Baryon masses in a chiral expansion with meson-baryon form factors

Abstract

The chiral expansion of the one-loop corrections to baryon masses is examined in a generic meson-cloud model with meson-baryon form factors. For pion loops, the expansion is rapidly convergent and at fourth order in $m_{\pi }$ accurately reproduces the full integral. In contrast, the expansion is found to converge very slowly for kaon loops, raising questions about the usefulness of chiral expansions for kaon-baryon physics. Despite the importance of high-order terms, relations like that of Gell-Mann and Okubo are well satisfied by the baryon masses calculated with the full integral. The pion cloud cloud makes a significant contribution to the $\pi N$ sigma commutator, while kaon cloud gives a very small strangeness content in the nucleon.

Comments: 20 pages (RevTeX), 2 figures (attached)