Measurement of the generalized form factors near threshold via gamma* p -> n pi(+) at high Q(2)

CLAS Collaboration, K. Park, R. W. Gothe, K. P. Adhikari, D. Adikaram, M. Anghinolfi, H. Baghdasaryan, J. Ball, M. Battaglieri, V. Batourine, I. Bedlinskiy, R. P. Bennett, A. S. Biselli, C. Bookwalter, S. Boiarinov, D. Branford, W. J. Briscoe, W. K. Brooks, V. D. Burkert, D. S. CarmanA. Celentano, S. Chandavar, G. Charles, P. L. Cole, M. Contalbrigo, V. Crede, A. D'Angelo, A. Daniel, N. Dashyan, R. De Vita, E. De Sanctis, A. Deur, C. Djalali, D. Doughty, R. Dupre, A. El Alaoui, L. El Fassi, P. Eugenio, G. Fedotov, A. Fradi, M. Y. Gabrielyan, N. Gevorgyan, G. P. Gilfoyle, K. L. Giovanetti, F. X. Girod, J. T. Goetz, W. Gohn, E. Golovatch, L. Graham, K. A. Griffioen, D. P. Watts

Research output: Contribution to journalArticlepeer-review


We report the first extraction of the pion-nucleon multipoles near the production threshold for the n pi(+) channel at relatively high momentum transfer (Q(2) up to 4.2 GeV2). The dominance of the s-wave transverse multipole (E0+), expected in this region, allowed us to access the generalized form factor G(1) within the light-cone sum-rule (LCSR) framework as well as the axial form factor G(A). The data analyzed in this work were collected by the nearly 4 pi CEBAF Large Acceptance Spectrometer (CLAS) using a 5.754-GeV electron beam on a proton target. The differential cross section and the pi-N multipole E0+/G(D) were measured using two different methods, the LCSR and a direct multipole fit. The results from the two methods are found to be consistent and almost Q(2) independent.

Original languageEnglish
Article number035208
Pages (from-to)-
Number of pages15
JournalPhysical Review C
Issue number3
Publication statusPublished - 26 Mar 2012

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