QCD quark cyclobutadiene and light tetraquark spectra

Abstract

The QCD quark cyclobutadiene (ring-like), a new color structure of tetraquark system, is proposed and studied in the flux-tube model with a multi-body confinement interaction. Numerical calculations show that the light tetraquark systems (u, d, s only) with cyclobutadiene, diquark-antidiquark flux-tube structures have similar energies and they can be regarded as QCD isomeric compounds. The energies of some tetraquark states are close to the masses of some excited mesons and so in the study of these mesons, the tetraquark components should be taken into account. There are also some meson states, σ, κ(800), f0(980), f0(1500), π1(1400), π1(1600), f2(1430) and K * (1410), where tetraquark components might be dominant. The meson states with exotic quantum numbers are studied as the tetraquark states. The multi-body confinement interaction reduces the energy of the tetraquark state in comparison with the usual additive two body confinement interaction model.

Possible $$D^{(*)}\bar{D}^{(*)}$$ D ( ∗ ) D ¯ ( ∗ ) and $$B^{(*)}\bar{B}^{(*)}$$ B ( ∗ ) B ¯ ( ∗ ) molecular states in the extended constituent quark models

“…In this work, we would like to study the possible neutral molecular states D ( * )D( * ) and B ( * )B( * ) by two constituent quark models, which are extended by including the one-gluon annihilation interaction between uū or dd light quark pairs. We solve the four-body Schroödinger equation by means of GEM, which is a high accuracy method for few-body systems developed by Kamimura, Hiyama et al [28] and extensively performed in studying the mass spectrum of multi-quark system [29,30,31,32,33,34].…”

InterpretingZc(3900)andZc(4025Deng1, Ping2, Huang3 et al. 2014Phys. Rev. DSelf Cite721700View full textAdd to dashboardCite

“…The previous research on the light tetraquark spectrum indicated that a tetraquark system has at least four possible color flux- [15]. Generally speaking, a tetraquark state should be a mixture of all the possible structures.…”

“…In the model, the color confinement used is not the sum of two-body interaction proportional to a color charge λ c i · λ c j but a multibody one, which has been successfully applied to study multiquark systems [14][15][16][17][18]. The study attempts not only to describe the reported charged states and to enrich the list of the possible charged states, but also to provide a new insight to charged states and to reveal the underlying mechanism behind these novel phenomena.…”

Baryonia and near-threshold enhancements

“…Nonstrange hexaquark states q 3q3 were systematically studied in a color flux-tube model with a six-body confinement potential instead of an additive two-body interaction in our previous work, and it was found that some ground states are stable against disintegrating into a baryon and an anti-baryon [11]. In the present work, the spectrum of the baryonia of the ground state consisting of strange, charm and bottom quarks is studied in the color flux-tube model.…”