Observation of B-s production at the Upsilon(5S) resonance

Abstract

Using the CLEO detector at the Cornell Electron Storage Ring, we have observed the B-s meson in e(+)e(-) annihilation at the Upsilon(5S) resonance. We find 14 candidates consistent with B-s decays into final states with a J/psi or a D-s(()*()-). The probability that we have observed a background fluctuation is less than 8x10(-10). We have established that at the energy of the Upsilon(5S) resonance B-s production proceeds predominantly through the creation of B-s*($) over bar (s)* pairs. We find sigma(e(+)e(-)-> B-s* (B) over bar (s)*)=[0.11(-0.03)(+0.04)(stat)+/- 0.02(syst)] nb, and set the following limits: sigma(e(+)e(-)-> B-s (B) over bar (s))/sigma(e(+)e(-)-> B-s*(B) over bar (s)*)< 0.16 and [sigma(e(+)e(-)-> B-s(B) over bar (s)*)+sigma(e(+)e(-)-> B-s*(B) over bar (s))]/sigma(e(+)e(-)-> B-s*(B) over bar (s)*)< 0.16 (90% C.L.). The mass of the B-s(*) meson is measured to be M-Bs*=[5.414 +/- 0.001(stat)+/- 0.003(syst)] GeV/c(2).