Year: 2025
Type: article
Abstract: A bstract We study the modifications to decay amplitudes in heavy to heavy semileptonic decays with multiple hadrons in the final state due to intermediate heavy hadrons being off-shell or having a finite width. Combining Heavy Hadron Chiral Perturbation Theory (HH χ PT) with a BCFW on-shell factorization formula, we show that these effects induce $$ \mathcal{O} $$ O (1/ M ) corrections to the standard results computed in the narrow-width approximation and therefore are important in extracting form factors from data. A combination of perturbative unitarity, analyticity, and reparameterization invariance fully determine these corrections in terms of known Isgur-Wise functions without the need to introduce new form factors. In doing so, we develop a novel technique to compute the boundary term at complex infinity in the BCFW formula for theories with derivatively coupled scalars. While we have used the $$ \overline{B} $$ B ¯ → Dπℓν decay as an example, these techniques can generally be applied to effective field theories with (multiple) distinct reference vectors.
Source: Journal of High Energy Physics
Authors: Michele Papucci, Ryan Plestid
Institution: California Institute of Technology
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4411465296