Quenched glueball spectrum from functional equations

We give an overview of results for the quenched glueball spectrum from two-body bound state equations based on the 3PI effective action. The setup, which uses self-consistently calculated two- and three-point functions as input, is completely self-contained and does not have any free parameters except for the coupling. The results for JPC = 0±+, 2±+, 3±+, 4±+ are in good agreement with recent lattice results where available. For the pseudoscalar glueball, we present first results from a two-loop complete calculation, rendering also the bound state calculation fully self-consistent.

Strange hidden-charm tetraquarks in constituent quark model

In the framework of the chiral quark model (ChQM), we systematically investigate the strange hidden-charm tetraquark systems $$cs{\bar{c}}{\bar{u}}$$ c s c ¯ u ¯ with two structures: $$q{\bar{q}}-q{\bar{q}}$$ q q ¯ - q q ¯ and $$qq-{\bar{q}}{\bar{q}}$$ q q - q ¯ q ¯ . The bound-state calculation shows that there is no any bound state in present work, which excludes the molecular state explanation ($$D^{0}D_{s}^{*-}/D^{*0}D_{s}^{-}/D^{*0}D_{s}^{*-}$$ D 0 D s ∗ - / D ∗ 0 D s - / D ∗ 0 D s ∗ - ) of the reported $$Z_{cs}(3985)^{-}$$ Z cs ( 3985 ) - or $$Z_{cs}(4000)^{+}$$ Z cs ( 4000 ) + . However, the effective potentials for the $$cs-{\bar{c}}{\bar{u}}$$ c s - c ¯ u ¯ systems show the possibility of some resonance states. By applying a stabilization calculation and coupling all channels of both two structures, two new resonance states are obtained, which are the $$IJ^{P}=\frac{1}{2} 0^{+}$$ I J P = 1 2 0 + state with the energy around 4111–4116 MeV and the $$IJ^{P} =\frac{1}{2} 1^{+}$$ I J P = 1 2 1 + state with energy around 4113–4119 MeV, respectively. Both of them are worthy of search in future experiments. Our results show that the coupling calculation between the bound channels and open channels is indispensable to provide the necessary information for experiments to search for exotic hadron states.