Measurement of the e+e- -> ZZ production cross-section at centre-of-mass energies of 183 and 189GeV

TL;DR

This paper reports measurements of the e+e- -> ZZ production cross-section at energies of 183 and 189 GeV using the ALEPH detector, confirming consistency with Standard Model predictions.

Contribution

First measurement of the ZZ production cross-section at these energies covering all visible final states using ALEPH data.

Findings

Measured cross-sections are consistent with Standard Model expectations.

Cross-section at 182.7 GeV: 0.11 +- 0.16 (stat.) +- 0.04 (syst.) pb.

Cross-section at 188.6 GeV: 0.67 +- 0.13 (stat.) +- 0.04 (syst.) pb.

Abstract

The ee -> ZZ cross section at sqrt(s)=182.7 and 188.6 GeV has been measured using the ALEPH detector. The analysis covers all of the visible ZZ final states and yields cross section measurements of sigma_ZZ(182.7 GeV) = 0.11 +- (0.16,0.11) (stat.) +- 0.04 (syst.) pb and sigma_ZZ(188.6 GeV) = 0.67 +- 0.13 (stat.) +- 0.04 (syst.) pb consistent with the Standard Model expectations.