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Gluonic contribution to $B\to η^{(\prime)}$ form factors

Yeo-Yie Charng·T. Kurimoto·Hsiang-nan Li
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Abstract

We calculate the flavor-singlet contribution to the $B\toη^{(\prime)}$ transition form factors from the gluonic content of the $η^{(\prime)}$ meson in the large-recoil region using the perturbative QCD approach. The formulation for the $η$-$η'$ mixing in the quark-flavor and singlet-octet schemes is compared, and employed to determine the chiral enhancement scales associated with the two-parton twist-3 $η^{(\prime)}$ meson distribution amplitudes. It is found that the gluonic contribution is negligible in the $B\toη$ form factors, and reaches few percents in the $B\toη'$ ones. Its impact on the accommodation of the measured $B\toη^{(\prime)} K$ branching ratios in the perturbative QCD and QCD-improved factorization approaches is elaborated.

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Yeo-Yie Charng, T. Kurimoto, Hsiang-nan Li. 2007-01-03. Gluonic contribution to $B\to η^{(\prime)}$ form factors. https://doi.org/10.1103/physrevd.74.074024

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