New heavy baryons discovered.

[Goth]

Not sure where this is sourced from, it was in an email from my nuclear physics lecturer the other day.

THE PERIODIC TABLE OF BARYONS has now been supplemented with
several heavyweight members. Like the addition of two new
elements (116 and 118) to the chemical periodic table, the
new members of the baryonic periodic table are unstable and
ephemeral, but their observed existence serves to expand our
understanding of matter in the universe. The new baryons,
the heaviest yet with masses around 5.8 GeV, were sifted
from trillions of proton-antiproton collisions conducted at
an energy of 2 TeV at Fermilab. According to the toolbox of
the standard model, all matter is assembled from a family of
six leptons or a family of six quarks. Among the leptons,
only the electron is of account in ordinary atoms, and among
the quarks only the up (u) and down (d) quarks help to fill
out protons and neutrons. Thus the proton is really a u-u-d
quark troika while the neutrons lineup is d-d-u. But one
can imagine other baryons (particles made of three quarks)
made of different quark combinations, or with different spin
values (the proton and neutron both have a nominal spin
value of 1/2). Although they can be made artificially in
particle collisions, baryons containing the other
quarks---strange (s), charm (c), bottom (b), or top
(t)---are unstable and quickly decay. Still, to understand
the strong force that governs nuclear matter, physicists
strive to create and measure all those other candidate
baryons. (For a picture of the baryon hierarchy see
http://www.aip.org/png/2006/270.htm ) Up to now there was
only one well established bottom-quark-bearing baryon, the
so called Lambda_b. The first evidence for its existence was
reported by CERN and Fermilab in late 1990s based on a
handful of events. Now the CDF collaboration at Fermilab
are claiming discovery of two baryon types, each on the
basis of about 100 events. Actually there are four new
so-called Sigma-b baryons: two positively charged baryons
with a u-u-b combination (one with spin 1/2, one with spin
3/2), the first of which constitutes a sort of
bottom-proton; and two negatively charged baryons with a
d-d-b combination (one each with a spin of 1/2 or 3/2). In
all cases, the Sigma decays almost immediately into a
Lambda-b particle (with a u-d-b set of quarks) plus a pion.
In the detector the Lambda typically flies about 100 microns
before decaying into Lambda-c (a Lambda baryon with a c
quark instead of a b), which quickly decays into an ordinary
proton. Is there sufficient data in this case to claim a
discovery of these particles? The new results were
announced at a recent talk at Fermilab by Petar Maksimovic, of Johns
Hopkins University. Jacobo Konigsberg, of the University of
Florida, the co-spokesperson for the CDF group says that the
statistical odds against the Sigma-b particles being real
are at the level of a few parts in 10^19.