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 t (t) over bar plus missing transverse momentum final state is presented. The analysis of 139 fb(-1) of root 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) over tilde -> t((*))(chi) over tilde (0)(1), with t((*)) denoting an on-shell (off-shell) top quark and (chi) over tilde (0)(1) the lightest neutralino. Three specific event selections are optimised for the following scenarios. In the scenario where m((t) over tilde) > m(t) + m((chi) over tilde 10), top squark masses are excluded in the range 400-1250 GeV for (chi) over tilde (0)(1) masses below 200 GeV at 95% confidence level. In the situation where m((t) over tilde) similar to m(t) + m((chi) over tilde 10), top squark masses in the range 300-630 GeV are excluded, while in the case where m((t) over tilde) < m(W) + m(b) + m(<(chi)over tilde>10) (with m((t) over tilde) - m((chi) over tilde 10) >= 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.

Aad, G., Abbott, B., Abbott, D.c., Abud, A.a., Abeling, K., Abhayasinghe, D.k., et al. (2020). Search for a scalar partner of the top quark in the all-hadronic tt¯ plus missing transverse momentum final state at √s=13 TeV with the ATLAS detector. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS, 80(8) [10.1140/epjc/s10052-020-8102-8].

Search for a scalar partner of the top quark in the all-hadronic tt¯ plus missing transverse momentum final state at √s=13 TeV with the ATLAS detector

Aielli G.;Camarri P.;Cerrito L.;De Sanctis U.;Di Ciaccio A.;Giuli F.;Loffredo S.;
2020-01-01

Abstract

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 t (t) over bar plus missing transverse momentum final state is presented. The analysis of 139 fb(-1) of root 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) over tilde -> t((*))(chi) over tilde (0)(1), with t((*)) denoting an on-shell (off-shell) top quark and (chi) over tilde (0)(1) the lightest neutralino. Three specific event selections are optimised for the following scenarios. In the scenario where m((t) over tilde) > m(t) + m((chi) over tilde 10), top squark masses are excluded in the range 400-1250 GeV for (chi) over tilde (0)(1) masses below 200 GeV at 95% confidence level. In the situation where m((t) over tilde) similar to m(t) + m((chi) over tilde 10), top squark masses in the range 300-630 GeV are excluded, while in the case where m((t) over tilde) < m(W) + m(b) + m(<(chi)over tilde>10) (with m((t) over tilde) - m((chi) over tilde 10) >= 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.
2020
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore FIS/01 - FISICA SPERIMENTALE
English
Con Impact Factor ISI
Aad, G., Abbott, B., Abbott, D.c., Abud, A.a., Abeling, K., Abhayasinghe, D.k., et al. (2020). Search for a scalar partner of the top quark in the all-hadronic tt¯ plus missing transverse momentum final state at √s=13 TeV with the ATLAS detector. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS, 80(8) [10.1140/epjc/s10052-020-8102-8].
Aad, G; Abbott, B; Abbott, Dc; Abud, Aa; Abeling, K; Abhayasinghe, Dk; Abidi, Sh; Abouzeid, Os; Abraham, Nl; Abramowicz, H; Abreu, H; Abulaiti, Y; Ach...espandi
Articolo su rivista
File in questo prodotto:
File Dimensione Formato  
epjc.80.737.pdf

accesso aperto

Tipologia: Versione Editoriale (PDF)
Licenza: Creative commons
Dimensione 2.57 MB
Formato Adobe PDF
2.57 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/275689
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 99
  • ???jsp.display-item.citation.isi??? 43
social impact