2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/194648We calculate decuplet contributions to the s-wave pseudoscalar meson octet-baryon scattering lengths to the third order in heavy baryon chiral perturbation theory (HB$χ$PT). Using experimental pion-nucleon and kaon-nucleon scattering lengths as inputs, we determine low-energy constants and predict other meson-baryon scattering lengths. Numerically we consider three cases: (1) the case with only baryon octet contributions; (2) with decuplet contributions and (3) in the large N_c limit. Hopefully, the analytical expressions and the predictions are helpful to future investigations of the meson-baryon scattering lengths.11 pages, 1 figure, 9 tablesHigh Energy Physics - PhenomenologyHigh Energy Physics - LatticeNuclear Theorytext