There is always a lot more to discover about our universe. LHC ( Large Hadron Collider ) which 2 years ago came in news for the discovery of the Higgs Boson. Recently two more new subatomic particles known as Xi_b'- and Xi_b*- ( pronounced as ZAI-bee-minus and ZAI-bee-star-minus respectively ) these particles were predicted to exist by the particle physicists, now they have been observed at LHC.
These both particles from the name suggest that they would have almost similar properties, consisting of down quark, strange quark and bottom quark. Spins of down and strange quark are different though lightly (5.935 GeV vs 5.955 GeV).
These two particles joins the list of hadrons. There are only 17 fudamental particles ( such as electrons, neutrons, higgs boson etc.) in the Standard Model. They are predicted to combine into hundreds of other composite particles. By smashing atoms together with the accelerators scientist have managed to glimpse many of these composite particles, usually as they quickly decay into fundamental particles but, many are still to be discovered.
The new Xi bayrons were discovered by the LHC's seven hyper-sensitive particle detedtor. LHCb's a special type of detectors are tunes to detect these kind of particles. Also earlier this year LHC discovered a new type of particle named as exotic hadrons with highly unusually made of four quarks instead of three