115913744
To the theory of high-energy elastic nucleon collisions
The commonly used West and Yennie integral formula for the relative phase between the Coulomb and elastic hadronic amplitudes requires for the phase of the elastic hadronic amplitude to be constant at all kinematically allowed values of t. More general interference formula based on the eikonal model approach does not exhibit such limitation. The corresponding differences will be demonstrated and some predictions of different phenomenological models for elastic pp scattering at energy of 14 TeV at the LHC will be given. Special attention will be devoted to determination of luminosity from elastic scattering data; it will be shown that the systematic error might reach till 5 % if the luminosity is derived from the values in the center of the interference region with the help of West and Yennie formula.
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.
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.
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.
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.
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.
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.
186674866
The First Three TILECAL Submodule Assembly in Prague