Automation of antenna subtraction in colour space: gluonic processes

Chen, Xuan; Gehrmann, Thomas; Glover, E. W. N.; Huss, A.; Marcoli, Matteo

doi:10.48550/arxiv.2203.13531

Cited by 4 publications

(8 citation statements)

References 74 publications

(124 reference statements)

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“…In particular, thanks to targeted analytic expansions and a hybrid-precision approach [17,68], OpenLoops 2 guarantees a numerically stable evaluation of the realvirtual NNLO contributions W (1) 01 in the full phase space, including the regions where the unresolved radiation becomes highly soft or collinear. This high degree of stability in the IR regions was demonstrated through successful applications of OpenLoops 2 to state-of-the-art NNLO calculations based on local subtraction methods, such as in the recent NNLO calculations of pp → 3 jets [48,98].…”

Section: Nnlomentioning

confidence: 99%

Two-loop tensor integral coefficients in OpenLoops

Pozzorini

Schär

Zoller

2022

J. High Energ. Phys.

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We present a new and fully general algorithm for the automated construction of the integrands of two-loop scattering amplitudes. This is achieved through a generalisation of the open-loops method to two loops. The core of the algorithm consists of a numerical recursion, where the various building blocks of two-loop diagrams are connected to each other through process-independent operations that depend only on the Feynman rules of the model at hand. This recursion is implemented in terms of tensor coefficients that encode the polynomial dependence of loop numerators on the two independent loop momenta. The resulting coefficients are ready to be combined with corresponding tensor integrals to form scattering probability densities at two loops. To optimise CPU efficiency we have compared several algorithmic options identifying one that outperforms naive solutions by two orders of magnitude. This new algorithm is implemented in the OpenLoops framework in a fully automated way for two-loop QED and QCD corrections to any Standard Model process. The technical performance is discussed in detail for several 2 → 2 and 2 → 3 processes with up to order 105 two-loop diagrams. We find that the CPU cost scales linearly with the number of two-loop diagrams and is comparable to the cost of corresponding real-virtual ingredients in a NNLO calculation. This new algorithm constitutes a key building block for the construction of an automated generator of scattering amplitudes at two loops.

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Section: Nnlomentioning

confidence: 99%

Two-loop tensor integral coefficients in OpenLoops

Pozzorini

Schär

Zoller

2022

J. High Energ. Phys.

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“…The construction of the antenna subtraction terms will be described in detail in sections 3-5, where we focus in particular on the novel features of the subtraction terms that appear for the first time in pp → jj at full colour. These considerations will in particular be important in view of a future automated generation [34] of antenna subtraction terms for generic processes.…”

Section: Jhep10(2022)040 2 Relevant Matrix Elementsmentioning

confidence: 99%

“…As even higher multiplicity B-type matrix elements (e.g. |B 0 5 |) will also contain remaining interference terms like the R-term R 0 4 at subleading colour levels, the approach at amplitude level works the same way as for the six-parton B-type matrix element to construct the dσ S,a subtraction, and would be the preferred method, if one seeks to automate the construction of the subtraction terms [34].…”

Section: Single Soft Limitmentioning

confidence: 99%

“…One could then also unintegrate dσ T,a to obtain dσ S,a which subtracts all single unresolved limits of the corresponding matrix element which forms the double real correction ( C0 2 in this example). This approach from using the infrared singularity structure of the virtual corrections to construct the virtual subtraction term first, and subsequently unintegrating to obtain the real subtraction term [34] works well at NLO due to its relative simplicity.…”

Section: Jhep10(2022)040mentioning

confidence: 99%

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Antenna subtraction for jet production observables in full colour at NNLO

Chen

Gehrmann

Glover

et al. 2022

J. High Energ. Phys.

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We describe the details of the calculation of the full colour NNLO QCD corrections to jet production observables at the LHC with antenna subtraction. All relevant matrix elements for the process pp → jj at NNLO in full colour are colour-decomposed and given in a Nc and nf expansion, making identification of leading and subleading colour contributions transparent. The colour-ordered antenna subtraction method has previously successfully been used to construct the NNLO subtraction terms for processes with up to five partons or in the leading colour approximation. However, it is challenged by the more involved subleading colour structure of the squared matrix elements in processes with six or more partons. Here, we describe the methods needed to successfully construct the NNLO subtraction terms for the subleading colour contributions to dijet production within the antenna subtraction formalism.

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“…Improvement of theoretical precision is also a critical component of the progress in Particle Physics, as we enter the precision LHC era with the upcoming Run 3 and high-luminosity phases. We have seen spectacular breakthroughs in perturbative QCD calculations in the recent years, with a number of 2 → 3 processes computed at NNLO QCD accuracy for fully massless final states [15][16][17][18][19][20]. This success stems from both the advancements in the scattering amplitude computations and the developments of NNLO subtraction schemes.…”

Section: Introductionmentioning

confidence: 99%

NNLO QCD corrections to $Wb\bar{b}$ production at the LHC

Hartanto¹,

Poncelet²,

Popescu³

et al. 2022

Preprint

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We compute theoretical predictions for the production of a W-boson in association with a bottomquark pair at hadron colliders at next-to-next-to-leading order (NNLO) in QCD, including the leptonic decay of the W-boson, while treating the bottom quark as massless. This calculation constitutes the very first 2 → 3 process with a massive external particle to be studied at such a perturbative order. We derive an analytic expression for the required two-loop five-particle amplitudes in the leading colour approximation employing finite-field methods. Numerical results for the cross section and differential distributions are presented for the Large Hadron Collider at √ s = 8 TeV. We observe an improvement of the perturbative convergence for the inclusive case and for the prediction with a jet veto upon the inclusion of the NNLO QCD corrections.

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Automation of antenna subtraction in colour space: gluonic processes

Cited by 4 publications

References 74 publications

Two-loop tensor integral coefficients in OpenLoops

Two-loop tensor integral coefficients in OpenLoops

Antenna subtraction for jet production observables in full colour at NNLO

NNLO QCD corrections to $Wb\bar{b}$ production at the LHC

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