840 research outputs found
Performance of the Electromagnetic Calorimeter of the HERMES Experiment
The performance of the electromagnetic calorimeter of the HERMES experiment
is described. The calorimeter consists of 840 radiation resistant F101
lead-glass counters. The response to positrons up to 27.5 GeV, the comparison
between the measured energy and the momentum reconstructed from tracking,
long-term stability, hadron rejection and neutral meson invariant mass
reconstruction are shown.Comment: 22 pages, 13 figures, LaTeX, accepted by NI
Single target-spin asymmetries in semi-inclusive pion electroproduction on longitudinally polarized protons
We evaluate the single target-spin sin(phi_h) and sin(2\phi_h) azimuthal asymmetries in the semi-inclusive deep inelastic lepton scattering off longitudinally polarized proton target under HERMES kinematic conditions. A good agreement with the HERMES data can be achieved using only the twist-2 distribution and fragmentation functions
Some new processes in the collisions of high energy ions and electrons with amorphous or crystalline target atoms
It is shown that taking into account the energy levels of the ions and/or of the crystalline atoms, some energy transfer and excitation processes with consequences similar to the Kossel and Okorokov effects can take place when some
additional resonance conditions are satisfied. Such resonance processes can be expected also when microbunched electron beams interact with ions. Since these processes have significant cross-sections and the interaction of projectile ions with atoms of crystals has not been almost studied, it is proposed to begin their study in Kossel- and Okorokov-type experiments
Investigations of Azimuthal Asymmetry in Semi-Inclusive Leptoproduction
We consider the azimuthal asymmetries in semi-inclusive deep inelastic
leptoproduction arising due to both perturbative and nonperturbative effects at
HERMES energies and show that the order corrections to and at large momentum transfers \cite{A1}
using the more recent sets of scale-dependent distribution and fragmentation
functions, which bring up to 18{%} difference in as well.Comment: 8 pages, LaTeX, 6 PS figures, final version, to appear in EPJ
Are there approximate relations among transverse momentum dependent distribution functions?
Certain exact relations among transverse momentum dependent parton
distribution functions due to QCD equations of motion turn into approximate
ones upon the neglect of pure twist-3 terms. On the basis of available data
from HERMES we test the practical usefulness of one such
``Wandzura-Wilczek-type approximation'', namely of that connecting
h_{1L}^{\perp(1)a}(x) to h_L^a(x), and discuss how it can be further tested by
future CLAS and COMPASS data.Comment: 9 pages, 3 figure
HAL/S-360 compiler system specification
A three phase language compiler is described which produces IBM 360/370 compatible object modules and a set of simulation tables to aid in run time verification. A link edit step augments the standard OS linkage editor. A comprehensive run time system and library provide the HAL/S operating environment, error handling, a pseudo real time executive, and an extensive set of mathematical, conversion, I/O, and diagnostic routines. The specifications of the information flow and content for this system are also considered
Determination of the cross section of the proton, pion and neutron inelastic interaction with lead and carbon nuclei at 0.5 - 5.0 TeV energies (PION experiment)
Experimental results on the cross section of the single pion, proton and neutron inelastic interaction with carbon and lead nuclei in the 0.5 to 5.0 TeV energy interval obtained on the PION installation (Mount Aragats, Armenia, 3250 m) are presented. For this purpose the (N pi)/(N p) and inelastic (p Fe)/(pi Fe) ratios measured directly on the installation as well as the calculated inelastic (p A)/(pi A) dependence on the target nucleus atomic numbers were used
Transverse-Momentum Distributions and Spherical Symmetry
Transverse-momentum dependent parton distributions (TMDs) are studied in the
framework of quark models. In particular, quark model relations among TMDs are
reviewed and their physical origin is discussed in terms of rotational-symmetry
properties of the nucleon state in its rest frame.Comment: 8 pages, 2 figures, prepared for the workshop "30 years of strong
interactions", Spa, Belgium, 6-8 April 201
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