Measurement of the p\bar{p}\to WZ + X cross section at \sqrt{s}=1.96 TeV and limits on WWZ trilinear gauge couplings

TL;DR

This paper reports the measurement of the WZ production cross section in proton-antiproton collisions at 1.96 TeV and sets new limits on anomalous WWZ gauge couplings using data from the D0 experiment.

Contribution

First measurement of the WZ production cross section at Tevatron energies and the most restrictive limits on WWZ trilinear gauge couplings to date.

Findings

Measured cross section: 2.7^{+1.7}_{-1.3} pb.

Observed 13 candidate events with expected background of 4.5 events.

Set limits on WWZ couplings: -0.17 to 0.21 for λ_Z.

Abstract

We present measurements of the process $p\bar{p} \to WZ+X \to \ell^{\prime} \nu_{\ell^{\prime}} \ell \bar{\ell}$ at $\sqrt{s}=1.96$ TeV, where $\ell$ and $\ell^{\prime}$ are electrons or muons. Using 1 fb$^{-1}$ of data from the D0 experiment, we observe 13 candidates with an expected background of $4.5\pm0.6$ events and measure a cross section $\sigma(WZ)=2.7^{+1.7}_{-1.3}$ pb. From the number of observed events and the $Z$ boson transverse momentum distribution, we limit the trilinear $WWZ$ gauge couplings to $-0.17 \le \lambda_Z \le 0.21$ $(\Delta \kappa_Z = 0)$ at the 95% C.L. for a form factor scale $\Lambda=2$ TeV. Further, assuming that $\Delta g^Z_1 = \Delta\kappa_Z$, we find $-0.12 \le \Delta\kappa_Z \le 0.29$ $(\lambda_Z=0)$ at the 95% C.L. These are the most restrictive limits on the $WWZ$ couplings available to date.