Extrapolating semileptonic form factors using Bayesian-inference fits regulated by unitarity and analyticity
Extrapolating semileptonic form factors using Bayesian-inference fits regulated by unitarity and analyticity
We discuss our recently proposed model-independent framework for fitting hadronic form-factor data, which are often only available at discrete kinematical points, using parameterisations based on unitarity and analyticity. The accompanying dispersive bound on the form factors (unitarity constraint) is used to regulate the ill-posed fitting problem and allow model-independent predictions over the entire physical range. Kinematical constraints, for example for the vector and scalar form factors in semileptonic meson decays, can be imposed exactly. The core formulae are straight-forward to implement with standard math libraries. We demonstrate the method for the exclusive semileptonic decay Bs→Kℓν, an example requiring one to use a generalisation of the original Boyd Grinstein Lebed (BGL) unitarity constraint. We further present a first application of the method to B→D∗ℓν decays.
hep-lat, hep-ph
Flynn, J.M.
d8e90963-ba56-415c-bbd4-496b7d91d343
Jüttner, A.
a90ff7c5-ae8f-4c8e-9679-b5a95b2a6247
Tsang, J.T.
e4648385-cecf-4c02-b13e-c06312f16b12
Flynn, J.M.
d8e90963-ba56-415c-bbd4-496b7d91d343
Jüttner, A.
a90ff7c5-ae8f-4c8e-9679-b5a95b2a6247
Tsang, J.T.
e4648385-cecf-4c02-b13e-c06312f16b12
[Unknown type: UNSPECIFIED]
Abstract
We discuss our recently proposed model-independent framework for fitting hadronic form-factor data, which are often only available at discrete kinematical points, using parameterisations based on unitarity and analyticity. The accompanying dispersive bound on the form factors (unitarity constraint) is used to regulate the ill-posed fitting problem and allow model-independent predictions over the entire physical range. Kinematical constraints, for example for the vector and scalar form factors in semileptonic meson decays, can be imposed exactly. The core formulae are straight-forward to implement with standard math libraries. We demonstrate the method for the exclusive semileptonic decay Bs→Kℓν, an example requiring one to use a generalisation of the original Boyd Grinstein Lebed (BGL) unitarity constraint. We further present a first application of the method to B→D∗ℓν decays.
Text
2312.14631v1
- Author's Original
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Accepted/In Press date: 22 December 2023
Additional Information:
2 figures, Proceedings contribution to "The 40th International Symposium on Lattice Field Theory (Lattice 2023)"
Keywords:
hep-lat, hep-ph
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Local EPrints ID: 486085
URI: http://eprints.soton.ac.uk/id/eprint/486085
PURE UUID: 60090457-ea07-4b2c-bae2-e29c1a1b44c2
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Date deposited: 09 Jan 2024 17:33
Last modified: 18 Mar 2024 02:59
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Author:
J.T. Tsang
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