Structure effects in polarization and cross sections for A(p, p’)X inelastic reactions on 40Ca and 12C nuclei at 1 GeV

Abstract

The polarization of the secondary protons in the inelastic (p, p') reaction on the 40 Ca and 12 C nuclei at the initial proton energy 1 GeV was measured in a wide range of the scattered proton momenta at a laboratory angle Θ=21• . The cross sections of the reaction were measured as well. The outgoing protons from the reaction were detected using a magnetic spectrometer equipped with a multiwire-proportional chambers polarimeter. A structure in the polarization and cross section data, related probably to scattering off the nucleon correlations in the nuclei, was observed.

Quasi-elastic scattering of proton with 1 GeV energy on eight-nucleon cluster inside nucleus

“…The momentum resolution of the spectrometer (± 2.5 MeV/c) was estimated by measuring the width of the clearly separated 2 + excited level in the (p, p ′ ) reaction with the 12 C nucleus at the scattering angle 21 • under investigation (Fig. 2) [3]. In this measurement we also observed a peak (Fig.…”

“…A high-momentum region, that begins close to the end of the IV range (Figs. 3, 4) corresponds mainly to quasi-elastic scattering on the residual nuclei X from the reactions 9 Be(p, p ′ NC)X noted above: 9 Be(p, p ′ 6 Li) 3 H, 9 Be(p, p ′ 6 He) 3 He, 9 Be(p, p ′ 7 Li) 2 H, and 9 Be(p, p ′ 5 He) 4 He. This overlap of the momentum intervals for the reaction 9 Be(p, p ′ 4 He) 5 He (interval IV) and, mainly, for the reactions 9 Be(p, p ′ 6 Li) 3 H and 9 Be(p, p ′ 6 He) 3 He with the light nucleus, 9 Be, is due to relatively close masses of the correlations and residual nuclei.…”

“…11 corresponding to scattering at an angle of 21 • on the Ca nucleus, an estimate of the polarization in quasi-elastic scattering on this cluster is given. in the inclusive reaction 12 C(p, p ′ )X versus the secondary proton momentum K [3,7]. The empty square corresponds to the polarization in the elastic p− 4 He scattering [12].…”

“…This work is a part of the experimental program in the framework of which the effects of nucleon clusterization in nuclear matter is studied in the inclusive (p, p ′ ) experiments at the PNPI synchrocyclotron with the 1 GeV proton beam [1,2,3,4,5,6,7].…”

“…The polarization of secondary protons in the (p, p ′ ) reaction was found from an azimuthal asymmetry of the proton scattering off the carbon analyzer A, using the track information from the proportional chambers (PC1÷P4 and PC1 ′ , PC4 ′ ) of the polarimeter. The main parameters of the MAP spectrometer and the polarimeter are given in [3].…”