Search for a scalar partner of the top quark in the all-hadronic t\bart plus missing transverse momentum final state at \sqrts=13 TeV with the ATLAS detector

Franconi, Laura; Haug, Sigve; Weber, Michele; Anders, John Kenneth; Fehr, Armin; Beck, Hans Peter; Ereditato, Antonio; Lehmann, Niklaus; Miucci, Antonio; Weston, Thomas Daniel (2020). Search for a scalar partner of the top quark in the all-hadronic t\bart plus missing transverse momentum final state at \sqrts=13 TeV with the ATLAS detector. The European physical journal. C, Particles and fields, 80(8) Springer 10.1140/epjc/s10052-020-8102-8

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A search for direct pair production of scalar partners of the top quark (top squarks or scalar third-generation up-type leptoquarks) in the all-hadronic tt¯ plus missing transverse momentum final state is presented. The analysis of 139 fb−1 of s√=13 TeV proton–proton collision data collected using the ATLAS detector at the LHC yields no significant excess over the Standard Model background expectation. To interpret the results, a supersymmetric model is used where the top squark decays via t~→t(∗)χ~01, with t(∗) denoting an on-shell (off-shell) top quark and χ~01 the lightest neutralino. Three specific event selections are optimised for the following scenarios. In the scenario where mt~>mt+mχ~01, top squark masses are excluded in the range 400–1250 GeV for χ~01 masses below 200 GeV at 95% confidence level. In the situation where mt~∼mt+mχ~01, top squark masses in the range 300–630 GeV are excluded, while in the case where mt~<mW+mb+mχ~01 (with mt~−mχ~01≥5 GeV), considered for the first time in an ATLAS all-hadronic search, top squark masses in the range 300–660 GeV are excluded. Limits are also set for scalar third-generation up-type leptoquarks, excluding leptoquarks with masses below 1240 GeV when considering only leptoquark decays into a top quark and a neutrino.

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)
08 Faculty of Science > Physics Institute

UniBE Contributor:

Franconi, Laura, Haug, Sigve, Weber, Michele, Anders, John Kenneth, Ilg, Armin, Beck, Hans Peter, Ereditato, Antonio, Lehmann, Niklaus, Miucci, Antonio, Weston, Thomas Daniel

Subjects:

500 Science > 530 Physics

ISSN:

1434-6044

Publisher:

Springer

Language:

English

Submitter:

BORIS Import LHEP

Date Deposited:

21 Apr 2021 13:19

Last Modified:

02 Mar 2023 23:34

Publisher DOI:

10.1140/epjc/s10052-020-8102-8

Additional Information:

Kollaboration - Es sind nur die Berner Autoren namentlich erwaehnt

BORIS DOI:

10.48350/155567

URI:

https://boris.unibe.ch/id/eprint/155567

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