New insights into the doubly charmed exotic mesons

Using effective Lagrangians constrained by the heavy quark spin symmetry and chiral symmetry, for the light quarks, we analyze the $D^0{D}^0{\pi }^{+}$, ${\bar{D}}^0{D}^0{\pi }^0$ and $D^0{\bar{D}}^{\ast 0}$ invariant mass spectra. Performing a simultaneous analysis of the doubly charmed and charm-anti-charm states gives further insights into the nature of the $T_{cc}^{+}$ and ${\chi }_{c1}^0(3872)$, exotic hadrons. It is confirmed that both states should lie below their respective $D{D}^{\ast }$/$D{\bar{D}}^{\ast }$ thresholds. Also, the contributions of the triangle and box diagrams are negligible.