We introduce a new parametrization of form factors using a partial-wave expansion and derive bounds on the series coefficients using analyticity and unitarity. This is the first generalization of the model-independent formalism developed by Boyd, Grinstein, and Lebed for to semileptonic decays with multihadron final states, and enables data-driven form-factor determinations with robust, systematically improvable uncertainties. Using this formalism, we extract the form-factor parameters for decays in a model-independent way from fits of data from the Belle Experiment. We find that the semileptonic data are compatible with the presence of two poles in the S-wave channel, which is the scenario preferred by nonleptonic decays and unitarized chiral perturbation theory.
Gustafson, Erik J., Herren, Florian, Van de Water, Ruth S., van Tonder, Raynette, & Wagman, Michael L. (2024). Model-independent description of <math display='inline'> <mrow> <mi>B</mi> <mo stretchy='false'>→</mo> <mi>D</mi> <mi>π</mi> <mo>ℓ</mo> <mi>ν</mi> </mrow> </math> decays. Physical Review. D., 110(9). https://doi.org/10.1103/PhysRevD.110.L091502
@article{osti_2477854,
author = {Gustafson, Erik J. and Herren, Florian and Van de Water, Ruth S. and van Tonder, Raynette and Wagman, Michael L.},
title = {Model-independent description of <math display='inline'> <mrow> <mi>B</mi> <mo stretchy='false'>→</mo> <mi>D</mi> <mi>π</mi> <mo>ℓ</mo> <mi>ν</mi> </mrow> </math> decays},
annote = { We introduce a new parametrization of B → D π ℓ ν form factors using a partial-wave expansion and derive bounds on the series coefficients using analyticity and unitarity. This is the first generalization of the model-independent formalism developed by Boyd, Grinstein, and Lebed for B → D ℓ ν to semileptonic decays with multihadron final states, and enables data-driven form-factor determinations with robust, systematically improvable uncertainties. Using this formalism, we extract the form-factor parameters for B → D 2 * ( → D π ) ℓ ν decays in a model-independent way from fits of data from the Belle Experiment. We find that the semileptonic data are compatible with the presence of two poles in the D π S-wave channel, which is the scenario preferred by nonleptonic decays and unitarized chiral perturbation theory. Published by the American Physical Society 2024 },
doi = {10.1103/PhysRevD.110.L091502},
url = {https://www.osti.gov/biblio/2477854},
journal = {Physical Review. D.},
issn = {ISSN 2470-0010},
number = {9},
volume = {110},
place = {United States},
publisher = {American Physical Society},
year = {2024},
month = {11}}
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 654, Issue 1https://doi.org/10.1016/j.nima.2011.06.008