Measurements of the ${\hat{I}}_v^{3}p\to p^{\prime }\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ cross section with the CLAS detector for $0.4$ GeV${}^2$ $<Q^2<$ $1.0$ GeV${}^2$ and $1.3$ GeV $<W<$ $1.825$ GeV

Abstract

New results on the single-differential and fully-integrated cross sections for the process ${\hat{I}}_v^{3}p\to p^{\prime }\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ are presented. The experimental data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the kinematic region of the reaction invariant mass $W$ from 1.3 to 1.825 GeV and the photon virtuality $Q^2$ from 0.4 to 1.0 GeV${}^2$. The cross sections were obtained in narrow $Q^2$ bins (0.05 GeV${}^2$) with the smallest statistical uncertainties achieved in double-pion electroproduction experiments to date. The results were found to be in agreement with previously available data where they overlap. A preliminary interpretation of the extracted cross sections, which was based on a phenomenological meson-baryon reaction model, revealed substantial relative contributions from nucleon resonances. The data offer promising prospects to improve knowledge on the $Q^2$-evolution of the electrocouplings of most resonances with masses up to $\sim$1.8 GeV.

22 pages, 22 figures, will be sent to Phys. Rev. C