Estimate of the $S$-wave $D^*K$ scattering length in the isospin-0 channel from Belle and LHCb data

Abstract

It is shown that the Belle and LHCb data on the interference of the amplitudes of the $S$ and $D$ partial waves in the decays $D_{s1}(2536 )^+\to D^{*+}K^0_S$ and $D_{s1}(2536)^-\to\bar D^{*0}K^-$ allow us to obtain an estimate of the $S$-wave $D^*K$ scattering length in the channel with isospin $I=0$: $|a^{(0)}_{D^*K}|=(0.94\pm0.06)$ fm. The possibility of explaining the found value by the contribution of the $D_{s1}(2460)$ resonance is discussed. The decay of $B_{s1}(5830)\to B^*\bar K$ is also briefly discussed.