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 $D^0 D^0\pi^+$, $\bar{D}^0D^0\pi^0$ and $D^0\bar{D}^{*0}$ 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 $\chi^0_{c1}(3872)$, exotic hadrons. It is confirmed that both states should lie below their respective $DD^*$/$D\bar{D}^*$ thresholds. Also, the contributions of the triangle and box diagrams are negligible.