Measurement of the cross section for $W$-boson production in association with jets in $p\overline{p}$ collisions at $\sqrt{s}=1.96\mathrm{TeV}$

We present a measurement of the cross section for $W$-boson production in association with jets in $p\overline{p}$ collisions at $\sqrt{s}=1.96\mathrm{TeV}$. The analysis uses a data sample corresponding to an integrated luminosity of $320{\mathrm{pb}}^{-1}$ collected with the CDF II detector. $W$ bosons are identified in their electron decay channel and jets are reconstructed using a cone algorithm. For each $W+\ge n\mathrm{\text{−}}\mathrm{\text{jet}}$ sample ($n=1-4$) we measure the differential cross section $d\sigma (p\overline{p}\to W+\ge n\mathrm{\text{−}}\mathrm{\text{jet}})/d{E}_T^{\mathrm{nth}\mathrm{\text{−}}\mathrm{jet}}\times \mathcal{B}(W\to e\nu )$ with respect to the transverse energy $E_T$ of the $n$th-highest $E_T$ jet above 20 GeV, and the total cross section $\sigma (p\overline{p}\to W+\ge n\mathrm{\text{−}}\mathrm{\text{jet}};E_T^{\mathrm{nth}\mathrm{\text{−}}\mathrm{jet}}>25\mathrm{GeV})\times \mathcal{B}(W\to e\nu )$, for a restricted $W\to e\nu$ decay phase space. The cross sections, corrected for all detector effects, can be directly compared to particle level $W+\mathrm{\text{jet}}(\mathrm{s})$ predictions. We present here comparisons to leading order and next-to-leading order predictions.

Figure 1

The results of fitting the signal and background ${\mathrm{E̸}}_T$ template distributions to the data in the $W+\ge 1\mathrm{\text{−}}\mathrm{\text{jet}}$ sample before the final ${\mathrm{E̸}}_T$ cut is applied.

Figure 2

Top: the ratio of data to theory for the total cross sections ${\sigma }_n=\sigma (W\to e\nu +\ge n\mathrm{\text{−}}\mathrm{\text{jet}};E_T^{\mathrm{nth}\mathrm{\text{−}}\mathrm{jet}}>25\mathrm{GeV})$ as a function of the jet multiplicity $n$. Bottom: ${\sigma }_n/{\sigma }_{n-1}$ for data, MLM, SMPR, and MCFM. Inner (outer) error bars denote the statistical (total) uncertainties on the measured cross sections.

Figure 3

Ratio of the measured cross sections $d\sigma (W\to e\nu +\ge n\mathrm{\text{−}}\mathrm{\text{jet}})/d{E}_T^{\mathrm{nth}\mathrm{\text{−}}\mathrm{jet}}$ to the MLM, SMPR and MCFM predictions for $n=1$ (top), $n=2$ (middle) and $n=3$ (bottom). MCFM predictions are not available for $n=3$. Inner (outer) error bars denote the statistical (total) uncertainties on the measured cross sections.