Il Nuovo Cimento A (1965-1970)

, Volume 106, Issue 10, pp 1309–1320 | Cite as

Are grand unified theories ruled out by the LEP data?

  • A. Galli


We consider the breaking of the grand unified groupsE6 andSO(10) to the standard model group through several extended gauge group hierarchy chains. Some general rules for the extended gauge group hierarchy models are discussed. Applications of these rules are considered to find a classification of all gauge group hierarchies which yield unification in agreement with the LEP data of the gauge coupling constants at the scaleMZ. This classification shows us that many popular models which predict extra Z-bosons are ruled out.

PACS 12.90

Miscellaneous theoretical ideas and models 

PACS 11.90

Other topics in general field and particle theory 


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Copyright information

© Società Italiana di Fisica 1993

Authors and Affiliations

  • A. Galli
    • 1
  1. 1.Paul Scherrer InstituteVilligen PSISwitzerland

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