New insights into the doubly charmed exotic mesons

TL;DR

This paper uses effective Lagrangians respecting heavy quark and chiral symmetries to analyze invariant mass spectra, providing new insights into the nature of doubly charmed and charm-anti-charm exotic mesons, confirming their sub-threshold positions.

Contribution

It offers a combined analysis of doubly charmed and charm-anti-charm states, clarifying their nature and threshold positions using symmetry-constrained effective Lagrangians.

Findings

Both $T^+_{cc}$ and $ ext{chi}^0_{c1}(3872)$ lie below their respective thresholds.

Triangle and box diagram contributions are negligible.

Analysis supports the exotic nature of these states.

Abstract

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.