B →ππ form factors from light-cone sum rules with B-meson distribution amplitudes

Cheng, Shan; Khodjamirian, Alexander; Virto Iñigo, Javier (2017). B →ππ form factors from light-cone sum rules with B-meson distribution amplitudes. Journal of High Energy Physics, 2017(5), pp. 1-25. Springer 10.1007/JHEP05(2017)157

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We study B → ππ form factors using QCD light-cone sum rules with B-meson distribution amplitudes. These form factors describe the semileptonic decay B → ππlν ̄l, and constitute an essential input in B → ππl+l− and B → πππ decays. We employ the correlation functions where a dipion isospin-one state is interpolated by the vector light-quark current. We obtain sum rules where convolutions of the P-wave B ̄0 → π+π0 form factors with the timelike pion vector form factor are related to universal B-meson distribution amplitudes. These sum rules are valid in the kinematic regime where the dipion state has a large energy and a low invariant mass, and reproduce analytically the known light-cone sum rules for B → ρ form factors in the limit of ρ-dominance and zero width, thus providing a systematics for so far unaccounted corrections to B → ρ transitions. Using data for the pion vector form factor, we estimate finite-width effects and the contribution of excited ρ-resonances to the B → ππ form factors. We find that these contributions amount up to ∼ 20% in the small dipion mass region where they can be effectively regarded as a nonresonant (P -wave) background to the B → ρ transition.

Item Type:

Journal Article (Original Article)

Division/Institute:

10 Strategic Research Centers > Albert Einstein Center for Fundamental Physics (AEC)
08 Faculty of Science > Institute of Theoretical Physics

UniBE Contributor:

Virto Iñigo, Javier

Subjects:

500 Science > 530 Physics

ISSN:

1029-8479

Publisher:

Springer

Language:

English

Submitter:

Esther Fiechter

Date Deposited:

27 Oct 2017 15:29

Last Modified:

27 Oct 2017 15:29

Publisher DOI:

10.1007/JHEP05(2017)157

ArXiv ID:

1701.01633

BORIS DOI:

10.7892/boris.102348

URI:

https://boris.unibe.ch/id/eprint/102348

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