Indications for an extra neutral gauge boson in electroweak precision data

Jens Erler, Paul Langacker

Research output: Contribution to journalArticlepeer-review

175 Scopus citations


A new analysis of the hadronic peak cross section at LEP 1 implies a small amount of missing invisible width in Z decays, while the effective weak charge in atomic parity violation has been determined recently to 0.6% accuracy, indicating a significantly negative S parameter. As a consequence of these two deviations, the data are described well if the presence of an additional Z' boson, such as predicted in Grand Unified Theories, is assumed. Moreover, the data are now rich enough to study an arbitrary extra Z' boson and to determine its couplings in a model independent way. An excellent best fit to the data is obtained in this case, suggesting the possibility of a family non-universal Z' with properties similar to ones predicted in a class of superstring theories.

Original languageEnglish (US)
Pages (from-to)212-215
Number of pages4
JournalPhysical review letters
Issue number2
StatePublished - 2000

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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