Parity nonconservation in the hydrogen atom. II

We give a complete phenomenological analysis of parity mixing in the hydrogen atom, showing the connection between relativistic neutral-current interactions and nonrelativistic potentials. The matrix elements of these potentials are evaluated for $n=2\mathrm{}$ hydrogen, and the mixing of $2S-2P$ states is computed at each of the level crossings. A systematic discussion of the invariant decomposition of $2S-2S^{\prime }$ microwave transitions is given, providing a catalogue of the possible parity experiments. One particular transition is analyzed to show its sensitivity to weak interactions. We conclude that it should be possible to detect weak interactions of universal strength by observing asymmetries of order ${10}^{-6\mathrm{}}$, with integration times of order ${10}^4$ sec. Such experiments are underway at this laboratory.