A search for a fourth-generation charge-13 (b′) quark using inclusive muons in e+e- annihilations at s=56.5-60.8 GeV

Abstract A search for fourth-generation charge - 1 3 ( b ′) quarks using inclusive muon events in e + e - annihilations at s =56.5-60.8 GeV is presented, considering its decays through loop-induced flavor-changing neutral-current as well as its charged current decays. Production of b′ (and top) was excluded as the cause of slightly high R -values observed at ∈ s =⩾56.0 GeV, if they decay dominantly through a charged-current (68%). One large aplanarity event ( A =0.17 with an isolated muon, observed at s =60.8 GeV, is also presented.