<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>S</mml:mi></mml:math>-wave fully charmed tetraquark resonant states
Guang-Juan Wang, Qi Meng, Makoto Oka
Abstract
We calculate the mass spectrum of the $S$-wave fully-charmed tetraquark resonant states $cc\overline{c}\overline{c}$ in the nonrelativistic quark model, which successfully describes the charmonium spectrum. The four-body system is solved with the Gaussian expansion method. The complex scaling technique is used to identify the genuine resonances. With the nonrelativistic quark model, our results show the existence of two $cc\overline{c}\overline{c}$ resonances in each of the ${J}^{PC}={0}^{++}$, ${1}^{+\ensuremath{-}}$, and ${2}^{++}$ sectors, respectively. In the $S$-wave sector, no resonance is found at the energy region of the $X(6200)$ and $X(6600)$ states. The lower ${0}^{++}$ and ${2}^{++}$ resonances are located around 100 MeV higher than the $X(6900)$ state observed in experiments but have the decay widths consistent with the experiment. The higher ${0}^{++}$ and ${2}^{++}$ resonances are found at around 7.2 GeV with the widths of 60.6 MeV and 91.2 MeV, respectively, and they may be good candidates for the $X(7200)$ state.