Feynman Rules of Higher-order Poles in CHY Construction
  In this paper, we generalize the integration rules for scattering equations to situations where higher-order poles are present. We describe the strategy to deduce the Feynman rules of higher-order poles from known analytic results of simple CHY-integrands, and propose the Feynman rules for single double pole and triple pole as well as duplex-double pole and triplex-double pole structures. We demonstrate the validation and strength of these rules by ample non-trivial examples. 
Rijun Huang, Bo Feng, Ming-xing Luo and Chuan-Jie Zhu
hep-th