FTP, name this class of subatomic particles composed of an even number of quarks and antiquarks and whose members include pi, K, and J/psi varieties.
These particles vary greatly in mass, ranging from 140 mega-electron volts to 10 giga-electron volts.  One of the early successes of the Eightfold Way was the prediction of their eta type. We know that they are sensitive to the strong force because their constituent quarks are strongly interacting, and as a result, they provided the means for discovering the charmed, bottom and top quarks.  Several types of them have been discovered since they were first postulated by Hideki Yukawa in 1935.  FTP, name this class of subatomic particles composed of an even number of quarks and antiquarks and whose members include pi, K, and J/psi varieties.
These particles vary greatly in mass, ranging from 140 mega-electron volts to 10 giga-electron volts.  
Mesons