Parity Violation Effect in Atomic Physics and the Structure of Neutral Currents in Gauge Theories

  • T. C. Yang
Part of the NATO Advanced Study Institutes Series book series (NSSB, volume 39)


We study here three models, namely, the SU(2) \( \otimes \) U(1) model, the SUL(2) \( \otimes \) SUR(2) \( \otimes \) U(1) model and the SUL(2) \( \otimes \) SUL(2) \( \otimes \) U(1) model, which seem to be the most natural extensions of the Weinberg-Salam model in order to accomodate the recent atomic Bismuth experimental results. The differences between the model predictions in neutrino reactions are small except for the elastic υμe and υμe cross sections. We remark on the other specific experiments which could provide meaningful checks between these models. We also comment on the “naturalness” of each model.


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References and Footnotes

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    See the lectures given by V. Telegdi. One should bear in mind that in heavy atoms like Bismuth, the time component of the hadronic neutral currents are enhanced by the atomic numbers. What the present experiments have measured is thus the parity violation effect induced by the vector hadronic neutral currents and the axial-vector electron currents.Google Scholar
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    The main point is that t, b, g, h quarks are heavier than \(\tau \) lepton. The \(\tau \) decay via “flavor” SU(2) interactions is just like the case of a sequential heavy lepton. The only place where the “fragrance” interaction contributes is in \(\tau \,\, \to \,\,e{\nu _e}{\nu _\tau }\). We thus find that \(\frac{{BR\left( {\tau \to {\nu _\tau }e{{\mathop \nu \limits^ - }_e}} \right)}}{{BR\left( {\tau \to {\nu _\tau }\mu \,\,\mathop {{{\mathop \nu \limits^ - }_\mu }}\limits^{} } \right)}}\,\, \ne \,\,1\) Google Scholar
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Copyright information

© Springer Science+Business Media New York 1979

Authors and Affiliations

  • T. C. Yang
    • 1
  1. 1.Deutsches Elektronen-Synchrotron DESYHamburgGermany

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