The Uses of Chiral Anomaly for Determination of the Number of Colors

Abstract

The $N_c$-dependence of the vertices $PPPγ$, where $P$ is a pseudoscalar meson and $N_c$ is the number of colors, is analyzed with regard for the $N_c$-dependence of the quark charges. It is shown that the best processes for the determination of $N_c$ are the reactions $Kγ\to Kπ$ and $π^pmγ\toπ^\pmη$ as well as the decay $η\raπ^+π^-γ$. The measurement of the cross section $σ(π^-γ\raπ^-η)$ at the VES facility at the IHEP agrees with the value $N_c=3$.