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

ATLAS, Collaboration; Agustoni, Marco; Beck, Hans Peter; Cervelli, Alberto; Ereditato, Antonio; Haug, Sigve; Kabana, Sonja; Marti, Lukas; Meloni, Federico; Pretzl, Klaus-Peter; Stramaglia, Maria Elena; Stucci, Stefania; Weber, Michael (2015). Measurement of Spin Correlation in Top-Antitop Quark Events and Search for Top Squark Pair Production in pp Collisions at √s=8 TeV Using the ATLAS Detector. Physical review letters, 114(14), p. 142001. American Physical Society 10.1103/PhysRevLett.114.142001

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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 A helicity =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.

Item Type:

Journal Article (Original Article)

Division/Institute:

10 Strategic Research Centers > Albert Einstein Center for Fundamental Physics (AEC)
08 Faculty of Science > Physics Institute > Laboratory for High Energy Physics (LHEP)

UniBE Contributor:

Agustoni, Marco; Beck, Hans Peter; Cervelli, Alberto; Ereditato, Antonio; Haug, Sigve; Marti, Lukas; Meloni, Federico; Pretzl, Klaus-Peter; Stramaglia, Maria Elena; Stucci, Stefania and Weber, Michael

Subjects:

500 Science > 530 Physics

ISSN:

0031-9007

Publisher:

American Physical Society

Language:

English

Submitter:

Annette Krebs-Wegenast

Date Deposited:

08 Sep 2016 14:13

Last Modified:

11 Sep 2016 02:13

Publisher DOI:

10.1103/PhysRevLett.114.142001

ArXiv ID:

1412.4742

Additional Information:

Kollaboration - Es sind nur die Berner Autoren namentlich erwähnt

BORIS DOI:

10.7892/boris.87670

URI:

https://boris.unibe.ch/id/eprint/87670

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