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Measurement of the W boson polarisation in tt¯ events from pp collisions at s√ = 8 TeV in the lepton + jets channel with ATLAS

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Resumo:This paper presents a measurement of the polarisation of W bosons from tt¯ decays, reconstructed in events with one high-p T lepton and at least four jets. Data from pp collisions at the LHC were collected at s√ = 8 TeV and correspond to an integrated luminosity of 20.2 fb−1. The angle θ∗ between the b-quark from the top quark decay and a direct W boson decay product in the W boson rest frame is sensitive to the W boson polarisation. Two different W decay products are used as polarisation analysers: the charged lepton and the down-type quark for the leptonically and hadronically decaying W boson, respectively. The most precise measurement of the W boson polarisation via the distribution of cosθ∗ is obtained using the leptonic analyser and events in which at least two of the jets are tagged as b-quark jets. The fitted fractions of longitudinal, left- and right-handed polarisation states are F0= 0.709 ± 0.019, FL= 0.299 ± 0.015 and FR= −0.008 ± 0.014, and are the most precisely measured W boson polarisation fractions to date. Limits on anomalous couplings of the Wtb vertex are set.
Autores principais:Onofre, A.
Outros Autores:Castro, Nuno Filipe Silva Fernandes; ATLAS Collaboration
Assunto:Ciências Naturais::Ciências Físicas
Ano:2017
País:Portugal
Tipo de documento:artigo
Tipo de acesso:acesso aberto
Instituição associada:Universidade do Minho
Idioma:inglês
Origem:RepositóriUM - Universidade do Minho
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author Onofre, A.
author2 Castro, Nuno Filipe Silva Fernandes
ATLAS Collaboration
author2_role author
author
author_facet Onofre, A.
Castro, Nuno Filipe Silva Fernandes
ATLAS Collaboration
author_role author
contributor_name_str_mv RepositóriUM - Universidade do Minho
country_str PT
creators_json_txt [{\"Person.name\":\"Onofre, A.\"},{\"Person.name\":\"Castro, Nuno Filipe Silva Fernandes\"},{\"Person.name\":\"ATLAS Collaboration\"}]
datacite.contributors.contributor.contributorName.fl_str_mv RepositóriUM - Universidade do Minho
datacite.creators.creator.creatorName.fl_str_mv Onofre, A.
Castro, Nuno Filipe Silva Fernandes
ATLAS Collaboration
datacite.date.Accepted.fl_str_mv 2017-01-01T00:00:00Z
datacite.date.available.fl_str_mv 2017-12-30T06:31:05Z
datacite.date.embargoed.fl_str_mv 2017-12-30T06:31:05Z
datacite.rights.fl_str_mv http://purl.org/coar/access_right/c_abf2
datacite.subjects.subject.fl_str_mv Ciências Naturais::Ciências Físicas
datacite.titles.title.fl_str_mv Measurement of the W boson polarisation in tt¯ events from pp collisions at s√ = 8 TeV in the lepton + jets channel with ATLAS
dc.contributor.none.fl_str_mv RepositóriUM - Universidade do Minho
dc.creator.none.fl_str_mv Onofre, A.
Castro, Nuno Filipe Silva Fernandes
ATLAS Collaboration
dc.date.Accepted.fl_str_mv 2017-01-01T00:00:00Z
dc.date.available.fl_str_mv 2017-12-30T06:31:05Z
dc.date.embargoed.fl_str_mv 2017-12-30T06:31:05Z
dc.format.none.fl_str_mv application/pdf
dc.identifier.none.fl_str_mv https://hdl.handle.net/1822/48900
dc.language.none.fl_str_mv eng
dc.publisher.none.fl_str_mv Springer Verlag
dc.rights.none.fl_str_mv http://purl.org/coar/access_right/c_abf2
dc.subject.none.fl_str_mv Ciências Naturais::Ciências Físicas
dc.title.fl_str_mv Measurement of the W boson polarisation in tt¯ events from pp collisions at s√ = 8 TeV in the lepton + jets channel with ATLAS
dc.type.none.fl_str_mv http://purl.org/coar/resource_type/c_6501
description This paper presents a measurement of the polarisation of W bosons from tt¯ decays, reconstructed in events with one high-p T lepton and at least four jets. Data from pp collisions at the LHC were collected at s√ = 8 TeV and correspond to an integrated luminosity of 20.2 fb−1. The angle θ∗ between the b-quark from the top quark decay and a direct W boson decay product in the W boson rest frame is sensitive to the W boson polarisation. Two different W decay products are used as polarisation analysers: the charged lepton and the down-type quark for the leptonically and hadronically decaying W boson, respectively. The most precise measurement of the W boson polarisation via the distribution of cosθ∗ is obtained using the leptonic analyser and events in which at least two of the jets are tagged as b-quark jets. The fitted fractions of longitudinal, left- and right-handed polarisation states are F0= 0.709 ± 0.019, FL= 0.299 ± 0.015 and FR= −0.008 ± 0.014, and are the most precisely measured W boson polarisation fractions to date. Limits on anomalous couplings of the Wtb vertex are set.
dirty 0
eu_rights_str_mv openAccess
format article
fulltext.url.fl_str_mv https://repositorium.uminho.pt/bitstreams/9b920078-6f59-42d7-9c99-ae7be0c82f4d/download
id rum_5d704f4ffdb05440e459e5f87eee7b3f
identifier.url.fl_str_mv https://hdl.handle.net/1822/48900
instacron_str repositorium
institution Universidade do Minho
instname_str Universidade do Minho
language eng
network_acronym_str rum
network_name_str RepositóriUM - Universidade do Minho
oai_identifier_str oai:repositorium.uminho.pt:1822/48900
organization_str_mv urn:organizationAcronym:repositorium
person_str_mv Onofre, A.
Castro, Nuno Filipe Silva Fernandes
ATLAS Collaboration
publishDate 2017
publisher.none.fl_str_mv Springer Verlag
reponame_str RepositóriUM - Universidade do Minho
repository_id_str urn:repositoryAcronym:rum
service_str_mv urn:repositoryAcronym:rum
spelling engSpringer VerlagporThis paper presents a measurement of the polarisation of W bosons from tt¯ decays, reconstructed in events with one high-p T lepton and at least four jets. Data from pp collisions at the LHC were collected at s√ = 8 TeV and correspond to an integrated luminosity of 20.2 fb−1. The angle θ∗ between the b-quark from the top quark decay and a direct W boson decay product in the W boson rest frame is sensitive to the W boson polarisation. Two different W decay products are used as polarisation analysers: the charged lepton and the down-type quark for the leptonically and hadronically decaying W boson, respectively. The most precise measurement of the W boson polarisation via the distribution of cosθ∗ is obtained using the leptonic analyser and events in which at least two of the jets are tagged as b-quark jets. The fitted fractions of longitudinal, left- and right-handed polarisation states are F0= 0.709 ± 0.019, FL= 0.299 ± 0.015 and FR= −0.008 ± 0.014, and are the most precisely measured W boson polarisation fractions to date. Limits on anomalous couplings of the Wtb vertex are set.application/pdfporMeasurement of the W boson polarisation in tt¯ events from pp collisions at s√ = 8 TeV in the lepton + jets channel with ATLASOnofre, A.Castro, Nuno Filipe Silva FernandesATLAS CollaborationHostingInstitutionOrganizationalRepositóriUM - Universidade do Minhoe-mailmailto:repositorium@usdb.uminho.ptrepositorium@usdb.uminho.ptCITATION13. Aaboud, M., Aad, G., Abbott, B., Abdallah, J., Abdinov, O., Abeloos, B., . . . Zwalinski, L. (2017). Measurement of the W boson polarisation in tt¯ events from pp collisions at √s = 8 TeV in the lepton + jets channel with ATLAS. [Article]. European Physical Journal C, 77(4). doi: 10.1140/epjc/s10052-017-4819-4ISSNIsPartOf1434-6044EISSNIsPartOf1434-6052DOIIsPartOf10.1140/epjc/s10052-017-4819-42017-12-30T06:31:05Z20172017-01-01T00:00:00ZHandlehttps://hdl.handle.net/1822/48900http://purl.org/coar/access_right/c_abf2open accesshttp://www.oecd.org/science/inno/38235147.pdfFields of Science and Technology (FOS)Ciências Naturais::Ciências Físicas2631394 bytesliteraturehttp://purl.org/coar/resource_type/c_6501journal articlehttp://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://repositorium.uminho.pt/bitstreams/9b920078-6f59-42d7-9c99-ae7be0c82f4d/download
spellingShingle Measurement of the W boson polarisation in tt¯ events from pp collisions at s√ = 8 TeV in the lepton + jets channel with ATLAS
Onofre, A.
Ciências Naturais::Ciências Físicas
status SINGLETON
subject.other.fl_str_mv Ciências Naturais::Ciências Físicas
title Measurement of the W boson polarisation in tt¯ events from pp collisions at s√ = 8 TeV in the lepton + jets channel with ATLAS
title_full Measurement of the W boson polarisation in tt¯ events from pp collisions at s√ = 8 TeV in the lepton + jets channel with ATLAS
title_fullStr Measurement of the W boson polarisation in tt¯ events from pp collisions at s√ = 8 TeV in the lepton + jets channel with ATLAS
title_full_unstemmed Measurement of the W boson polarisation in tt¯ events from pp collisions at s√ = 8 TeV in the lepton + jets channel with ATLAS
title_short Measurement of the W boson polarisation in tt¯ events from pp collisions at s√ = 8 TeV in the lepton + jets channel with ATLAS
title_sort Measurement of the W boson polarisation in tt¯ events from pp collisions at s√ = 8 TeV in the lepton + jets channel with ATLAS
topic Ciências Naturais::Ciências Físicas
topic_facet Ciências Naturais::Ciências Físicas
url https://hdl.handle.net/1822/48900
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