The knock-out reaction A(p, p)X has been used to search for narrow p-nucleus states. The experiment was performed using the 600 MeV/c antiproton beam at LEAR and the high-resolution and large-acceptance magnetic spectrometer SPES II. The A-dependence of the annihilation-induced proton spectra has been studied on 2H, 6Li, 12C, 63Cu, 208Pb and 209Bi. The quasi-free elastic pp scattering observed in the lighter targets, and the comparison with the free pp scattering, also observed in this experiment, determine an effective proton number Neff for 1s- and 1p-shell protons. No evidence for narrow bound or resonant p-nucleus states could be found. Upper limits for their production are one order of magnitude lower than certain theoretical predictions, but consistent with the properties of the p-nucleus interaction, as established from recent elastic and inelastic scattering as well as from studies of antiprotonic atoms.
- Nuclear reactions
ASJC Scopus subject areas
- Nuclear and High Energy Physics