Inclusive search for a fourth generation of quarks with the CMS experiment

We present a search for fourth generation chiral quarks of the up- and down-type in 7 TeV proton collisions recorded by the CMS experiment at the LHC. Final state topologies with $b'$ and $t'$ quarks produced singly or in pairs are studied in the 2011 data corresponding to an integrated luminosity of 1.1~fb$^{-1}$. Degenerate masses are assumed for the fourth generation quarks. The inclusive search is performed in the decay channel where one isolated muon with a high transverse momentum is identified and results in model dependent limits on the mass of the chiral quarks and the relevant CKM4 matrix elements. For minimal off-diagonal mixing between the third and the fourth generation, a limit $m_{t'} >$ 490\GeVcc is obtained at 95\% C.L.