Skip to main content

Research Repository

Advanced Search

New NLOPS predictions for tt¯+btt¯+b -jet production at the LHC

Ježo, Tomáš; Lindert, Jonas M.; Moretti, Niccolo; Pozzorini, Stefano

New NLOPS predictions for tt¯+btt¯+b -jet production at the LHC Thumbnail


Authors

Tomáš Ježo

Jonas M. Lindert

Niccolo Moretti

Stefano Pozzorini



Abstract

Measurements of tt¯H production in the H→bb¯ channel depend in a critical way on the theoretical uncertainty associated with the irreducible tt¯+b -jet background. In this paper, analysing the various topologies that account for b-jet production in association with a tt¯ pair, we demonstrate that the process at hand is largely driven by final-state g→bb¯ splittings. We also show that in five-flavour simulations based on tt¯+ multi-jet merging, b-jet production is mostly driven by the parton shower, while matrix elements play only a marginal role in the description of g→bb¯ splittings. Based on these observations we advocate the use of NLOPS simulations of pp→tt¯bb¯ in the four-flavour scheme, and we present a new Powheg generator of this kind. Predictions and uncertainties for tt¯+b -jet observables at the 13 TeV LHC are presented both for the case of stable top quarks and with spin-correlated top decays. Besides QCD scale variations we consider also theoretical uncertainties related to the Powheg matching method and to the parton shower modelling, with emphasis on g→bb¯ splittings. In general, matching and shower uncertainties turn out to be remarkably small. This is confirmed also by a consistent comparison against Sherpa+OpenLoops.

Citation

Ježo, T., Lindert, J. M., Moretti, N., & Pozzorini, S. (2018). New NLOPS predictions for tt¯+btt¯+b -jet production at the LHC. The European Physical Journal C, 78(6), Article 502. https://doi.org/10.1140/epjc/s10052-018-5956-0

Journal Article Type Article
Acceptance Date May 31, 2018
Online Publication Date Jun 18, 2018
Publication Date Jun 18, 2018
Deposit Date Jun 28, 2018
Publicly Available Date Jun 28, 2018
Journal European Physical Journal C: Particles and Fields
Print ISSN 1434-6044
Electronic ISSN 1434-6052
Publisher SpringerOpen
Peer Reviewed Peer Reviewed
Volume 78
Issue 6
Article Number 502
DOI https://doi.org/10.1140/epjc/s10052-018-5956-0
Public URL https://durham-repository.worktribe.com/output/1356069

Files

Published Journal Article (3.5 Mb)
PDF

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

Copyright Statement
© The Author(s) 2018.
This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.






You might also like



Downloadable Citations