123416860
Applicability of Martin’s equations in high-energy elastic hadron scattering
The validity region of Martin`s equations enabling one to determine the t dependence of the real part of the elastic hadron amplitude from its imaginary part is critically reexamined. It can be concluded on the basis of a more precise analysis that quite unjustified and in principle incorrect physical results are obtained if the equations are used outside this region, i.e., for {vert_bar}t{vert_bar}{approx_gt}0.15 GeV{sup 2}. {copyright} {ital 1997} {ital The American Physical Society}
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.
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.
469908
Performance of the Totem Detectors at the LHC
The TOTEM Experiment is designed to measure the total proton–proton cross-section with the luminosity-independent method and to study elastic and diffractive pp scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the interaction point IP5, two tracking telescopes, T1 and T2, are installed on each side of the IP in the pseudorapidity region 3.1≤|η|≤6.5, and special movable beam-pipe insertions — called Roman Pots (RP) — are placed at distances of ±147 m and ±220 m from IP5. This article describes in detail the working of the TOTEM detector to produce physics results in the first three years of operation and data taking at the LHC.
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.
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.
125171490
CROSS-SECTIONS, AVERAGE MULTIPLICITIES AND ENERGY FRACTIONS OF NEUTRAL pi- AND K MESONS IN anti-p p ANNIHILATIONS AT 22.4-GeV/c
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.
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.
119422558
Experience with a 30 cm2 silicon pixel plane in CERN experiment WA97
Abstract A multi-chip, large area hybrid silicon pixel detector has been integrated in a particle physics experiment for the first time. The plane had 72K 75 μ m × 500 μ m sensor elements, covering a total area of about 30 cm 2 . It was constructed and characterized in a collaboration between heavy-ion experiment WA97 and R&D project RD19. Several such planes will be incorporated in a hyperon telescope, in order to improve tracking in the high multiplicity environment of central lead-lead collisions at the SPS. Results on the characterization of this detector in a proton beam at the Omega spectrometer at CERN are presented and discussed.
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