Measurement of the W boson polarisation in tt¯ events from pp collisions at √s = 8 TeV in the lepton + jets channel with ATLAS
Aaboud, M ; Aad, G. ; Abbott, B ; Abdallah, J. ; Abdinov, O ; Abeloos, B ; Åkesson, Torsten LU
; Bocchetta, Simona
LU
; BRYNGEMARK, LENE
LU
and Doglioni, Caterina
LU
, et al.
(2017)
In European Physical Journal C
77(4).
- Abstract
- This paper presents a measurement of the polarisation of W bosons from tt¯ decays, reconstructed in events with one high-pT 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 cos θ∗ is obtained using the leptonic analyser and... (More)
- This paper presents a measurement of the polarisation of W bosons from tt¯ decays, reconstructed in events with one high-pT 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 cos θ∗ 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. © 2017, CERN for the benefit of the ATLAS collaboration. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/0dde6cc8-f6ea-4180-a994-2e1f7c416153
- author
- Aaboud, M
; Aad, G.
; Abbott, B
; Abdallah, J.
; Abdinov, O
; Abeloos, B
; Åkesson, Torsten
LU
; Bocchetta, Simona
LU
; BRYNGEMARK, LENE
LU
and Doglioni, Caterina
LU
, et al. (More)
- Aaboud, M
; Aad, G.
; Abbott, B
; Abdallah, J.
; Abdinov, O
; Abeloos, B
; Åkesson, Torsten
LU
; Bocchetta, Simona
LU
; BRYNGEMARK, LENE
LU
; Doglioni, Caterina
LU
; Hedberg, Vincent
LU
; Jarlskog, Göran
LU
; Lytken, Else
LU
; Mjörnmark, Ulf
LU
; Smirnova, Oxana
LU
and Viazlo, Oleksandr
LU
(Less)
- author collaboration
- organization
- publishing date
- 2017
- type
- Contribution to journal
- publication status
- published
- subject
- in
- European Physical Journal C
- volume
- 77
- issue
- 4
- article number
- 264
- publisher
- Springer
- external identifiers
-
- pmid:28515670
- scopus:85018254033
- ISSN
- 1434-6044
- DOI
- 10.1140/epjc/s10052-017-4819-4
- language
- English
- LU publication?
- yes
- additional info
- Export Date: 12 June 2017
- id
- 0dde6cc8-f6ea-4180-a994-2e1f7c416153
- date added to LUP
- 2017-06-12 10:48:28
- date last changed
- 2023-04-07 17:21:49
@article{0dde6cc8-f6ea-4180-a994-2e1f7c416153,
abstract = {{This paper presents a measurement of the polarisation of W bosons from tt¯ decays, reconstructed in events with one high-pT 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 cos θ∗ 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. © 2017, CERN for the benefit of the ATLAS collaboration.}},
author = {{Aaboud, M and Aad, G. and Abbott, B and Abdallah, J. and Abdinov, O and Abeloos, B and Åkesson, Torsten and Bocchetta, Simona and BRYNGEMARK, LENE and Doglioni, Caterina and Hedberg, Vincent and Jarlskog, Göran and Lytken, Else and Mjörnmark, Ulf and Smirnova, Oxana and Viazlo, Oleksandr}},
issn = {{1434-6044}},
language = {{eng}},
number = {{4}},
publisher = {{Springer}},
series = {{European Physical Journal C}},
title = {{Measurement of the W boson polarisation in tt¯ events from pp collisions at √s = 8 TeV in the lepton + jets channel with ATLAS}},
url = {{http://dx.doi.org/10.1140/epjc/s10052-017-4819-4}},
doi = {{10.1140/epjc/s10052-017-4819-4}},
volume = {{77}},
year = {{2017}},
}