Future prospects in photon and electron physics at Saclay

Search for the Δ++ component in the C ground state using the C(γ,π+p) reaction

“…As for the experimental search for the isobar admixture in nuclei with A ≥ 4, the observation of ∆ knock-out from 9 Be [5] and the recent double charge exchange experiment (π + , π − ) on 3 H, 4 He, 6 Li, 7 Li, 12,13 C, 90 Zr, and 208 Pb [6] are of the greatest interest. The first experiment [5] was carried out at the proton beam of the synchrocyclotron at the Petersburg Nuclear Physics Institute where the inclusive differential cross sections for the 9 Be(p, 8 He) reaction at the proton energy of 1 GeV have been measured. An enhancement of the 8 He yield was observed for the spectator momentum less than 300 MeV/c, which was connected with the ∆ ++ knock-out from 9 Be.…”

“…In Ref. [8] a combined study of (e, e ′ ∆ ++ ) and (e, e ′ ∆ o ) reactions on 3 He was proposed. The corresponding investigations are being realized at MAMI (Mainz) [9] and Jefferson Lab.…”

Photoproduction of the $πN$ pair on nuclei and isobar configurations

“…The possible existence of bound and resonance delta-nucleon and delta-nucleus states was widely discussed in [5][6][7][8][9]. From the experimental point of view, conclusion of the work [4] that a quasibound delta-nucleon state of isospin T = 2 and spin-parity J P = 2 + may exist is the most appealing.…”