TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhysProc.16.008
TI  - On the scalar $\pi K$ form factor beyond the elastic region
PY  - 2025/07/14
UR  - https://www.scipost.org/SciPostPhysProc.16.008
JF  - SciPost Physics Proceedings
JA  - SciPost Phys. Proc.
VL  - 
IS  - 16
SP  - 008
A1  - Noel, Frederic
AU  - von Detten, Leon
AU  - Hanhart, Christoph
AU  - Hoferichter, Martin
AU  - Kubis, Bastian
AB  - Pion-kaon ($\pi K$) final states, often appearing in heavy-particle decays at the precision frontier, are important for Standard-Model tests, to describe crossed channels with exotic states, and for spectroscopy of excited kaon resonances. We construct a representation of the $\pi K$ $S$-wave form factor using the elastic $\pi K$ scattering phase shift via dispersion relations in the elastic region and extend this model into the inelastic region using resonance exchange, while maintaining unitarity and the correct analytic structure. As a first application, we successfully described the $\tau \to K_S \pi \nu_\tau$ spectrum to not only achieve a better distinction between $S$- and $P$-wave contributions, but also to provide an improved estimate of the $CP$ asymmetry produced by a tensor operator as well as the forward-backward asymmetry, both of which can be confronted with future data at Belle II. The work presented here is published in [L. von Detten et al., Eur. Phys. J. C 81, 420 (2021)].
ER  -

@Article{10.21468/SciPostPhysProc.16.008,
	title={{On the scalar $\pi K$ form factor beyond the elastic region}},
	author={Frederic Noël and Leon von Detten and Christoph Hanhart and Martin Hoferichter and Bastian Kubis},
	journal={SciPost Phys. Proc.},
	pages={008},
	year={2025},
	publisher={SciPost},
	doi={10.21468/SciPostPhysProc.16.008},
	url={https://scipost.org/10.21468/SciPostPhysProc.16.008},
}