Machine-enhanced CP-asymmetries in the electroweak sector

Clarke Hall, N., Criddle, I., Crossland, A., Englert, C. , Forbes, P., Hankache, R. and Pilkington, A. D. (2023) Machine-enhanced CP-asymmetries in the electroweak sector. Physical Review D, 107(1), 016008. (doi: 10.1103/PhysRevD.107.016008)

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The violation of charge conjugation ( C ) and parity ( P ) symmetries are a requirement for the observed dominance of matter over antimatter in the Universe. As an established effect of beyond the Standard Model physics, this could point towards additional C P violation in the Higgs-gauge sector. The phenomenological footprint of the associated anomalous couplings can be small, and designing measurement strategies with the highest sensitivity is therefore of the utmost importance in order to maximize the discovery potential of the Large Hadron Collider. There are, however, very few measurements of C P -sensitive observables in processes that probe the weak-boson self-interactions. In this article, we study the sensitivity to new sources of C P violation for a range of experimentally accessible electroweak processes, including W γ production, W W production via photon fusion, electroweak Z j j production, electroweak Z Z j j production, and electroweak W ± W ± j j production. We study simple angular observables as well C P -sensitive observables constructed using the outputs of machine-learning algorithms. We find that the machine-learning-constructed C P -sensitive observables improve the sensitivity to C P -violating effects by up to a factor of five, depending on the process. We also find that inclusive W γ and electroweak Z j j production have the potential to set the best possible constraints on certain C P -odd operators in the Higgs-gauge sector of dimension-six effective field theories.

Item Type:Articles
Additional Information:C. E. is supported by the STFC under Grant No. ST/ T000945/1, by the Leverhulme Trust under Grant No. RPG-2021-031, and the IPPP Associateship Scheme. A. D. P. is supported by the Royal Society and STFC under Grants No. UF160396, No. ST/S000925/1, and No. ST/ W000601/1. R. H. and A. D. P. are supported by the Leverhulme Trust under Grant No. RPG-2020-004.
Glasgow Author(s) Enlighten ID:Englert, Professor Christoph
Authors: Clarke Hall, N., Criddle, I., Crossland, A., Englert, C., Forbes, P., Hankache, R., and Pilkington, A. D.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Physical Review D
Publisher:American Physical Society
ISSN (Online):2470-0029
Published Online:18 January 2023
Copyright Holders:Copyright © 2023 The American Physical Society
First Published:First published in Physical Review D 107(1): 016008
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
306883Research in Particle Physics Theory - Phenomenology from lattice QCD and collider physicsChristine DaviesScience and Technology Facilities Council (STFC)ST/T000945/1P&S - Physics & Astronomy
311961BSM interference effects in Higgs and Top-associated final states.Christoph EnglertLeverhulme Trust (LEVERHUL)RPG-2021-031P&S - Physics & Astronomy