Investigation of the structure of light exotic nuclei by proton elastic scattering in inverse kinematics

Abstract

In order to study the spatial structure of exotic nuclei, it was proposed at the Petersburg Nuclear Physics Institute (PNPI) to measure the differential cross section for small-angle proton elastic scattering in inverse kinematics. Several experiments in beams of 0.7-GeV/nucleon exotic nuclei were performed at the heavy-ion accelerator facility of GSI (Gesellschaft f¨ur Schwerionenforschung, Darmstadt, Germany) by using the IKAR ionization spectrometer developed at PNPI. The IKAR ionization chamber filled with hydrogen at a pressure of 10 bar served simultaneously as a target and as a recoil-proton detector, which measured the recoil-proton energy. The beam-particle scattering angle was also measured. The results obtained for the cross sections in question were analyzed on the basis of the Glauber-Sitenko theory using phenomenological nuclear-density distributions with two free parameters. Nuclear-matter distributions and root-mean-square radii were found for the nuclei under investigation. The size of the halo in the 6 Не, 8 Не, 11 Li, and 14 Ве nuclei was determined among other things. Information about neutron distributions in nuclei was deduced by combining the data obtained here with the known values of the radii of proton distributions. A sizable neutron skin was revealed in the 8 Li, 9 Li, and 12 Be nuclei.

Matter Density Distributions, Root-mean Square Radii and Elastic Electron Scattering Form Factors of Some Exotic Nuclei (17B, 11Li, 8He)

“…Two body nucleon density distribution (2BNDD'S) in fm -3 of ground state are plotted versus r (in fm) as shown in Fig. 3(a), the black line represents the normal contribution of core 9 Li, The valence (two-neutron exotic nuclei in the state of 1p1/2) is represented by the blue line, which takes the shape of a long tail in this distribution, the matter density distribution (core + valence) is defined by a red line, which has a long tail as well and agrees well with 11 Li's experimental data, which were taken from Dobrovolsky [21] and is represented by the shaded space. Fig.…”

Empirical parametrization of the nucleon-nucleon elastic scattering amplitude at high beam momenta for Glauber calculations and Monte Carlo simulations

“…Parameterizations of nucleon-nucleon elastic scattering amplitude are widely used in many Glauber calculations, for example, for studies of the structure of exotic nuclei and the neutron skin of nuclei [1] - [17], calculations of differential and total reaction cross sections for hadron-nucleus and nucleus-nucleus interactions [18,19], experimental research of high energy nucleus-nucleus collisions at various impact parameters [20,21], etc. Considering a nucleon-nucleus interaction, it is sufficient for a first approximation to know the amplitude at zero scattering angle, where the nucleon-nucleon interaction radius (∼ 1 fm) is smaller than the nuclear size.…”