Measurement of the parity violating 6S-7S transition amplitude in cesium achieved within 2x10{sup -13} atomic-unit accuracy by stimulated-emission detection
- Laboratoire Kastler Brossel and Federation de Recherche, Departement de Physique de l'Ecole Normale Superieure, 24 Rue Lhomond, F-75231 Paris Cedex 05 (France)
We exploit the process of asymmetry amplification by stimulated emission which provides an original method for parity violation (PV) measurements in a highly forbidden atomic transition. The method involves measurements of a chiral, transient, optical gain of a cesium vapor on the 7S-6P{sub 3/2} transition, probed after it is excited by an intense, linearly polarized, collinear laser, tuned to resonance for one hyperfine line of the forbidden 6S-7S transition in a longitudinal electric field. We report here a 3.5-fold increase of the one-second-measurement sensitivity and subsequent reduction by a factor of 3.5 of the statistical accuracy compared with our previous result [J. Guena et al., Phys. Rev. Lett. 90, 143001 (2003)]. Decisive improvements to the setup include an increased repetition rate, better extinction of the probe beam at the end of the probe pulse, and, for the first time to our knowledge, the following: a polarization-tilt magnifier, quasisuppression of beam reflections at the cell windows, and a Cs cell with electrically conductive windows. We also present real-time tests of systematic effects and consistency checks on the data, as well as a 1% accurate measurement of the electric field seen by the atoms, from atomic signals. PV measurements performed in seven different vapor cells agree within the statistical error. Our present result is compatible with the more precise result of Wood et al. within our present relative statistical accuracy of 2.6%, corresponding to a 2x10{sup -13} atomic-unit uncertainty in E{sub 1}{sup pv}. Theoretical motivations for further measurements are emphasized and we give a brief overview of a recent proposal that would allow the uncertainty to be reduced to the 0.1% level by creating conditions where asymmetry amplification is much greater.
- OSTI ID:
- 20653255
- Journal Information:
- Physical Review. A, Vol. 71, Issue 4; Other Information: DOI: 10.1103/PhysRevA.71.042108; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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