FTP, name this  subclass of hadrons which include the upsilon, K, pi, and J/psi  varieties, first predicted by Hideki Yukawa.
This class of subatomic particles was, prior to the advent of  quark theory, thought to be the fundamental particles that held  nuclei together. Their study has led to the discovery of the  nonconservation of parity & the charmed quark, and the prediction  and subsequent discovery of the eta variety was a success for Gell-  Mann's Eightfold Way classification system. FTP, name this  subclass of hadrons which include the upsilon, K, pi, and J/psi  varieties, first predicted by Hideki Yukawa.
This class of subatomic particles was, prior to the advent of  quark theory, thought to be the fundamental particles that held  nuclei together.
{meson}s