English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The recently discovered fully charmed tetraquark candidate $X(6900)$ isanalyzed within the frameworks of effective-range expansion, compositenessrelation and width saturation, and a coupled multichannel dynamical study. Bytaking into account constraints from heavy-quark spin symmetry, thecoupled-channel amplitude including the $J/\psi J/\psi,~ \chi_{c0}\chi_{c0}$and $\chi_{c1}\chi_{c1}$ is constructed to fit the experimental di-$J/\psi$event distributions around the energy region near $6.9$ GeV. Another dynamicaltwo-coupled-channel amplitude with the $J/\psi J/\psi$ and $\psi(3770) J/\psi$is also considered to describe the same datasets. The three differenttheoretical approaches lead to similar conclusions that the two-mesoncomponents do not play dominant roles in the $X(6900)$. Our determinations ofthe resonance poles in the complex energy plane from the refinedcoupled-channel study are found to be consistent with the experimentalanalyses. The coupled-channel amplitudes also have another pole correspondingto a narrow resonance $X(6825)$ that we predict sitting below the$\chi_{c0}\chi_{c0}$ threshold and of molecular origin. We give predictions tothe line shapes of the $\chi_{c0}\chi_{c0}$ and $\chi_{c1}\chi_{c1}$ channels,which could provide a useful guide for future experimental measurements.

Insights into the inner structures of the fully charmed tetraquark state $X(6900)$