Related papers: A Selection Rule for Multiquark Decays
Inspired by the observation of hidden-charm pentaquark $P_c$ and $P_{cs}$ states by the LHCb Collaboration, we explore the $qqc\bar{c}c$ ($q~=~u$ or $d$) pentaquark systems in the quark delocalization color screening model. The interaction…
The reaction $\gamma p \to pK^+K^-$ was studied at Jefferson Lab with photon energies from 1.8 to 3.8 GeV using a tagged photon beam. The goal was to search for a $\Theta^{++}$ pentaquark, a narrow doubly charged baryon state having…
In a particle theory model whose most readily discovered new particle is the $\sim 1$TeV bilepton resonance in same-sign leptons, currently being sought at CERN's LHC, there exist three quarks ${\cal D, S, T}$ which will be bound by QCD…
We analyse fall-apart decays of poliquark (tetra, penta and molecule type) hadrons within the constituent quark picture. For processes in which a poliquark hadron goes to final states containing a light pseudoscalar meson the constraints…
Motivated by the recent discovery of the exotic S=+1 narrow baryon resonance Theta^+ at 1540 MeV, with quark content {uudd sbar}, we conjecture the existence of its anti-charmed analogue Theta_c, with quark content {uudd cbar}, and compute…
Recently LHCb reported the discovery of five extremely narrow excited $\Omega_c$ baryons decaying into $\Xi_c^+ K^-$. We interpret these baryons as bound states of a $c$-quark and a $P$-wave $ss$-diquark. For such a system there are exactly…
We investigate the consequences of heavy quark spin symmetry (HQSS) on hidden-charm pentaquark $P_c$ states. As has been proposed before, assuming the $P_c(4440)$ and the $P_c(4457)$ as $S$-wave $\bar{D}^*\Sigma_c$ molecules, seven hadronic…
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…
The status of the search for pentaquark baryons is reviewed in light of new results from the first two dedicated experiments from CLAS at Jefferson Lab and of new analyses from several laboratories on the $Theta^+(1540)$. Evidence for and…
A narrow pentaquark state, $P_c(4312)^+$, decaying to $J/\psi p$ is discovered with a statistical significance of $7.3\sigma$ in a data sample of ${\Lambda_b^0\to J/\psi p K^-}$ decays which is an order of magnitude larger than that…
We discuss the possibility of determining the parity of the $\Theta^+$ baryon from photoproduction $\gamma N\to K\Theta^+$ process near threshold. We utilize the conservation laws of parity and angular momentum for the analysis of angular…
Pentaquarks and dibaryons are natural possibilities if diquarks are used as the building blocks to assemble hadrons. In this short note, motivated by the very recent discovery of two pentaquark states, we highlight some possible channels to…
The problem of the long life time of the pentaquark $\Theta^+$ is investigated on the basis of the color molecular dynamics simulation. We find that it takes a long time (typically of 50-100 fm/c) for the initial pentaquark-state to…
We study the spectra of the doubly charmed tetraquark states in a diquark-antidiquark model. The doubly charmed tetraquark states form an antitriplet and a sextet configurations according to flavor SU(3) symmetry. For the tetraquark state…
QCD instantons are known to produce deeply bound diquarks which may be used as building blocks in the formation of multiquark states, in particular pentaquarks and dibaryons. We suggest a simple model in which the lowest scalar diquark (and…
We develop a moment QCD sum rule method augmented by fundamental inequalities to study the existence of exotic doubly hidden-charm/bottom tetraquark states made of four heavy quarks. Using the compact diquark-antidiquark configuration, we…
We estimate the mass of the pentaquark state with QCD sum rules and find that pentaquark states with isospin $I=0, 1, 2$ lie close to each other around $(1.55\pm 0.15)$ GeV. The experimentally observed baryon resonance $\Theta^+ (1540)$…
Symmetrization selection rules for the decay of four-quark states to two J=0 mesons are analysed in a non - field theoretic context with isospin symmetry. The OZI allowed decay of an isoscalar J^PC = (1,3,...)^{-+} exotic state to eta' eta…
The exploration of exotic hadrons provides a crucial testing ground for quantum chromodynamics in its non-perturbative regime. In this work, we perform a systematic study of the two-body strong decay properties of single-charm molecular…
I introduce an entirely new dynamical description for exotic charmoniumlike hadrons, based upon the competing effects of the strong attraction between quarks in a diquark, and the inability of the diquark to hadronize on its own due to…