Flavour classification of hadrons

Although the data (mostly from neutrino experiments) on the c—s coupling are not conclusive, the evidence suggests that it is also left-handed. The apparent connection between quarks and leptons is fascinating. Both sets of doublets are point-like s = 5 fermions their electric charges are quantized in a related way (Q, Q — 1 with Q = 0 for leptons and Q = for quarks) furthermore, the sum of the electric charges of all fermions (in a colour scheme) vanishes as required to cancel triangle anomalies (see Section 9.5.3). It should be noted, however, that serious questions arise if one tries to put the above quark-lepton connection on a quantitative 

As already mentioned, the flavour symmetry SU 3)p of Gell-Mann and Neeman was very successful in providing a classification of the old (i.e. pre-charm) spectroscopy. The quantum numbers of each hadron were 

Examples of the quark-antiquark content are given in Fig. 11.2. The quark content of the particles at the centre of the diagrams, assuming SU 3)f symmetry, are 

Similarly, singlets, octets and decuplets of baryons are obtmned by combining quarks according to 

For examples, see Fig. 11.3. For the baryon octet, 517(3) f does not imiquely specify the flavour wave function. 

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