Related papers: On tetraquark meson states
Masses of the ground and excited (1P, 2S, 1D, 2P, 3S) states of the fully-heavy tetraquarks, composed of charm ($c$) and bottom ($b$) quarks and antiquarks, are calculated in the diquark-antidiquark picture within the relativistic quark…
The compact tetraquark states with fully heavy quark contents $QQ\bar Q\bar Q$ are studied as the bound states of the diquark-antidiquark within the Bethe-Salpeter framework. The (anti)diquark masses and form factors used are the same as we…
We investigate four-body states with only charm quarks. Working in a large but finite oscillator basis, we present a net binding analysis to determine if the resulting states are stable against breakup into a pair of c-cbar mesons. We find…
A salient feature shared by all tetraquark candidates observed in experiment is the absence of flavor-exotic states of the type $\bar a b\bar c d$, with four different quark flavors. This phenomenon may be understood from the properties of…
In a recent paper by N. Santowsky et al. [Phys. Rev. D 102, 056014 (2020)], covariant coupled equations were derived to describe a tetraquark in terms of a mix of four-quark states $2q 2\bar{q}$ and two-quark states $q\bar{q}$. These…
When studying tetraquark states using the method of QCD sum rules, we find some tetraquark currents, such as $\bar u_L \gamma_\mu d_L~\bar d_L \gamma^\mu u_L$ and $\bar u_L \gamma_\mu d_L~\bar d_R \gamma^\mu u_R$, etc. We calculate their…
Several experimental groups have reported evidence for baryons with flavor exotic quantum numbers that cannot be explained as $qqq$ bound states but require a minimum of five quarks -- $qqqq \bar q$. These pentaquark states include the…
Inspired by the recent report of the exotic states $X_{0}(2900)$ and $X_{1}(2900)$ with four different quark flavors in the $D^{-}K^{+}$ invariant mass distributions of the decay process $B^{+}\rightarrow D^{+}D^{-}K^{+}$ by the LHCb…
In this paper, we have systematically explored the mass spectrum of fully strange tetraquark candidates within the framework of QCD sum rules, focusing on states with quantum numbers $J^{PC}=0^{++}$, $0^{-+}$, $0^{--}$, $1^{--}$, $1^{+-}$,…
The neutral, flavor singlet scalar uuddss bound state -- the sexaquark, S -- may have a low enough mass to be stable or extremely long-lived. Here we review mass estimates and production expectations and show that laboratory experiments to…
In this exploratory study the spectrum of tetraquarks of type $c \bar c s \bar s$ is calculated within a simple quark model with chromomagnetic interaction and effective quark masses extracted from meson and baryon spectra. It is tempting…
In this work, a color structure dependent flip-flop potential is developed for the two quarks and two antiquarks system. Then, this potential is applied to a microscopic quark model which, by integrating the internal degrees of freedom, is…
The vast majority of mesons can be understood as quark-antiquark states. Yet, various other possibilities exists: glueballs (bound-state of gluons), hybrids (quark-antiquark plus gluon), and four-quark states (either as diquark-antidiquark…
Searches for tetraquarks and mesonic molecules in lattice QCD are briefly reviewed. In the light quark sector the most serious candidates are the lightest scalar resonances sigma, kappa, a0 and f0. In the hidden-charm sector I discuss…
It is argued that exotic mesons consisting of two quarks and two antiquarks are not ruled out in quantum chromodynamics with a large number $N$ of colors, as generally thought. They can come in two varieties: short-lived tetraquarks with…
Stimulated by the observation of the $X(6900)$ from LHCb in 2020 and the recent results from CMS and ATLAS in the di-$J/\psi$ invariant mass spectrum, in this work we systemically study all possible configurations for the ground fully heavy…
The new members of the charm-strange family $D_{sJ}^{*}(2317)$, $D_{sJ}(2460)$ and $D_s(2632)$, which have the surprising properties, are challenging the present models. Many theoretical interpretations have been devoted to this issue. Most…
The ${q}\bar{q}$ spectrum is studied within a chiral constituent quark model. It provides with a good fit of the available experimental data from light (vector and pseudoscalar) to heavy mesons. The new $D$ states measured at different…
For very heavy quarks, relations derived from heavy-quark symmetry imply novel narrow doubly heavy tetraquark states containing two heavy quarks and two light antiquarks. We predict that double-beauty states will be stable against strong…
We discuss the likely tetraquark interpretation of the X(1576) K+ K- isovector resonance recently reported by BES with J^{PC}=1^{--}. We point out that if this interpretation as a four-quark state is correct, the (s u sbar dbar) tetraquark…