Exploring Possible Triangle Singularities in the Ξ b − → K − J / ψ Λ Decay

An updated review of the new hadron states

The past decades witnessed the golden era of hadron physics. Many excited open heavy flavor mesons and baryons have been observed since 2017. We shall provide an updated review of the recent experimental and theoretical progresses in this active field. Besides the conventional heavy hadrons, we shall also review the recently observed open heavy flavor tetraquark statesX(2900) andTcc+(3875)as well as the hidden heavy flavor multiquark statesX(6900),Pcs(4459)0,Zcs(3985)-,Zcs(4000)+, andZcs(4220)+. We will also cover the recent progresses on the glueballs and light hybrid mesons, which are the direct manifestations of the non-AbelianSU(3) gauge interaction of the Quantum Chromodynamics in the low-energy region.

Implications of the Zcs(3985) and Zcs(4000) as two different states

Recently, the hidden charm tetraquark states Z_cs(3985) and Z_cs(4000) with strangeness were observed by the BESIII and LHCb collaborations, respectively, which are great breakthroughs for exploring exotic quantum chromodynamics (QCD) structures. The first and foremost question is whether they are the same state. In this work, we explore the implications of the narrower state Z_cs(3985) in BESIII and the wider one Z_cs(4000) in LHCb as two different states. Within a solvable nonrelativistic effective field theory, we include the possible violations of heavy quark spin symmetry and SU(3) flavor symmetry in a comprehensive approach. If Z_cs(3985) and Z_cs(4000) are two different states, our results show that Z_cs(4000)/Z_cs(3985) is the pure (|D‾_s^∗D〉+/-|D‾_sD^∗〉)/2 state, and the SU(3) flavor partner of Z_c(3900) is Z_cs(4000) rather than the Z_cs(3985). Another two important consequences are the existence of a tensor D‾_s^∗D^∗ resonance with mass about 4126 MeV and width 13 MeV, and the suppression of the decay mode Z_cs(3985)→J/ψK. The two consequences can be tested in experiments and distinguish the two-state interpretation from the one-state scheme.

Special Issue on Advances in Chiral Quark Models

QCD is the strong interaction part of the Standard Model of Particle Physics, and solving it presents a fundamental problem that is unique in the history of science [...]

Predicting the D‾s(*)Ds(*) bound states as the partners of X(3872)

In this work, we investigate the SU(3) flavor symmetry, heavy quark spin symmetry and their breaking effects in the di-meson systems. We prove the existence of the [Formula: see text] , [Formula: see text] , and [Formula: see text] bound states as the consequence of two prerequisites in the SU(3) flavor symmetry and heavy quark spin symmetry. The first prerequisite, the X(3872) as the weakly D‾^∗D/D‾D^∗ bound state is supported by its mass and decay branching ratios. The second prerequisite, the existence of the [Formula: see text] bound state is supported by the lattice QCD calculation and the observation of χ_c0(3930) by the LHCb Collaboration. We hope the future experimental analyses can search for these bound states in the B→D_(s)^(*)D‾_(s)^(*)h processes (h denotes the light hadrons). The [Formula: see text] bound state is also expected to be reconstructed in the J/ψϕ final state in the B→J/ψϕK decay.