Berlin 2001 – wissenschaftliches Programm

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AMPD: EPS AMPD

AMPD 6: Sitzung 6

AMPD 6.6: Vortrag

Mittwoch, 4. April 2001, 11:45–12:10, H104

The electric dipole moment of the electron — •B.E. Sauer, J.J. Hudson, and E.A. Hinds — Sussex Centre for Optical and Atomic Physics, University of Sussex, Falmer, Brighton BN1 9QH, UK

The existence of permanent electric dipole moment (edm) of a fundamental particle, an electron, proton or neutron, would violate both parity and time reversal symmetries. All searches for edm’s thus far have measured zero; the existence of a non-zero edm would have great consequences for theories of particle interactions. In particular, the Standard Model of particle physics predicts that the electron edm d_e is very small, at least ten orders of magnitude smaller than the current experimental limit, but many extensions to the Standard Model predict a d_e which might be observable. Measurement of a non-zero value for d_e would therefore be evidence of physics beyond the Standard Model.

All measurements of the electron edm take advantage of the relativistic enhancement of d_e in heavy atoms [1]. The previous best limits on d_e come from experiments on Cs [2], d_e≤ ± 6 × 10⁻²⁶e.cm and Tl [3], d_e ≤ ± 4 × 10⁻²⁷e.cm. The talk will review the field, with particular emphasis on the current experiment underway at Sussex using the YbF molecule. Because of the large polarizability of YbF compared to an atom, the molecule is roughly three orders of magnitude more sensitive to d_e than Tl is. YbF is also less tractable experimentally and is subject to different and smaller systematic effects which mimic d_e than Tl. New results on d_e from YbF will be reported as well as the prospects of novel molecular beam techniques which might increase the sensitivity of the experiment.

Work supported by EPSRC and PPARC.

[1] E. A. Hinds, Testing Time Reversal Symmetry Using Molecules, Phys. Scripta, T70 34–41 (1997).

[2] S. A. Murtha, D. Krause Jr., Z. L. Li, L. R. Hunter, Phys. Rev. Lett. 63 965 (1989).

[3] E. D. Commins, S. B. Ross, D. DeMille, B. C. Regan, Phys Rev. A50 2960 (1994).