Lepton angular distribution of Z boson production and jet discrimination

Jen Chieh Peng, Wen Chen Chang, Randall Evan McClellan, Oleg Teryaev

Research output: Contribution to journalArticlepeer-review


High precision data of lepton angular distributions in inclusive Z boson production, reported by the CMS and ATLAS Collaborations, showed pronounced transverse momentum (qT) dependencies of the A0 and A2 coefficients. Violation of the Lam-Tung relation, A0=A2, was also found. An intuitive understanding of these results can be obtained from a geometric approach. We predict that A0 and A2 for Z plus single gluon-jet events are very different from that of Z plus single quark-jet events, allowing a new experimental tool for checking various algorithms which attempt to discriminate quark jets from gluon jets. We also predict that the Lam-Tung relation would be more severely violated for the Z plus multiple-jet data than what has been observed so far for inclusive Z production data. These predictions can be readily tested using existing LHC data.

Original languageEnglish (US)
Article number134895
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
StatePublished - Oct 10 2019


  • Jet discrimination
  • Z decay angular distribution
  • Z-boson production

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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