The gluonic decay of the b quark and the $\eta '$ meson

The inclusive decay of B-mesons into eta' + X is the consequence of the gluonic decay of the b-quark into an s-quark. As a result of the QCD anomaly this decay proceeds partly as the decay b --> s + eta', similar to b ---> s + J/psi. The hadronic recoiling system is found to have a relatively large mass. Analogously one expects a decay of the type b ---> s + sigma. The branching ratios for these decays are large (of the order of 10%). The results indicate that there is no room for an anomalously large chromomagnetic decay mode of the b-quark. Gluon jets are expected to exhibit an anomalously large tendency to fragment into eta'- and sigma- mesons.