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Title: The fully differential top decay distribution

Abstract

We write down the four-dimensional fully differential decay distribution for the top quark decay t → Wb → ℓνb. We discuss how its eight physical parameters can be measured, either with a global fit or with the use of selected one-dimensional distributions and asymmetries. We give expressions for the top decay amplitudes for a general tbW interaction, and show how the untangled measurement of the two components of the fraction of longitudinal W bosons – those with b quark helicities of 1/2 and –1/2, respectively – could improve the precision of a global fit to the tbW vertex.

Authors:
 [1];  [2];  [3];  [2]
  1. Univ. of Granada (Spain). Dept. of Theoretical and Cosmic Physics
  2. Univ. of Pittsburgh, PA (United States). Dept. of Physics and Astronomy
  3. CSIC-Univ. of Valencia, Paterna (Spain). Inst. of Corpuscular Physics
Publication Date:
Research Org.:
Univ. of Pittsburgh, PA (United States); Univ. of Granada (Spain); CSIC-Univ. of Valencia, Paterna (Spain)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25); Ministry of Economy and Competitiveness (MINECO) (Spain); Regional Government of Andalusia; Generalitat Valenciana; European Commission (EC)
OSTI Identifier:
1348965
Alternate Identifier(s):
OSTI ID: 1368400
Grant/Contract Number:
SC0007914; FPA 2016-78220-C3-1-P; FPA2015-65652-C4-1-R; FPA 2013-47836-C3-2-P; FQM-101; PROMETEO/2010/021; PITN-GA-2012-316704
Resource Type:
Journal Article: Published Article
Journal Name:
European Physical Journal. C, Particles and Fields
Additional Journal Information:
Journal Volume: 77; Journal Issue: 3; Journal ID: ISSN 1434-6044
Publisher:
Springer
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Aguilar-Saavedra, J. A., Boudreau, J., Escobar, C., and Mueller, J. The fully differential top decay distribution. United States: N. p., 2017. Web. doi:10.1140/epjc/s10052-017-4761-5.
Aguilar-Saavedra, J. A., Boudreau, J., Escobar, C., & Mueller, J. The fully differential top decay distribution. United States. doi:10.1140/epjc/s10052-017-4761-5.
Aguilar-Saavedra, J. A., Boudreau, J., Escobar, C., and Mueller, J. Wed . "The fully differential top decay distribution". United States. doi:10.1140/epjc/s10052-017-4761-5.
@article{osti_1348965,
title = {The fully differential top decay distribution},
author = {Aguilar-Saavedra, J. A. and Boudreau, J. and Escobar, C. and Mueller, J.},
abstractNote = {We write down the four-dimensional fully differential decay distribution for the top quark decay t → Wb → ℓνb. We discuss how its eight physical parameters can be measured, either with a global fit or with the use of selected one-dimensional distributions and asymmetries. We give expressions for the top decay amplitudes for a general tbW interaction, and show how the untangled measurement of the two components of the fraction of longitudinal W bosons – those with b quark helicities of 1/2 and –1/2, respectively – could improve the precision of a global fit to the tbW vertex.},
doi = {10.1140/epjc/s10052-017-4761-5},
journal = {European Physical Journal. C, Particles and Fields},
number = 3,
volume = 77,
place = {United States},
year = {Wed Mar 29 00:00:00 EDT 2017},
month = {Wed Mar 29 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1140/epjc/s10052-017-4761-5

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  • We write down the four-dimensional fully differential decay distribution for the top quark decay t → Wb → ℓνb. We discuss how its eight physical parameters can be measured, either with a global fit or with the use of selected one-dimensional distributions and asymmetries. We give expressions for the top decay amplitudes for a general tbW interaction, and show how the untangled measurement of the two components of the fraction of longitudinal W bosons – those with b quark helicities of 1/2 and –1/2, respectively – could improve the precision of a global fit to the tbW vertex.
  • In this study, the mass of the top quark is measured in a data set corresponding to 4.6 fb -1 of proton–proton collisions with centre-of-mass energy √s=7 TeV collected by the ATLAS detector at the LHC. Events consistent with hadronic decays of top–antitop quark pairs with at least six jets in the final state are selected. The substantial background from multijet production is modelled with data-driven methods that utilise the number of identified b-quark jets and the transverse momentum of the sixth leading jet, which have minimal correlation. The top-quark mass is obtained from template fits to the ratio ofmore » three-jet to dijet mass. The three-jet mass is calculated from the three jets produced in a top-quark decay. Using these three jets the dijet mass is obtained from the two jets produced in the W boson decay. The top-quark mass obtained from this fit is thus less sensitive to the uncertainty in the energy measurement of the jets. A binned likelihood fit yields a top-quark mass of m t=175.1±1.4(stat.) ±1.2(syst.) GeV.« less
  • In this study, the mass of the top quark is measured in a data set corresponding to 4.6 fb -1 of proton–proton collisions with centre-of-mass energy √s=7 TeV collected by the ATLAS detector at the LHC. Events consistent with hadronic decays of top–antitop quark pairs with at least six jets in the final state are selected. The substantial background from multijet production is modelled with data-driven methods that utilise the number of identified b-quark jets and the transverse momentum of the sixth leading jet, which have minimal correlation. The top-quark mass is obtained from template fits to the ratio ofmore » three-jet to dijet mass. The three-jet mass is calculated from the three jets produced in a top-quark decay. Using these three jets the dijet mass is obtained from the two jets produced in the W boson decay. The top-quark mass obtained from this fit is thus less sensitive to the uncertainty in the energy measurement of the jets. A binned likelihood fit yields a top-quark mass of m t=175.1±1.4(stat.) ±1.2(syst.) GeV.« less
  • © 2015, CERN for the benefit of the ATLAS Collaboration. The mass of the top quark is measured in a data set corresponding to 4.6 fb -1 of proton–proton collisions with centre-of-mass energy √ = 7TeV collected by the ATLAS detector at the LHC. Events consistent with hadronic decays of top–antitop quark pairs with at least six jets in the final state are selected. The substantial background from multijet production is modelled with data-driven methods that utilise the number of identified b-quark jets and the transverse momentum of the sixth leading jet, which have minimal correlation. The top-quark mass ismore » obtained from template fits to the ratio of three-jet to dijet mass. The three-jet mass is calculated from the three jets produced in a top-quark decay. Using these three jets the dijet mass is obtained from the two jets produced in the W boson decay. The top-quark mass obtained from this fit is thus less sensitive to the uncertainty in the energy measurement of the jets. A binned likelihood fit yields a top-quark mass of m t = 175.1 ± 1.4 (stat.) ± 1.2 (syst.) GeV.« less