Strangeness $S=-1$ hyperon-nucleon scattering in covariant chiral   effective field theory
  Motivated by the successes of covariant baryon chiral perturbation theory in one-baryon systems and in heavy-light systems, we study relevance of relativistic effects in hyperon-nucleon interactions with strangeness $S=-1$. In this exploratory work, we follow the covariant framework developed by Epelbaum and Gegelia to calculate the $YN$ scattering amplitude at leading order. By fitting the five low-energy constants to the experimental data, we find that the cutoff dependence is mitigated, compared with the heavy-baryon approach. Nevertheless, the description of the experimental data remains quantitatively similar at leading order. 
Kai-Wen Li, Xiu-Lei Ren, Li-Sheng Geng, and Bing-Wei Long
hep-ph nucl-th