is better described within the TW model. This quantity is practically independent of the $\omega-\rho$ interaction strength in the NL$\omega\rho$ model as far as the HO numerical prescription is used. The neutron radius, on the other had, is strongly model dependent with drastic consequences in the neutron skin thickness calculation. The experimental values for $\theta$ are still very uncertain and all our results fall inside the experimental confidence interval. We shall comment on possible restrictions to the neutron skin thickness in the next section. NL3 provides the best results for the binding energy.

In [@nl3], the results shown for the proton and neutron radius are respectively 5.52 and 5.85 fm, yielding a skin of 0.33 fm, larger than ours. Notice, however, that in [@nl3] the Dirac equation was explicity solved. In [@piek06], the authors obtained a value of 0.21 fm for the neutron skin thickness and a binding energy of -7.89 MeV within a different parametrization of the NL$\omega\rho$ model. Again in this case the Dirac equation was solved.

In Fig. \[ronp1\] we show the difference between neutron and proton densities at the $Pb$ surface for the models discussed in the present work with the Thomas-Fermi approximation solved in a 