761 articles – 7600 Notices  [english version]
 HAL : in2p3-00732442, version 1
 arXiv : 1205.3948
 Physical Review C 86 (2012) 035203
 Experimental study of the P11(1440) and D13(1520) resonances from the CLAS data on ep→e′π+π−p′
 CLAS Collaboration(s)
 (2012)
 The transition helicity amplitudes from the proton ground state to the $P_{11}(1440)$ and $D_{13}(1520)$ excited states ($\gamma_{v}pN^*$ electrocouplings) were determined from the analysis of nine independent one-fold differential $\pi^{+} \pi^{-} p$ electroproduction cross sections off a proton target, taken with CLAS at photon virtualities 0.25\enskip {\rm GeV$^{2}$} $<$ $Q^{2}$ $<$ 0.60 \enskip {\rm GeV$^{2}$}. The phenomenological reaction model was employed for separation of the resonant and non-resonant contributions to the final state. The $P_{11}(1440)$ and $D_{13}(1520)$ electrocouplings were obtained from the resonant amplitudes parametrized within the framework of a unitarized Breit-Wigner ansatz. They are consistent with results obtained in the previous CLAS analyses of the $\pi^+n$ and $\pi^0p$ channels. The successful description of a large body of data in dominant meson-electroproduction channels off protons with the same $\gamma_{v}pN^*$ electrocouplings offers clear evidence for the reliable extraction of these fundamental quantities from meson-electroproduction data. This analysis also led to the determination of the long-awaited hadronic branching ratios for the $D_{13}(1520)$ decay into $\Delta\pi$ (24%-32%) and $N\rho$ (8%-17%).
 Thème(s) : Physique/Physique des Hautes Energies - PhénoménologiePhysique/Physique Nucléaire ExpérimentalePhysique/Physique Nucléaire Théorique
 Lien vers le texte intégral : http://fr.arXiv.org/abs/1205.3948
 in2p3-00732442, version 1 http://hal.in2p3.fr/in2p3-00732442 oai:hal.in2p3.fr:in2p3-00732442 Contributeur : Emmanuelle Vernay <> Soumis le : Vendredi 14 Septembre 2012, 16:15:50 Dernière modification le : Mardi 30 Octobre 2012, 09:22:57