Study of weak corrections to Drell-Yan, top-quark pair, and dijet production at high energies with MCFM

We construct predictions for top quark pair differential distributions at hadron colliders that combine state-of-the-art NNLO QCD calculations with double resummation at NNLL accuracy of threshold logarithms arising from soft gluon emissions and of small mass logarithms. This is the first time a resummed calculation at full NNLO+NNLL accuracy in QCD for a process with non-trivial color structure has been completed at the differential level. Of main interest to us is the stability of the M tt and top-quark p T distributions in the boosted regime where fixed order calculations may become strongly dependent JHEP05 (2018)149 on the choice of dynamic scales. With the help of numeric and analytic arguments we confirm that the choice for the factorization and renormalization scales advocated recently by some of the authors is indeed optimal. We further derive a set of optimized kinematicsdependent scales for the matching functions which appear in the resummed calculations. Our NNLO+NNLL prediction for the top-pair invariant mass is significantly less sensitive to the choice of factorization scale than the fixed order prediction, even at NNLO. Notably, the resummed and fixed order calculations are in nearly perfect agreement with each other in the full M tt range when the optimal dynamic scale is used. For the top-quark p T distribution the resummation performed here has less of an impact and instead we find that upgrading the matching with fixed-order from NLO+NNLL to NNLO+NNLL to be an important effect, a point to be kept in mind when using NLO-based Monte Carlo event generators to calculate this distribution.

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“…The transverse momentum distribution can be obtained by integrating overŷ in the range 20) while the range of p T is…”

Section: Jhep05(2018)149mentioning

confidence: 99%

Resummation for (boosted) top-quark pair production at NNLO+NNLL′ in QCD

Czakon

Ferroglia

Heymes

et al. 2018

J. High Energ. Phys.

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“…12 11 In a future release of NLOX, we will enable the user to generate process code on their own. 12 Interfaces to QCDLoop 2 [74] and LoopTools [75] are also available, but have not been thoroughly tested and are not delivered with NLOX util in the current release. In a future release of NLOX, including the capabilities to generate process code, NLOX util will further contain compatible versions of QGRAF and FORM.…”

Section: Components Of the Nlox Packagementioning

confidence: 99%

NLOX, a one-loop provider for Standard Model processes

Honeywell

Quackenbush

Reina

et al. 2020

Computer Physics Communications

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NLOX is a computer program for calculations in high-energy particle physics. It provides fully renormalized scattering matrix elements in the Standard Model of particle physics, up to one-loop accuracy for all possible coupling-power combinations in the strong and electroweak couplings, and for processes with up to six external particles. PROGRAM SUMMARYProgram Title: NLOX Licensing provisions: CC BY NC 3.0 Programming language: C++. Fortran interface available, and Fortran compiler required for dependencies. Required External Dependencies: QCDLoop 1.95, OneLOop 3.6 (available for download in utility tarball).NLOX provides fully renormalized QCD and EW one-loop corrections to SM processes at the squared-amplitude level, for all the possible QCD and EW mixed coupling-power combinations to a certain parton-level process up to one-loop accuracy, including the full mass dependence on initialand final-state particle masses. 5 Based on a Feynman-diagram approach, with optimized parsing and storing of recurrent building blocks,NLOX has been developed with the intent of providing oneloop QCD and EW corrections in the SM, while maintaining the flexibility to be further extended.The generation and evaluation of one-loop QCD and EW corrections of a large variety of 2 → 3 and 2 → 4 SM processes has been thoroughly tested and, with this paper, we are releasing a description of the code functionalities, archives of pre-generated process code, and the core code to evaluate and interface to the pre-generated process code.The conventions used in building renormalized one-loop QCD and EW amplitudes with NLOX are summarized in Sec. 2, while the NLOX workflow and code generation is briefly illustrated in Sec. 3. The TRed tensor-reduction library, an essential part of the NLOX package, is described in Sec. 4. Sec. 5 provides some practical instructions on how to download, install, and use the current public version of NLOX. Finally, in Sec. 6 we report benchmark results for selected processes. A brief summary is provided in Sec. 7. In the two appendices we collect more details about renormalization and tensor reduction in NLOX.

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“…Such matrix elements are defined as 26) JHEP06 (2018)013 where {|c I } is an orthogonal color basis. In accordance with [33], we choose the singlet-octet basis with 27) where a i is the color index of the i-th parton. We have compared the resulting NLO matrices with those (up to order ǫ 0 ) in [33] and find complete agreement.…”

Section: Jhep06(2018)013mentioning

confidence: 99%

The next-to-next-to-leading order soft function for top quark pair production

Wang

Yang

et al. 2018

J. High Energ. Phys.

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We present the first calculation of the next-to-next-to-leading order threshold soft function for top quark pair production at hadron colliders, with full velocity dependence of the massive top quarks. Our results are fully analytic, and can be entirely written in terms of generalized polylogarithms. The scale-dependence of our result coincides with the well-known two-loop anomalous dimension matrix including the three-parton correlations, which at the two-loop order only appear when more than one massive partons are involved in the scattering process. In the boosted limit, our result exhibits the expected factorization property of mass logarithms, which leads to a consistent extraction of the soft fragmentation function. The next-to-next-to-leading order soft function obtained in this paper is an important ingredient for threshold resummation at the next-to-next-to-nextto-leading logarithmic accuracy.

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Study of weak corrections to Drell-Yan, top-quark pair, and dijet production at high energies with MCFM

Cited by 40 publications

References 153 publications

Resummation for (boosted) top-quark pair production at NNLO+NNLL′ in QCD

Resummation for (boosted) top-quark pair production at NNLO+NNLL′ in QCD

NLOX, a one-loop provider for Standard Model processes

The next-to-next-to-leading order soft function for top quark pair production

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