G. Barreira

The production of j/

Abstract The study of oxygen-uranium reactions at 200 GeV/nucleon shows a significant transverse energy dependence of the yield of J Ψ s relative to muon pairs produced in the mass continuum. This feature, observed for the first time, is in agreement with predictions from quark-gluon plasma formation, although alternative explanations by hadronic effects cannot be ruled out at this stage.

\psi

Abstract The Small angle TIle Calorimeter (STIC) provides calorimetric coverage in the very forward region of the DELPHI experiment at the CERN LEP collider. The structure of the calorimeters, built with a so-called “shashlik” technique, gives a perfectly hermetic calorimeter and still allows for the insertion of tracking detectors within the sampling structure to measure the direction of the showering particle. A charged-particle veto system, composed of two scintillator layers, makes it possible to trigger on single photon events and provides e–γ separation. Results are presented from the extensive studies of these detectors in the CERN testbeams prior of installation and of the detector performance at LEP.

in 200 GeV/nucleon oxygen-uranium interactions

Abstract The dimuon production in 200 GeV/nucleon O-U, O-Cu, S-U and p-U reactions is studied in function of transverse energy E T produced by the collision. The J / ψ production relative to continuum events is suppressed for heavy ion induced reactions when E T increases. This suppression is enhanced at low transverse momentum. The π and K meson distributions extracted from the data, have, for each reaction, a similar average transverse momentum which increases only slightly with the transverse energy.

The small angle tile calorimeter in the DELPHI experiment

The small angle tile Calorimeter (STIC) provides calorimetric coverage in the very forward region for the DELPHI experiment at the CERN LEP collider. A veto system composed of two scintillator layers allows one to trigger on single photon events and provides e-/spl gamma/ separation. We present here some results of extensive measurements performed on part of the calorimeter and the veto system in the CERN test beams prior to installation and report on the performance achieved during the 1994 LEP run. >

Dimuon production in collisions of proton, oxygen and sulfur ions on heavy targets at 200 GeV/nucleon ; J/ψ production, π and K distributions

Abstract The Alpha Magnetic Spectrometer in a precursor version (AMS-01), was flown in June 1998 on a 51.6° orbit and at altitudes ranging between 320 and 390 km , on board of the space shuttle Discovery (flight STS-91). AMS-01 included an Aerogel Threshold Cherenkov counter (ATC) to separate p from e − and e + from p, for momenta below 3.5 GeV /c . This paper presents a description of the ATC counter and reports on its performances during the flight STS-91.

The DELPHI small angle tile calorimeter

The structure of a shashlik calorimeter allows the insertion of tracking detectors within the longitudinal sampling to improve the accuracy in the determination of the direction of the showering particle and the eπ separation ability. The new forward calorimeter of the DELPHI detector has been equipped with two planes of silicon pad detectors respectively after 4 and 7.4 radiation lengths. The novelty of these silicon detectors is that to cope with the shashlik readout fibers, they had to incorporate 1.4 mm holes every cm2. The detector consists of circular strips with a radial pitch of 1.7 mm and an angular granularity of 22.5°, read out by means of the MX4 preamplifier. The preamplifier is located at 35 cm from the silicon detector and the signal is carried by Kapton cables bonded to the detector. The matching to the MX4 input pitch of 44 μm was made by a specially developed fanin hybrid.

The AMS-01 Aerogel Threshold Cherenkov counter

The STIC calorimeter was installed in the DELPHI detector in 1994. The main goal is to measure the luminosity with an accuracy better than 0.1%. The calorimeter was built using the “Shashlik” technique. The light is collected by wavelength shifting fibers and readout by phototetrodes that can operate inside the magnetic field. The detector performance during the 1994–1995 data taking is presented. The different contributions to the systematic error on the luminosity measurement are discussed.

The silicon shower maximum detector for the STIC

Libro de los trabajos presentados al 5th Ibergrid celebrado en Santander del 8 al 10 de junio de 2011.

Performance of the new high precision luminosity monitor of DELPHI

Launched in 2006, the Portuguese National Grid Initiative aims to support the development of resource sharing for demanding computing applications and ensure the enhancement of strategic competences and capacities of special interest for this type of computing in Portugal. In this paper we provide an overview of grid computing in Portugal and we describe the Portuguese National Initiative activities, current status and future plans. Among these is the deployment of a grid infrastructure for scientific computing that is now being prepared within the context of the Initiative.

Ibergrid 2011, 5th Iberian Grid Infrastructure Conference Proceedings

Abstract The Small Angle TIle Calorimeter (STIC) is a sampling lead-scintillator calorimeter, built with “shashlik’ technique. Results are presented from extensive studies of the detector performance at LEP.