Limits on anomalous trilinear gauge couplings from $WW\to e^{+}{e}^{-}$, $WW\to e^{\pm }{\mu }^{\mp }$, and $WW\to {\mu }^{+}{\mu }^{-}$ events from $p\overline{p}$ collisions at $\sqrt{s}=1.96\mathrm{TeV}$

Limits are set on anomalous $WW\gamma$ and $WWZ$ trilinear gauge couplings using $W^{+}{W}^{-}\to e^{+}{\nu }_e{e}^{-}{\overline{\nu }}_e$, $W^{+}{W}^{-}\to e^{\pm }{\nu }_e{\mu }^{\mp }{\nu }_{\mu }$, and $W^{+}{W}^{-}\to {\mu }^{+}{\nu }_{\mu }{\mu }^{-}{\overline{\nu }}_{\mu }$ events. The data set was collected by the Run II D0 detector at the Fermilab Tevatron Collider and corresponds to approximately $250{\mathrm{pb}}^{-1}$ of integrated luminosity at $\sqrt{s}=1.96\mathrm{TeV}$. Under the assumption that the $WW\gamma$ couplings are equal to the $WWZ$ couplings and using a form factor scale of $\Lambda =2.0\mathrm{TeV}$, the combined 95% C.L. one-dimensional coupling limits from all three channels are $-0.32<\Delta \kappa <0.45$ and $-0.29<\lambda <0.30$.

Figure 1

Leading lepton $p_T$ distributions for data (points), SM MC (solid line), and two anomalous coupling MC scenarios (dashed lines), from the $WW\to e^{\pm }{\mu }^{\mp }$ channel, binned as used to calculate likelihood.

Figure 2

One- and two-dimensional 95% C.L. limits when $WWZ$ couplings are equal to $WW\gamma$ couplings, at $\Lambda =2.0\mathrm{TeV}$. The bold curve is the unitarity limit, the inner curve is the two-dimensional 95% C.L. contour, and the ticks along the axes are the one-dimensional 95% C.L. limits.

Figure 3

One- and two-dimensional 95% C.L. limits for (a) $WW\gamma =WWZ$ at $\Lambda =1.5\mathrm{TeV}$, (b) HISZ at $\Lambda =1.5\mathrm{TeV}$, (c) SM $WW\gamma$ at $\Lambda =2.0\mathrm{TeV}$, and (d) SM $WWZ$ at $\Lambda =1.0\mathrm{TeV}$. The bold curve is the unitarity limit (where it fits within the plot boundaries), the inner curve is the two-dimensional 95% C.L. contour, and the ticks along the axes are the one-dimensional 95% C.L. limits.