Very lately, the PREX and the CREX collaboration present skin values, rskin208​(newPREX2)=0.278±0.078 (exp)±0.012 (theor.)fm and rskin48​=0.121±0.026 (exp)±0.024 (model), respectively. We recently determined a neutron-skin
value rskin208​=0.278±0.035fm from measured reaction cross
sections σR​(exp) of p+208Pb scattering in a range of
incident energies 10 \lsim E_{\rm in} \lsim 100 MeV where the chiral (Kyushu)
g-matrix folding model is reliable for 12C+12C scattering. The data
σR​(exp) are available for proton scattering on 58Ni,
40,48Ca, 12C targets. Our first aim is to test the Kyushu g-matrix
folding model for p+208Pb scattering in 20 \lsim E_{\rm in} \lsim 180
MeV. Our second aim is to determine skin values rskin​ and matter and
neutron radii, rm​ and rn​, for 208Pb, 58Ni,
40,48Ca, 12C from the σR​(exp). Our method is the
Kyushu g-matrix folding model with the densities scaled from the D1S-GHFB+AMP
densities, where D1S-GHFB+AMP stands for Gogny-D1S HFB (GHFB) with the angular
momentum projection (AMP). As for proton scattering, we find that our model is
reliable in 20 \lsim E_{\rm in} \lsim 180 MeV. For 208Pb, the skin value
deduced from σR​(exp) in 20 \lsim E_{\rm in} \lsim 180 MeV
is rskin208​(σR​)=0.299±0.020 fm. Our results on
rskin​ are compared with the previous works. Our result rskin208​(σR​)=0.299±0.020 fm agrees with rskin208​(PREX2)=0.283±0.071 fm. In addition, our result rskin48​=0.103±0.022 fm is consistent with the CREX value