The beam-helicity asymmetry in exclusive electroproduction of real photons by the longitudinally polarized Hera positron beam scattering on 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->epg events with detection of all particles in the fnal 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->eNpig 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.

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

CIULLO, Giuseppe;CONTALBRIGO, Marco;LENISA, Paolo;PAPPALARDO, Luciano Libero;STATERA, Marco;
2012

Abstract

The beam-helicity asymmetry in exclusive electroproduction of real photons by the longitudinally polarized Hera positron beam scattering on 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->epg events with detection of all particles in the fnal 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->eNpig 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.
A., Airapetian; N., Akopov; Z., Akopov; E. C., Aschenauer; W., Augustyniak; R., Avakian; A., Avetissian; E., Avetisyan; S., Belostotski; H. P., Blok; A., Borissov; J., Bowles; I., Brodski; V., Bryzgalov; J., Burns; M., Capiluppi; G. P., Capitani; E., Cisbani; Ciullo, Giuseppe; Contalbrigo, Marco; P. F., Dalpiaz; W., Deconinck; R., Leo; L., Nardo; E., Sanctis; M., Diefenthaler; P., Nezza; M., Düren; M., Ehrenfried; G., Elbakian; F., Ellinghaus; E., Etzelmüller; R., Fabbri; A., Fantoni; L., Felawka; S., Frullani; G., Gapienko; V., Gapienko; F., Garibaldi; G., Gavrilov; V., Gharibyan; F., Giordano; S., Gliske; M., Golembiovskaya; I. M., Gregor; H., Guler; M., Hartig; D., Hasch; A., Hillenbrand; M., Hoek; Y., Holler; I., Hristova; A., Ivanilov; H. E., Jackson; H. S., Jo; S., Joosten; R., Kaiser; G., Karyan; T., Keri; E., Kinney; A., Kisselev; V., Korotkov; V., Kozlov; B., Krauss; P., Kravchenko; V. G., Krivokhijine; L., Lagamba; L., Lapikás; I., Lehmann; Lenisa, Paolo; A., López Ruiz; W., Lorenzon; S., Lu; X., Lu; B. Q., Ma; D., Mahon; N. C. R., Makins; S. I., Manaenkov; L., Manfré; Y., Mao; B., Marianski; A., Martinez 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; A., Osborne; Pappalardo, Luciano Libero; R., Perez Benito; A., Petrosyan; P. E., Reimer; A. R., Reolon; C., Riedl; K., Rith; G., Rosner; A., Rostomyan; L., Rubacek; J., Rubin; D., Ryckbosch; A., Schäfer; G., Schnell; K. P., Schüler; B., Seitz; C., Shearer; T. A., Shibata; V., Shutov; M., Stancari; Statera, Marco; J. J. M., Steijger; J., Stewart; S., Taroian; A., Terkulov; R., Truty; A., Trzcinski; M., Tytgat; Y., Haarlem; C., Hulse; D., Veretennikov; V., Vikhrov; I., Vilardi; S., Wang; S., Yaschenko; Z., Ye; S., Yen; V., Zagrebelnyy; D., Zeiler; B., Zihlmann; P., Zupranski
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/2018013
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