Observation of Bs Production at the Υ(5S) Resonance

Abstract

Using the CLEO detector at the Cornell Electron Storage Ring, we have observed the Bs meson in e+e- annihilation at the Υ(5S) resonance. We find 14 candidates consistent with Bs decays into final states with a J/ψ or a Ds(*)-. The probability that we have observed a background fluctuation is less than 8×10-10. We have established that at the energy of the Υ(5S) resonance Bs production proceeds predominantly through the creation of Bs*B̄s* pairs. We find σ(e+e-→Bs*B̄s*)=[0.11-0.03+0.04(stat)±0.02(syst)]nb, and set the following limits: σ(e+e-→BsB̄s)/σ (e+e-→Bs*B̄s*)<0.16 and [σ(e+e-→BsB̄s*) +σ(e+e-→Bs*B̄s)]/σ(e+e-→Bs*B̄ s*)<0.16 (90% C.L.). The mass of the Bs* meson is measured to be MBs*=[5.414±0.001(stat)±0.003(syst)]GeV/c2. © 2006 The American Physical Society.