LHC signals of the $SO(5)\times U(1)$ gauge-Higgs unification

Abstract

Signatures of the $SO(5)\times U(1)$ gauge-Higgs unification at LHC and future colliders are explored. The Kaluza-Klein (KK) mass spectra of $\gamma, Z, Z_R$ and the Higgs self-couplings obey universality relations with the Aharonov-Bohm (AB) phase $\theta_H$ in the fifth dimension. The current data at low energies and at LHC indicate $\theta_H <0.2$. Couplings of quarks and leptons to KK gauge bosons are determined. Three neutral gauge bosons, the first KK modes $Z_R^{(1)}$, $Z^{(1)}$, and $\gamma^{(1)}$, appear as $Z'$ bosons in dilepton events at LHC. For $\theta_H = 0.114$, the mass and decay width of $Z_R^{(1)}$, $Z^{(1)}$, and $\gamma^{(1)}$ are (5.73TeV, 482GeV), (6.07TeV, 342GeV), and (6.08TeV, 886GeV), respectively. For $\theta_H = 0.073$ their masses are 8.00TeV$\sim$8.61TeV. An excess of events in the dilepton invariant mass should be observed in the $Z'$ search at the upgraded LHC at 14TeV.