Related papers: Stable Pentaquarks from Strange Chiral Multiplets
It is shown that the decay amplitude for the Jaffe-Wilczek type pentaquarks is not suppressed by chiral symmetry. On the other hand, pentaquarks of positive or negative parity built up of an antiquark and two chirally different diquarks in…
We demonstrate that a five quark state of positive parity with an internal P-wave structure - usually pictured as a composite of an antiquark and two diquarks in a P-wave state - can couple to nucleons and Goldstone particles in a chirally…
We conjecture that in the chiral limit of QCD the spectrum of hadrons is comprised of decoupled, reducible chiral multiplets. A simple rule is developed which identifies the chiral representations filled out by the ground-state hadrons. Our…
We point out that meson spectrum indicates the existence of a degenerate chiral nonet in the energy region around 1.4 GeV with a slightly inverted spectrum with respect to a qq nonet. Based on this observation, the approximately linear…
QCD string picture of highly excited hadrons very naturally explains parity doubling once the chiral symmetry is restored high in the spectrum. In particular, the spin-orbit and tensor interactions of quarks at the ends of the string,…
We study the multiquark hadrons in large $N$ QCD under the 't-Hooft limit, extending Witten's picture of the baryons. We explore the decay widths of tetraquarks, pentaquarks and dibaryons. Based on the decay behaviors, we point out in the…
In this talk, multiquarks are studied microscopically in a standard quark model. In pure ground-state pentaquarks the short-range interaction is computed and it is shown to be repulsive. An additional quark-antiquark pair is then…
We point out that the spectrum of pseudoscalar and scalar mesons exhibits a cuasi-degenerate chiral nonet in the energy region around 1.4 GeV whose scalar component has a slightly inverted spectrum. Based on the empirical linear rising of…
The last decade has seen a marked shift in how the internal structure of hadrons is understood. Modern experimental facilities, new theoretical techniques for the continuum bound-state problem and progress with lattice-regularised QCD have…
We present a very general argument that the analogue of a heavy pentaquark (a state with the quantum numbers of a baryon combined with an additional light quark and a heavy antiquark) must exist as a particle stable under strong…
At a critical finite chemical potential and low temperature QCD undergoes the chiral restoration phase transition. The folklore tradition is that simultaneously hadrons are deconfined and there appears the quark matter. We demonstrate that…
It has recently been suggested that the parity doublet structure seen in the spectrum of highly excited baryons may be due to effective chiral symmetry restoration for these states. We review the recent developments in this field. We…
It is shown that standard constituent quark models produce $(\bar c c qqq)$ hidden-charm pentaquarks, where $c$ denotes the charmed quark and $q$ a light quark, which lie below the lowest threshold for spontaneous dissociation and thus are…
We investigate modifications of hadron masses at finite quark chemical potential in two-flavor and two-color QCD, of which the data are available from lattice simulations, within a linear sigma model based on approximate Pauli-Gursey…
We apply the dynamical diquark model to predict the spectrum of hidden-charm pentaquark states in both unflavored and open-strange sectors. Using only Hamiltonian parameters introduced in the tetraquark $S$- and $P$-wave multiplets, the…
A chiral effective theory of quarks and diquarks is formulated and applied to exotic tetraquarks and pentaquarks. The effective theory is similar to the chiral quark effective theory with the addition of diquark degrees of freedom and…
Spontaneous chiral symmetry breaking, mesons and baryons are illustrated in the language of the Dirac theory. Various forces acting between quarks inside baryons are discussed. I explain why the naive quark models typically overestimate…
We consider hidden charm pentaquarks as hadroquarkonium states in a QCD inspired approach. Pentaquarks arise naturally as bound states of quarkonia excitations and ordinary baryons. The LHCb $P_c(4450)$ pentaquark is interpreted as a…
We determine constraints on the partial widths of mixed pentaquark multiplets in the framework of heavy baryon chiral perturbation theory (HB$\chi$PT). The partial widths satisfy a GMO-type relation at leading order in HB$\chi$PT, for…
If supersymmetry exists at low energies, it is necessary to understand why the squark spectrum exhibits sufficient degeneracy to suppress flavor changing neutral currents. In this note, we point out that gauged horizontal symmetries can…