Results in Physics (Feb 2022)
Neutron skin in 48Ca determined from p+48Ca and 48Ca+12C scattering
Abstract
Background:: In our previous paper, we determined rskin208(exp)=0.278±0.035 fm from measured reaction cross sections σRfor p+208Pb scattering, using the Kyushu (chiral) g-matrix folding model with the densities calculated with the Gogny-D1S Hartree–Fock–Bogoliubov (D1S-GHFB) with the angular momentum projection (AMP). The value agrees with that of PREX2. Reaction cross sections σRare available for p+48Ca scattering, whereas interaction cross sections σI(≈σR)are available for 48Ca + 12C scattering. As for 48Ca, the high-resolution E1polarizability experiment (E1pE) yields rskin48(E1pE)=0.14∼0.20fm. Purpose:: We determine rskin48(exp)from the data on σRfor p+48Ca scattering and from the data on σIfor 48Ca+12C scattering. Methods:: We use the Kyushu g-matrix folding model with the densities calculated with the D1M-GHFB+AMP densities. The D1M-GHFB+AMP proton and neutron densities are scaled so as to reproduce the data under the condition that the radius rpof the scaled proton density equals the data rp(exp)determined from the electron scattering. We deduce skin values rskin=rn(exp)−rp(exp)from the resulting rn(exp)and the rp(exp)determined from electron scattering. The same procedure is taken for D1S-GHFB+AMP. Results:: We regard rskin48(E1pE)as a reference skin value. Using the reference skin value and taking D1M-GHFB+AMP, we determine rskin48(exp)=0.158±0.025 fm for p+48Ca scattering and 0.160±0.058 fm for 48Ca + 12C scattering. Conclusion:: We take the weighted mean and its error for the two skin values. The result is rskin48(exp)=0.158±(0.023)exp±(0.012)thfm.
