Measurement of the Beam-Spin Azimuthal Asymmetry Associated with Deeply-Virtual Compton Scattering

Airapetian, A.; Акопов, Н.; Akopov, Z.; Amarian, M.; Aschenauer, E. C.; Avakian, H.; Avakian, R.; Avetissian, A.; Avetissian, E.; Bailey, P.; Bains, B.; Baturin, V.; Baumgarten, C.; Beckmann, M.; Belostotski, S.; Bernreuther, S.; Bianchi, N.; Böttcher, H.; Borissov, A.; Bouhali, O.; Bouwhuis, M.; Brack, J.; Brauksiepe, S.; Brückner, W.; Brüll, A.; Brunn, I.; Bulten, H.; Capitani, G. P.; Chumney, P.; Cisbani, E.; Ciullo, G.; Court, G.R.; Dalpiaz, P.; Лео, Р. Де; Nardo, L. De; Sanctis, E. De; Schepper, D. De; Devitsin, E.; Huberts, P.K.A. de Witt; Nezza, P. Di; Düren, M.; Ehrenfried, M.; Elbakian, G.; Ellinghaus, F.; Ely, James H.; Fabbri, R.; Fantoni, A.; Fechtchenko, A.; Felawka, L.; Filippone, B. W.; Fischer, H.; Fox, B. D.; Franz, J.; Frullani, S.; Gärber, Y.; Garibaldi, F.; Garutti, E.; Gavrilov, G.; Gharibyan, V.; Golendukhin, A.; Graw, G.; Grebeniouk, O.; Green, P. W.; Greeniaus, L.G.; Gute, A.; Haeberli, W.; Hafidi, K.; Hartig, M.; Hasch, D.; Heesbeen, D.; Heinsius, F. H.; Henoch, M.; Hertenberger, R.; Hesselink, W.H.A.; Hofman, G.; Holler, Y.; Holt, R. J.; Hommez, B.; Iarygin, G.; Izotov, A.; Jackson, H. E.; Jgoun, A.; Jung, P.; Kaiser, R.; Kanesaka, J.; Kinney, E.; Kisselev, A.; Kitching, P.; Kobayashi, Haruo; Koch, Norbert; Königsmann, K.; Kolster, H.; Коротков, В. А.; Kotik, E.; Kozlov, V.; Krauß, Bernhard; Krivokhijine, V. G.; Kyle, G. S.; Lagamba, L.; Laziev, A.; Lenisa, P.; Liebing, P.; Lindemann, T.; Lorenzon, W.; Maas, Axel; Makins, N.; Marukyan, H.; Masoli, F.; McAndrew, M.; McIlhany, K.; Meißner, F.; Menden, F.; Meyners, N.; Mikloukho, O.; Miller, C. A.; Milner, R.; Muccifora, V.; Mussa, R.; Нагайцев, А.; Nappi, E.; Naryshkin, Y.; Nass, A.; Negodaeva, K.; Nowak, W.-D.; Oganessyan, K.; O’Neill, T. G.; Owen, B.; Pate, S. F.; Potashov, S.; Potterveld, D. H.; Raithel, Martin; Rakness, G.; Rappoport, V.; Redwine, R.; Reggiani, D.; Reolon, A. R.; Rith, Klaus; Robinson, D.; Rostomyan, A.; Ruh, M.; Ryckbosch, D.; Sakemi, Y.; Sanjiev, I.; Sato, Fuminobu; Savin, I.; Scarlett, C.; Schäfer, Andreas; Schill, C.; Schmidt, Friedrich; Schnell, G.; Schüler, K. P.; Schwind, A.; Seibert, J. Anthony; Seitz, B.; Shibata, T. A.; Shutov, V.; Simani, M. C.; Simon, A.; Sinram, K.; Steffens, E.; Steijger, J. J. M.; Stewart, J.; Stößlein, U.; Suetsugu, K.; Taroian, S.; Terkulov, A.; Tessarin, S.; Thomas, E.; Tipton, B.; Tytgat, M.; Urciuoli, G. M.; Brand, J. van den; Steenhoven, G. van der; Vyver, R. Van de; Hunen, J. J. van; Vetterli, M. C.; Vikhrov, V.; Vincter, M. G.; Visser, J.; Weiskopf, C.; Wendland, J.; Wilbert, Jürgen; Wise, T.; Yen, S.; Yoneyama, Satoshi; Zohrabian, H.

doi:10.1103/physrevlett.87.182001

Cited by 288 publications

(77 citation statements)

References 13 publications

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“…COMPASS focussed on a little larger x B -from ' 0:01 to ' 0:1 [23]. The data from HERMES is in the range 0:03 < x B < 0:35 [24,25]. The study of the high x B domain, where valence quarks should dominate, requires high luminosity and a high energy electron beam.…”

Section: Introductionmentioning

confidence: 99%

First moments of nucleon generalized parton distributions

Wang

Thomas

2010

Phys. Rev. D

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We extrapolate the first moments of the generalized parton distributions using heavy baryon chiral perturbation theory. The calculation is based on the one loop level with the finite range regularization. The description of the lattice data is satisfactory and the extrapolated moments at physical pion mass are consistent with the results obtained with dimensional regularization, although the extrapolation in the momentum transfer to t = 0 does show sensitivity to form factor effects which lie outside the realm of chiral perturbation theory. We discuss the significance of the results in the light of modern experiments as well as QCD inspired models.

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Section: Introductionmentioning

confidence: 99%

First moments of nucleon generalized parton distributions

Wang

Thomas

2010

Phys. Rev. D

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“…The measurement of the DVCS process on unpolarized protons is most sensitive to GPD H, which describes the transition that conserves the helicities of both the struck quark and the nucleon. Such measurements were performed by Hermes [6][7][8][9], H1 [10][11][12][13], and Zeus [14,15] at Hera, by the Hall A Collaboration [16] and by Clas [17][18][19] at Jefferson Lab.…”

Section: Jhep10(2012)042mentioning

confidence: 99%

Beam-helicity asymmetry arising from deeply virtual Compton scattering measured with kinematically complete event reconstruction

Airapetian¹,

Акопов²,

Akopov³

et al. 2012

J. High Energ. Phys.

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The beam-helicity asymmetry in exclusive electroproduction of real photons by the longitudinally polarized Hera positron beam scattering off an unpolarized hydrogen target is measured at Hermes. The asymmetry arises from deeply virtual Compton scattering and its interference with the Bethe-Heitler process. Azimuthal amplitudes of the beam-helicity asymmetry are extracted from a data sample consisting of ep → epγ events with detection of all particles in the final state including the recoiling proton. The installation of a recoil detector, while reducing the acceptance of the experiment, allows the elimination of background from ep → eN πγ events, which was estimated to contribute an average of about 12% to the signal in previous Hermes publications. The removal of this background from the present data sample is shown to increase the magnitude of the leading asymmetry amplitude by 0.054 ± 0.016 to −0.328 ± 0.027 (stat.) ± 0.045 (syst.).

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“…Experimentally, this relies on several new electron facilities combining high luminosity and advanced detectors which allow for measuring with an impressive precision exclusive processes, including deep virtual Compton scattering (DVCS) and meson production. This lead to the first studies of non-perturbative non forward parton distributions, now called generalized parton distributions (GPDs), first in the fixed target experiment HERMES [1][2][3], and then at H1 and ZEUS, using the dominance of the DVCS contribution at small x Bj [4][5][6]. Almost simultaneously, the DVCS contribution was measured at JLAB, at CLAS [7,8] and at Hall A [9].…”

Section: Introductionmentioning

confidence: 99%

Resumming soft and collinear contributions in deeply virtual Compton scattering

Altinoluk

Pire

Szymanowski

et al. 2012

J. High Energ. Phys.

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Abstract:We calculate the quark coefficient function T q (x, ξ) that enters the factorized amplitude for deeply virtual Compton scattering (DVCS) at all order in a soft and collinear gluon approximation, focusing on the leading double logarithmic behavior in (x ± ξ), where x ± ξ is the light cone momentum fraction of the incoming/outgoing quarks. We show that the dominant part of the known one loop result can be understood in an axial gauge as the result of a semi-eikonal approximation to the box diagram. We then derive an all order result for the leading contribution of the ladder diagrams and deduce a resummation formula valid in the vicinity of the boundaries of the regions defining the energy flows of the incoming/outcoming quarks, i.e. x = ±ξ. The resummed series results in a simple closed expression.

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Measurement of the Beam-Spin Azimuthal Asymmetry Associated with Deeply-Virtual Compton Scattering

Cited by 288 publications

References 13 publications

First moments of nucleon generalized parton distributions

First moments of nucleon generalized parton distributions

Beam-helicity asymmetry arising from deeply virtual Compton scattering measured with kinematically complete event reconstruction

Resumming soft and collinear contributions in deeply virtual Compton scattering

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