Gluonic tetracharm configuration of X(6900)

Recently, a new hadronic structure at around 6.9GeV was observed in an LHCb experiment. From its limited yet known decay mode, one could still determine that it contains at least four charm quarks and hence belongs to the category of exotic state. This finding indicates for the first time the tetracharm exotic states and is therefore quite importance. In this letter, we propose a nature hybrid interpretation for the structure of X(6900), i.e. in [(3) over bar (c)](cc) circle times [8(c)](G) circle times [3(c)]((c) over bar(c) over bar) configuration with J(PC) = 0(++), and by using the QCD Sum Rule technique we performed mass spectrum calculation. The results showed that the observed X(6900) could be a gluonic tetracharm state, and some other structures may exist, e.g., one around 7.2 GeV in the tetracharm hybrid configuration and with J(PC) = 0(-+). We also predict the tetrabottom hybrid states, leaving for future experiment. (C) 2021 The Author(s). Published by Elsevier B.V.

Automated summary

A new hadronic structure around 6.9GeV containing at least four charm quarks was observed in an LHCb experiment, indicating the existence of tetracharm exotic states. A nature hybrid interpretation for this structure was proposed, suggesting it could be a gluonic tetracharm state. Other structures, such as a tetracharm state around 7.2GeV, were also predicted, awaiting future experiments.