Neutron skin thickness of 116,118,120,122,124Sn determined from reaction cross sections of proton scattering

Background: The cross sections of the isovector spin-dipole resonances (SDR) in the Sb isotopes have been measured. Within the model used, the neutron-skin thicknesses..skin(exp) deduced 0.12 +/- 0.06 fm for Sn-116, 0.13 +/- 0.06 fm for Sn-118, 0.18 +/- 0.07 fm for Sn-120, 0.22 +/- 0.07 fm for Sn-122, 0.19 +/- 0.07 fm for Sn-124. We tested the chiral (Kyushu). g-matrix folding model for C-12+C-12 scattering, and found that the Kyushu. g-matrix folding model is reliable for reaction cross sections sigma(R) in 30 less than or similar to E-in less than or similar to 100 MeV and 250 less than or similar to E-in less than or similar to 400 MeV. We determine neutron skin thickness r(skin)(exp), using measured sigma(R) of He-4+Sn-116,Sn-120,Sn-224 scattering. The results are r(skin)(exp) = 0.242 +/- 0.140 fm for 116Sn, r(skin)(exp) = 0.377 +/- 0.140 fm for Sn-120, r(skin)(exp) = 0.180 +/- 0.142 fm for Sn-124. The sigma(R) are available for proton scattering on Sn-116,Sn-118,Sn-120,Sn-122,Sn-124 with high accuracy of 2 similar to 3% as a function of incident energy E-in. Purpose: Our aim is to determine r(skin)(exp) for Sn-116,Sn-118,Sn-120,Sn-122,Sn-124 with small errors by using the Kyushu g-matrix folding model. Methods: Our model is the Kyushu g-matrix folding model with the densities scaled from the D1S-GHFB+AMP neutron density, where D1S-GHFB+AMP stands for Gogny-D1S HFB (D1S-GHFB) with the angular momentum projection (AMP). Results: The proton radii of D1S-GHFB+AMP agree with those calculated with the isotope shift method based on the electron scattering. We then scale the D1S-GHFB+AMP neutron densities so as to reproduce the sigma(R)(exp). In 30 less than or similar to E-in less than or similar to 65 MeV, we determine r(skin)(exp) from measured sigma(R). The values are r(skin)(exp) = 0.118 +/- 0.021 fm for Sn-116, 0.112 +/- 0.021 fm for Sn-118, 0.124 +/- 0.021 fm for Sn-120, 0.156 +/- 0.022 fm for Sn-124. As for Sn-122, the skin value in 30 < less than or similar to E-in less than or similar to 50 MeV is 0.122 +/- 0.024 fm. Conclusions: Our results are consistent with the previous values.

Automated summary

The neutron-skin thicknesses of Sb isotopes were measured, and a chiral g-matrix folding model was used to determine the reaction cross sections. The results were found to be consistent with previous values.