Axial Currents of Virtual Charm in Light Quark Processes

Abstract

The systematic investigations of the role of the virtual charm axial currents in the decay of $B$-mesons to ${\eta }^{\prime }$ $K$ and the spin structure of the nucleon are performed. We reduce the divergence of the virtual charm axial current to a specific gluon operator. Since this operator receives the main contribution from topologically nontrivial components of the QCD vacuum, we rederive the Dyakonov-Petrov Effective Action, based on the instanton QCD vacuum model. This action is applied to the calculations of the coupling of ${\eta }^{\prime }$ to the charm axial current and found $f_{{\eta }^{\prime }}^{(c)}(\mu \simeq m_c)=-(12.3\sim 18.4\mathrm{MeV}),$ providing a possibility for the explanations of the recent experimental data on $B\to {\eta }^{\prime }K$-decay. Analogous calculations of the virtual charm content of the nucleon spin leads to $\Delta c(\mu \simeq m_c)=-(0.015\sim 0.024),$ which is one order of magnitude smaller than the analogous contribution of the strange quark.

Comments: 26 pages, revtex, new references and PACS Codes added, minor corrections are made