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

Czakon, Michal; Ferroglia, Andrea; Heymes, David; Mitov, Alexander; Pecjak, Ben D.; Scott, Darren J.; Wang, Xing; Yang, Li Lin

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


Authors

Michal Czakon

Andrea Ferroglia

David Heymes

Alexander Mitov

Darren J. Scott

Xing Wang

Li Lin Yang



Abstract

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 Mtt¯ and top-quark p T distributions in the boosted regime where fixed order calculations may become strongly dependent 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 kinematics-dependent 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 Mtt¯ 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.

Citation

Czakon, M., Ferroglia, A., Heymes, D., Mitov, A., Pecjak, B. D., Scott, D. J., Wang, X., & Yang, L. L. (2018). Resummation for (boosted) top-quark pair production at NNLO+NNLL′ in QCD. Journal of High Energy Physics, 2018(5), Article 149. https://doi.org/10.1007/jhep05%282018%29149

Journal Article Type Article
Acceptance Date May 14, 2018
Online Publication Date May 24, 2018
Publication Date May 24, 2018
Deposit Date Jun 7, 2018
Publicly Available Date Jun 8, 2018
Journal Journal of High Energy Physics
Print ISSN 1126-6708
Publisher Scuola Internazionale Superiore di Studi Avanzati (SISSA)
Peer Reviewed Peer Reviewed
Volume 2018
Issue 5
Article Number 149
DOI https://doi.org/10.1007/jhep05%282018%29149
Public URL https://durham-repository.worktribe.com/output/1324874

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Publisher Licence URL
http://creativecommons.org/licenses/by/4.0/

Copyright Statement
© The Authors. Article funded by SCOAP3. This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.






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