Measurements of $WW$ and $WZ$ production in $W$ + jets final states in $p\bar p$ collisions

Abstract

We study $WW$ and $WZ$ production with $ℓνqq\ (ℓ=e,μ)$ final states using data collected by the D0 detector at the Fermilab Tevatron Collider corresponding to $4.3 \text{fb}^{−1}$ of integrated luminosity from $p\bar p$ collisions at $\sqrt s=1.96 \text{TeV}$. Assuming the ratio between the production cross sections $σ(WW)$ and $σ(WZ)$ as predicted by the standard model, we measure the total $WV (V=W,Z)$ cross section to be $σ(WV)=19.6^{+3.2}_{−3.0} \text{pb}$ and reject the background-only hypothesis at a level of 7.9 standard deviations. We also use $b$-jet discrimination to separate the $WZ$ component from the dominant $WW$ component. Simultaneously fitting $WW$ and $WZ$ contributions, we measure $σ(WW)=15.9^{+3.7}_{−3.2} \text{pb}$ and $σ(WZ)=3.3^{+4.1}_{−3.3} \text{pb}$, which is consistent with the standard model predictions.