Measurement of the 6S-7S transition polarizablility in atomic cesium and an improved test of the standard model

摘要

The ratio of the off-diagonal hyperfine amplitude to the tensor transitionpolarizability (Mhf/beta) for the 6S-7S transition in cesium has been measured.The value of beta=27.024(43)(expt)(67)(theory)a_0^3 is then obtained using anaccurate semi-empirical value of Mhf. This is combined with a previousmeasurement of parity nonconservation in atomic cesium and previous atomicstructure calculations to determine the value of the weak charge. Theuncertainties in the atomic structure calculations are updated (and reduced) inlight of new experimental tests. The result Q_W=-72.06(28)(expt) (34)(theory)differs from the prediction of the standard model of elementary particlephysics by 2.5 sigma.