Exclusive Leptoproduction of Real Photons on a Longitudinally Polarised Hydrogen Target
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.
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Cite
@article{arxiv.1004.0177,
title = {Exclusive Leptoproduction of Real Photons on a Longitudinally Polarised Hydrogen Target},
author = {The HERMES Collaboration and A. Airapetian and N. Akopov and Z. Akopov and E. C. Aschenauer and W. Augustyniak and R. Avakian and A. Avetissian and E. Avetisyan and B. Ball and S. Belostotski and N. Bianchi and H. P. Blok and H. Boettcher and A. Borissov and J. Bowles and I. Brodski and V. Bryzgalov and J. Burns and M. Capiluppi and G. P. Capitani and E. Cisbani and G. Ciullo and M. Contalbrigo and P. F. Dalpiaz and W. Deconinck and R. De Leo and L. De Nardo and E. De Sanctis and M. Diefenthaler and P. Di Nezza and M. Dueren and M. Ehrenfried and G. Elbakian and F. Ellinghaus and R. Fabbri and A. Fantoni and L. Felawka and S. Frullani and D. Gabbert and G. Gapienko and V. Gapienko and F. Garibaldi and G. Gavrilov and V. Gharibyan and F. Giordano and S. Gliske and M. Golembiovskaya and C. Hadjidakis and M. Hartig and D. Hasch and G. Hill and A. Hillenbrand and M. Hoek and Y. Holler and I. Hristova and Y. Imazu and A. Ivanilov and A. Izotov and H. E. Jackson and H. S. Jo and S. Joosten and R. Kaiser and G. Karyan and T. Keri and E. Kinney and A. Kisselev and N. Kobayashi and V. Korotkov and V. Kozlov and P. Kravchenko and V. G. Krivokhijne and L. Lagamba and R. Lamb and L. Lapikas and I. Lehmann and P. Lenisa and L. A. Linden-Levy and A. Lopez~Ruiz and W. Lorenzon and X. -G. Lu and X. -R. Lu and B. -Q. Ma and D. Mahon and N. C. R. Makins and S. I. Manaenkov and L. Manfre and Y. Mao and B. Marianski and A. Martinez de la Ossa and H. Marukyan and C. A. Miller and Y. Miyachi and A. Movsisyan and V. Muccifora and M. Murray and A. Mussgiller and E. Nappi and Y. Naryshkin and A. Nass and M. Negodaev and W. -D. Nowak and L. L. Pappalardo and R. Perez-Benito and N. Pickert and M. Raithel and P. E. Reimer and A. R. Reolon and C. Riedl and K. Rith and G. Rosner and A. Rostomyan and J. Rubin and D. Ryckbosch and Y. Salomatin and F. Sanftl and A. Schaefer and G. Schnell and K. P. Schueler and B. Seitz and T. -A. Shibata and V. Shutov and M. Stancari and M. Statera and E. Steffens and J. J. M. Steijger and H. Stenzel and J. Stewart and F. Stinzing and S. Taroian and A. Terkulov and A. Trzcinski and M. Tytgat and A. Vandenbroucke and P. B. van der Nat and Y. Van Haarlem and C. Van Hulse and D. Veretennikov and V. Vikhrov and I. Vilardi and C. Vogel and S. Wang and S. Yaschenko and H. Ye and Z. Ye and S. Yen and W. Yu and D. Zeiler and B. Zihlmann and P. Zupranski},
journal= {arXiv preprint arXiv:1004.0177},
year = {2014}
}
Comments
18 pages, 2 figures, 5 tables