Zgamma* production in e+e- interactions at sqrt{s} = 183 - 209 GeV

TL;DR

This paper reports measurements of Zgamma* production in electron-positron collisions at energies between 183 and 209 GeV, analyzing various four-fermion final states and confirming consistency with Standard Model predictions.

Contribution

It provides comprehensive measurements of Zgamma* production across multiple final states at high energies, extending previous analyses and validating Standard Model expectations.

Findings

Measured Zgamma* cross-sections align with Standard Model predictions.

Confirmed consistency of four-fermion final state production with theoretical models.

Provided total cross-section measurement for four-lepton final states.

Abstract

Measurements of Zgamma* production are presented using data collected by the DELPHI detector at centre-of-mass energies ranging from 183 to 209 GeV, corresponding to an integrated luminosity of about 667 pb^{-1}. The measurements cover a wide range of the possible final state four-fermion configurations: hadronic and leptonic (e+ e- q qbar, mu+ mu- q qbar, q qbar nu nubar), fully leptonic (l+ l- l'+ l'-) and fully hadronic final states (q qbar q qbar, with a low mass q qbar pair). Measurements of the Zgamma* cross-section for the various final states have been compared with the Standard Model expectations and found to be consistent within the errors. In addition, a total cross-section measurement of the l+ l- l'+ l'- cross-section is reported, and found to be in agreement with the prediction of the Standard Model.