Renormalization group analysis of ultracold Fermi gases with two-body attractive interaction Xiaoyong Guo, Zimeng Chi, Qiang Zheng and Zaijun Wang Eur. Phys. J. D, 70 1 (2016) 23 Published online: 26 January 2016 DOI: 10.1140/epjd/e2015-60597-1