Observation of the decay Bs0J/ in p»p collisions at s =1.8 TeV

This Letter reports the observation and mass measurement of fully reconstructed [ital B][sub [ital s]][sup 0] mesons through the decay chain [ital B][sub [ital s]][sup 0][r arrow][ital J]/[psi] [psi], [ital J]/[psi][r arrow][mu][sup +][mu][sup [minus]], [phi][r arrow][ital K][sup +][ital K[minus]] using data obtained at the Collider Detector at Fermilab in [ital [bar p]p] collisions at [radical][ital s] =1.8 TeV. A signal of 14.0[plus minus]4.7 events is observed. Comparison of the [ital B][sub [ital s]][sup 0] signal with the kinematically similar decays [ital B][sup +][r arrow][ital J]/[psi] [ital K][sup +] and [ital B][sup 0][r arrow][ital J]/[psi] K[sup *](892)[sup 0] is presented. The mass of the [ital B][sub [ital s]][sup 0] meson is determined to be 5383.3[plus minus]4.5(stat)[plus minus]5.0(syst) MeV/[ital c][sup 2].