A search for the electric dipole of the electron
We report a new upper limit on the electric dipole moment (EDM) of the electron of d{sub e} = 0.1 {plus minus} 3.2 {times} 10{sup {minus}26} e-cm. This precision is one hundred times better than any previously published limit and a factor of two better than that of unofficial reports. Recently there has been a great deal of theoretical interest in the possibility of a non-zero electron EDM. Models such as the left-right-symmetric Standard Model and an off-standard'' model with new heavy neutrinos are constrained by the new limit on d{sub e}. A non-zero electron EDM would violate the time reversal and parity space-time symmetries. T-violation was observed in neutral kaon decay and is still not fully explained by the Standard Model. Our experimental technique involves searching for an energy shift, linear in applied electric field, between the m{sub F} = 1 and m{sub F} = {minus}1 magnetic sublevels of the F=1 hyperfine level of the 6{sup 2}P{sub 1/2} ground state of atomic thallium. If the electron has a non-zero EDM, this thallium state will exhibit an atomic electric dipole moment that is roughly 600 times larger. The energy shift is detected with the technique of magnetic resonance spectroscopy, employing separated oscillating fields, applied to an atomic beam of thallium. In the approach, any relative phase-shift between the m{sub F} = {plus minus}1 components of the F=1 wavefunction acquired by the atom as it travels through an electric field is detected through interference with two separate oscillating magnetic fields located on either side of the electric field. The new level of precision is achieved through several improvements on previous experiments including employment of a vertical apparatus, two opposing atomic beams, and optical pumping for atomic state selection and analysis.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- DOE/ER
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 5540639
- Report Number(s):
- LBL-27723; ON: DE90001572; TRN: 89-028701
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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74 ATOMIC AND MOLECULAR PHYSICS
ELECTRONS
ELECTRIC DIPOLE MOMENTS
CP INVARIANCE
ELECTRIC FIELDS
MAGNETIC FIELDS
MEASURING METHODS
OPTICAL PUMPING
POLARIZATION
STANDARD MODEL
WAVE FUNCTIONS
DIPOLE MOMENTS
ELECTRIC MOMENTS
ELEMENTARY PARTICLES
FERMIONS
FUNCTIONS
INVARIANCE PRINCIPLES
LEPTONS
MATHEMATICAL MODELS
PARTICLE MODELS
PUMPING
UNIFIED GAUGE MODELS
645102* - High Energy Physics- Particle Interactions & Properties-Experimental- Weak Interactions & Properties
640302 - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory