The researchers think it might be a strange type of composite particle called a tetraquark. These are an exotic kind of meson, which normally has two quarks. But a tetraquark is composed of four quarks – well, two quarks and two antiquarks, to be more accurate. Observational evidence of tetraquarks has been pretty elusive to date, and that is also the case here. Evidence of the candidate particle, called Zc-(4100) and including two heavy charm quarks, was detected in the decay of heavier B-mesons.
The new bottom baryons, you'll be pleased to know, blew that threshold out of the water: Σb(6097)+ and Σb(6097)- had significances of 12.7 and 12.6 standard deviations respectively.