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arXiv · 1709.00173

Timelike-helicity $B\to \pi\pi$ form factor from light-cone sum rules with dipion distribution amplitudes

Shan Cheng·Alexander Khodjamirian·Javier Virto
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Abstract

We complete the set of QCD light-cone sum rules for $B\to \pi\pi$ transition form factors, deriving a new sum rule for the timelike-helicity form factor $F_t$ in terms of dipion distribution amplitudes. This sum rule, in the leading twist-2 approximation, is directly related to the pion vector form factor. Employing a relation between $F_t$ and other $B\to \pi\pi$ form factors we obtain also the longitudinal-helicity form factor $F_0$. In this way, all four (axial-)vector $B\to \pi\pi$ form factors are predicted from light-cone sum rules with dipion distribution amplitudes. These results are valid for small dipion masses with large momentum.

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Shan Cheng, Alexander Khodjamirian, Javier Virto. 2017-09-01. Timelike-helicity $B\to \pi\pi$ form factor from light-cone sum rules with dipion distribution amplitudes. https://doi.org/10.1103/physrevd.96.051901

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