e/Theta meson

Information
has gloss	eng: The theta meson is a hypothetical form of quarkonium (i.e. a flavourless meson) formed by a top quark and top antiquark. It is the equivalent of the phi (strange quark, strange antiquark), psi (charm quark, charm antiquark) and upsilon (bottom quark, bottom antiquark) mesons. Due to the top quark's shortlifetime, the theta meson is not expected to be observed in nature.
lexicalization	eng: theta meson
instance of	(noun) an elementary particle responsible for the forces in the atomic nucleus; a hadron with a baryon number of 0 mesotron, meson