The study of double-charm and double-strange tetraquarks

Abstract

In the framework of the quark delocalization color screening model (QDCSM), we systematically investigate the double-charm and double-strange tetraquark systems ccss with two structures: meson-meson and diquark-antidiquark. The bound-state calculation shows that there is no any bound state in present work. However, by applying a stabilization calculation and coupling all channels of both two structures, two new resonance states with IJ P = 00 + are obtained. One is more possible to be a molecular resonance state with a mass and width around 4256 MeV and 60 MeV, respectively; another one is more likely to be a compact resonance state with a mass and width around 4308 MeV and 19 MeV, respectively. Although no significant signals were observed in present experiment at the Belle collaboration, there is still some structures around 4.3 GeV in the distributions of M D + s D + s and M D * + s D * + s . We suggest that the experiment can be further tested with a larger amount of data.

Improved XTZ masses and mass ratios from Laplace Sum Rules at NLO

“…This is not often the case of some other approaches. In particular, a lattice calculation [89] and some quark models [97][98][99][101][102][103] expect a mass of the T ccss and T bbss 0 + states well above the physical threshold while in our case the T bbss state lies below the physical threshold and the one of the T ccss 0 + state is slightly above (see Table 5). This peculiar feature of SU3 breakings for exotic states needs to be checked experimentally.…”

“…In Fig. 25, we confront our results from LSR ⊕ DRSR with the ones from different approaches in the literature (lattice calculations [89][90][91][92], light front holographic [93], quark and potential models ⊕heavy quark symmetry [94][95][96][98][99][100][101][102][103]). We refrain to comment on the technical details of the estimates from different approaches being non-experts in these fields.…”

Tetraquarks and Pentaquarks from Quark Model Perspective

“…Recently, Belle Collaboration searched for the tetraquark state X ccss in D s D s (D * s D * s ) final states, but no significant signals were observed [190]. In the quark models [154,191], T ++ ccss , T + bcss , and T 0 bbss cannot form stable states because all interactions in the states cannot provide enough attraction because the ground state antidiquark s s cannot form a good antidiquark [28]. The lattice QCD investigations on the states T ++ ccss , T 0 bbss , and T + bcss indicated that no clear indication of any level below their respective threshold can be found [176].…”

“…The lattice QCD investigations on the isospin symmetric states indicated that no clear signal of any level below their respective thresholds can be found [176]. All of the isospin symmetrical states T + cc , T − bb , and T 0 bc and the V-spin symmetrical states T + ccs , T − bbs , and T 0 bcs cannot form stable states because all interactions in the states cannot provide enough attraction in the models [140,154,191]. The optimal spin-isospin-color-orbital combination of a good heavy diquark QQ and a good light antidiquark q q is a necessary condition to produce a stable double heavy tetraquark state from the perspective of diquarks [28].…”