The hadronic decays of charmed mesons at BESIII

In this presentation, we discuss the recent hadronic decays of charmed mesons observed in the BESIII experiment, specifically focusing on the decay processes $D^+ \to K_S^0 \pi^+ \eta$, $D^0 \to \pi^+ \pi^- \eta$, $D^+ \to \pi^+ \pi^0 \eta$, $D_s^+ \to \pi^+ \pi^+ \pi^- \pi^0$, $D_s^+ \to \pi^+ \pi^+ \pi^- \pi^0 \pi^0$, $D_s^+ \to K_S^0 K_L^0 \pi^+$, and $D^+ \to K_S^0 K_S^0 \pi^+$. We present results from amplitude analyses revealing rich structures in these decay processes. Furthermore, we report on the $\phi$ decay ratio in $D_s^{\pm}$ decays. Our findings have significant implications for fundamental inputs related to non-perturbative QCD, hadronic matter structure, and studies of $\mathit{CP}$ violation.