On the $\pi$ and $K$ as $q\bar{q}$ Bound States and Approximate Nambu-Goldstone Bosons

Shmuel Nussinov, Robert Shrock

We reconsider the two different facets of $\pi$ and $K$ mesons as $q\bar{q}$ bound states and approximate Nambu-Goldstone bosons. We address several topics, including masses, mass sp…