الفهرس 
ContentsOnly 14 pages are availabe for public view
 |  | from | 143 |  |  |
| | | from | 143 | | |
Abstract
Since 1947 a large number of fundamental particles have been discovered in cosmic-radiation and among the secondary particles produced by accelerators. It was suggested to classify these particles into three categories according to their masses,
i. leptons, the masses of wich are smaller than the mass of the mesons.
ii. Baryons, with masses of the order of magnitude of the masses of the proton.
iii. Mesons of intermediate masses.