The future experiment \PANDA@FAIR is a fixed-target $\bar p p$ experiment that will run in the antiproton momentum range [1.5-15.0] GeV/$c$, and is supposed to reach a peak luminosity up to 2$\cdot$10$^{31}$ cm$^{-2}$ s$^{-1}$ in the first phase of data taking. This will allow to perform analyses of a number of reactions which are suppressed or forbidden at running experiments, especially in the sector of charm and charmonium physics. Investigating narrow resonances, measure their width and understand their properties is the core of the \PANDA~physics program in the {\it day-one} experiment. This contribution reports about the feasibility studies to measure the width of very narrow states by performing a threshold scan. The case of the $D_{s0}^*(2317)^+$ will be discussed with new theoretical developments to evaluate the cross section and the rate for the process $\bar p p \rightarrow D_s^- D_{s0}^*(2317)^+$, as an original contribution to the \PANDA~physics program. Eventually new resonances with $\bar c c \bar s s$ quark content could be investigated in the $D_s^- D_{s0}^*(2317)^+$ invariant mass system. We recall that recently the LHCb experiment published about four resonances with the above mentioned quark content in the $J/\psi \phi$ invariant mass system through B decays, only. Therefore the hereby presented study might be of high interest from experimental as well as theoretical point of view, and offers a complementary search in a different reaction mechanism.