D. Ren

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.

A TIME EXPANSION CHAMBER AS A VERTEX DETECTOR

Abstract A high-resolution drift chamber based on the time expansion principle has been built as a vertex detector for the Mark J experiment at DESY. The chamber design and the associated control and readout system are described. Results on chamber performance obtained from test beam measurements and first results from running at PETRA are reported.

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 silicon microstrip tracker in space: Experience with the AMS silicon tracker on STS-91

SummaryThe Alpha Magnetic Spectrometer (AMS) is designed as an independent module for installation on the International Space Station (ISS) in the year 2003 for an operational period of three years. The principal scientific objectives include the searches for antimatter and dark matter in cosmic rays. The AMS tracker uses silicon microstrip sensors to reconstruct charged-particle trajectories. A first version of the AMS, equipped with 2.1 m2 of silicon sensors and a permanent magnet, was flown on the NASA space shuttle Discovery duringJune 2–12, 1998. In this contribution, we describe the detector and present results of the tracker performance duringthe flight.

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.

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.

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.

Search for {SUSY} Particles Photino, Sneutrino, Selectron, Wino 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.