Enhanced CP violation in D 0→ρ 0(ω)ρ 0(ω)→π + π − π + π − Gang Lü, Z.-H. Zhang, X.-H. Guo, Jun-Chao Lu and Shi-Ming Yan Eur. Phys. J. C, 73 8 (2013) 2519 Published online: 21 August 2013 DOI: 10.1140/epjc/s10052-013-2519-2