What atom is the only atom that has neutrons?

In 1964, physicist Murray Gell-Mann made a groundbreaking statement when he declared that protons and neutrons - the components that make up the bulk of the weight in atoms - …are each made up of three "quarks." Murray went on to theorize that quarks are subatomic particles carrying a fraction of a charge (as opposed to a full +1 or -1 charge) that together create baryons, or arrangements of quarks that result in what we call matter. Since Gell-Mann's famous discovery, our understanding of the components of matter have been supplemented with experimental evidence, and scientists have even been able to extend Gell-Mann's arguments with evidence of another type of baryon, the pentaquark, recently making headlines.

The Large Hadron Collider near Geneva, Switzerland allows scientists to experimentally test theories concerning high-energy physics, subatomic particles, and other yet-unanswered questions about physics. The researchers identified several pathways by which these neutron-like particles could decay, noting the existence of "exotic" pathways that did not result in the typical triquark formation of matter. Thus, several expotic pathways that involved resonant forms of pentaquarks were hypothesized and confirmed by extensive experimental analysis.