Related papers: Justifying the exotic Theta+ pentaquark
The properties of ground-state baryons of light-quarks are investigated in U(12)-classification scheme of hadrons, recently proposed by us. In U(12), in addition to the ordinary 56 of SU(6)SF, the existence of the extra 56 with…
The spectroscopy of light, strange baryons have been an important aspect with still unknown resonances and intrinsic baryonic properties. The present document is focused on the $\Delta$ baryons unlike earlier work, here all the four isospin…
Using kaon secondary interactions in the material of the Belle detector, we search for both inclusive and exclusive production of the Theta(1540)+. We set an upper limit of 2.5% at the 90% C.L. on the ratio of the Theta(1540)+ to…
The possibility for an observation of a narrow penta-quark $Z^+$ baryon in $NN$ reactions is discussed. It is shown that the $pp{\to}n\Sigma^+K^+$ reaction at excess energies around 100 MeV above threshold provides optimal conditions for…
A new mechanism of the production of hypothetical $\Theta(ud\bar{s}ud)^+$ pentaquark state is suggested. The considered mechanism is based on the exchange by exotic Regge trajectories in the $t$ channel. It is shown that the momentum…
The recently discovered pentaquark $\Theta^+$ is described within the chiral constituent quark model. Within this picture the flavor-spin interaction between valence quarks inverts the $(1s)^4$ and $(1s)^3(1p)$ levels of the four-quark…
SVD-2 experiment data have been analyzed to search for an exotic baryon state, the $\Theta^+$-baryon, in a $pK^0_s$ decay mode at $70 GeV/c$ on IHEP accelerator. The reaction $pA \to pK^0_s+X$ with a limited multiplicity was used in the…
The 2m propane bubble chamber experimental data have been analyzed to search for an exotic baryon state, the $\Theta^+$ -baryon, in the $pK^0_s$ decay mode for the reaction p+$C_3H_8$ at 10 GeV/c. The $pK^0_s$ invariant mass spectrum shows…
The proper description of hadronic decays of baryon resonances has been a long standing problem in soliton models for baryons. In this talk I present a solution to this problem in the three flavor Skyrme model that is consistent with…
Recent discoveries of manifestly exotic, narrow baryon resonances present a fundamental challenge for our theoretical understanding of low-energy QCD. This is a brief survey of their interpretation, emphasizing the possibility that diquark…
Recently several proposals were put forward to determine the parity of narrow baryonic resonances, in particular the $\Theta^+$. In these proceedings we will briefly comment on the general problems in this task and then discuss in detail…
The pp -> p K0 Sigma+ reaction was investigated with the TOF spectrometer at COSY at 3.059 GeV/c incident beam momentum. The main objective was to clarify whether or not a narrow exotic S = +1 resnance, the Theta+ pentaquark, is populated…
In the Relativistic Mean Field Approximation three quarks in baryons from the lowest octet and the decuplet are bound by the self-consistent chiral field, and there are additional quark-antiquark pairs whose wave function also follows from…
We discuss the properties of the pentaquark in a collective stringlike model with a nonplanar configuration of the four quarks and the antiquark. In an application to the mass spectrum of exotic Theta baryons, we find that the ground state…
Using the DIANA data on the charge-exchange reaction $K^+n \rightarrow pK^0$ on a bound neutron, in which the s-channel formation of the pentaquark baryon $\Theta^+(1538)$ has been observed, we analyze the dependence of the…
The newly discovered exotic $\Theta$ baryon of mass 1540 MeV (and very small width) truly has a very low mass, if it is a pentaquark system of even parity. A schematic model in which the coherent interaction of $u\bar s$ and $d\bar s$ pairs…
In this paper we explain and discuss some fundamental features of various models which are QCD-based and proposed to explain the hadron spectrum.
We use a theoretical model of the $\gamma ~d \to ~K^+ K^- ~n ~p $ reaction adapted to the experiment done at LEPS where a peak was observed and associated to the $\Theta^{+}(1540)$ pentaquark. The study shows that the method used in the…
It has been ten years since the first report for a positive strangeness pentaquark-like baryon state. However the existence of the pentaquark state is still controversial. Some contradictions between the experiments are unsolved. In this…
Using data on K^+ collisions on xenon and deuterium we derive values and limits on the width of the reported Theta(1540)^+ exotic baryon resonance. The xenon experiment gives a width of 0.9\pm 0.3 MeV. The other experiments give upper…