In the beginning of '60 of last century, Gell-Mann and Neewman independently noticed, that due to the same spin, parity and strangeness, and due to similar masses, hadrons can be grouped into so called multiplets, which than are grouped into supermultiplets consisting of singlets, octets and decouplets. Introducing values descibing the multicity - like isospin I=(N-1)/2 and hypercharge (Y=B+S, where B - barion number, S - strangeness) and after plotting dependences of these values (to be exact - hypercharge vs. isospin's projection on "selected direction" I3) characteristic geometrical figures can be obtained. That situation was similar to first trials of classification of chemical elements into Mendelejew's table.
Supermultiplets allowed to predict existence of new particles. Quark's hypothesis was "on the way".
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Mesons octet with spin s=0 |
Barions octet with spin s=(1/2)- |
