We report the first measurement of the parity-violating asymmetry A PV in the elastic scattering of polarized electrons from Pb208. A PV is sensitive to the radius of the neutron distribution (R n). The result A PV=0.656±0.060(stat)±0. 014(syst)ppm corresponds to a difference between the radii of the neutron and proton distributions R n-R p=0.33-0.18+0.16fm and provides the first electroweak observation of the neutron skin which is expected in a heavy, neutron-rich nucleus.
ASJC Scopus subject areas
- Physics and Astronomy(all)