Measurement of the $WW$ Production Cross Section with Dilepton Final States in $p\overline{p}$ Collisions at $\sqrt{s}=1.96\mathrm{TeV}$ and Limits on Anomalous Trilinear Gauge Couplings

We provide the most precise measurement of the $WW$ production cross section in $p\overline{p}$ collisions to date at a center of mass energy of 1.96 TeV, and set limits on the associated trilinear gauge couplings. The $WW\to \ell \nu {\ell }^{\prime }\nu$ ($\ell$, ${\ell }^{\prime }=e$, $\mu$) decay channels are analyzed in $1{\mathrm{fb}}^{-1}$ of data collected by the D0 detector at the Fermilab Tevatron Collider. The measured cross section is $\sigma (p\overline{p}\to WW)=11.5\pm 2.1(\mathrm{stat}+\mathrm{syst})\pm 0.7(\mathrm{lumi})\mathrm{pb}$. One- and two-dimensional 95% C.L. limits on trilinear gauge couplings are provided.

Figure 1

Distributions of the (a) leading and (b) trailing lepton $p_T$ after final selection, combined for all channels ($ee+e\mu +\mu \mu$). Data are compared to estimated signal, $\sigma (WW)=12\mathrm{pb}$, and background sum.

Figure 2

One and two-dimensional 95% C.L. limits when enforcing $SU(2{)}_L\otimes U(1{)}_Y$ symmetry at $\Lambda =2\mathrm{TeV}$, for (a) $\Delta {\kappa }_{\gamma }$ vs ${\lambda }_{\gamma }$, (b) $\Delta {\kappa }_{\gamma }$ vs $\Delta g_1^Z$, and (c) ${\lambda }_{\gamma }$ vs $\Delta g_1^Z$, each when the third free coupling is set to its SM value; limits when enforcing the $WW\gamma =WWZ$ constraints are shown in (d). The curve represents the two-dimensional 95% C.L. contour and the ticks along the axes represent the one-dimensional 95% C.L. limits. An asterisk (*) marks the point with the highest likelihood in the two-dimensional plane.