# Experimental study of the P11(1440) and D13(1520) resonances from the CLAS data on ep→e′π+π−p′

Abstract : 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%).
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Journal articles
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http://hal.in2p3.fr/in2p3-00732442
Contributor : Emmanuelle Vernay <>
Submitted on : Friday, September 14, 2012 - 4:15:50 PM
Last modification on : Friday, November 27, 2020 - 5:52:10 AM

### Citation

V.I. Mokeev, V.D. Burkert, L. Elouadrhiri, G.V. Fedotov, E.N. Golovatch, et al.. Experimental study of the P11(1440) and D13(1520) resonances from the CLAS data on ep→e′π+π−p′. Physical Review C, American Physical Society, 2012, 86, pp.035203. ⟨10.1103/PhysRevC.86.035203⟩. ⟨in2p3-00732442⟩

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