- An article I saw on r/physics today announced Fermilab's discovery of xi-sub-b, a baryon that had been predicted, but not previously observed. How exactly do the CDF/LHC and other particle detectors conclusively observe and determine the existence of a particle if it has never been observed before? http://www.conceivablytech.com/8516/science-research/fermilab-scientists-discover-new-particle 5 comments askscience