An experimental limit on parity mixing in atomic hydrogen
An experiment was performed to detect the forbidden E1 transition between two hyperfine levels of the 2S state of atomic hydrogen. Such a transition, with {Delta}l = 0, violates parity symmetry. The technique used was to induce an interference between the forbidden transition and a parity-allowed E1 transition polarized by a DC electric field. The two induced transitions were driven coherently in a single microwave cavity. A magnetic field was used to shift the atoms into resonance with the RF radiation and to make the 2S and 2P states degenerate in energy, which would maximize any parity-violating mixing between these states. The measurements were made by passing a beam of hydrogen through the microwave cavity, and monitoring the state of the emerging atoms. To separate the parity-violating component of the transition rate from the parity-conserving part, the change in the transition rate was monitored when the handedness of the interaction region was reversed. From the transition asymmetry it was possible to extract the size of the proton-spin dependent part of a general parity-violating interaction between an electron and a proton. This can be stated in terms of a dimensionless constant C{sub 2}. The result of this experiment is C{sub 2p} = 1.5 {plus_minus} 22. The error bound represents a 95% confidence level and is an improvement of an order of magnitude over previous limits set by similar experiments in hydrogen.
- Research Organization:
- Univ. of Michigan, Ann Arbor, MI (United States)
- OSTI ID:
- 106814
- Resource Relation:
- Other Information: TH: Thesis (Ph.D.); PBD: 1993
- Country of Publication:
- United States
- Language:
- English
Similar Records
Parity and time reversal invariance in the hydrogen atom
Parity nonconservation in the hydrogen atom