Measurement of Spin Correlation in Top-Antitop Quark Events and Search for Top Squark Pair Production in pp Collisions at $\sqrt{s}=8$ TeV Using the ATLAS Detector

ATLAS Collaboration; Yvonne Peters; Fabrice Balli; Sarah Barnes; Alessandra Forti; Julia Iturbe Ponce; Kiran Joshi; Joel Klinger; Frederick Loebinger; Stephen Marsden; Jiri Masik; Thomas Neep; Mark Owen; Yang Qin; Michaela Queitsch-Maitland; James Robinson; Christian Schwanenberger; Lee Tomlinson; Samuel Webb; Martin Woudstra

doi:10.1103/PhysRevLett.114.142001

Measurement of Spin Correlation in Top-Antitop Quark Events and Search for Top Squark Pair Production in pp Collisions at $\sqrt{s}=8$ TeV Using the ATLAS Detector

ATLAS Collaboration , Yvonne Peters, Fabrice Balli, Sarah Barnes, Alessandra Forti, Julia Iturbe Ponce, Kiran Joshi, Joel Klinger, Frederick Loebinger, Stephen Marsden, Jiri Masik, Thomas Neep, Mark Owen, Yang Qin, Michaela Queitsch-Maitland, James Robinson, Christian Schwanenberger, Lee Tomlinson, Samuel Webb, Martin Woudstra

Research output: Contribution to journal › Article › peer-review

Abstract

A measurement of spin correlation in tt¯ production is presented using data collected with the ATLAS detector at the Large Hadron Collider in proton-proton collisions at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3 fb−1. The correlation between the top and antitop quark spins is extracted from dilepton tt¯ events by using the difference in azimuthal angle between the two charged leptons in the laboratory frame. In the helicity basis the measured degree of correlation corresponds to Ahelicity=0.38±0.04, in agreement with the Standard Model prediction. A search is performed for pair production of top squarks with masses close to the top quark mass decaying to predominantly right-handed top quarks and a light neutralino, the lightest supersymmetric particle. Top squarks with masses between the top quark mass and 191 GeV are excluded at the 95% confidence level.

Original language	English
Article number	142001
Journal	Phys. Rev. Lett.
Volume	114
Issue number	14
DOIs	https://doi.org/10.1103/PhysRevLett.114.142001
Publication status	Published - 8 Apr 2015

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ATLAS Collaboration , Peters, Y., Balli, F., Barnes, S., Forti, A., Iturbe Ponce, J., Joshi, K., Klinger, J., Loebinger, F., Marsden, S., Masik, J., Neep, T., Owen, M., Qin, Y., Queitsch-Maitland, M., Robinson, J., Schwanenberger, C., Tomlinson, L., Webb, S., & Woudstra, M. (2015). Measurement of Spin Correlation in Top-Antitop Quark Events and Search for Top Squark Pair Production in pp Collisions at $\sqrt{s}=8$ TeV Using the ATLAS Detector. Phys. Rev. Lett., 114(14), Article 142001. https://doi.org/10.1103/PhysRevLett.114.142001

@article{24c5a9b7df6e4eae89c1105665ce6887,

title = "Measurement of Spin Correlation in Top-Antitop Quark Events and Search for Top Squark Pair Production in pp Collisions at $\sqrt{s}=8$ TeV Using the ATLAS Detector",

abstract = "A measurement of spin correlation in tt¯ production is presented using data collected with the ATLAS detector at the Large Hadron Collider in proton-proton collisions at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3 fb−1. The correlation between the top and antitop quark spins is extracted from dilepton tt¯ events by using the difference in azimuthal angle between the two charged leptons in the laboratory frame. In the helicity basis the measured degree of correlation corresponds to Ahelicity=0.38±0.04, in agreement with the Standard Model prediction. A search is performed for pair production of top squarks with masses close to the top quark mass decaying to predominantly right-handed top quarks and a light neutralino, the lightest supersymmetric particle. Top squarks with masses between the top quark mass and 191 GeV are excluded at the 95% confidence level.",

author = "Brian Cox and Stephen Watts and Terence Wyatt and {Da Via}, Cinzia and Joleen Pater and Andrew Pilkington and Darren Price and Alexander Oh and {ATLAS Collaboration} and Yvonne Peters and Fabrice Balli and Sarah Barnes and Alessandra Forti and {Iturbe Ponce}, Julia and Kiran Joshi and Joel Klinger and Frederick Loebinger and Stephen Marsden and Jiri Masik and Thomas Neep and Mark Owen and Yang Qin and Michaela Queitsch-Maitland and James Robinson and Christian Schwanenberger and Lee Tomlinson and Samuel Webb and Martin Woudstra",

year = "2015",

month = apr,

day = "8",

doi = "10.1103/PhysRevLett.114.142001",

language = "English",

volume = "114",

journal = "Phys. Rev. Lett.",

issn = "1079-7114",

publisher = "American Physical Society",

number = "14",

}

ATLAS Collaboration , Peters, Y, Balli, F, Barnes, S, Forti, A, Iturbe Ponce, J, Joshi, K, Klinger, J, Loebinger, F, Marsden, S, Masik, J, Neep, T, Owen, M, Qin, Y, Queitsch-Maitland, M, Robinson, J, Schwanenberger, C, Tomlinson, L, Webb, S & Woudstra, M 2015, 'Measurement of Spin Correlation in Top-Antitop Quark Events and Search for Top Squark Pair Production in pp Collisions at $\sqrt{s}=8$ TeV Using the ATLAS Detector', Phys. Rev. Lett., vol. 114, no. 14, 142001. https://doi.org/10.1103/PhysRevLett.114.142001

TY - JOUR

T1 - Measurement of Spin Correlation in Top-Antitop Quark Events and Search for Top Squark Pair Production in pp Collisions at $\sqrt{s}=8$ TeV Using the ATLAS Detector

AU - Cox, Brian

AU - Watts, Stephen

AU - Wyatt, Terence

AU - Da Via, Cinzia

AU - Pater, Joleen

AU - Pilkington, Andrew

AU - Price, Darren

AU - Oh, Alexander

AU - ATLAS Collaboration

AU - Peters, Yvonne

AU - Balli, Fabrice

AU - Barnes, Sarah

AU - Forti, Alessandra

AU - Iturbe Ponce, Julia

AU - Joshi, Kiran

AU - Klinger, Joel

AU - Loebinger, Frederick

AU - Marsden, Stephen

AU - Masik, Jiri

AU - Neep, Thomas

AU - Owen, Mark

AU - Qin, Yang

AU - Queitsch-Maitland, Michaela

AU - Robinson, James

AU - Schwanenberger, Christian

AU - Tomlinson, Lee

AU - Webb, Samuel

AU - Woudstra, Martin

PY - 2015/4/8

Y1 - 2015/4/8

N2 - A measurement of spin correlation in tt¯ production is presented using data collected with the ATLAS detector at the Large Hadron Collider in proton-proton collisions at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3 fb−1. The correlation between the top and antitop quark spins is extracted from dilepton tt¯ events by using the difference in azimuthal angle between the two charged leptons in the laboratory frame. In the helicity basis the measured degree of correlation corresponds to Ahelicity=0.38±0.04, in agreement with the Standard Model prediction. A search is performed for pair production of top squarks with masses close to the top quark mass decaying to predominantly right-handed top quarks and a light neutralino, the lightest supersymmetric particle. Top squarks with masses between the top quark mass and 191 GeV are excluded at the 95% confidence level.

AB - A measurement of spin correlation in tt¯ production is presented using data collected with the ATLAS detector at the Large Hadron Collider in proton-proton collisions at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3 fb−1. The correlation between the top and antitop quark spins is extracted from dilepton tt¯ events by using the difference in azimuthal angle between the two charged leptons in the laboratory frame. In the helicity basis the measured degree of correlation corresponds to Ahelicity=0.38±0.04, in agreement with the Standard Model prediction. A search is performed for pair production of top squarks with masses close to the top quark mass decaying to predominantly right-handed top quarks and a light neutralino, the lightest supersymmetric particle. Top squarks with masses between the top quark mass and 191 GeV are excluded at the 95% confidence level.

U2 - 10.1103/PhysRevLett.114.142001

DO - 10.1103/PhysRevLett.114.142001

M3 - Article

SN - 1079-7114

VL - 114

JO - Phys. Rev. Lett.

JF - Phys. Rev. Lett.

IS - 14

M1 - 142001

ER -

Measurement of Spin Correlation in Top-Antitop Quark Events and Search for Top Squark Pair Production in pp Collisions at $\sqrt{s}=8$ TeV Using the ATLAS Detector

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