74 research outputs found

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

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    Radiative effects in the electroproduction of photons in polarized epep-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.Comment: 22 pages, 7 figures, 4 appendice

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

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    We perform updated and detailed calculations of the complete NLO set of electroweak radiative corrections to parity violating e- e- --> e- e- (gamma) 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. We also provide very compact expressions analytically free from non-physical parameters and show them to be valid for fast yet accurate estimations.Comment: 15 pages, 5 tables and 5 figure

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

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    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.Comment: 23 pages, 4 figure

    One-loop chiral amplitudes of Moller scattering process

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    The high energy amplitudes of the large angles Moller scattering are calculated in frame of chiral basis in Born and 1-loop QED level. Taking into account as well the contribution from emission of soft real photons the compact relations free from infrared divergences are obtained. The expressions for separate chiral amplitudes contribution to the cross section are in agreement with renormalization group predictions.Comment: 15 pages, 3 figure

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

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    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.Comment: 11 pages, 8 figure

    Lowest-order QED radiative corrections in unpolarized elastic electron-deuteron scattering beyond the ultra-relativistic limit for the proposed deuteron charge radius measurement at Jefferson Laboratory

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    Analogous to the well-known proton charge radius puzzle, a similar puzzle exists for the deuteron charge radius, rdr_{d}. There are discrepancies observed in the results of rdr_{d}, measured from electron-deuteron (ede-d) scattering experiments, as well as from atomic spectroscopy. In order to help resolve the charge radius puzzle of the deuteron, the PRad collaboration at Jefferson Lab has proposed an experiment for measuring rdr_{d}, named DRad. This experiment is designed to measure the unpolarized elastic ede-d scattering cross section in a low-Q2Q^{2} region. To extract the cross section with a high precision, having reliable knowledge of QED radiative corrections is important. In this paper, we present complete numerical calculations of the lowest-order radiative corrections in ede-d scattering for the DRad kinematics. The calculations have been performed within a covariant formalism and beyond the ultra-relativistic approximation (me2Q2m_{e}^{2} \ll Q^{2}). Besides, we present a systematic uncertainty on rdr_{d} arising from higher-order radiative corrections, estimated based on our cross-section results.Comment: 16 pages and 6 figure

    Artificial Epitope-Based Immunogens in HIV-Vaccine Design

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    One of the promising approaches for designing HIV vaccines is construction of synthetic polyepitope HIV-1 immunogen using a wide range of conservative T- and B-cell epitopes of the main virus antigens. In theory this approach helps cope with HIV-1 antigenic variability, focuses immune responses on protective determinants and enables to exclude from the vaccine compound adverse regions of viral proteins that can induce autoantibodies or antibodies enhancing infectivity of virus. The paper presents the experience of our team in development of artificial polyepitope HIV-1 immunogens, which can induce both a humoral response, and responses of cytotoxic (CD8 + CTL) and helpers (CD4 + Th) T-cells. The design of HIV-immunogens has been done using our original software, TEpredict and PolyCTLDesigner. We describe development of the candidate HIV-1/AIDS vaccine – CombiHIVvac, which included two artificial polyepitope immunogens TBI and TCI for stimulating humoral and cellular responses. The results of the specific activity and safety of CombiHIVvac vaccine, obtained during preclinical and clinical trials, are presented

    SIDIS-RC EvGen: a Monte-Carlo event generator of semi-inclusive deep inelastic scattering with the lowest-order QED radiative corrections

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    SIDIS-RC EvGen is a C++ standalone Monte-Carlo event generator for studies of semi-inclusive deep inelastic scattering (SIDIS) processes at medium to high lepton beam energies. In particular, the generator contains binary and library components for generating SIDS events and calculating cross sections for unpolarized or longitudinally polarized beam and unpolarized, longitudinally or transversely polarized target. The structure of the generator incorporates transverse momentum-dependent parton distribution and fragmentation functions, whereby we obtain multi-dimensional binned simulation results, which will facilitate the extraction of important information about the three-dimensional nucleon structure from SIDIS measurements. In order to build this software, we have used recent elaborate QED calculations of the lowest-order radiative effects, applied to the leading order Born cross section in SIDIS. In this paper, we provide details on the theoretical formalism as well as the construction and operation of SIDIS-RC EvGen, e.g., how we handle the event generation process and perform multi-dimensional integration. We also provide example programs, flowcharts, and numerical results on azimuthal transverse single-spin asymmetries.Comment: 53 pages, 10 figures, and 3 listing
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