121692314
Test of a compact Si-strip detector for the forward region in DELPHI
Abstract The DELPHI detector will be upgraded by a new silicon detector in the very forward region to fulfil the physics demands of the LEP200 program. This detector will cover the angular region between 10° and 25° with respect to the beam pipe and will have a two dimensional readout. The severe space restrictions in this region lead us to develop a new arrangement of detectors and electronic hybrids. In beam tests the layout of the detectors was optimised. Special attention was given to the charge loss in intermediate strips for detectors with large strip pitch. Beam test results obtained with different detector layouts, e.g. various implant widths, and different angle of the incident particles will be shown.
99212985
STUDY OF THE REACTION anti-D P ---> anti-P P anti-N AT 12-GeV/c AND anti-N P ELASTIC SCATTERING AT 6-GeV/c
136042277
RD19: status report and addendum. Development of hybrid and monolithic silicon micropattern detectors
120572228
First operation of a 72 k element hybrid silicon micropattern pixel detector array
Abstract We have constructed and tested silicon pixel detector arrays of 96 × 378 (36 288) sensor elements with 75 μm × 500 μm area. The low-noise signal processing circuit associated with each element occupies an identical area on a bump-bonded readout chip. The pixel cell response for ionizing particles is binary with an adjustable threshold between 4000 e − and 15 000 e − . Single chips, the array of 6 ladders and a double array have been characterized in particle test beams and in the Omega experiment WA97 at CERN. The two arrays together, staggered by ∼ 4 mm cover hermetically a 53 mm × 55 mm area with 72 576 pixels. The proportion of properly functioning pixels was 98% in the first 36 k pixel array and 80% in the second one. The ∼ 1% “always-on” pixels could be masked electronically. After masking the rate of “spurious noise hits” was −8 of the identified particle hits while with beam off no hits at all were recorded With a beam trigger most events consisted of a single cluster with a single hit. At the 8000 e − threshold an efficiency > 99% was measured. Tracks were reconstructed with a precision of 22 μm. The proportion of double hits (∼ 11%) depends only slightly on threshold and detector bias voltage, and for these double hits a precision of 10 μm on the particle position was obtained.
117103549
Theoretical aspects of high energy elastic nucleon scattering
The eikonal model must be denoted as strongly preferable for the analysis of elastic high-energy hadron collisions. The given approach allows to derive corresponding impact parameter profiles that characterize important physical features of nucleon collisions, e.g., the range of different forces. The contemporary phenomenological analysis of experimental data is, however, not able to determine these profiles unambiguously, i.e., it cannot give the answer whether the elastic hadron collisions are more central or more peripheral than the inelastic ones. However, in the collisions of mass objects (like protons) the peripheral behavior of elastic collisions should be preferred.
109716342
Monitoring setup of Prague T2 site
Quality monitoring is a crucial part in struggle for reliability of every Tier 2 site. We present a solution based on Nagios installation in Prague. Our solution includes both third party and in-house developed add-ons and plug-ins. We focus on integrating results from grid-wise monitoring tools (such as SAM or Gstat) at one place (our Nagios instance). We also present an automated way to generate configuration files for Nagios from local database of hardware and services.
116197291
High-Energy Elastic Scattering and Nucleon Structure
The current model of elastic nucleon scattering based on hadronic amplitude with dominant imaginary part is still made use of in analyses of measured data even if it involves assumptions being not in harmony with known experimental facts. These assumptions are critically examined and a more general model is considered. Possible consequences following for elastic and diffractive production channels from such a model approach are discussed. An opaque nucleon structure against a transparent one is shown to be preferred.
22796813
Double diffractive cross-section measurement in the forward region at the LHC.
The first double diffractive cross-section measurement in the very forward region has been carried out by the TOTEM experiment at the LHC with a center-of-mass energy of sqrt[s]=7  TeV. By utilizing the very forward TOTEM tracking detectors T1 and T2, which extend up to |η|=6.5, a clean sample of double diffractive pp events was extracted. From these events, we determined the cross section σDD=(116±25)  μb for events where both diffractive systems have 4.7<|η|min<6.5.
120849445
Performance of almost edgeless silicon detectors in CTS and 3D-planar technologies
The physics programme of the TOTEM experiment requires the detection of very forward protons scattered by only a few microradians out of the LHC beams. For this purpose, stacks of planar Silicon detectors have been mounted in moveable near-beam telescopes (Roman Pots) located along the beamline on both sides of the interaction point. In order to maximise the proton acceptance close to the beams, the dead space at the detector edge had to be minimised. During the detector prototyping phase, different sensor technologies and designs have been explored. A reduction of the dead space to less than 50 μm has been accomplished with two novel silicon detector technologies: one with the Current Terminating Structure (CTS) design and one based on the 3D edge manufacturing. This paper describes performance studies on prototypes of these detectors, carried out in 2004 in a fixed-target muon beam at CERN's SPS accelerator. In particular, the efficiency and accuracy in the vicinity of the beam-facing edges are discussed.
122290860
The unstable system withN states and the propagator matrix with a pole of higher order
Starting from the general quantum-mechanical laws, the general form of the mass-matrix for a special unstable system withN states and of the propagator with higher order pole is derived.
9612950
High-energy elastic hadron collisions and space structure of hadrons
The elastic and inelastic profiles have been derived from the measured elastic differential cross section data with the help of exact impact parameter representation of elastic scattering amplitude. The results obtained for $pp$ scattering at energy of 53 GeV and $\bar{p} p$ scattering at energy of 541 GeV have been presented. They indicate that nucleons can be regarded as objects characterized by a small core (diameter $\sim$ 0.4$\div$0.8 fm) and a half transparent outer shell (responsible mainly for elastic hadron scattering).