Related papers: A Mass Inequality for the $\Xi^*$ and $\Theta^+$ P…
We show that the mass intervals among the pentaquark baryons $\Theta^{+}$, $N^{*}(1685)$ and $\Xi_{3/2}^{-}$ proposed to be the members of the SU(3) antidecuplet are exact integral multiples of the mass difference between a neutral pion and…
In this work we investigate the consequences of the Jaffe and Wilczek diquark model in the framework of QCD sum rules. An analysis of the Theta^+(1540) as (ud)^2\bar{s} state shows that the mass of the pentaquark is compatible with the…
According to QCD, there exists a broken dynamical supersymmetry between an antiquark and a diquark. This supersymmetry can be used to relate the mass of a pentaquark to the mass of an antibaryon by replacing two antiquarks in an antibaryon…
Assuming that the recently observed $\Theta^+$ and $\Xi^{--}$ are members of an anti-decuplet of SU(3), decays to ground state baryons and mesons are calculated using an effective Lagrangian which incorporates chiral and SU(3) symmetry. We…
The contradiction between evidence for and against the existence of the Theta+ pentaquark might be resolved if it only appears as a result of a particular production mechanism which is present in some experiments and absent in others. We…
Dynamical calculations are performed for all members of the flavor antidecuplet to which the pentaquark $\Theta^+$ belongs. The framework is a constituent quark model where the short-range interaction has a flavor-spin structure. From…
Masses of heavy mesons, tetraquarks and pentaquarks computed in a potential model are shown. Tetraquarks are studied as bound states of a diquark and an antidiquark. Pentaquarks are constructed from a series of two-body interactions between…
We study the pentaquark $uudd\bar s$ with $J=3/2$ and I=1 ($\Theta^{++}$) in the QCD sum rule approach. We derive the QCD sum rules for positive and negative parity states of the pentaquark. The QCD sum rule predicts that there exists…
Recent experimental evidence for the Theta^+(1540) has given rise to much theoretical interest in exotic baryons. The Theta^+ is a baryon that has strangeness S=+1, meaning that it contains an anti-strange quark. Thus it cannot be…
In this work we study the Theta(1540) in the framework of QCD sum rules based on (ud)^2\bar{s} diquark clustering as suggested by Jaffe and Wilczek. Within errors, the mass of the pentaquark is compatible with the experimentally measured…
The mass of the newly discovered pentaquark is calculated within the framework of the SU(3) Skyrme Model. Various estimates based on the \emph{model independent} approach are compared with the model results and with the Chiral Quark Model.…
The existence of the $\Theta^+$ pentaquark requires a peculiar mechanism to explain its stability. Looking at quark clusters, notably diquark and triquark configurations, such a mechanism may be found in the color-magnetic interaction…
The masses of pentaquarks $uudd\bar s$ are calculated within the framework of a semirelativistic effective QCD Hamiltonian, using a diquark picture. This approximation allows a correct treatment of the confinement, assumed here to be…
We examine SU(3) constraints on the spectrum and decay widths of cryptoexotic nucleon-like states in antidecuplet of pentaquarks. We show that in the ideal mixing scenario the number of free matrix elements describing splittings reduces…
We study the recently discovered Theta^+ baryon in the context of the perturbative chiral quark model. The basic configuration of the Theta^+ is set up as a pentaquark bound state, where the single particle wave functions are the ground…
We perform a constituent quark model analysis for the masses of the doubly heavy tetraquark states $T_{QQ}$ after we fix the parameters to fit the masses of the newly observed $\Xi_{cc}^{++}$ and hadrons involving heavy quarks relevant to…
We have investigated negative-parity uudd\bar{s} pentaquarks by employing a quark model with the meson exchange and the effective gluon exchange as qq and q\bar{q} interactions. The system for the five quarks is dynamically solved; the…
In a diquark-diquark-antiquark picture of pentaquarks, we use two interpolating currents to calculate the mass of the recently measured $\Xi^{--}$ state in the framework of QCD sum rules. We show that, even though yielding similar values…
Recently several experiments have reported evidences for pentaquark $\Theta^+$. H1 experiment at HERA-B has also reported evidence for $\Theta_c$. $\Theta^+$ is interpreted as a bound state of an $\bar s$ with other four light quarks $udud$…
We propose a model for the recently discovered Theta^+ exotic KN resonance as a novel kind of a pentaquark with an unusual color structure: a color triplet (ud) diquark, coupled to a color anti-triplet (ud s-bar) triquark in a relative…