Measurement of the pp¯→WZ+X cross section at s=1.96 TeV and limits on WWZ trilinear gauge couplings

Le résumé fourni par la source

We present measurements of the process $p\overline{p}\ensuremath{\rightarrow}WZ+X\ensuremath{\rightarrow}{\ensuremath{\ell}}^{\ensuremath{'}}{\ensuremath{\nu}}_{{\ensuremath{\ell}}^{\ensuremath{'}}}\ensuremath{\ell}\overline{\ensuremath{\ell}}$ at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$, where $\ensuremath{\ell}$ and ${\ensuremath{\ell}}^{\ensuremath{'}}$ are electrons or muons. Using $1\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data from the D0 experiment, we observe 13 candidates with an expected background of $4.5\ifmmode\pm\else\textpm\fi{}0.6$ events and measure a cross section $\ensuremath{\sigma}(WZ)={2.7}_{\ensuremath{-}1.3}^{+1.7}\text{ }\text{ }\mathrm{pb}$. From the number of observed events and the $Z$ boson transverse momentum distribution, we limit the trilinear $WWZ$ gauge couplings to $\ensuremath{-}0.17\ensuremath{\le}{\ensuremath{\lambda}}_{Z}\ensuremath{\le}0.21(\ensuremath{\Delta}{\ensuremath{\kappa}}_{Z}=0)$ at the 95% C.L. for a form factor scale $\ensuremath{\Lambda}=2\text{ }\text{ }\mathrm{TeV}$. Further, assuming that $\ensuremath{\Delta}{g}_{1}^{Z}=\ensuremath{\Delta}{\ensuremath{\kappa}}_{Z}$, we find $\ensuremath{-}0.12\ensuremath{\le}\ensuremath{\Delta}{\ensuremath{\kappa}}_{Z}\ensuremath{\le}0.29({\ensuremath{\lambda}}_{Z}=0)$ at the 95% C.L. These are the most restrictive limits on the $WWZ$ couplings available to date.

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