Studies of W boson plus jets production in p\bar{p} collisions at sqrt(s)=1.96 TeV

TL;DR

This study delivers the most extensive Tevatron-era measurements of W(→eν)+n-jet production to date, detailing forty observables across up to four jets and correcting all results to particle level with regularized unfolding. It contrasts a broad set of theoretical predictions, including MC generators, all-order resummation (HEJ), and NLO pQCD (BlackHat-SHERPA), highlighting strengths and gaps in modeling QCD radiation, jet correlations, and jet multiplicity growth with HT. The work emphasizes the role of non-perturbative corrections and jet-veto dynamics, providing essential input for background modeling in VBF Higgs and other new-physics searches, and offering valuable data for tuning Monte Carlo event generators. Overall, the paper advances the precision and scope of W+n-jet studies and informs both SM tests and beyond-SM explorations at hadron colliders.

Abstract

We present a comprehensive analysis of inclusive W(\to eν)+n-jet (n\geq 1,2,3,4) production in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV at the Tevatron collider using a 3.7 fb^{-1} dataset collected by the D0 detector. Differential cross sections are presented as a function of the jet rapidities (y), lepton transverse momentum (p_T) and pseudorapidity (η), the scalar sum of the transverse energies of the W boson and all jets (H_T), leading dijet p_T and invariant mass, dijet rapidity separations for a variety of jet pairings for p_T-ordered and angular-ordered jets, dijet opening angle, dijet azimuthal angular separations for p_T-ordered and angular-ordered jets, and W boson transverse momentum. The mean number of jets in an event containing a W boson is measured as a function of H_T, and as a function of the rapidity separations between the two highest-p_T jets and between the most widely separated jets in rapidity. Finally, the probability for third-jet emission in events containing a W boson and at least two jets is studied by measuring the fraction of events in the inclusive W+2-jet sample that contain a third jet over a p_T threshold. The analysis employs a regularized singular value decomposition technique to accurately correct for detector effects and for the presence of backgrounds. The corrected data are compared to particle level next-to-leading order perturbative QCD predictions, predictions from all-order resummation approaches, and a variety of leading-order and matrix-element plus parton-shower event generators. Regions of the phase space where there is agreement or disagreement with the data are discussed for the different models tested.

Figures (65)

• Figure 1: Probability that a real electron candidate passing the loose electron identification requirements also passes the tight electron identification requirements. The shaded band represents the systematic uncertainty originating from the determination of the tight and loose electron efficiencies.
• Figure 2: (color online) Parametrized $\epsilon_\mathrm{MJ}$ (as defined in Eq. \ref{['eqn:eqcd5']}), used for the determination of the multijet component of reconstructed data distributions. $\epsilon_\mathrm{MJ}$ is parametrized as a function of electron $p_T$, electron pseudorapidity, inclusive jet multiplicity, and determined separately for Run IIa and Run IIb data. Fig. \ref{['fig:QCDFakeRates']}(a) shows the variation of $\epsilon_\mathrm{MJ}$ as a function of electron $p_T$ for three electron pseudorapidity intervals in Run IIb. Fig. \ref{['fig:QCDFakeRates']}(b) shows the variation of $\epsilon_\mathrm{MJ}$ with jet multiplicity for Run IIa and Run IIb data. Similar variations with respect to electron pseudorapidity and jet multiplicity are also observed for Run IIa.
• Figure 3: (color online) Uncorrected inclusive jet multiplicity distributions in the $W(\rightarrow e\nu)+\mathrm{jet}$ event selection. Hatched regions indicate normalization and shape uncertainties on the sum of the predicted contributions. All signal and background sources are derived from MC simulations with the exception of the QCD multijet component which is estimated from data.
• Figure 4: (color online) Uncorrected electron $p_T$ distribution for events with a $W$ boson candidate and one or more jets. Hatched regions indicate normalization and shape uncertainties on the predicted distributions.
• Figure 5: (color online) Uncorrected kinematic distributions of (a) leading jet $p_T$, (b) $W$ boson transverse mass for events with a $W$ boson candidate and one or more jets. Hatched regions indicate normalization and shape uncertainties on the predicted distributions.