couplings between mesons and baryons (singlet and octet)

What is the basic meaning and good reference for the deep and simple meaning(in simple language) of couplings between mesons and baryons, e.g., g1 and g8 couplings (singlet and octet) from where these couplings come and what is the motivation behind it ?

• WP too heavy? – Cosmas Zachos Nov 7 '19 at 0:37