Light Scalar Mesons as Manifestation of Spontaneously Broken Chiral Symmetry

摘要

Attention is paid to the production mechanisms of light scalars that reveal their nature. We reveal the chiral shielding of the σ(600) meson. We show that the kaon loop mechanism of the radiative decays, ratified by experiment, points to the four-quark nature of light scalars. We show also that the light scalars are produced in the two photon collisions via four-quark transitions in contrast to the classic P wave tensor qq? mesons that are produced via two-quark transitions γγ → qq?. The history of spontaneous breaking of symmetry in quantum physics is discussed in Appendix.