Neutron densities from parity-violating elastic electron scaterring.

We analyze parity-violating elastic electron scattering as a complementary tool for precise determination of neutron densities in nuclei. In particular we discuss how to extract the ratio between neutron and proton rms radii and monopole form factors from theoretical and experimental asymmetries. The structure of the nuclear target is obtained from a Skyrme Hartree-Fock mean field with pairing interactions in BCS approximation. We focus on the parity-violation asymmetry for 208Pb and for 12C as examples of N > Z and N = Z nuclei. In the latter case we study the influence of nuclear isospin mixing by means of the asymmetry deviation. Distorted wave calculations are shown and are compared to plane wave impulse approximation.This work was supported by Ministerio de Ciencia e Innovaci´on (Spain) under Contract FIS2008- 01301 and grants FPA-2007-62616 and FPA-2006-07393, by INTAS Open Call grant No 05- 1000008-8272, and by UCM and Comunidad de Madrid under grant Grupo de F´ısica Nuclear (910059).Peer Reviewe