https://doi.org/10.1140/epjc/s10052-023-11362-9
Regular Article - Theoretical Physics
Weak radiative decay 
using light-cone sum rules
1
Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, 53115, Bonn, Germany
2
Tsung-Dao Lee Institute, Shanghai Jiao Tong University, 200240, Shanghai, China
3
Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics, Forschungszentrum Jülich, 52425, Jülich, Germany
4
Tbilisi State University, 0186, Tbilisi, Georgia
Received:
10
December
2022
Accepted:
26
February
2023
Published online:
17
March
2023
We calculate the decay width of the using light-cone sum rules. For the initial quark radiation an effective Hamiltonian is constructed, where the internal quark line shrinks to a point. The final quark radiation is studied within the full theory. The leading twist light-cone distribution amplitudes of the 
serve as the non-perturbative input for the sum rules calculation, and the perturbative kernel is calculated at leading order. The branching fraction we obtain is 
, which is below the recent upper limits 
and 
given by the Belle collaboration and the BESIII collaboration, respectively.
© The Author(s) 2023
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