Z Z production in gluon fusion at NLO matched to parton shower

We consider QCD radiative corrections to the production of four charged leptons in hadron collisions. We present the computation of the next-to-leading order QCD corrections to the loop-induced gluon fusion contribution. Our predictions include, for the first time, also the quark-gluon partonic channels. The computed corrections, which are formally of O(α 3 S ), turn out to increase the loop-induced Born-level result by an amount ranging from 75% to 71% as √ s ranges from 8 to 13 TeV. We combine our result with state-of-the-art NNLO corrections to the quark annihilation channel, and present updated predictions for fiducial cross sections and distributions for this process.

Section: Introductionmentioning

confidence: 90%

Section: Calculation Within the Matrix Frameworkmentioning

confidence: 99%

Section: Validationmentioning

confidence: 99%

Section: Validationmentioning

confidence: 99%

See 2 more Smart Citations

ZZ production at the LHC: NLO QCD corrections to the loop-induced gluon fusion channel

Grazzini

Kallweit

Wiesemann

et al. 2019

“…The contribution of this gg → V V channel to chargeneutral final states is quite sizeable. It has been computed to one order higher in perturbation theory [30,32,[80][81][82][83][84], which is assumed to be the dominant O(α 3 S ) correction to these processes. In the combination of NNLO QCD and NLO EW corrections presented in this paper, the gg → V V channels are included at O(α 2 S ) as part of the NNLO QCD corrections, i.e.…”

Section: Higher-order Qcd Correctionsmentioning

confidence: 99%

NNLO QCD + NLO EW with Matrix+OpenLoops: precise predictions for vector-boson pair production

Grazzini

Kallweit

Lindert

et al. 2020

We present the first combination of NNLO QCD and NLO EW corrections for vectorboson pair production at the LHC. We consider all final states with two, three and four charged leptons, including resonant and non-resonant diagrams, spin correlations and off-shell effects. Detailed predictions are discussed for three representative channels corresponding to W + W − , W ± Z and ZZ production. Both QCD and EW corrections are very significant, and the details of their combination can play a crucial role to achieve the level of precision demanded by experimental analyses. In this context we point out nontrivial issues that arise at large transverse momenta, where the EW corrections are strongly enhanced by Sudakov logarithms and the QCD corrections can feature so-called giant K-factors. Our calculations have been carried out in the Matrix+OpenLoops framework and can be extended to the production of an arbitrary colour singlet in hadronic collisions, provided that the required two-loop QCD amplitudes are available. Combined NNLO QCD and NLO EW predictions for the full set of massive diboson processes will be made publicly available in the next release of Matrix and will be instrumental in advancing precision diboson studies and new-physics searches at the LHC and future hadron colliders.

Next-to-leading-order electroweak corrections to the production of four charged leptons at the LHC

Biedermann

Denner

Dittmaier

et al. 2017

We present a state-of-the-art calculation of the next-to-leading-order electroweak corrections to ZZ production, including the leptonic decays of the Z bosons into µ + µ − e + e − or µ + µ − µ + µ − final states. We use complete leading-order and next-to-leadingorder matrix elements for four-lepton production, including contributions of virtual photons and all off-shell effects of Z bosons, where the finite Z-boson width is taken into account using the complex-mass scheme. The matrix elements are implemented into Monte Carlo programs allowing for the evaluation of arbitrary differential distributions. We present integrated and differential cross sections for the LHC at 13 TeV both for an inclusive setup where only lepton identification cuts are applied, and for a setup motivated by Higgsboson analyses in the four-lepton decay channel. The electroweak corrections are divided into photonic and purely weak contributions. The former show the well-known pronounced tails near kinematical thresholds and resonances; the latter are generically at the level of ∼ −5% and reach several −10% in the high-energy tails of distributions. Comparing the results for µ + µ − e + e − and µ + µ − µ + µ − final states, we find significant differences mainly in distributions that are sensitive to the µ + µ − pairing in the µ + µ − µ + µ − final state. Differences between µ + µ − e + e − and µ + µ − µ + µ − channels due to interferences of equal-flavour leptons in the final state can reach up to 10% in off-shell-sensitive regions. Contributions induced by incoming photons, i.e. photon-photon and quark-photon channels, are included, but turn out to be phenomenologically unimportant.