Pseudoscalar Goldstone Bosons Scattering off Charmed Baryons with Chiral   Perturbation Theory
  We have systematically calculated the pseudoscalar Goldstone boson and charmed baryon scattering lengths to the third order with heavy baryon chiral perturbation theory. The scattering lengths can reveal the interaction of $K \Lambda_c$, $K \Sigma_c$, $\pi \Omega_c$ etc. For each channel, we take into account of the interaction between the external particle and every possible charmed baryon in the triplet, sextet, and excited sextet. We use dimensional regularization and modified minimal subtraction to get rid of the divergences in the loop-diagram corrections. We notice that the convergence of chiral expansion for most of the channels becomes better after we let the low energy constants absorb the analytic contributions of the loop-diagram corrections and keep the nonanalytic terms only. 
Zhan-Wei Liu, Shi-Lin Zhu
hep-ph nucl-th