CP violation at ATLAS in effective field theory

Das Bakshi, S., Chakrabortty, J., Englert, C. , Spannowsky, M. and Stylianou, P. (2021) CP violation at ATLAS in effective field theory. Physical Review D, 103(5), 055008. (doi: 10.1103/PhysRevD.103.055008)

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Abstract

CP violation beyond the Standard Model (SM) is a crucial missing piece for explaining the observed matter-antimatter asymmetry in the Universe. Recently, the ATLAS experiment at the Large Hadron Collider has performed an analysis of electroweak Z j j production, thereby excluding the SM locally at 95% confidence level in the measurement of CP-sensitive observables. We take the excess’ interpretation in terms of anomalous gauge-Higgs interactions at face value and discuss further steps that are required to scrutinize its origin. In particular, we discuss the relevance of multi-boson production using adapted angular observables to show how they can be used to directly tension the reported Z j j excess in a more comprehensive analysis. To connect the excess to a concrete UV scenario for which the underlying assumptions of the Z j j analysis are valid, we identify vector-like leptons as a candidate theory consistent with the observed CP-odd Wilson coefficient hierarchy observed by ATLAS. We perform a complete one-loop matching calculation to motivate further model-specific and correlated new physics searches. In parallel, we provide estimates of the sensitivity reach of the LHC’s high luminosity phase for this particular scenario of CP-violation in light of electroweak precision and Run-2 Higgs data. These provide strong constraints on the model’s CP-even low-energy phenomenology, but also inform the size of the CP-odd SM deformation indirectly via our model hypothesis.

Item Type:Articles
Additional Information:The work of S.D.B. and J.C. is supported by the Science and Engineering Research Board, Government of India, under the agreements SERB/PHY/2016348 (Early Career Research Award) and SERB/PHY/2019501 (MATRICS). C.E. is supported by the UK Science and Technology Facilities Council (STFC) under grants ST/P000746/1 and ST/T000945/1 and by the IPPP Associateship Scheme. M.S. is supported by the STFC under grant ST/P001246/1. P.S. is supported by an STFC studentship under grant ST/T506102/1.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Stylianou, Mr Panagiotis and Englert, Dr Christoph
Authors: Das Bakshi, S., Chakrabortty, J., Englert, C., Spannowsky, M., and Stylianou, P.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Physical Review D
Publisher:American Physical Society
ISSN:2470-0010
ISSN (Online):2470-0029
Copyright Holders:Copyright © 2021 The Authors
First Published:First published in Physical Review D 103(5):055008
Publisher Policy:Reproduced under a Creative Commons licence
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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
173809Phenomenology from Lattice QCD and Collider PhysicsChristine DaviesScience and Technology Facilities Council (STFC)ST/P000746/1P&S - Physics & Astronomy
306883Research in Particle Physics Theory - Phenomenology from lattice QCD and collider physicsChristine DaviesScience and Technology Facilities Council (STFC)ST/T000945/1P&S - Physics & Astronomy