Measurements of top-quark pair spin correlations in the eμ channel at \sqrts = 13 TeV using pp collisions in the ATLAS detector

Franconi, Laura; Haug, Sigve; Weber, Michele; Anders, John Kenneth; Beck, Hans Peter; Ereditato, Antonio; Merlassino, Claudia; Miucci, Antonio; Weston, Thomas Daniel (2020). Measurements of top-quark pair spin correlations in the eμ channel at \sqrts = 13 TeV using pp collisions in the ATLAS detector. European physical journal. C - particles and fields, 80(8) EDP Sciences 10.1140/epjc/s10052-020-8181-6

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A measurement of observables sensitive to spincorrelations int ̄tproduction is presented, using 36.1 fb−1ofppcollision data at√s=13 TeV recorded with theATLAS detector at the Large Hadron Collider. Differentialcross-sections are measured in events with exactly one elec-tron and one muon with opposite-sign electric charge as afunction of the azimuthal opening angle and the absolutedifference in pseudorapidity between the electron and muoncandidates in the laboratory frame. The azimuthal openingangle is also measured as a function of the invariant mass ofthet ̄tsystem. The measured differential cross-sections arecompared to predictions by several NLO Monte Carlo gen-erators and fixed-order calculations. The observed degree ofspin correlation is somewhat higher than predicted by thegenerators used. The data are consistent with the predic-tion of one of the fixed-order calculations at NLO, but agreeless well with higher-order predictions. Using these leptonicobservables, a search is performed for pair production ofsupersymmetric top squarks decaying into Standard Modeltop quarks and light neutralinos. Top squark masses between170 and 230 GeV are largely excluded at the 95% confidencelevel for kinematically allowed values of the neutralinomass

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:

Franconi, Laura; Haug, Sigve; Weber, Michele; Anders, John Kenneth; Beck, Hans Peter; Ereditato, Antonio; Merlassino, Claudia; Miucci, Antonio and Weston, Thomas Daniel

Subjects:

500 Science > 530 Physics

ISSN:

1434-6044

Publisher:

EDP Sciences

Language:

English

Submitter:

BORIS Import LHEP

Date Deposited:

06 Jun 2021 21:14

Last Modified:

13 Jun 2021 03:08

Publisher DOI:

10.1140/epjc/s10052-020-8181-6

Additional Information:

Kollaboration - Es sind nur die Berner Autoren namentlich erwaehnt

BORIS DOI:

10.48350/155623

URI:

https://boris.unibe.ch/id/eprint/155623

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