Combined search for the quarks of a sequential fourth generation (CROSBI ID 201182)
Prilog u časopisu | izvorni znanstveni rad | međunarodna recenzija
Podaci o odgovornosti
Chatrchyan, S. ; ... ; Godinović, Nikola ; Lelas, Damir ; Pleština, Roko ; Polić, Dunja ; Puljak, Ivica ; Antunović, Željko ; Kovač, Marko ; Brigljević, Vuko ; Đurić, Senka ; Kadija, Krešo ; Luetić, Jelena ; Morović, Srećko ; ... ; Mekterović, Darko ; ... ; Swanson, J.
engleski
Combined search for the quarks of a sequential fourth generation
Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.
LHC ; CMS ; fourth generation
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Podaci o izdanju
86 (11)
2012.
112003
20
objavljeno
1550-7998
1550-2368
10.1103/PhysRevD.86.112003