Polarisation asymmetries are measured for the hard exclusive leptoproduction of real photons from a longitudinally polarised hydrogen target. These asymmetries arise from the deeply virtual Compton scattering and Bethe-Heitler processes. From the data are extracted two asymmetries in the azimuthal distribution of produced real photons about the direction of the exchanged virtual photon: A(UL) with respect to the target polarisation and A(LL) with respect to the product of the beam and target polarisations. Results for both asymmetries are compared to the predictions from a generalised parton distribution model. The sin phi and cos(0 phi) amplitudes observed respectively for the A(UL) and A(LL) asymmetries are compatible with the sizeable predictions from the model. Unexpectedly, a sin(2 phi) modulation in the A(UL) asymmetry with a magnitude similar to that of the sin phi modulation is observed.

Exclusive leptoproduction of real photons on a longitudinally polarised hydrogen target

CAPILUPPI, Marco;CIULLO, Giuseppe;CONTALBRIGO, Marco;FERRETTI, Paola;GIORDANO, Francesca;LENISA, Paolo;PAPPALARDO, Luciano Libero;STANCARI, Michelle Dawn;STATERA, Marco;
2010

Abstract

Polarisation asymmetries are measured for the hard exclusive leptoproduction of real photons from a longitudinally polarised hydrogen target. These asymmetries arise from the deeply virtual Compton scattering and Bethe-Heitler processes. From the data are extracted two asymmetries in the azimuthal distribution of produced real photons about the direction of the exchanged virtual photon: A(UL) with respect to the target polarisation and A(LL) with respect to the product of the beam and target polarisations. Results for both asymmetries are compared to the predictions from a generalised parton distribution model. The sin phi and cos(0 phi) amplitudes observed respectively for the A(UL) and A(LL) asymmetries are compatible with the sizeable predictions from the model. Unexpectedly, a sin(2 phi) modulation in the A(UL) asymmetry with a magnitude similar to that of the sin phi modulation is observed.
A., Airapetian; N., Akopov; Z., Akopov; E. C., Aschenauer; W., Augustyniak; R., Avakian; A., Avetissian; E., Avetisyan; B., Ball; S., Belostotski; N., Bianchi; H. P., Blok; H., Bottcher; A., Borissov; J., Bowles; I., Brodski; V., Bryzgalov; J., Burns; Capiluppi, Marco; G. P., Capitani; E., Cisbani; Ciullo, Giuseppe; Contalbrigo, Marco; Ferretti, Paola; W., Deconinck; R. D., Leo; L. D., Nardo; E. D., Sanctis; M., Diefenthaler; P. D., Nezza; M., Duren; 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; Giordano, Francesca; S., Gliske; M., Golembiovskaya; C., Hadjidakis; M., Hartig; D., Hasch; G., Hill; A., Hillenbrand; M., Hoek; Y., Holler; I., Hristova; Y., Imazu; A., Ivanilov; A., Izotov; H., Jackson; H. S., Jo; S., Joosten; R., Kaiser; G., Karyan; T., Keri; E., Kinney; A., Kisselev; N., Kobayashi; V., Korotkov; V., Kozlov; P., Kravchenko; V. G., Krivokhijine; L., Lagamba; R., Lamb; L., Lapikas; I., Lehmann; Lenisa, Paolo; L. A., Linden Levy; A. L., 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. M., de la Ossa; H., Marukyan; C. A., Miller; Y., Miyachi; A., Movsisyan; V., Muccifora; M., Murray; A., Mussgiller; E., Nappi; Y., Naryshkin; A., Nass; M., Negodaev; W. D., Nowak; Pappalardo, Luciano Libero; R., Perez Benito; N., Pickert; M., Raithel; P. E., Reimer; A. R., Reolon; C., Riedl; K., Rith; G., Rosner; A., Rostomyan; J., Rubin; D., Ryckbosch; Y., Salomatin; F., Sanftl; A., Schafer; G., Schnell; K. P., Schuler; B., Seitz; T. A., Shibata; V., Shutov; Stancari, Michelle Dawn; Statera, Marco; E., Steffens; J. J. M., Steijger; H., Stenzel; J., Stewart; F., Stinzing; S., Taroian; A., Terkulov; A., Trzcinski; M., Tytgat; A., Vandenbroucke; P. B., van der Nat; Y. v., Haarlem; C. V., Hulse; D., Veretennikov; V., Vikhrov; I., Vilardi; C., Vogel; S., Wang; S., Yaschenko; H., Ye; Z., Ye; S., Yen; W., Yu; D., Zeiler; B., Zihlmann; P., Zupranski
File in questo prodotto:
File Dimensione Formato  
Airapetian2010_Article_ExclusiveLeptoproductionOfReal.pdf

accesso aperto

Descrizione: versione editoriale
Tipologia: Full text (versione editoriale)
Licenza: Creative commons
Dimensione 744.2 kB
Formato Adobe PDF
744.2 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/1436911
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 49
  • ???jsp.display-item.citation.isi??? 57
social impact