Measurement of the W boson polarisation in t(t)over-barevents from pp collisions at root s=8 TeV in the lepton plus jets channel with ATLAS

M. Aaboud; G. Aad; B. Abbott; J. Abdallah; O. Abdinov; B Abeloos; O.S. AbouZeid; NL Abraham; H. Abramowicz; H. Abreu; R. Abreu; Y. Abulaiti; B.S. Acharya; S. Adachi; L. Adamczyk; David L. Adams; J P Adelman; T. Adye; Mogens Dam; Jørn Dines Hansen; Jørgen Beck Hansen; Stefania Xella; Peter Henrik Hansen; Troels Christian Petersen; Ask Emil Løvschall-Jensen; Alejandro Alonso Diaz; James William Monk; Lars Egholm Pedersen; Graig Wiglesworth; Gorm Aske Gram Krohn Galster; Simon Holm Stark; Geert-Jan Besjes; Fabian Alexander Jürgen Thiele; Flavia de Almeida Dias; Milena Bajic

doi:10.1140/epjc/s10052-017-4819-4

Measurement of the W boson polarisation in t(t)over-barevents from pp collisions at root s=8 TeV in the lepton plus jets channel with ATLAS

M. Aaboud, G. Aad, B. Abbott, J. Abdallah, O. Abdinov, B Abeloos, O.S. AbouZeid, NL Abraham, H. Abramowicz, H. Abreu, R. Abreu, Y. Abulaiti, B.S. Acharya, S. Adachi, L. Adamczyk, David L. Adams, J P Adelman, T. Adye, Mogens Dam, Jørn Dines HansenJørgen Beck Hansen, Stefania Xella, Peter Henrik Hansen, Troels Christian Petersen, Ask Emil Løvschall-Jensen, Alejandro Alonso Diaz, James William Monk, Lars Egholm Pedersen, Graig Wiglesworth, Gorm Aske Gram Krohn Galster, Simon Holm Stark, Geert-Jan Besjes, Fabian Alexander Jürgen Thiele, Flavia de Almeida Dias, Milena Bajic

Experimental Particle Physics

34 Citations (Scopus)

55 Downloads (Pure)

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.

Original language	English
Article number	264
Journal	European Physical Journal C
Volume	77
Issue number	4
ISSN	1434-6044
DOIs	https://doi.org/10.1140/epjc/s10052-017-4819-4
Publication status	Published - 1 Apr 2017

Access to Document

10.1140/epjc/s10052-017-4819-4Licence: CC BY

10.1140_epjc_s10052-017-4819-4Final published version, 1.68 MBLicence: CC BY

Cite this

Aaboud, M., Aad, G., Abbott, B., Abdallah, J., Abdinov, O., Abeloos, B., AbouZeid, O. S., Abraham, NL., Abramowicz, H., Abreu, H., Abreu, R., Abulaiti, Y., Acharya, B. S., Adachi, S., Adamczyk, L., Adams, D. L., Adelman, J. P., Adye, T., Dam, M., ... Bajic, M. (2017). Measurement of the W boson polarisation in t(t)over-barevents from pp collisions at root s=8 TeV in the lepton plus jets channel with ATLAS. European Physical Journal C, 77(4), [264]. https://doi.org/10.1140/epjc/s10052-017-4819-4

Aaboud, M, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Abeloos, B, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adachi, S, Adamczyk, L, Adams, DL, Adelman, JP, Adye, T, Dam, M , Hansen, JD , Hansen, JB , Xella, S , Hansen, PH , Petersen, TC, Løvschall-Jensen, AE, Alonso Diaz, A, Monk, JW, Pedersen, LE, Wiglesworth, G, Galster, GAGK, Stark, SH, Besjes, G-J, Thiele, FAJ, de Almeida Dias, F & Bajic, M 2017, 'Measurement of the W boson polarisation in t(t)over-barevents from pp collisions at root s=8 TeV in the lepton plus jets channel with ATLAS', European Physical Journal C, vol. 77, no. 4, 264. https://doi.org/10.1140/epjc/s10052-017-4819-4

@article{deb7069c5a8a42a6a5c1f820bf10c292,

title = "Measurement of the W boson polarisation in t(t)over-barevents from pp collisions at root s=8 TeV in the lepton plus jets channel with ATLAS",

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.",

author = "M. Aaboud and G. Aad and B. Abbott and J. Abdallah and O. Abdinov and B Abeloos and O.S. AbouZeid and NL Abraham and H. Abramowicz and H. Abreu and R. Abreu and Y. Abulaiti and B.S. Acharya and S. Adachi and L. Adamczyk and Adams, {David L.} and Adelman, {J P} and T. Adye and Mogens Dam and Hansen, {J{\o}rn Dines} and Hansen, {J{\o}rgen Beck} and Stefania Xella and Hansen, {Peter Henrik} and Petersen, {Troels Christian} and L{\o}vschall-Jensen, {Ask Emil} and {Alonso Diaz}, Alejandro and Monk, {James William} and Pedersen, {Lars Egholm} and Graig Wiglesworth and Galster, {Gorm Aske Gram Krohn} and Stark, {Simon Holm} and Geert-Jan Besjes and Thiele, {Fabian Alexander J{\"u}rgen} and {de Almeida Dias}, Flavia and Milena Bajic",

year = "2017",

month = apr,

day = "1",

doi = "10.1140/epjc/s10052-017-4819-4",

language = "English",

volume = "77",

journal = "The European Physical Journal C: Particles and Fields",

issn = "1434-6044",

publisher = "Springer",

number = "4",

}

TY - JOUR

T1 - Measurement of the W boson polarisation in t(t)over-barevents from pp collisions at root s=8 TeV in the lepton plus jets channel with ATLAS

AU - Aaboud, M.

AU - Aad, G.

AU - Abbott, B.

AU - Abdallah, J.

AU - Abdinov, O.

AU - Abeloos, B

AU - AbouZeid, O.S.

AU - Abraham, NL

AU - Abramowicz, H.

AU - Abreu, H.

AU - Abreu, R.

AU - Abulaiti, Y.

AU - Acharya, B.S.

AU - Adachi, S.

AU - Adamczyk, L.

AU - Adams, David L.

AU - Adelman, J P

AU - Adye, T.

AU - Dam, Mogens

AU - Hansen, Jørn Dines

AU - Hansen, Jørgen Beck

AU - Xella, Stefania

AU - Hansen, Peter Henrik

AU - Petersen, Troels Christian

AU - Løvschall-Jensen, Ask Emil

AU - Alonso Diaz, Alejandro

AU - Monk, James William

AU - Pedersen, Lars Egholm

AU - Wiglesworth, Graig

AU - Galster, Gorm Aske Gram Krohn

AU - Stark, Simon Holm

AU - Besjes, Geert-Jan

AU - Thiele, Fabian Alexander Jürgen

AU - de Almeida Dias, Flavia

AU - Bajic, Milena

PY - 2017/4/1

Y1 - 2017/4/1

N2 - 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.

AB - 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.

U2 - 10.1140/epjc/s10052-017-4819-4

DO - 10.1140/epjc/s10052-017-4819-4

M3 - Journal article

SN - 1434-6044

VL - 77

JO - The European Physical Journal C: Particles and Fields

JF - The European Physical Journal C: Particles and Fields

IS - 4

M1 - 264

ER -

Measurement of the W boson polarisation in t(t)over-barevents from pp collisions at root s=8 TeV in the lepton plus jets channel with ATLAS

Abstract

Access to Document

Fingerprint

Cite this