Inclusive search for a sequential fourth generation of quarks

One of the simplest extensions of the standard model is a model with a sequential fourth generation of fermions. Despite the many searches for new quarks, no evidence for their existence has been found. The aforementioned searches cover a large part of the parameter space in which a fourth generation would be consistent with the standard model measurements. We have developed an inclusive search strategy for a new generation of quarks of the up- and down-type that reduces the parameter space even further. This document presents a search for final states with fourth-generation quarks produced singly or in pairs in a dataset corresponding to an integrated luminosity of 5\,fb$^{-1}$ recorded by the CMS experiment at the LHC in 2011. The inclusive search is performed in the decay channels with at least one isolated muon or electron. We derive model dependent limits on the mass of the fourth-generation quarks and the relevant CKM matrix elements. The existence of fourth-generation quarks with masses below 685 GeV is excluded at 95\% CL for minimal off-diagonal mixing between the third and the fourth-generation quarks.