Observation of New Charmless Decays of Bottom Hadrons
Abstract
We search for new charmless decays of neutral b-hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb-1 of integrated luminosity, we report the first observation of the B0s->K-pi+ decay, with a significance of 8.2 sigma, and measure BR(B0s->K-pi+)= (5.0+-0.7(stat)+-0.8(syst))*10-6. We also report the first observation of charmless b-baryon decays in the channels Lambdab -> p pi and Lambdab -> pK with significances of 6.0 sigma and 11.5 sigma respectively, and we measure BR(Lambdab->p pi-) = (3.5+-0.6(stat)+-0.9(syst))*10-6 and BR(Lambdab->p K-) = (5.6+-0.8(stat)+-1.5(syst))*10-6. No evidence is found for the decays B0->K+K- and B0s -> pi+pi-, and we set an improved upper limit BR(B0s -> pi+pi-) < 1.2*10-6 at the 90% confidence level. All quoted branching fractions are measured using BR(B0->K+pi-) as a reference.