Topping-up multilepton plus b-jets anomalies at the LHC with a Z′ boson

Autores
Alvarez, Ezequiel; Juste, Aurelio; Szewc, Manuel; Schroeder, Tamara Vazquez
Año de publicación
2021
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
During the last years ATLAS and CMS have reported a number of slight to mild discrepancies in signatures of multileptons plus b-jets in analyses such as tt¯ H, tt¯ W±, tt¯ Z and tt¯ tt¯. Among them, a recent ATLAS result on tt¯ H production has also reported an excess in the charge asymmetry in the same-sign dilepton channel with two or more b-tagged jets. Motivated by these tantalizing discrepancies, we study a phenomenological New Physics model consisting of a Z′ boson that couples to up-type quarks via right-handed currents: tRγμt¯ R, tRγμc¯ R, and tRγμu¯ R. The latter vertex allows to translate the charge asymmetry at the LHC initial state protons to a final state with top quarks which, decaying to a positive lepton and a b-jet, provides a crucial contribution to some of the observed discrepancies. Through an analysis at a detector level, we select the region in parameter space of our model that best reproduces the data in the aforementioned tt¯ H study, and in a recent ATLAS tt¯ tt¯ search. We find that our model provides a better fit to the experimental data than the Standard Model for a New Physics scale of approximately ∼500 GeV, and with a hierarchical coupling of the Z′ boson that favours the top quark and the presence of FCNC currents. In order to estimate the LHC sensitivity to this signal, we design a broadband search featuring many kinematic regions with different signal-to-background ratio, and perform a global analysis. We also define signal-enhanced regions and study observables that could further distinguish signal from background. We find that the region in parameter space of our model that best fits the analysed data could be probed with a significance exceeding 3 standard deviations with just the full Run-2 dataset.
Fil: Alvarez, Ezequiel. Universidad Nacional de San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Juste, Aurelio. Universitat Autònoma de Barcelona; España. Institució Catalana de Recerca I Estudis Avançats; España
Fil: Szewc, Manuel. Universidad Nacional de San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Schroeder, Tamara Vazquez. Cern - European Organization for Nuclear Research; Suiza
Materia
PHENOMENOLOGICAL MODELS
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/154401
Acceder
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network_name_str CONICET Digital (CONICET)
spelling Topping-up multilepton plus b-jets anomalies at the LHC with a Z′ bosonAlvarez, EzequielJuste, AurelioSzewc, ManuelSchroeder, Tamara VazquezPHENOMENOLOGICAL MODELShttps://purl.org/becyt/ford/1.3https://purl.org/becyt/ford/1During the last years ATLAS and CMS have reported a number of slight to mild discrepancies in signatures of multileptons plus b-jets in analyses such as tt¯ H, tt¯ W±, tt¯ Z and tt¯ tt¯. Among them, a recent ATLAS result on tt¯ H production has also reported an excess in the charge asymmetry in the same-sign dilepton channel with two or more b-tagged jets. Motivated by these tantalizing discrepancies, we study a phenomenological New Physics model consisting of a Z′ boson that couples to up-type quarks via right-handed currents: tRγμt¯ R, tRγμc¯ R, and tRγμu¯ R. The latter vertex allows to translate the charge asymmetry at the LHC initial state protons to a final state with top quarks which, decaying to a positive lepton and a b-jet, provides a crucial contribution to some of the observed discrepancies. Through an analysis at a detector level, we select the region in parameter space of our model that best reproduces the data in the aforementioned tt¯ H study, and in a recent ATLAS tt¯ tt¯ search. We find that our model provides a better fit to the experimental data than the Standard Model for a New Physics scale of approximately ∼500 GeV, and with a hierarchical coupling of the Z′ boson that favours the top quark and the presence of FCNC currents. In order to estimate the LHC sensitivity to this signal, we design a broadband search featuring many kinematic regions with different signal-to-background ratio, and perform a global analysis. We also define signal-enhanced regions and study observables that could further distinguish signal from background. We find that the region in parameter space of our model that best fits the analysed data could be probed with a significance exceeding 3 standard deviations with just the full Run-2 dataset.Fil: Alvarez, Ezequiel. Universidad Nacional de San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Juste, Aurelio. Universitat Autònoma de Barcelona; España. Institució Catalana de Recerca I Estudis Avançats; EspañaFil: Szewc, Manuel. Universidad Nacional de San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Schroeder, Tamara Vazquez. Cern - European Organization for Nuclear Research; SuizaSpringer2021-05-14info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/154401Alvarez, Ezequiel; Juste, Aurelio; Szewc, Manuel; Schroeder, Tamara Vazquez; Topping-up multilepton plus b-jets anomalies at the LHC with a Z′ boson; Springer; Journal of High Energy Physics; 5; 125; 14-5-2021; 1-331029-8479CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/doi/10.1007/JHEP05(2021)125info:eu-repo/semantics/altIdentifier/url/https://link.springer.com/article/10.1007/JHEP05(2021)125info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T09:52:04Zoai:ri.conicet.gov.ar:11336/154401instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-29 09:52:04.661CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Topping-up multilepton plus b-jets anomalies at the LHC with a Z′ boson
title Topping-up multilepton plus b-jets anomalies at the LHC with a Z′ boson
spellingShingle Topping-up multilepton plus b-jets anomalies at the LHC with a Z′ boson
Alvarez, Ezequiel
PHENOMENOLOGICAL MODELS
title_short Topping-up multilepton plus b-jets anomalies at the LHC with a Z′ boson
title_full Topping-up multilepton plus b-jets anomalies at the LHC with a Z′ boson
title_fullStr Topping-up multilepton plus b-jets anomalies at the LHC with a Z′ boson
title_full_unstemmed Topping-up multilepton plus b-jets anomalies at the LHC with a Z′ boson
title_sort Topping-up multilepton plus b-jets anomalies at the LHC with a Z′ boson
dc.creator.none.fl_str_mv Alvarez, Ezequiel
Juste, Aurelio
Szewc, Manuel
Schroeder, Tamara Vazquez
author Alvarez, Ezequiel
author_facet Alvarez, Ezequiel
Juste, Aurelio
Szewc, Manuel
Schroeder, Tamara Vazquez
author_role author
author2 Juste, Aurelio
Szewc, Manuel
Schroeder, Tamara Vazquez
author2_role author
author
author
dc.subject.none.fl_str_mv PHENOMENOLOGICAL MODELS
topic PHENOMENOLOGICAL MODELS
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.3
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv During the last years ATLAS and CMS have reported a number of slight to mild discrepancies in signatures of multileptons plus b-jets in analyses such as tt¯ H, tt¯ W±, tt¯ Z and tt¯ tt¯. Among them, a recent ATLAS result on tt¯ H production has also reported an excess in the charge asymmetry in the same-sign dilepton channel with two or more b-tagged jets. Motivated by these tantalizing discrepancies, we study a phenomenological New Physics model consisting of a Z′ boson that couples to up-type quarks via right-handed currents: tRγμt¯ R, tRγμc¯ R, and tRγμu¯ R. The latter vertex allows to translate the charge asymmetry at the LHC initial state protons to a final state with top quarks which, decaying to a positive lepton and a b-jet, provides a crucial contribution to some of the observed discrepancies. Through an analysis at a detector level, we select the region in parameter space of our model that best reproduces the data in the aforementioned tt¯ H study, and in a recent ATLAS tt¯ tt¯ search. We find that our model provides a better fit to the experimental data than the Standard Model for a New Physics scale of approximately ∼500 GeV, and with a hierarchical coupling of the Z′ boson that favours the top quark and the presence of FCNC currents. In order to estimate the LHC sensitivity to this signal, we design a broadband search featuring many kinematic regions with different signal-to-background ratio, and perform a global analysis. We also define signal-enhanced regions and study observables that could further distinguish signal from background. We find that the region in parameter space of our model that best fits the analysed data could be probed with a significance exceeding 3 standard deviations with just the full Run-2 dataset.
Fil: Alvarez, Ezequiel. Universidad Nacional de San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Juste, Aurelio. Universitat Autònoma de Barcelona; España. Institució Catalana de Recerca I Estudis Avançats; España
Fil: Szewc, Manuel. Universidad Nacional de San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Schroeder, Tamara Vazquez. Cern - European Organization for Nuclear Research; Suiza
description During the last years ATLAS and CMS have reported a number of slight to mild discrepancies in signatures of multileptons plus b-jets in analyses such as tt¯ H, tt¯ W±, tt¯ Z and tt¯ tt¯. Among them, a recent ATLAS result on tt¯ H production has also reported an excess in the charge asymmetry in the same-sign dilepton channel with two or more b-tagged jets. Motivated by these tantalizing discrepancies, we study a phenomenological New Physics model consisting of a Z′ boson that couples to up-type quarks via right-handed currents: tRγμt¯ R, tRγμc¯ R, and tRγμu¯ R. The latter vertex allows to translate the charge asymmetry at the LHC initial state protons to a final state with top quarks which, decaying to a positive lepton and a b-jet, provides a crucial contribution to some of the observed discrepancies. Through an analysis at a detector level, we select the region in parameter space of our model that best reproduces the data in the aforementioned tt¯ H study, and in a recent ATLAS tt¯ tt¯ search. We find that our model provides a better fit to the experimental data than the Standard Model for a New Physics scale of approximately ∼500 GeV, and with a hierarchical coupling of the Z′ boson that favours the top quark and the presence of FCNC currents. In order to estimate the LHC sensitivity to this signal, we design a broadband search featuring many kinematic regions with different signal-to-background ratio, and perform a global analysis. We also define signal-enhanced regions and study observables that could further distinguish signal from background. We find that the region in parameter space of our model that best fits the analysed data could be probed with a significance exceeding 3 standard deviations with just the full Run-2 dataset.
publishDate 2021
dc.date.none.fl_str_mv 2021-05-14
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/154401
Alvarez, Ezequiel; Juste, Aurelio; Szewc, Manuel; Schroeder, Tamara Vazquez; Topping-up multilepton plus b-jets anomalies at the LHC with a Z′ boson; Springer; Journal of High Energy Physics; 5; 125; 14-5-2021; 1-33
1029-8479
CONICET Digital
CONICET
url http://hdl.handle.net/11336/154401
identifier_str_mv Alvarez, Ezequiel; Juste, Aurelio; Szewc, Manuel; Schroeder, Tamara Vazquez; Topping-up multilepton plus b-jets anomalies at the LHC with a Z′ boson; Springer; Journal of High Energy Physics; 5; 125; 14-5-2021; 1-33
1029-8479
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/doi/10.1007/JHEP05(2021)125
info:eu-repo/semantics/altIdentifier/url/https://link.springer.com/article/10.1007/JHEP05(2021)125
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv Springer
publisher.none.fl_str_mv Springer
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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score 13.070432

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