Femtoscopic signatures of the lightest S-wave scalar open-charm mesons

We predict femtoscopy correlation functions for $S$--wave $D_{(s)}\phi$ pairs of lightest pseudoscalar open charm mesons and Goldstone bosons from next-to-leading order unitarized heavy-meson chiral perturbation theory amplitudes. The effect of the two-state structure around $2300\,\text{MeV}$ can be clearly seen in the $(S,I)=(0,1/2)$ $D\pi$, $D\eta$, $D_s \overline{K}$ correlation functions, while in the scalar-strange $(1,0)$ sector, the $D^\ast_{s0}(2317)^{\pm}$ state lying below the $DK$ threshold produces a depletion of the correlation function near threshold. These exotic states owe their existence to the nonperturbative dynamics of Goldstone-boson scattering off $D_{(s)}$. The predicted correlation functions could be experimentally measured and will shed light into the hadron spectrum confirming that it should be viewed as more than a collection of quark model states.