Neutron density distributions of 204,206,208Pb deduced via proton elastic scattering at Ep=295 MeV

Cross sections and analyzing powers for polarized proton elastic scattering from Ni-58, and Pb-204,Pb-206,Pb-208 were measured at intermediate energy E-p = 295 MeV. An effective relativistic Love-Franey interaction is tuned to reproduce Ni-58 scattering data within the framework of the relativistic impulse approximation. The neutron densities of the lead isotopes are deduced using model-independent sum-of-Gaussians distributions. Their error envelopes are estimated by a new chi(2) criterion including uncertainties associated with the reaction model. The systematic behaviors of extracted error envelopes of the neutron density distributions in Pb-204,Pb-206,Pb-208 are presented. The extracted neutron and proton density distribution of 208Pb gives a neutron skin thickness of Delta r(np) = 0.211(-0.063)(+0.054) fm.