Searches for Prompt Heavy Quarkonia & ${\rm B}^\pm_{\rm c}$ Mesons and Evidence for Radially Excited B Mesons in Z0 Decays

Abstract

We have searched for prompt heavy quarkonia and Bc mesons in 3 × 106 hadronic Z0 decays recorded with the DELPHI detector at LEP. No signal was observed in any of these modes. We achieved the highest sensitivities for gluon fragmentation into J/ψ and for semileptonic [Formula: see text] decays, yielding branching ratio upper limits of [Formula: see text] and [Formula: see text] @ 90% CL, respectively. We found the first evidence for radially excited B mesons, by observing a signal in the B(*)π+ π- final state at Q = m(B(*) π+π-) - m(B(*)) - 2m(π) = 301 ± 4 ± 10 MeV.