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.
44874120
Momentum-transfer dependence of the elastic-amplitude phase in high-energy hadron scattering.
The phase of the elastic-scattering amplitude is responsible for the probability distribution of events in the impact-parameter space. A rather steep increase of it around t = 0 can lead to a peripheral behavior of elastic collisions. The experimental data from the interference regions of hadronic and Coulomb scatterings have been shown to be fully consistent with such a peripherality. Other reasons supporting peripherality have been mentioned, also.
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.
121853587
Predictions on the total cross-section and real part at LHC and SSC
Abstract An overall fit to the data on the total cross section and on the real part of the forward amplitude for p p and pp was performed using dispersion relations. The energy dependence of the total cross section was studied up to s = 100 TeV . Numerical predictions are presented for LHC and SSC energies.
119975839
Impact parameter structure derived from elastic collisions
Impact parameter profiles derived from elastic scattering data within the framework of standard model cannot be regarded as definite being burdened by two defficiences: influenced strongly by an a priori (physically non-reasoned) assumption and by non-unique relation to elastic hadron amplitude. A mathematically consistent general model providing a unique relation is presented and some new formulas allowing to evaluate mean-square values of corresponding impact parameters (for elastic and inelastic processes directly from the t dependent amplitude) are introduced. Critical arguments against the mentioned a priori assumption are discussed as well.
122588297
Elastic partial-wave amplitude and poles of higher order
Starting from the usual formula for the elastic partial-wave scattering amplitude a new formal decomposition of the phase shift is given which leads to a new more general expression for energy-dependence exhibiting poles of higher order. This decomposition is in agreement with a multichannel decay model of unstable particles, which stands behind this approach.
125171490
CROSS-SECTIONS, AVERAGE MULTIPLICITIES AND ENERGY FRACTIONS OF NEUTRAL pi- AND K MESONS IN anti-p p ANNIHILATIONS AT 22.4-GeV/c
186674866
The First Three TILECAL Submodule Assembly in Prague
120268916
Experimental tests of neutron shielding for the ATLAS forward region
Abstract Experimental tests devoted to the optimization of the neutron shielding for the ATLAS forward region were performed at the CERN-PS with a 4 GeV/ c proton beam. Spectra of fast neutrons, slow neutrons and gamma rays escaping a block of iron (40×40×80 cm 3 ) shielded with different types of neutron and gamma shields (pure polyethylene – PE; borated polyethylene – BPE; lithium filled polyethylene – LiPE; lead; iron) were measured by means of plastic scintillators, a Bonner spectrometer, a HPGe detector and a slow neutron detector. Effectiveness of different types of shielding against neutrons and γ-rays were compared. The idea of a segmented outer layer shielding (iron, BPE, iron, LiPE) for the ATLAS forward region was also tested.