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  • Search for invisible particles produced in association with single-top-quarks in proton-proton collisions at $\sqrt{s}$ = 8 TeV with the ATLAS detector
    Publication . ATLAS collaboration (2879 authors); Aguilar-Saavedra, Juan Antonio; Amor Dos Santos, Susana Patricia; Anjos, Nuno; Araque, Juan Pedro; Cantrill, Robert; Carvalho, João; Castro, Nuno Filipe; Conde Muiño, Patricia; Da Cunha Sargedas De Sousa, Mario Jose; Fiolhais, Miguel; Galhardo, Bruno; Gomes, Agostinho; Gonçalo, Ricardo; Jorge, Pedro; Lopes, Lourenco; Machado Miguens, Joana; Maio, Amélia; Maneira, José; Onofre, António; Palma, Alberto; Pedro, Rute; Pina, João Antonio; Pinto, Belmiro; Santos, Helena; Saraiva, João; Silva, José; Tavares Delgado, Ademar; Veloso, Filipe; Wolters, Helmut
    A search for the production of single-top-quarks in association with missing energy is performed in proton–proton collisions at a centre-of-mass energy of $\sqrt{s}=\mathrm {8~TeV}$ with the ATLAS experiment at the large hadron collider using data collected in 2012, corresponding to an integrated luminosity of $20.3$  fb$^{-1}$ . In this search, the $W$ boson from the top quark is required to decay into an electron or a muon and a neutrino. No deviation from the standard model prediction is observed, and upper limits are set on the production cross-section for resonant and non-resonant production of an invisible exotic state in association with a right-handed top quark. In the case of resonant production, for a spin- $0$ resonance with a mass of $500$  GeV, an effective coupling strength above $0.15$ is excluded at 95 $\,\%$ confidence level for the top quark and an invisible spin- $1/2$ state with mass between $0$ and $100$  GeV. In the case of non-resonant production, an effective coupling strength above $0.2$ is excluded at 95 $\,\%$ confidence level for the top quark and an invisible spin- $1$ state with mass between $0$ and $657$  GeV.
    2015-02-18Journal article Open access Show more