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Main Authors: Gillies, Daniel, Banfi, Andrea, Martin, Adam, Lim, Matthew A.
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2412.16020
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author Gillies, Daniel
Banfi, Andrea
Martin, Adam
Lim, Matthew A.
author_facet Gillies, Daniel
Banfi, Andrea
Martin, Adam
Lim, Matthew A.
contents We investigate the impact of dimension-8 operators on $W^+W^-$ production at the LHC for the incoming gluon-gluon channel. To this end, we have identified all dimension-8 CP-even operators contributing to the process in question, and computed the corresponding tree-level helicity amplitudes for fully-leptonic decays of the $W$ bosons. These are implemented in the program MCFM-RE, which automatically incorporates the effect of a jet-veto to reduce the otherwise overwhelming $t\bar t$ background. We find that, unless we break the hierarchy of the effective field theory (EFT), the interference of the dimension-8 operators with the Standard Model is negligible across the considered distributions. This justifies including the square of dimension-6 operators when performing EFT fits with this channel. We then present new constraints on CP-even and CP-odd dimension-6 operators within the EFT regime. Lastly, we postulate a scenario in which the hierarchy of the EFT is broken, justified by the strong constraints on dimension-6 operators from existing on-shell Higgs data. In this scenario, we discuss the constraints that can be reasonably set on CP-even dimension-8 operators with current and future data. We remark that the effect of the jet-veto on the ability to constrain new physics in the $W^+W^-$ channel is quite dramatic and must be properly taken into account.
format Preprint
id arxiv_https___arxiv_org_abs_2412_16020
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Dimension-8 operators in $W^+W^-$ production via gluon fusion
Gillies, Daniel
Banfi, Andrea
Martin, Adam
Lim, Matthew A.
High Energy Physics - Phenomenology
High Energy Physics - Experiment
We investigate the impact of dimension-8 operators on $W^+W^-$ production at the LHC for the incoming gluon-gluon channel. To this end, we have identified all dimension-8 CP-even operators contributing to the process in question, and computed the corresponding tree-level helicity amplitudes for fully-leptonic decays of the $W$ bosons. These are implemented in the program MCFM-RE, which automatically incorporates the effect of a jet-veto to reduce the otherwise overwhelming $t\bar t$ background. We find that, unless we break the hierarchy of the effective field theory (EFT), the interference of the dimension-8 operators with the Standard Model is negligible across the considered distributions. This justifies including the square of dimension-6 operators when performing EFT fits with this channel. We then present new constraints on CP-even and CP-odd dimension-6 operators within the EFT regime. Lastly, we postulate a scenario in which the hierarchy of the EFT is broken, justified by the strong constraints on dimension-6 operators from existing on-shell Higgs data. In this scenario, we discuss the constraints that can be reasonably set on CP-even dimension-8 operators with current and future data. We remark that the effect of the jet-veto on the ability to constrain new physics in the $W^+W^-$ channel is quite dramatic and must be properly taken into account.
title Dimension-8 operators in $W^+W^-$ production via gluon fusion
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
url https://arxiv.org/abs/2412.16020