%0 Journal Article
%A von Detten, L.
%A Noël, F.
%A Hanhart, Christoph
%A Hoferichter, M.
%A Kubis, B.
%T On the scalar ${\pi K}$ form factor beyond the elastic region
%J The European physical journal / C
%V 81
%N 5
%@ 1434-6052
%C Heidelberg
%I Springer
%M FZJ-2021-02196
%P 420
%D 2021
%X Pion–kaon (πK) pairs occur frequently as final states in heavy-particle decays. A consistent treatment of πK scattering and production amplitudes over a wide energy range is therefore mandatory for multiple applications: in Standard Model tests; to describe crossed channels in the quest for exotic hadronic states; and for an improved spectroscopy of excited kaon resonances. In the elastic region, the phase shifts of πK scattering in a given partial wave are related to the phases of the respective πK form factors by Watson’s theorem. Going beyond that, we here construct a representation of the scalar πK form factor that includes inelastic effects via resonance exchange, while fulfilling all constraints from πK scattering and maintaining the correct analytic structure. As a first application, we consider the decay τ→KSπντ, in particular, we study to which extent the S-wave K∗0(1430) and the P-wave K∗(1410) resonances can be differentiated and provide an improved estimate of the CP asymmetry produced by a tensor operator.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000650628100001
%R 10.1140/epjc/s10052-021-09169-7
%U https://juser.fz-juelich.de/record/892607