Observation of the doubly strange b baryon Omegab-
Abstract
We report the observation of the doubly strange b baryon Omegab- in the decay channel Omegab- to J/psi Omega-, with J/psi to mu+ mu- and Omega- to Lambda K-, in pp collisions at s=1.96 TeV. Using approximately 1.3 fb-1 of data collected with the D0 detector at the Fermilab Tevatron Collider, we observe 17.8 +/- 4.9 (stat) +/- 0.8 (syst) Omegab- signal events at a mass of 6.165 +/- 0.010 (stat) +/- 0.013(syst.) GeV. The significance of the observed signal is 5.4 sigma, corresponding to a probability of 6.7 x 10-8 of it arising from a background fluctuation.
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