Speaker
Description
I discuss a model-independent framework for fitting hadronic
form-factor data, which is 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. I demonstrate the method for the exclusive
semileptonic decay $B_s\to K \ell \nu$, an example requiring one to use
a generalisation of the original Boyd~Grinstein~Lebed (BGL) unitarity
constraint.
| Topical area | Quark and Lepton Flavor Physics |
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