A Bound on $m_η/m_{η'}$ for Large $N_C$
arXiv:hep-ph/9310337 · doi:10.1103/PhysRevD.49.1666
Abstract
If the number of colors is large, the ratio $m_η/m_{η'}$ is bounded from above. The bound is not satisfied by the observed $η$ and $η'$ masses.
5 pages, \#HUTP-93/A029