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Xi_b'- and Xi_b*-
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New subatomic particles predicted by Canadians found at CERN

The discovery of the particles, known as Xi_b'- and Xi_b*-, were announced by CERN, the European Organization for Nuclear Research today and published online on the physics preprint server Arxiv.
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Observation of two new Xi_b^- baryon resonances

http://arxiv.org/abs/1411.4849



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Omega-sub-b
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Physicists of the DZero experiment at the U.S. Department of Energy's Fermi National Accelerator Laboratory have discovered a new particle made of three quarks, the Omega-sub-b (b). The particle contains two strange quarks and a bottom quark (s-s-b). It is an exotic relative of the much more common proton and weighs about six times the proton mass.
The discovery of the doubly strange particle brings scientists a step closer to understanding exactly how quarks form matter and to completing the "periodic table of baryons." Baryons (derived from the Greek word "barys," meaning "heavy") are particles that contain three quarks, the basic building blocks of matter. The proton comprises two up quarks and a down quark (u-u-d).

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b baryon Omega_b-
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Title: Observation of the doubly strange b baryon Omega_b-
Authors: D0 Collaboration: V. Abazov, et al

We report the observation of the doubly strange b baryon Omega_b- in the decay channel Omega_b- to J/psi Omega-, with J/psi to mu+ mu- and Omega- to Lambda K-, in p\bar{p} collisions at \sqrt{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) Omega_b- 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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RE: Cascade b baryon
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baryon_e2
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Credit: Image courtesy of DOE/Fermi National Accelerator Laboratory



Title: Direct observation of the strange b baryon Xi_b^{-}
Authors: D0 Collaboration, V. Abazov, et al
(Version v2)

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. Normalising 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.).

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Fermilab physicists discover "triple-scoop" baryon
Three-quark particle contains one quark from each family.
Physicists of the DZero experiment at the Department of Energy's Fermi National Accelerator Laboratory have discovered a new heavy particle, the b (pronounced "zigh sub b") baryon, with a mass of 5.7740.019 GeV/c, approximately six times the proton mass. The newly discovered electrically charged b baryon, also known as the "cascade b," is made of a down, a strange and a bottom quark. It is the first observed baryon formed of quarks from all three families of matter. Its discovery and the measurement of its mass provide new understanding of how the strong nuclear force acts upon the quarks, the basic building blocks of matter.
The DZero experiment has reported the discovery of the cascade b baryon in a paper submitted to Physical Review Letters on June 12.

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