B → η′ + X and the QCD anomaly

Abstract

Mechanisms for the observed large $Br(B \to \eta' +X_s)$ are examined. We propose that the dominant fraction of the $B \to \eta' +X_s$ rate is due mainly to $b \to s g^*$, where $g^*$ is an off-shell gluon, followed by $g^* \to g\eta'$ via the anomalous coupling of the $\eta'$ to two gluons. The calculated rate for $B \to \eta'+X_s$ is in rough accord with experiment using a fairly constant glue-glue-$\eta'$ form factor. This behavior of the form factor may be indicative of glueball dominance of the channel. Searches via the modes $\eta' h^+h^-$ ($h=\pi$ or $K$) may be worthwhile. Charmonia contributions [i.e $B \to \eta_c, \psi (\to \eta'+X) +X_s$] can only account for at most 20% of the central value of the signal. Implications for $B \to \eta' +X_d$ and for the corresponding $\eta$ modes are also given.