LEP collidcr arc described. Chapter 4 gives details about the Monte Carlo generation of signal samples that is critical in several aspects; the Monte Carlo simu- lation of backgrounds processes is described as well. Chapter 5 is dedicated to the detailed description of the selections used to search for squark signal, while in the chapter 7 the re- sults and their interpretation are discussed after the description of systematic uncertainties of chapter 6