Neutron density distributions of $^{204,206,208}$Pb observed via polarized proton elastic scattering

Cross sections and analyzing powers of polarized proton elastic scattering from $^{204,206,208}$Pb at $E_p=$295 MeV have been measured with the high-resolution magnetic spectrometer ``Grand Raiden'' at RCNP. For the data analysis, special cares for trigger efficiencies, charge collections of Faraday Cups, and so on, have been paid to deduce absolute values of the cross sections in the measurement and data reduction. We have used relativistic impulse approximation (RIA) with medium-modified nucleon-nucleon interaction and realistic point proton density distributions unfolded from charge distributions obtained by electron scattering data. We will show preliminary results of the deduced neutron density distributions of $^{204,206,208}$Pb and their error envelopes.