Four-lepton production in gluon fusion at NLO matched to parton showers

Abstract

We present a calculation of the next-to-leading order (NLO) QCD corrections to gluon-induced electroweak gauge boson pair production, $$gg \rightarrow ZZ$$ g g → Z Z and $$gg \rightarrow W^+W^-$$ g g → W + W - , matched to the parton shower in the approach. The calculation consistently incorporates the continuum background, the Higgs-mediated $$gg\rightarrow H^* \rightarrow VV$$ g g → H ∗ → V V process, and their interference. We consider leptonic decay modes of the vector bosons and retain offshell and non-resonant contributions. The processes considered are loop-induced at leading order and thus contain two-loop virtual contributions as well as loop-squared real contributions. Parton-shower effects are found to be marginal in inclusive observables and quite sizeable in observables that are exclusive in additional jet radiation. The Monte Carlo generator presented here allows for realistic experimental effects to be incorporated in state-of-the-art precision analyses of diboson production and of the Higgs boson in the offshell regime.

Off-shell Higgs production at the LHC as a probe of the trilinear Higgs coupling

“…at the next-to-next-to-leading order (NNLO) in QCD. State-of-the-art predictions for fourlepton production at the LHC, obtained at NNLO in QCD [63][64][65][66] and matched to parton shower [67,68], are reaching an impressive accuracy of O(2%) for inclusive cross sections and O(5%) in the case of differential distributions.…”

“…While a precision phenomenological study of ZZ production a la [63][64][65][66][67][68][69][70] including the O(λ) corrections associated to the insertions of O 6 is beyond the scope of this work, we wish to assess at least approximately the impact of higher-order QCD corrections on our analysis, in particular the effects on the D S spectra. To this purpose we proceed in the following way.…”

Probing Higgs portals with matrix-element based kinematic discriminants in $ZZ \to 4 \ell$ production

“…Given the limitations (cf. [51,63,64]) of the state-of-the-art SM predictions of pp → ZZ production for kinematic configurations above the two topquark threshold, achieving the assumed systematic uncertainties of ∆ = 8% and ∆ = 4% is certainly more challenging in the case of the m 4 distribution. The steady progress of perturbative QCD calculations, in particular the exact evaluations of the two-loop on-shell amplitudes for gg → ZZ involving top quarks [65,66] makes us, however, confident that systematic uncertainties in the ballpark of 10% or below are attainable till 3 ab −1 of data are collected at the HL-LHC.…”

W+W− production at NNLO+PS with MINNLOPS

“…In our calculation and throughout this paper we omit the loop-induced gluon-fusion contribution, as it is already known to higher-order in QCD [123,124] and can be evaluated with known tools at LO+PS, such as the gg2ww generator [161,162] used by ATLAS and CMS. In fact, also a NLO+PS generator was presented for this process recently [163] in the Powheg-Box-Res framework. Finally, we define W + W − signal events free of top-quark contamination by exploiting the four-flavour scheme with massive bottom quarks and drop all contributions with final-state bottom quarks.…”