In this note, we study the Q-cut representation by combining it with BCFW deformation. As a consequence, the one-loop integrand is expressed in terms of a recursion relation, i.e., n-point one-loop integrand is constructed using tree-level amplitudes and m-point one-loop integrands with m≤n−1. By giving explicit examples, we show that the integrand from the recursion relation is equivalent to that from Feynman diagrams or the original Q-cut construction, up to scale free terms.
@article{arxiv.1610.04453,
title = {Note on recursion relations for the $\mathcal{Q}$-cut representation},
author = {Bo Feng and Song He and Rijun Huang and Ming-xing Luo},
journal= {arXiv preprint arXiv:1610.04453},
year = {2017}
}