Integrability of the $C_{n}$ and $BC_{n}$ Ruijsenaars-Schneider models
  We study the $C_{n}$ and $BC_{n}$ Ruijsenaars-Schneider(RS) models with interaction potential of trigonometric and rational types. The Lax pairs for these models are constructed and the involutive Hamiltonians are also given. Taking nonrelativistic limit, we also obtain the Lax pairs for the corresponding Calogero-Moser systems. 
Kai Chen, Bo-yu Hou and Wen-Li Yang