Dimension-8 operators in W + W − production via gluon fusion

Abstract 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...

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Bibliographic Details
Main Authors: Daniel Gillies, Andrea Banfi, Adam Martin, Matthew A. Lim
Format: Article
Language:English
Published: SpringerOpen 2025-06-01
Series:Journal of High Energy Physics
Subjects:
Online Access:https://doi.org/10.1007/JHEP06(2025)111
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Summary:Abstract 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 t ¯ $$ t\overline{t} $$ 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.
ISSN:1029-8479