hyperon

A hyperon is a composite particle (a hadron) that has 1/2 spin (and obeys Fermi-Dirac statistics, i.e., a fermion) that consists of an odd number of quarks (a baryon), in which at least one is a strange quark and any of the others is either an up quark or a down quark. Various hyperon types are known, depending upon their quark flavor combinations. They generally decay immediately, in some cases into more familiar baryons. Such fleeting existence is detected in for in particle accelerator experiments. Matter consisting of stable hyperons (hyperonic matter or hyperon condensate) is considered a possibility within some neutron stars, where hyperons may be a factor in their cooling through reactions that produce neutrinos, the latter of which may sometimes escape the star with their energy.