Proton Distribution Radii ofC12–19Illuminate Features of Neutron Halos

Abstract

Proton radii of 12−19 C densities derived from first accurate charge changing cross section measurements at 900A MeV with a carbon target are reported. A thick neutron surface evolves from ∼ 0.5 fm in 15 C to ∼ 1 fm in 19 C. The halo radius in 19 C is found to be 6.4±0.7 fm as large as 11 Li. Ab initio calculations based on chiral nucleon-nucleon and three-nucleon forces reproduce well the radii.

Chiral g -matrix folding-model approach to reaction cross sections for scattering of Ca isotopes on a C target

“…I, the present folding model is successful in reproducing the differential cross sections of p scattering at E lab = 65 MeV [42] and of 4 He scattering at E lab = 30 ∼ 200 MeV [23,43]. To show the reliability of the present DFB for σ R , we apply the present DFM for the data on 12 C scattering on 9 Be, 12 C, 27 Al targets in 30 < E lab < 400 MeV, and show that the present DFM is good in 30 < E lab < 100 MeV and 250 < E lab < 400 MeV. For light nuclei 9 Be, 12 C, 27 Al, we take the phenomenological densities [38] deduced from the electron scattering; note that the phenomenological densities reproduce the experimental data [7] on r m .…”

“…To show the reliability of the present DFB for σ R , we apply the present DFM for the data on 12 C scattering on 9 Be, 12 C, 27 Al targets in 30 < E lab < 400 MeV, and show that the present DFM is good in 30 < E lab < 100 MeV and 250 < E lab < 400 MeV. For light nuclei 9 Be, 12 C, 27 Al, we take the phenomenological densities [38] deduced from the electron scattering; note that the phenomenological densities reproduce the experimental data [7] on r m . For the densities of even Ca isotopes, we take GHFB with β = 0 and GHFB+AMP with β deformation in order to investigate effects of β deformation.…”

“…In many papers using the Glauber model, nuclear matter radii r m are extracted from interaction cross sections σ I and reaction cross sections σ R (σ R ≈ σ I ); see Refs. [5][6][7][8][9][10][11][12] as important papers. Particularly for halo nuclei, the r m are determined for 6 He, 8 B, 11 Li, 11 Be in Refs.…”

“…High precision measurements of σ R within 2% error were made for 12 C scattering on 9 Be, 12 C, 27 Al targets in a wide range of incident energies [7]; say 30 < E lab < 400 MeV for E lab being the incident energy per nucleon. In fact, the r m of 9 Be, 12 C, 27 Al were determined by the Glauber model. Very lately, in RIKEN, Tanaka el.…”

“…However, it is not clear whether the Kyushu g-matrix DFM is reliable for σ R . In order to investigate the reliability, we apply the Kyushu g-matrix DFM for measured σ R on 12 C scattering from 9 Be, 12 C, 27 Al targets in 30 < E lab < 400 MeV, and confirm that the present DFM is reliable in 30 < E lab < 100 MeV and 250 < E lab < 400 MeV. We then predict σ R for scattering of Ca isotopes on a 12 C target at E lab = 280 MeV, using the Kyushu g-matrix DFM [23].…”