Title | High-precision measurements in atomic cesium supporting a low-energy test of the standard model |
Publication Type | Thesis |
Year of Publication | 1998 |
Authors | Bennett, SC |
Abstract | The measurement of parity nonconservation (PNC) in atomic cesium provides the most precise low-energy test of the standard model of electroweak interactions. However, the test is limited by the uncertainty in the ab initio calculations that are required to interpret the measurement. This thesis describes one measurement that suggests that the accuracy of the theory may be better than its authors claim, and a second measurement that may be used in place of a less accurate calculation. A 0.16% measurement of M_{hf}/β using similar methods is also presented. The quantity Mhf is the o-diagonal hyperne-interaction-induced magnetic dipole amplitude, and β is the tensor transition polarizability; both are for the 6S → 7S transition in cesium. This ratio is combined with a 0.25% semi-empirical determination of M_{hf } from another group to determine the value of β with a precision of 0.30%. Previously, the value of β used in the test of the standard model was calculated using the ab initio theory, thus increasing the uncertainty due to theory in the nal test. Using the new measured value of β, the current values of the theory with improved precision, and the previous measurement of PNC in cesium we make a 0.61% test of the standard model. |