R. Leiste

The L3 silicon microvertex detector

Abstract The design and construction of the silicon strip microvertex detector (SMD) of the L3 experiment at LEP are described. We present the sensors, readout electronics, data acquisition system, mechanical assembly and support, displacement monitoring systems and radiation monitoring system of the recently installed double-sided, double-layered SMD. This detector utilizes novel and sophisticated techniques for its readout.

The L3+C detector, a unique tool-set to study cosmic rays

AbstractThe L3 detector at the CERN electron–positron collider, LEP, has been employed for the study of cosmic ray muons.The muon spectrometer of L3 consists of a set of high-precision drift chambers installed inside a magnet with avolume of about 1000 m 3 and a field of 0:5T: Muon momenta are measured with a resolution of a few percentat 50 GeV: The detector is located under 30 m of overburden. A scintillator air shower array of 54 m by 30 mis installed on the roof of the surface hall above L3 in order to estimate the energy and the core position of theshower associated with a sample of detected muons. Thanks to the unique properties of the L3þC detector, muonresearch topics relevant to various current problems in cosmic ray and particle astrophysics can be studied. r 2002Elsevier Science B.V. All rights reserved. PACS: 95.55.Vj; 98.70.Sa; 96.40.Tv; 95.85.RyKeywords: L3+C detector; Cosmic rays; Muon spectrum; Astroparticle physics 1. IntroductionThe L3þ C experiment (Figs. 1 and 2), installedat the Large Electron Positron collider (LEP) atCERN, Geneva, consists of two major parts:firstly, below ground, the L3 muon spectrometer[1], which is comprised of a large 0:5 T magnetwith a volume of 1000 m

The L3 Silicon Microvertex Detector: installation and results on 1993 performance

Abstract The status of the Silicon Microvertex Detector (SMD) and its installation into the LEP-L3 experiment are presented, highlighting novel features and sophisticated techniques. Preliminary results based on 1993 data are given and compared with Monte Carlo predictions, to understand the detector performances and its tracking capabilities.

A time expansion chamber as a vertex detector for the experiment mark j at desy

Abstract The design and results from a beam test for a small vertex detector, now installed in the DESY MARK J experiment, are presented. The concept of this drift chamber is based on the time expansion principle with readout planes inclined to solve the left-right ambiguity. A spatial resolution of 35 μm, varying weakly as a function of drift length and azimuthal angle, has been achieved.

The L3 vertex detector: design and performance

Abstract The L3 vertex detector is comprised of the time expansion chamber (TEC), the Z -chamber and a layer of plastic scintillating fibers. The TEC has shown a high spatial resolution and an excellent multi-track reconstruction capability at LEP luminosity. The Z -chamber provides information about the z -coordinates of the tracks and the fibers are used for calibrating the drift velocity with a high precision. A description of the L3 vertex detector, its readout and data acquisition and its performance during the 1990 LEP running period is presented in this paper.

A measurement of the strong coupling constant αs to complete second order

The strong interaction coupling constant αs has been measured with a new method, the planar triple energy correlation in the reaction e+e- → hadrons at center-of-mass energies ranging from 14 GeV to 46.78 GeV. A complete second-order perturbative QCD calculation was used. ΛMS = 110 ± 30 −55+70 MeV is found.

Status of the L3 silicon microvertex detector

Abstract A report on the status of the construction of the L3 Silicon Microvertex Detector is presented here. The detector will consist of two double sided AC coupled silicon layers equipped with rφ and z readout with an expected intrinsic resolution of ≈ 6 μ m and ≈ 25 μ m respectively. A description of the detector with its mechanical support, alignment system and readout electronics is presented.

Search for SUSY particles γ̃, ṽ, ẽ, W̃ in electron positron annihilation at 44 GeV

We study the production of single γ, e and μ at high πt using the high energy data of the Mark-J detector at PETRA. We find good agreement with QED. We give mass limits of the SUSY particles γ, v, e and W studying the associated production of W and ẽ and radiative production of pairs of γ or v in three-body reactions.

The production and decay of tau leptons

Abstract A study of τ-lepton production in the CMS energy region from 14 to 46.8 GeV at PETRA is reported. The cross section, the decay branching ratio into μν ν , and the electroweak parameters are determined with a total integrated luminosity of 115 pb −1 .

The readout and DAQ system of the L3 silicon microstrip detector

Abstract In 1993 the L3 detector at LEP has been equipped with a Silicon Microstrip Detector (SMD). In this paper we give a full description of the various components of the SMD readout and DAQ system.