New insight into the exotic states strongly coupled with the DD‾ ∗ from the T cc .

We have investigated the internal structure of the open- and hidden-charmed (DD ^∗ /D¯D ^∗ ) molecules in the unified framework. We first fit the experimental lineshape of the T _cc ⁺ state and extract the DD ^∗ interaction, from which the T _cc ⁺ is assumed to arise solely. Then we obtain the DD¯ ^∗ interaction by charge conjugation. Our results show that the DD¯ ^∗ interaction is attractive but insufficient to form X(3872) as a bound state. Instead, its formation requires the crucial involvement of the coupled channel effect between the DD¯ ^∗ and cc¯ components, although the cc¯ accounts for approximately 1% only. Besides X(3872), we have obtained a higher-energy state around 3957.9 MeV with a width of 16.7 MeV, which may be a potential candidate for the X(3940). In J ^PC =1 ^+- sector, we have found two states related to the iso-scalar X̃(3872) and h _c (2P), respectively. Our combined study provides valuable insights into the nature of these DD ^∗ /DD¯ ^∗ exotic states.
Competing Interests: Conflict of interest The authors declare that they have no conflict of interest.
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