Jet-veto resummation at N3LLp + NNLO in boson production processes

In view of the persisting tension between theoretical predictions and the LHC data for the pp → $$ t\overline{t}W $$ t t ¯ W ± production process, we present the state-of-the-art full off-shell NLO QCD result for pp → $$ t\overline{t}W $$ t t ¯ W +j + X. We concentrate on the multi-lepton decay channel at the LHC with $$ \sqrt{s} $$ s = 13 TeV. In our calculation off-shell top quarks and gauge bosons are described by Breit-Wigner propagators, furthermore, double-, single- as well as non-resonant top-quark contributions along with all interference effects are consistently incorporated at the matrix element level. We present results for both integrated and differential fiducial cross sections for various renormalisation and factorisation scale settings and different PDF sets. With a fairly inclusive choice of cuts and regardless of the scale and PDF choice, non-flat differential $$ \mathcal{K} $$ K -factors are obtained for many observables that we have examined. Since from an experimental point of view, both processes pp → $$ t\overline{t}W $$ t t ¯ W ±j + X and pp → $$ t\overline{t}W $$ t t ¯ W ± + X consist of similar final states we investigate the effect of additional jet activity on the integrated and differential fiducial cross sections. For this purpose, the normalised differential distributions for pp → e+νeμ−$$ \overline{\nu} $$ ν ¯ μτ+ντ$$ b\overline{b} $$ b b ¯ j + X and pp → e+νeμ−$$ \overline{\nu} $$ ν ¯ μτ+ντ$$ b\overline{b} $$ b b ¯ + X are compared. The theoretical results for the latter process are also recalculated.

“…In order to reduce theoretical uncertainties, the latter would need to be resummed using approaches similar to those outlined in refs. [111][112][113][114][115][116][117].…”

Section: Additional Jet Activity In T Tw + Productionmentioning

confidence: 99%

NLO QCD predictions for off-shell $$ t\overline{t}W $$ production in association with a light jet at the LHC

Bi,

Kraus,

Reinartz

et al. 2023

Refining the GENEVA method for Higgs boson production via gluon fusion

Alioli

Billis

Broggio

et al. 2023

We describe a number of improvements to the Geneva method for matching NNLO calculations to parton shower programs. In particular, we detail changes to the resummed calculation used in the matching procedure, including disentangling the cross section dependence on factorisation and beam scales, and an improved treatment of timelike logarithms. We also discuss modifications in the implementation of the splitting functions which serve to make the resummed calculation differential in the higher multiplicity phase space. These changes improve the stability of the numerical cancellation of the nonsingular term at small values of the resolution parameter. As a case study, we consider the gluon-initiated Higgs boson production process gg → H. We validate the NNLO accuracy of our predictions against independent calculations, and compare our showered and hadronised results with recent data taken at the ATLAS and CMS experiments in the diphoton decay channel, finding good agreement.

Four top final states with NLO accuracy in perturbative QCD: 4 lepton channel

Dimitrakopoulos,

Worek

2024

Triggered by the observation of four top-quark production at the LHC by the ATLAS and CMS collaboration we report on the calculation of the next-to-leading order QCD corrections to the Standard Model process pp → $$ t\overline{t}t\overline{t} $$ t t ¯ t t ¯ in the 4ℓ top-quark decay channel. We take into account higher-order QCD effects in both the production and decays of the four top quarks. The latter effects are treated in the narrow width approximation, which preserves top-quark spin correlations throughout the calculation. We present results for two selected renormalisation and factorisation scale settings and three different PDF sets. Furthermore, we study the main theoretical uncertainties that are associated with the neglected higher-order terms in the perturbative expansion and with the parameterisation of the PDF sets. The results at the integrated and differential fiducial cross-section level are shown for the LHC Run III center-of-mass energy of $$ \sqrt{s} $$ s = 13.6 TeV. Our findings are particularly relevant for precise measurements of the four top-quark fiducial cross sections and for the modelling of top-quark decays at the LHC.