A gauge model without parity violation in heavy atoms

The authors address the question: 'are weak right-handed non-singlet representations of quarks and leptons necessary.' An extension of the Weinberg-Salam model to SU(2)XU(1)XU(1) is found to adequately describe all existing weak interaction data including the lack of parity violation in atomic physics experiments. These data tightly constrain the additional parameters introduced by adding the second weak hypercharge. Although such a model may seem regressive when considered from the standpoint of 'simple' unification schemes, the authors feel that it is aesthetics rather than experiment which leads to non-trivial right-handed multiplet structure. In contrast to most other models, the present model predicts a substantial parity-violation effect in atomic experiments on hydrogen. The authors note that the second weak boson in the model is not constrained to be heavy by existing data and thus might already be accessable in pp→μ+μ-X or possibly in the next generation of colliding beam facilities through e+e-→μ+μ-. (Auth.)