A. Chaumeaux

Σ hypernuclear states in (K−, π±) reactions on 12C

Abstract Using negative kaons of momenta 400 and 450 MeV/c, Σ hypernuclear states have been produced in (K−, π−) and (K−, π+) reactions on 12C. The observed states are interpreted as the recoilless production of Σ particles on carbon. The upper limit for the widths of these states is estimated to be 5 MeV, independent of the charge of the Σ particle.

The (K−, π+) strangeness exchange reaction on 16O

Abstract Using negative kaons of 450 MeV/c momentum, Σ hypernuclear states have been produced in the (K−, π+) reaction on 16O. The observed states are interpreted as the recoilless production of Σ− particles in the p 3 2 and p 1 2 orbits of the Σ16C hypernucleus. Their energy splitting gives a constraint to the magnitude of the spin-orbit coupling for the Σ− particles in the nucleus.

Comparative study of the elastic scattering of 178.4 MeV antiprotons by the 16O and 18O isotopes

Abstract Elastic scattering of 178.4 MeV p has been measured on 16 O and 18 O isotopes. Both macroscopic and microscopic analyses of the data show differences which can be related to the neutron excess in 18 O

Search for p-nucleus states using the (p, p) knock-out reaction at 600 MeV/c

Abstract 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 2 H, 6 Li, 12 C, 63 Cu, 208 Pb and 209 Bi. The quasi-free elastic p p scattering observed in the lighter targets, and the comparison with the free p p scattering, also observed in this experiment, determine an effective proton number N eff 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.

Search for antiproton-nucleus states with (p̄p) reactions

Abstract We have studied (p, p) reactions on 12 C , 63 Cu, and 209 Bi to search for possible nuclear states formed ny antiprotons and nuclei. The experiments used the 180 MeV antiproton beam from LEAR, and the high-resolution magnetic spectrometer, SPES II, to detect the outgoing protons. No evidence of antiproton-nucleus states was found. The gross features of the proton spectra are reasonably well described by intranuclear cascade model calculations, which consider proton emission following antiproton annihilations in the target nucleus.

Elastic and inelastic scattering of 1 GeV protons on the 144, 150, 152Sm isotopes

Abstract We present the results of measurements of 1.04 GeV proton elastic and inelastic scattering on the 144,150,152 Sm isotopes. The use of HFB p- and n-densities gives a quite good description of the elastic scattering data. Neutron transition strengths are deduced for the 2 1 + and 3 1 − levels in 144 Sm. The channel coupling in the fairly well deformed 152 Sm nucleus is shown to be important. It can be well accounted for in a microscopic way in the Glauber model.

The (p, π+) reaction on 9Be and 10B at intermediate energies and a coherent π-exchange analysis

Abstract Proton-induced pion production at intermediate energies, leaving the final nucleus in discrete, resolved states, has been measured at the Saclay Synchrotron Saturne I, using the high resolution spectrometer facility SPES I. The (p, π+) reaction has been investigated on 9Be at proton energies of 410 and 605 MeV, and on 10B at incident energies of 320,410, 483 and 605 MeV. These data are presented and analysed in a coherent way, together with previous results at intermediate energies, by means of a pion exchange model. It is found that all the characteristic features of the data are reproduced satisfactorily.