Strong decays of fully-charm tetraquarks into di-charmonia

Abstract

We study strong decays of the possible fully-charm tetraquarks recently observed by LHCb, and calculate their relative branching ratios through the Fierz rearrangement. Together with our previous QCD sum rule study [Phys. Lett. B 773, 247 (2017)], our results suggest that the broad structure around $6.2$-$6.8$ GeV can be interpreted as an $S$-wave $cc\bar{c}\bar{c}$ tetraquark state with $J^{PC}=0^{++}$ or $2^{++}$, and the narrow structure around 6.9 GeV can be interpreted as a $P$-wave one with $J^{PC}=0^{-+}$ or $1^{-+}$. These structures were observed in the di-$J/\psi$ invariant mass spectrum, and we propose to confirm them in the di-${\eta }_c$, $J/\psi h_c$, ${\eta }_c{\chi }_{c0}$, and ${\eta }_c{\chi }_{c1}$ channels. We also propose to search for their partner states having the negative charge-conjugation parity in the $J/\psi {\eta }_c$, $J/\psi {\chi }_{c0}$, $J/\psi {\chi }_{c1}$, and ${\eta }_c{h}_c$ channels.

Comments: 8 pages, 1 figure, 3 tables, to be published in Science Bulletin