Molecular tetraquarks and pentaquarks in chiral effective field theory

Abstract

We studied the $D{\bar{D}}^{\ast }/\bar{D}{D}^{\ast }$, $D^{\ast }{\bar{D}}^{\ast }$, ${\bar{D}}_s{D}^{\ast }/{\bar{D}}_s^{\ast }D$, $B{\bar{B}}^{\ast }/\bar{B}{B}^{\ast }$ and $B^{\ast }{\bar{B}}^{\ast }$ di-hadron interactions in chiral effective field theory ($\chi$EFT) up to the next-to-leading (NLO) order. The above-threshold tetraquark states $Z_c(3900)$, $Z_c(4020)$, $Z_{cs}(3985)$, $Z_b(10610)$, $Z_b(10650)$ can be explained as the corresponding di-hadron resonances, respectively. We also studied the ${\Sigma }_c^{(\ast )}{\bar{D}}^{(\ast )}$ interactions to investigate the three hidden-charm pentaquarks $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$. We further used the parameters fixed from the $P_c$ states to predict the possible molecular states in ${\Xi }_c{\bar{D}}^{(\ast )}$, ${\Xi }_c^{\prime }{\bar{D}}^{(\ast )}$ and ${\Xi }_c^{\ast }{\bar{D}}^{(\ast )}$ systems. Our predictions of the ${\Xi }_c{\bar{D}}^{(\ast )}$ bound states are very consistent with two new near-threshold structures recently observed by the LHCb Collaboration.

Comments: Talk presented at QCD22, 25th International Conference in QCD (4-7, July, 2022, Montpellier - FR). 4 pages, 5 figs, 1 table