 Under SSB, this is spontaneously broken to the diagonal flavor "SU"(3) subgroup, generating eight Nambu–Goldstone bosons, which are the pseudoscalar mesons transforming as an octet representation of this flavor "SU"(3).Beyond this idealization of massless quarks, the actual small quark masses also break the chiral symmetry explicitly as well (providing non-vanishing pieces to the divergence of chiral currents, commonly referred to as PCAC