Ratios of Helicity Amplitudes for Exclusive rho-0 Electroproduction
Abstract
Exclusive rho^0-meson electroproduction is studied in the HERMES experiment, using a 27.6 GeV longitudinally polarized electron/positron beam and unpolarized hydrogen and deuterium targets in the kinematic region 0.5 GeV^2 < Q^2 < 7.0 GeV^2, 3.0 GeV < W < 6.3 GeV, and -t' < 0.4 GeV^2. Real and imaginary parts of the ratios of the natural-parity-exchange helicity amplitudes T_{11} (\gamma^*_T --> \rho_T), T_{01} (\gamma^*_T --> \rho_L), T_{10} (\gamma^*_L --> \rho_T), and T_{1-1} (\gamma^*_{-T} -->\rho_T) to T_{00} (\gamma^*_L --> \rho_L) are extracted from the data. For the unnatural-parity-exchange amplitude U_{11}, the ratio |U_{11}/T_{00}| is obtained. The Q^2 and t' dependences of these ratios are presented and compared with perturbative QCD predictions.
Keywords
Cite
@article{arxiv.1012.3676,
title = {Ratios of Helicity Amplitudes for Exclusive rho-0 Electroproduction},
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 S. Belostotski and N. Bianchi and H. P. Blok and A. Borissov and J. Bowles 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 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. Krivokhijine 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 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 F. Stinzing and S. Taroian and A. Terkulov and A. Trzcinski and M. Tytgat and A. Vandenbroucke and Y. Van Haarlem and C. Van Hulse and D. Veretennikov and V. Vikhrov and I. Vilardi and S. Wang and S. Yaschenko and S. Yen and W. Yu and B. Zihlmann and P. Zupranski},
journal= {arXiv preprint arXiv:1012.3676},
year = {2011}
}
Comments
27 pages, 8 tables, 13 figures; minor textual changes on pages 2, 3,9, 10, 11, and some changes to the list of references