LHC signatures of neutral pseudo-Goldstone boson in the E₆CHM

Abstract

The breakdown of the SU(6) global symmetry to its SU(5) subgroup, that contains the standard model (SM) gauge group, in the E6 inspired composite Higgs model (E6CHM) results in a set of pseudo-Nambu–Goldstone bosons (pNGBs). This set, in particular, involves the SM-like Higgs doublet and a SM singlet boson. In the limit when CP is conserved the SM singlet scalar A is a CP-odd state that does not mix with the SM-like Higgs. The interactions of A with exotic matter beyond the SM, which ensures anomaly cancellation and approximate gauge coupling unification, can induce couplings of this pseudoscalar to the SM gauge bosons. We specify the interactions of the SM singlet pNGB state with the exotic vector-like fermions, top quark and SM gauge bosons. Also we explore the dependence of the branching ratios of the pseudoscalar A and its LHC production cross section on the parameters of the E₆CHM.