Understanding open-charm Mesons

We present a theoretical framework that accounts for the new D-J and D-sJ mesond measured in the open-charm sector. These resonances are properly described if considered as a mixture of conventional P-wave quark-antiquark components. The narrowest states are basically P-wave quark-antiquark mesons, while the dominantly four-quark states are shifted above the correspondidng two-meson threshold. We study the electromagnetic decay widths as basic tools to scrutiny their nature.