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Constraining four-fermion operators using rare top decays

Chala, Mikael; Santiago, Jose; Spannowsky, Michael

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Mikael Chala

Jose Santiago


New physics can manifest itself by an appreciable increase of the decay rate of top quarks in rare flavour-changing final states. Exploiting the large top quark production rate at the LHC, we bound four-fermion operators contributing to non-resonant t → ℓ+ℓ−j using different signal regions of the latest LHC searches for t → Zj. We also provide prospects for the high-luminosity LHC to test these as well as four-fermion operators contributing to t→bb¯¯j , based on improved analysis strategies of existing searches. We single out all weakly-coupled ultraviolet completions inducing such contact interactions at tree level and translate the previous bounds to the parameter space of specific complete models. Being above the TeV, LHC bounds from rare top decays improve over those from flavour physics, electroweak precision data and other LHC searches in several cases.


Chala, M., Santiago, J., & Spannowsky, M. (2019). Constraining four-fermion operators using rare top decays. Journal of High Energy Physics, 2019(4), Article 14.

Journal Article Type Article
Acceptance Date Mar 24, 2019
Online Publication Date Apr 2, 2019
Publication Date Apr 30, 2019
Deposit Date Apr 12, 2019
Publicly Available Date Apr 12, 2019
Journal Journal of High Energy Physics
Print ISSN 1126-6708
Publisher Scuola Internazionale Superiore di Studi Avanzati (SISSA)
Peer Reviewed Peer Reviewed
Volume 2019
Issue 4
Article Number 14


Published Journal Article (689 Kb)

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Copyright Statement
This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.

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