Associated Production of Z Boson and a Pair of New Quarks at LHC

The associated production of Z boson and a pair of new quarks at the Large Hadron Collider (LHC) is studied. The cross sections for both sequential fermions and vector-like fermions are presented. It is found that for sequential fermions the cross sections can reach 1 similar to 10(2) fb for heavy quark mass m(Q) from 1000 GeV to 200 GeV. For vector-like quarks, the cross sections are suppressed by mixing parameter sin theta(L). Focusing on process pp -> b'b', we investigate the possibility of detecting the 6l + 2j signal. For ab' with light mass and a large branching ratioof b' -> bZ, it is found that only several signal events (parton level) can be produced with 1000 fb(-1) integrated luminosity. Although the signal events are rare, all the final states are produced centrally and multi lepton final states are clear at hadron collider, which could be easily detected.