Search

Vector-like quarks are introduced in various new physics models beyond the standard model (SM) at the TeV scale. We especially consider the case that the quark is singlet (triplet) under the SU(2)L (SU(3)c) gauge group and couples only to the third-generation quarks of the SM. The vector-like quark of this kind is often called a top partner. The top partner tp decays into bW, tZ, and th. In the ATLAS and CMS Collaborations, the top partner has been searched in the final states of bW and tZ, while the search based on the decay mode tp → th has not been started yet. However, the decay into th is important, since it is significantly enhanced if some strong dynamics exists in the TeV scale. In the presence of a light Higgs boson, the decay mode tp → th followed by h → bb produces three bottom quarks. We study the sensitivity for the top partner using multi-b-jet events at the 8 TeV run of the Large Hadron Collider (LHC) experiment. The multi-b-jet events turn out to play a complementary role to the existing tp --* bW and tZ searches by the ATLAS and CMS Collaborations. [ABSTRACT FROM AUTHOR]