Resummation for (boosted) top-quark pair production at NNLO+NNLL′ in QCD
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...
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doaj-0b58968d3aef458390140cb8f4dcea002020-11-24T22:10:52ZengSpringerOpenJournal of High Energy Physics1029-84792018-05-012018514510.1007/JHEP05(2018)149Resummation for (boosted) top-quark pair production at NNLO+NNLL′ in QCDMichal Czakon0Andrea Ferroglia1David Heymes2Alexander Mitov3Ben D. Pecjak4Darren J. Scott5Xing Wang6Li Lin Yang7Institut für Theoretische Teilchenphysik und Kosmologie, RWTH Aachen UniversityNew York City College of TechnologyCavendish Laboratory, University of CambridgeCavendish Laboratory, University of CambridgeInstitute for Particle Physics Phenomenology, University of DurhamInstitute for Theoretical Physics, University of AmsterdamSchool of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversitySchool of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityAbstract 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¯ $$ {M}_{t\overline{t}} $$ 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¯ $$ {M}_{t\overline{t}} $$ 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.http://link.springer.com/article/10.1007/JHEP05(2018)149QCD Phenomenology |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Michal Czakon Andrea Ferroglia David Heymes Alexander Mitov Ben D. Pecjak Darren J. Scott Xing Wang Li Lin Yang |
spellingShingle |
Michal Czakon Andrea Ferroglia David Heymes Alexander Mitov Ben D. Pecjak Darren J. Scott Xing Wang Li Lin Yang Resummation for (boosted) top-quark pair production at NNLO+NNLL′ in QCD Journal of High Energy Physics QCD Phenomenology |
author_facet |
Michal Czakon Andrea Ferroglia David Heymes Alexander Mitov Ben D. Pecjak Darren J. Scott Xing Wang Li Lin Yang |
author_sort |
Michal Czakon |
title |
Resummation for (boosted) top-quark pair production at NNLO+NNLL′ in QCD |
title_short |
Resummation for (boosted) top-quark pair production at NNLO+NNLL′ in QCD |
title_full |
Resummation for (boosted) top-quark pair production at NNLO+NNLL′ in QCD |
title_fullStr |
Resummation for (boosted) top-quark pair production at NNLO+NNLL′ in QCD |
title_full_unstemmed |
Resummation for (boosted) top-quark pair production at NNLO+NNLL′ in QCD |
title_sort |
resummation for (boosted) top-quark pair production at nnlo+nnll′ in qcd |
publisher |
SpringerOpen |
series |
Journal of High Energy Physics |
issn |
1029-8479 |
publishDate |
2018-05-01 |
description |
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¯ $$ {M}_{t\overline{t}} $$ 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¯ $$ {M}_{t\overline{t}} $$ 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. |
topic |
QCD Phenomenology |
url |
http://link.springer.com/article/10.1007/JHEP05(2018)149 |
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