Note on the mass square of the eta′ meson

We propose to use as a mathematical tool to study the mass square of the eta′ meson an infinitely heavy supplementary quark flavor Q. This is understood in the framework of QCD with one light quark flavor (→nfl light flavors) and the gauge group SU3c (→SUNc). The full system thus consists of n(+)fl=nfl+1 flavors, including the infinitely heavy one. The purpose of this note is to show how the heavy flavor can be made to represent the anomalies of the subtheory describing the remnant physical degrees of freedom. In the large Nc limit the mass square of eta′ tends to a finite limit. The essential deviations from (semi) perturbative derivations are related to simple properties of the `heavyʹ flavor.