We study the scattering of a pseudoscalar meson off one ground state octet baryon up to the next-to-next-to-leading order in covariant baryon chiral perturbation theory (BChPT) with the extended-on-mass-shell scheme. We perform the first combined study of the pion-nucleon and kaon-nucleon scattering data in covariant BChPT and show that it can provide a reasonable description of the experimental data. In addition, we find that it is possible to fit the experimental baryon masses and the pion-nucleon and kaon-nucleon scattering data simultaneously at this order, thus providing a consistency check on covariant BChPT. We compare the scattering lengths of all the pertinent channels with available experimental data and those of the heavy baryon ChPT and infrared BChPT and discuss the convergence of SU(3) BChPT.

• Received 12 February 2019

DOI:https://doi.org/10.1103/PhysRevD.99.054024