Measurement of differential cross sections and W+/W− cross-section ratios for W boson production in association with jets at $$ \sqrt{s}=8 $$ TeV with the ATLAS detector

Abstract

This paper presents a measurement of the W boson production cross section and the W + /W − cross-section ratio, both in association with jets, in proton-proton collisions at $$ \sqrt{s}=8 $$ s = 8 TeV with the ATLAS experiment at the Large Hadron Collider. The measurement is performed in final states containing one electron and missing transverse momentum using data corresponding to an integrated luminosity of 20.2 fb−1. Differential cross sections for events with at least one or two jets are presented for a range of observables, including jet transverse momenta and rapidities, the scalar sum of transverse momenta of the visible particles and the missing transverse momentum in the event, and the transverse momentum of the W boson. For a subset of the observables, the differential cross sections of positively and negatively charged W bosons are measured separately. In the cross-section ratio of W + /W − the dominant systematic uncertainties cancel out, improving the measurement precision by up to a factor of nine. The observables and ratios selected for this paper provide valuable input for the up quark, down quark, and gluon parton distribution functions of the proton.

Measurement of the cross-section and charge asymmetry of W bosons produced in proton–proton collisions at $$\sqrt{s}=8~\text {TeV}$$ with the ATLAS detector

“…The uncertainties of the cross-sections are given in percent and those of the asymmetry as an absolute difference from the nominal. Table 4 are consistent, within about one standard deviation, with those measured using W boson decays in the electron channel in data at a centre-of-mass energy of 8 TeV [64].…”

Combined subleading high-energy logarithms and NLO accuracy for W production in association with multiple jets

“…[14] and figure 16 shows examples for W + 2-jet production at 8 TeV for distributions which appear in ref. [30]. We chose a central scale of µ r = µ f = H T /2.…”

“…This study has introduced two elements targeted at systematically improving the precision in regions away from asymptotic large energies compared to transverse scales: subleading corrections and matching of distributions to next-to-leading order. This section compares predictions to analyses by ATLAS of W +dijets at LHC energies of 7 TeV [14] and 8 TeV [30], where we focus on distributions where the new components lead to important improvements. The data was collected using slightly different cuts for the electron and muon channel, and then extrapolated to a "combined" selection contrasted with predictions generated with the following cuts listed in table 2.…”

“…Figure16. The NLO matching corrections for the following distributions presented in ref [30]. for inclusive W + + 2j production (blue, solid) and W − + 2j production (red, dashed): (a) transverse momentum of the leading jet, (b) transverse momentum of the second jet and (c) the transverse momentum of the W boson.…”

“…Figure18. Predictions for pp → (W → lν)+ ≥ 2j for LHC@8TeV, compared to ATLAS data from[30]. The original HEJ1 predictions are shown in blue, the pure NLO predictions are shown in red and the new HEJ2 predictions incorporating the methods of sections 3 and 4 are shown in green.…”