Hadronic $ZZ$, $W^- W^+$, and $W^{\pm} Z$ Production with QCD Corrections and Leptonic Decays

TL;DR

This work delivers next-to-leading-order QCD predictions for hadronic production of weak-boson pairs ZZ, WW, and WZ with leptonic decays at Tevatron and LHC energies. It extends prior on-shell results by incorporating leptonic decays via a narrow-width approximation and employing a Monte Carlo framework to apply realistic acceptance cuts and study exclusive 0-jet and 1-jet channels. The NLO corrections substantially enhance high-pT lepton spectra, especially at the LHC, and scale invariantly modify invariant-mass and angular distributions, driven largely by real qg-initiated emissions. The results improve precision for Standard Model tests and provide improved background modeling for new-physics searches, highlighting the growing importance of gluon-initiated contributions at higher collider energies.

Abstract

The processes $p p \rightarrow V_1 V_2 + X \rightarrow \ell_1 \bar \ell_1 \ell_2 \bar \ell_2 + X$, where $V_i = W^{\pm}$ or $Z$ and $\ell_i$ denotes a lepton, are calculated to ${\cal O}(α_s)$. Total and differential cross sections, with acceptance cuts imposed on the final state leptons, are given for the Tevatron and LHC center of mass energies. Inclusive and exclusive $0$-jet and $1$-jet cross sections are given. The transverse momenta spectra of the leptons are significantly enhanced at high $p_T^{}$ by the QCD radiative corrections, especially at the LHC energy. Invariant mass and angular distributions are scaled up in magnitude by the QCD radiative corrections, but are little changed in shape.

Figures (16)

• Figure 1: The dependance of the total NLO cross section for $p\,p \rightarrow ZZ + X \rightarrow e^- e^+ \mu^- \mu^+ + X$ at ${\sqrt{s}} = 14$ TeV on the soft and collinear cutoff parameters. In part a) the total NLO cross section is plotted versus the soft cutoff parameter $\delta_s$ for a fixed value of $\delta_c = 5 \times 10^{-4}$. In part b) the total NLO cross section is plotted versus the collinear cutoff parameter $\delta_c$ for a fixed value of $\delta_s = 10^{-2}$. The 4- and 5-body contributions are also shown. The cuts listed in Sec. IIIB have been imposed.
• Figure 2: The invariant mass of the four leptons in the process $p\,p \hbox{$^{^{(\!-\!)}}$} \to Z Z + X \to e^- e^+ \mu^- \mu^+ + X$. Parts a) and b) are for the Tevatron and LHC center of mass energies, respectively. The NLO (solid line) and LO (dashed line) cross sections are shown. The cuts listed in Sec. IIIB have been imposed.
• Figure 3: Same as Fig. \ref{['FIG:ZZ:M']} but for the inclusive lepton transverse momentum distribution. The 0-jet (dotted line) and 1-jet (dot-dashed line) exclusive cross sections are also shown.
• Figure 4: Same as Fig. \ref{['FIG:ZZ:M']} but for the inclusive lepton pseudorapidity distribution.
• Figure 5: Same as Fig. \ref{['FIG:ZZ:M']} but for the angular distribution of the $e^-$. The angle $\theta_{e^-}$ is measured in the parent $Z$-boson rest frame with respect to the parent $Z$-boson direction in the $ZZ$ rest frame.