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We report the first observation of Z/gamma* production in Compton scattering of quasi-real photons. This is a subprocess of the reaction e+e- to e+e-Z/gamma*, where one of the final state electrons is undetected. Approximately 55 pb-1 of…

High Energy Physics - Experiment · Physics 2008-11-26 OPAL Collaboration , G. Abbiendi et al

Virtual Compton Scattering on the nucleon: $\gamma^* N \to \gamma N$ is a new and rapidly developing field at low and high energies. This lecture is about the low energy part, i.e. for energies in the $(\gamma p)$ center-of-mass mainly up…

High Energy Physics - Phenomenology · Physics 2008-12-18 H. Fonvieille

The handbag contribution to Compton scattering at moderately large momentum transfer factorises into parton-photon subprocess amplitudes and new form factors representing 1/x-moments of skewed parton distributions. A detailed…

High Energy Physics - Phenomenology · Physics 2009-10-31 M. Diehl , T. Feldmann , R. Jakob , P. Kroll

Spatial distribution of intensity, degree and direction of linear polarization of tagged photon beam, which is obtained due to Compton backscattering of laser light on high-energy electron beam, are calculated. Effects of angular dispersion…

Instrumentation and Detectors · Physics 2007-05-23 Yu. P. Peresunko

We consider the Generalized Parton Distributions for spin-1 nuclei in general and on the deuteron in particular. We use the impulse approximation to obtain a convolution model for them. Sum rules are used to check the validity of the…

High Energy Physics - Phenomenology · Physics 2009-11-07 F. Cano , B. Pire

Information about the 3-dimensional description of the quark and gluon content of hadrons, described by the generalized parton distributions (GPDs), can be probed by exclusive processes in electron - proton ($ep$) collisions. In this…

High Energy Physics - Phenomenology · Physics 2024-09-18 Ya-Ping Xie , V. P. Gonçalves

The Compton scattering cross section on the proton has been measured at laboratory angles of 90$^\circ$ and 135$^\circ$ using tagged photons in the energy range 70--100 MeV and simultaneously using untagged photons in the range…

Nuclear Experiment · Physics 2008-11-26 B. E. MacGibbon , G. Garino , M. A. Lucas , A. M. Nathan , G. Feldman , B. Dolbilkin

Polarization characteristics of the gamma beam obtained by the Compton back scattering of laser photons on high energy electrons are evaluated by Monte-Carlo simulations. It is assumed that outgoing photons are tagged; the energy dispersion…

Instrumentation and Detectors · Physics 2007-05-23 A. S. Omelaenko , Yu. P. Peresunko , Yu. M. Ranyuk , I. M. Shapoval , V. G. Nedorezov

Synchrotron radiation and Compton scattering are widely accepted as the most likely emission mechanisms of some astrophysical phenomena, such as gamma-ray bursts (GRBs) and active galactic nuclei (AGNs). The measurement on polarization of…

High Energy Astrophysical Phenomena · Physics 2014-02-18 Zhe Chang , Hai-Nan Lin , Yunguo Jiang

Generalized Parton Distributions (GPDs) are multidimensional structure functions of hadrons, encoding mechanical and spin properties through the correlation of the momentum and transverse position of partons. While channels like Deeply…

High Energy Physics - Phenomenology · Physics 2025-09-16 J. S. Alvarado , M. Hoballah , E. Voutier

The Compton double-polarization observable $\Sigma_{2z}$ has been measured for the first time in the $\Delta(1232)$ resonance region using a circularly polarized photon beam incident on a longitudinally polarized target at the Mainz…

Preliminary results on azimuthal asymmetries in leptoproduction of real photons on an unpolarized hydrogen target measured at the HERMES experiment are presented. The analysis of data taken with different beam charges and helicities allows…

High Energy Physics - Experiment · Physics 2019-08-13 Dietmar Zeiler

We report on a recent work proposing measurements of the deeply virtual Compton amplitude (DVCS) $\gamma^* \to h \bar h \gamma$ in the timelike kinematic domain which is accessible at electron-positron colliders via the radiative…

High Energy Physics - Phenomenology · Physics 2011-03-10 Asmita Mukherjee

A measurement is presented of elastic Deeply Virtual Compton Scattering e^+ + p -> e^+ + photon + p at HERA using data taken with the H1 detector. The cross section is measured as a function of the photon virtuality, Q^2, and the invariant…

High Energy Physics - Experiment · Physics 2010-05-28 H1 Collaboration , C. Adloff

Compton scattering by the proton has been measured using the tagged-photon facility at MAMI (Mainz) and the large-acceptance arrangement LARA. The new data are interpreted in terms of dispersion theory based on the SAID-SM99K…

Differential cross sections for Compton scattering from the deuteron were measured at MAX-lab for incident photon energies of 55 MeV and 66 MeV at nominal laboratory angles of $45^\circ$, $125^\circ$, and $135^\circ$. Tagged photons were…

We discuss polarized lepton-proton scattering with special emphasis on the difference between target polarization defined relative to the lepton beam or to the virtual photon direction. In particular, this difference influences azimuthal…

High Energy Physics - Phenomenology · Physics 2011-09-13 M. Diehl , S. Sapeta

A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision…

Double-spin asymmetries in exclusive electroproduction of real photons from a transversely polarized hydrogen target are measured with respect to the product of target polarization with beam helicity and beam charge, and with respect to the…

High Energy Physics - Experiment · Physics 2011-09-16 The HERMES Collaboration , A. Airapetian , N. Akopov , Z. Akopov , E. C. Aschenauer , W. Augustyniak , R. Avakian , A. Avetissian , E. Avetisyan , S. Belostotski , N. Bianchi , H. P. Blok , A. Borissov , J. Bowles , I. Brodski , V. Bryzgalov , J. Burns , M. Capiluppi , G. P. Capitani , E. Cisbani , G. Ciullo , M. Contalbrigo , P. F. Dalpiaz , W. Deconinck , R. De Leo , L. De Nardo , E. De Sanctis , P. Di Nezza , M. Dueren , M. Ehrenfried , G. Elbakian , F. Ellinghaus , R. Fabbri , A. Fantoni , L. Felawka , S. Frullani , D. Gabbert , G. Gapienko , V. Gapienko , F. Garibaldi , G. Gavrilov , V. Gharibyan , F. Giordano , S. Gliske , M. Golembiovskaya , M. Hartig , D. Hasch , M. Hoek , Y. Holler , I. Hristova , Y. Imazu , A. Ivanilov , H. E. Jackson , H. S. Jo , S. Joosten , R. Kaiser , G. Karyan , T. Keri , E. Kinney , A. Kisselev , V. Korotkov , V. Kozlov , P. Kravchenko , V. G. Krivokhijine , L. Lagamba , L. Lapikas , I. Lehmann , P. Lenisa , A. Lopez Ruiz , W. Lorenzon , X. -G. Lu , X. -R. Lu , B. -Q. Ma , D. Mahon , N. C. R. Makins , S. I. Manaenkov , L. Manfre , Y. Mao , B. Marianski A. Martinez de la Ossa , H. Marukyan , C. A. Miller , Y. Miyachi , A. Movsisyan , M. Murray , A. Mussgiller , E. Nappi , Y. Naryshkin , A. Nass , M. Negodaev , W. -D. Nowak , L. L. Pappalardo , R. Perez-Benito , M. Raithel , P. E. Reimer , A. R. Reolon , C. Riedl , K. Rith , G. Rosner , A. Rostomyan , J. Rubin , D. Ryckbosch , Y. Salomatin , A. Schaefer , G. Schnell , K. P. Schueler , B. Seitz , T. -A. Shibata , V. Shutov , M. Stancari , M. Statera , E. Steffens , J. J. M. Steijger , F. Stinzing , S. Taroian , A. Terkulov , R. Truty , A. Trzcinski , M. Tytgat , Y. Van Haarlem , C. Van Hulse , D. Veretennikov , V. Vikhrov , I. Vilardi , S. Wang , S. Yaschenko , Z. Ye , S. Yen , V. Zagrebelnyy , D. Zeiler , B. Zihlmann , P. Zupranski

We address the question of interpolation of the virtual Compton scattering process off a polarized nucleon target between the deeply virtual regime for the initial-state photon and its near on-shell kinematics making use of the photon…

High Energy Physics - Phenomenology · Physics 2014-01-30 Andrei V. Belitsky , Dieter Mueller , Yao Ji