ABSORPTIVE PART OF MESON–BARYON SCATTERING AMPLITUDE AND BARYON POLARIZATION IN CHIRAL PERTURBATION THEORY

We compute the spin asymmetry and polarization of the final-state baryon in its rest frame in two-body meson–baryon low-energy scattering with an unpolarized initial state to lowest non-trivial order in BChPT. The required absorptive amplitudes are obtained analytically at the one-loop level. We discuss the polarization results numerically for several meson–baryon processes. Even at low energies above threshold, where BChPT can reasonably be expected to be applicable, sizable values of polarization are found for some processes.

GROUND-STATE BARYON MASSES IN THE PERTURBATIVE CHIRAL QUARK MODEL

The mass differences of the flavor octet and decuplet ground-state baryons are studied in the perturbative chiral quark model. We present a way to understand the nontrivial spin- and flavor-dependent mass differences, whereby both pseudoscalar mesons and gluons play a significant role.