Alexander Ilyichev

POLRAD 2.0. FORTRAN code for the radiative corrections calculation to deep inelastic scattering of polarized particles

Abstract The FORTRAN code POLRAD 2.0 for radiative correction calculation in inclusive and semi-inclusive deep inelastic scattering of polarized leptons by polarized nucleons and nuclei is described. Its theoretical basis, structure and algorithms are discussed in detail.

Electroweak radiative corrections for polarized Moller scattering at the future 11 GeV JLab experiment

We perform updated and detailed calculations of the complete NLO set of electroweak radiative corrections to parity violating e– e– → e– e– (γ) scattering asymmetries at energies relevant for the ultra-precise Moller experiment coming soon at JLab. Our numerical results are presented for a range of experimental cuts and relative importance of various contributions is analyzed. In addition, we also provide very compact expressions analytically free from non-physical parameters and show them to be valid for fast yet accurate estimations.

QED Radiative Corrections to Asymmetries of Elastic ep-scattering in Hadronic Variables

Abstract Compact analytical formulae for QED radiative corrections in the processes of elastic e – p scattering are obtained in the case when kinematic variables are reconstructed from the recoil proton momentum measured. Numerical analysis is presented under kinematic conditions of current experiments at JLab.

MERADGEN 1.0 : Monte carlo generator for the simulation of radiative events in parity conserving doubly-polarized Møller scattering

Abstract The Monte Carlo generator MERADGEN 1.0 for the simulation of radiative events in parity conserving doubly-polarized Moller scattering has been developed. Analytical integration wherever it is possible provides rather fast and accurate generation. Some numerical tests and histograms are presented. Program summary Program title: MERADGEN 1.0 Catalogue identifier:ADYM_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/ADYM_v1_0 Program obtainable from: CPC Program Library, Queens University of Belfast, N. Ireland Licensing provisions: none Programming language: FORTRAN 77 Computer(s) for which the program has been designed: all Operating system(s) for which the program has been designed: Linux RAM required to execute with typical data: 1 MB No. of lines in distributed program, including test data, etc.:2196 No. of bytes in distributed program, including test data, etc.:23 501 Distribution format:tar.gz Has the code been vectorized or parallelized?: no Number of processors used: 1 Supplementary material: none External routines/libraries used: none CPC Program Library subprograms used: none Nature of problem: Simulation of radiative events in parity conserving doubly-polarized Moller scattering. Solution method: Monte Carlo method for simulation within QED, analytical integration wherever it is possible that provides rather fast and accurate generation. Restrictions: none Unusual features: none Additional comments: none Running time: The simulation of 108 radiative events for itest : = 1 takes up to 45 seconds on AMD Athlon 2.80 GHz processor.

Monte Carlo generator ELRADGEN 2.0 for simulation of radiative events in elastic ep-scattering of polarized particles☆

Abstract 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. Program summary Program title: ELRADGEN 2.0 Catalogue identifier: AELO_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AELO_v1_0.html Program obtainable from: CPC Program Library, Queenʼs University, Belfast, N. Ireland Licensing provisions: Standard CPC license, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 1299 No. of bytes in distributed program, including test data, etc.: 11 348 Distribution format: tar.gz Programming language: FORTRAN 77 Computer: All Operating system: Any RAM: 1 MB Classification: 11.2, 11.4 Nature of problem: Simulation of radiative events in polarized ep-scattering. Solution method: Monte Carlo simulation according to the distributions of the real photon kinematic variables that are calculated by the covariant method of QED radiative correction estimation. The approach provides rather fast and accurate generation. Running time: The simulation of 108 radiative events for itest : = 1 takes up to 52 seconds on Pentium(R) Dual-Core 2.00 GHz processor.

Radiative effects in the processes of exclusive photon electroproduction from polarized protons

Radiative effects in the electroproduction of photons in polarized ep-scattering are calculated in the leading log approximation and analyzed numerically for kinematical conditions of current measurement at Jefferson Lab. Radiative corrections to the cross sections, their azimuthal distributions and Fourier coefficients are in particular focus. Kinematical regions where the radiative corrections are considerable are identified.

Lowest order QED radiative corrections to five-fold differential cross section of hadron leptoproduction

Abstract The contribution of exclusive radiative tail to the cross section of semi-inclusive hadron leptoproduction has been calculated exactly for the first time. Although the experience of inclusive data analyses suggests us that the contribution of radiative tail from the elastic peak is of particular importance, similar effects in the semi-inclusive process were only recently estimated in the peaking approximation. The explicit expressions for the lepton part of the lowest order QED contribution of exclusive radiative tail to the five-fold differential cross section are obtained and discussed. Numerical estimates, provided within Jefferson Lab kinematic conditions, demonstrate rather large effects of the exclusive radiative tail in the region at semi-inclusive threshold and for high energy of detected hadron.

Radiative electroweak effects in deep inelastic scattering of polarized leptons by polarized nucleons

The one-loop electroweak radiative correction of the lowest order to lepton current for deep inelastic scattering of longitudinally polarized leptons by polarized nucleons is obtained in a model-independent way. Detailed numerical analysis within the kinematical requirements of future polarization collider experiments is performed. The possibility of reducing radiative effects by detection of hard photons is studied.

QED radiative effects in the processes of exclusive photon electroproduction from polarized protons with the next-to-leading accuracy

Radiative effects in the electroproduction of photons in polarized ep-scattering are calculated with the next-to-leading (NLO) accuracy. The contributions of loops and two photon emission were presented in analytical form. The covariant approach of Bardin and Shumeiko was used to extract the infrared divergence. All contributions to the radiative correction were presented in the form of the correction to the leptonic tensor thus allowing for further applications in other experiments, e.g., deep inelastic scattering. The radiative corrections (RC) to the cross sections and polarization asymmetries were analyzed numerically for kinematical conditions of the current measurement at Jefferson Lab. Specific attention was paid on analyzing kinematical conditions for the process with large radiative effect when momenta of two photons in the final state are collinear to momenta of initial and final electrons, respectively.

RADIATIVE CORRECTIONS TO THE STRUCTURE FUNCTIONS AND SUM RULES IN POLARIZED DIS

The one-loop NLO radiative corrections to the observables in polarized DIS using assumption that a quark is an essential massive particle are considered. If compared with classical QCD formulae the obtained results are identical for the unpolarized and different for polarized sum rules, that can be explained as the influence of the finite quark mass effects on NLO QCD corrections. The explicit expression for one-loop NLO QCD contribution to the structure function g_2 is presented.