Yerevan Physics Institute, Yerevan, Armenia.
Phys Rev Lett. 2012 Mar 16;108(11):112502. doi: 10.1103/PhysRevLett.108.112502. Epub 2012 Mar 15.
We report the first measurement of the parity-violating asymmetry A(PV) in the elastic scattering of polarized electrons from 208Pb. 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)(+0.16) fm and provides the first electroweak observation of the neutron skin which is expected in a heavy, neutron-rich nucleus.
我们报告了第一个从 208Pb 极化电子弹性散射中测量到的宇称破坏不对称性 A(PV)。A(PV)对中子分布半径（R(n)）敏感。结果 A(PV)=0.656±0.060(stat)±0.014(syst)ppm 对应于中子和质子分布半径之间的差异 R(n)-R(p)=0.33(-0.18)(+0.16)fm，并首次观测到预期在重核中存在的中子皮的电弱效应。
