Abstract

The detailed study of vector-boson pair production processes at the LHC will lead to a better understanding of electroweak physics. As pointed out before, a consistent inclusion of higher-order electroweak effects in the analysis of corresponding experimental data may be crucial to properly predict the relevant phenomenological features of these important reactions. Those contributions lead to dramatic distortions of invariant-mass and angular distributions at high energies, but may also significantly affect the cross section near threshold, as is the case e.g. for Z-pairs. For this reason, we present an analysis of the next-to-leading-order electroweak corrections to WW, WZ, and ZZ production at the LHC, taking into account mass effects as well as leptonic decays. Hence, our predictions are valid in the whole kinematic reach of the LHC and, moreover, respect the spin correlations of the leptonic decay products at next-to-leading-order accuracy. Starting from these fixed-order results, a simple and straightforward method is motivated to combine the electroweak corrections with state-of-the-art Monte Carlo predictions, focusing on a meaningful combination of higher-order electroweak and QCD effects. To illustrate our approach, the electroweak corrections are implemented in the HERWIG++ generator, and their phenomenological effects within a QCD environment are studied explicitly.

Highlights

  • Given the experimental accuracy already achieved by LHC experiments in the 7- and 8-TeV runs [1,2,3,4,5,6], at least the next-to-leading-order (NLO) QCD corrections are mandatory for a robust prediction of V -boson pair-production processes

  • Approximate NNLO results for W+Z and WW production have been provided for high-transverse-momentum observables [15,16], as well as for WW production in the threshold limit [17]

  • The corresponding EW corrections have been computed in Ref. [20] in the high-energy limit, including leptonic decays and off-shell effects

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Summary

Introduction

Given the experimental accuracy already achieved by LHC experiments in the 7- and 8-TeV runs [1,2,3,4,5,6], at least the next-to-leading-order (NLO) QCD corrections are mandatory for a robust prediction of V -boson pair-production processes (for selected references see Refs. [7,8]). Expecting first results for the full NNLO QCD corrections to W-pair production in the near future [24], a natural step would be the combination of EW and QCD predictions at O(αsα) accuracy on a consistent theory basis, as has been partially done for the Drell–Yan process [25,26,27,28,29,30,31,32,33] already, where important contributions from mixed EW×QCD corrections in the resonance region were found [34] These multiscale two-loop calculations are beyond feasibility at present.

Electroweak corrections
On-shell gauge-boson pair productions
K -factors for the electroweak corrections
Gauge-boson polarization and four-lepton production
Electroweak and QCD corrections: combined
Results from
Summary and conclusions
Full Text
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