Direct observation of the strange b baryon Xi_b^{-}
High Energy Physics - Experiment
2008-11-26 v3
Abstract
We report the first direct observation of the strange b baryon Xi_b^{-}. We reconstruct the decay Xi_b^{-} to J/psi Xi^{-}, with J/psi to dimuons and Xi^{-} to Lambda pion, in ppbar collisions at sqrt(s) = 1.96 TeV. Using 1.3 fb^{-1} of data collected by the D0 detector, we observe 15.2 +/- 4.4(stat.)+ 1.9/-0.4(syst.) Xi_b^{-} candidates at a mass of 5.774 +/- 0.011(stat.) +/- 0.015 (syst.) GeV. The significance of the observed signal is 5.5 sigmas, equivalent to a probability of 3.3 X 10^{-8} of it arising from a background fluctuation. Normalizing to the decay Lambda_b to J/psi Lambda, we measure the relative rate to be 0.28 +/- 0.09(stat.)+ 0.09/-0.08 (syst.).
Keywords
Cite
@article{arxiv.0706.1690,
title = {Direct observation of the strange b baryon Xi_b^{-}},
author = {D0 Collaboration and V. Abazov},
journal= {arXiv preprint arXiv:0706.1690},
year = {2008}
}
Comments
Version published in Phys. Rev. Lett