345 research outputs found
Monte Carlo generator ELRADGEN 2.0 for simulation of radiative events in elastic ep-scattering of polarized particles
The structure and algorithms of the Monte-Carlo generator ELRADGEN 2.0
designed to simulate radiative events in polarized ep-scattering are presented.
The full set of analytical expressions for the QED radiative corrections is
presented and discussed in detail. Algorithmic improvements implemented to
provide faster simulation of hard real photon events are described. Numerical
tests show high quality of generation of photonic variables and radiatively
corrected cross section. The comparison of the elastic radiative tail simulated
within the kinematical conditions of the BLAST experiment at MIT BATES shows a
good agreement with experimental data.Comment: 36 pages, 7 figures, 3 table
QED Radiative Corrections in Processes of Exclusive Pion Electroproduction
Formalism for radiative correction (RC) calculation in exclusive pion
electroproduction on the proton is presented. A FORTRAN code EXCLURAD is
developed for the RC procedure. The numerical analysis is done in the
kinematics of current Jefferson Lab experiments.Comment: 13 pages, 9 figures; requires RevTeX
Partonic calculation of the two-photon exchange contribution to elastic electron-proton scattering at large momentum transfer
We estimate the two-photon exchange contribution to elastic electron-proton
scattering at large momentum transfer through the scattering off a parton in
the proton. We relate the process on the nucleon to the generalized parton
distributions which also enter in other wide angle scattering processes. We
find that when taking the polarization transfer determinations of the form
factors as input, adding in the 2 photon correction, does reproduce the
Rosenbluth data.Comment: 4 pages, 4 figure
ESFRAD. FORTRAN code for calculation of QED corrections to polarized ep-scattering by the electron structure function method
The main features of the electron structure function method for calculations
of the higher order QED radiative effects to polarized deep-inelastic
ep-scattering are presented. A new FORTRAN code ESFRAD based on this method was
developed. A detailed quantitative comparison between the results of ESFRAD and
other methods implemented in the codes POLRAD and RADGEN for calculation of the
higher order radiative corrections is performed.Comment: Contribution to: 17th International Workshop on High-Energy Physics
and Quantum Field Theory (QFTHEP 2003), 154-16
Radiative Correction to the Transferred Polarization in Elastic Electron-Proton Scattering
Model independent radiative correction to the recoil proton polarization for
the elastic electron-proton scattering is calculated within method of electron
structure functions. The explicit expressions for the recoil proton
polarization are represented as a contraction of the electron structure and the
hard part of the polarization dependent contribution into cross-section. The
calculation of the hard part with first order radiative correction is
performed. The obtained representation includes the leading radiative
corrections in all orders of perturbation theory and the main part of the
second order next-to-leading ones. Numerical calculations illustrate our
analytical results.Comment: 14 pages, 4 figure
Improved radiative corrections for (e,e'p) experiments: Beyond the peaking approximation and implications of the soft-photon approximation
Analysing (e,e'p) experimental data involves corrections for radiative
effects which change the interaction kinematics and which have to be carefully
considered in order to obtain the desired accuracy. Missing momentum and energy
due to bremsstrahlung have so far always been calculated using the peaking
approximation which assumes that all bremsstrahlung is emitted in the direction
of the radiating particle. In this article we introduce a full angular Monte
Carlo simulation method which overcomes this approximation. The angular
distribution of the bremsstrahlung photons is reconstructed from H(e,e'p) data.
Its width is found to be underestimated by the peaking approximation and
described much better by the approach developed in this work.Comment: 11 pages, 13 figure
Biologically active peptides of meat and meat product proteins: a review. Part 2. Functionality of meat bioactive peptides
Biologically active peptides (BAP) are regarded as the main products of protein hydrolysis. BAP activity depends on the amino acid sequence molecular weight and chain length, type and charge of an amino acid at the N-terminus and C-terminus, hydrophobic and hydrophilic properties, spatial structure. They positively influence many systems of the human body, including the blood circulatory, nervous, immune, gastrointestinal and other systems. The health-improving effect of bioactive peptides is formed due to their antioxidant, antihypertensive, antithrombotic, immunomodulatory, antimicrobial, anti-allergic, opioid, anti-inflammatory, hypocholesterolemic and anticancer properties. Angiotensin-I-converting enzyme (ACE) inhibitory peptides are most studied due to their effect on blood pressure regulation. Unlike synthetic preparations, biologically active peptides do not have side effects and, therefore, can be used as their alternative. There is a growing commercial interest in peptides generated from meat proteins is in the context of health saving functional foods. The paper describes prospects, pros and cons of using bioactive peptides as functional food ingredients and biologically active food additives
Soft Contributions to Hard Pion Photoproduction
Hard, or high transverse momentum, pion photoproduction can be a tool for
probing the parton structure of the beam and target. We estimate the soft
contributions to this process, with an eye toward delineating the region where
perturbatively calculable processes dominate. Our soft process estimate is
based on vector meson dominance and data based parameterizations of
semiexclusive hadronic cross sections. We find that soft processes dominate in
single pion photoproduction somewhat past 2 GeV transverse momentum at a few
times 10 GeV incoming energy. The recent polarization asymmetry data is
consistent with the perturbative asymmetry being diluted by polarization
insensitive soft processes. Determining the polarized gluon distribution using
hard pion photoproduction appears feasible with a few hundred GeV incoming
energy (in the target rest frame).Comment: 6 pages, 5 figure
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