HAL : in2p3-00172413, version 1
 arXiv : 0709.1946
 Physical Review C 77 (2008) 015208
 Cross sections and beam asymmetries for $\vev{e}p \to en\pi^+$ in the nucleon resonance region for $1.7 \le Q^2 \le 4.5 (GeV)^2$
 CLAS Collaboration(s)
 (2008)
 The exclusive electroproduction process $\vec{e}p \to e^\prime n \pi^+$ was measured in the range of the photon virtuality $Q^2 = 1.7 - 4.5 \rm{GeV^2}$, and the invariant mass range for the $n\pi^+$ system of $W = 1.15 - 1.7 \rm{GeV}$ using the CEBAF Large Acceptance Spectrometer. For the first time, these kinematics are probed in exclusive $\pi^+$ production from protons with nearly full coverage in the azimuthal and polar angles of the $n\pi^+$ center-of-mass system. The $n\pi^+$ channel has particular sensitivity to the isospin 1/2 excited nucleon states, and together with the $p\pi^0$ final state will serve to determine the transition form factors of a large number of resonances. The largest discrepancy between these results and present modes was seen in the $\sigma_{LT'}$ structure function. In this experiment, 31,295 cross section and 4,184 asymmetry data points were measured. Because of the large volume of data, only a reduced set of structure functions and Legendre polynomial moments can be presented that are obtained in model-independent fits to the differential cross sections.
 Thème(s) : Physique/Physique Nucléaire Expérimentale
 Lien vers le texte intégral : http://fr.arXiv.org/abs/0709.1946
 in2p3-00172413, version 1 http://hal.in2p3.fr/in2p3-00172413 oai:hal.in2p3.fr:in2p3-00172413 Contributeur : Dominique Girod <> Soumis le : Lundi 17 Septembre 2007, 10:06:32 Dernière modification le : Mercredi 23 Janvier 2008, 10:23:06