Strange hidden-charm tetraquarks in constituent quark model

Abstract

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.

Investigation of the bottom analog of the Zcs(3985) state

“…More recently, the LHCb Collaboration reported two charmonium-like states with strangeness , named Z cs (4000) + and Z cs (4220) + , in the J/ψK invariant mass spectrum [55], where the mass of the former one is similar to the one of Z cs (3985) observed by BESIII Collaboration. Similar to the case of Z b (10610) and Z c (3900)/Z c (3885), the observed masses of Z cs (3985)/Z cs (4000) are close to the threshold of D * s D, the properties of Z cs (3985)/Z cs (4000) have been investigated in molecular [56][57][58][59][60][61][62][63][64][65][66] and tetraquark [67][68][69][70][71][72] scenarios.…”

“…In Ref. [69], we investigate the Z cs in the chiral quark model (ChQM) and we find a resonance state with J P = 0 + , the energy of which is close to the one of Z cs (3985). Besides, two more new resonances were predicated in the vicinity of 4410 MeV, with J P = 0 + and J P = 1 + , respectively, which could be tested by further experiments.…”

The low-lying hidden- and double-charm tetraquark states in a constituent quark model with Instanton-induced Interaction

“…For example, in Ref. [9], the diquark-antidiquark [cs][cn] configurations have been investigated, and it's found that there would be resonance states falling in the mass range of 3916.5 ∼ 3964.6 MeV with quantum numbers J P = 0 + , and 4008.8 ∼ 4091.2 MeV with J P = 1 + . Thus, one may conclude that a compact tetraquark state with J P = 0 + or J P = 1 + may take considerable probability in Z cs (3985).…”

“…The typical mesonic exotic states, such as the charmonium-like state Z c (3900) ± observed in the π ± J/ψ invariant mass spectra of the process e + e − → π + π − J/ψ [3] and the Z cs (3985) state observed in the D − s D * 0 and D * − s D 0 final states of the e + e − → K + D − s D * 0 (D * − s D 0 ) reaction [4], may contain at least four ccq q quarks. Theoretically, the exotic meson states can be explained as compact tetraquark states in quark potential model [5][6][7][8][9][10][11], QCD sum rule [12][13][14][15], and diquark-diquark picture [16,17]. While, they could be also described as the molecular states in effective field theory [18][19][20][21][22].…”

A combined analysis of the $Z_c(3900)$ and the $Z_{cs}(3985)$ exotic states

“…Refs. [58][59][60][61][62][63][64][65][66]. An analysis of the D * 0 Ds +D 0 D * s invariant mass spectra was performed in Ref.…”