Regular Article - Theoretical Physics
QCD factorization of the four-lepton decay
Physik Department T31, Technische Universität München, James-Franck-Straße 1, 85748, Garching, Germany
2 Gravitational Waves and Fundamental Physics (GWFP), Maastricht University, Duboisdomein 30, 6229 GT, Maastricht, The Netherlands
3 Nikhef, Science Park 105, 1098 XG, Amsterdam, The Netherlands
Accepted: 25 June 2021
Published online: 21 July 2021
Motivated by the first search for the rare charged-current B decay to four leptons, , we calculate the decay amplitude with factorization methods. We obtain the form factors, which depend on the invariant masses of the two lepton pairs, at leading power in an expansion in to next-to-leading order in , and at at next-to-leading power. Our calculations predict branching fractions of a few times in the mass-squared bin up to GeV with GeV. The branching fraction rapidly drops with increasing . An important further motivation for this investigation has been to explore the sensitivity of the decay rate to the inverse moment of the leading-twist B meson light-cone distribution amplitude. We find that in the small- bin, the sensitivity to is almost comparable to when is small, but with an added uncertainty from the light-meson intermediate resonance contribution. The sensitivity degrades with larger .
© The Author(s) 2021
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