Related papers: Pentaquark $\Theta^+$ mass and width in dense matt…
The experimental evidence for pentaquarks, both old an new, is discussed. Constraints due to $K^+N$ scattering data from previous decades is first reviewed, followed by experiments with positive evidence and those with null results.…
Production of pentaquark $\Theta^+$ baryons in central relativistic heavy ion collisions is studied in a kinetic model. Assuming that a quark-gluon plasma is produced in the collisions, we first determine the number of $\Theta^+$ produced…
The in-medium properties of $\eta$ mesons are studied in hot and dense isospin asymmetric strange magnetized matter using the chiral SU(3) hadronic mean-field model. The scalar and vector density of baryons are expressed in terms of thermal…
We calculate the widths of the various pentaquarks in a relativistic model in which the pentaquark is considered to be composed of a scalar diquark and a spin 1/2 triquark. We consider both positive and negative parity for the pentaquark.…
We analyse the decay $\Theta_s(1/2^+)\to NK$ in a non-relativistic Fock space description using three and five constituent quarks for the nucleon and the pentaquark, respectively. Following Jaffe and Wilczek \cite{jw}, we assume that…
In this paper, we consider an exotic baryon (pentaquark) as a bound state of two-particle systems composed of a baryon (nucleon) and a meson.We used a baryon - meson picture to reduce a complicated five-body problem to a simple two-body…
We study the kaon nuclear optical potential including the effect of the \Theta^+ pentaquark in a self-consistent approach, starting from an extension of the Juelich meson-exchange potential as bare kaon-nucleon interaction. Significant…
Long-standing anomalies in K^+ nucleus integral cross sections could be resolved by extending the impulse-approximation t*rho optical-potential framework to incorporate K^+ absorption on pairs of nucleons. Substantially improved fits to the…
The exclusive reactions $\gamma p \to \bar K^0 K^+ n$ and $\gamma p \to \bar K^0 K^0 p$ have been studied in the photon energy range 1.6--3.8 GeV, searching for evidence of the exotic baryon $\Theta^+(1540)$ in the decays $\Theta^+\to nK^+$…
We investigate the mass spectrum of the pentaquark baryon ($ udud \bar s $) in quenched lattice QCD with exact chiral symmetry. Using 3 different interpolating operators for $ \Theta $, we measure the $ 3 \times 3 $ correlation matrix and…
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…
We consider the $\Theta^+(1540)$ pentaquark in the string model that correctly reproduces the linear Regge trajectories for the case of orbital excitations of light $q\bar q$ mesons and $qqq$ baryons. Assuming (and arguing in favour of) the…
We analyze recent experimental information on the excitation of the Theta+(1540) pentaquark in the hadronic reaction pp -> p Sigma+ K0. Upon describing the conventional production process - which serves as a normalization - in a meson…
The existence of an anti-decuplet of pentaquark particles has been predicted some year ago within the chiral soliton model. In the last year, several experimental groups have reported evidence for a S=+1 baryon resonance, with mass ranging…
We present in this talk recent results of the vector and axial-vector transitions of the nucleon to the pentaquark baryon Theta^{+}, based on the SU(3) chiral quark-soliton model. The results are summarized as follows: K^{*}-N-Theta vector…
Extending the hadronic Lagrangians that we recently introduced for studying pentaquark $\Theta^+$ baryon production from meson-proton, proton-proton, and photon-proton reactions near threshold to include the anomalous interaction between…
By assuming SU(6)_cs symmetry for pentaquark decays one finds a selection rule, which strongly reduces the number of states able to decay into a baryon and a meson final state and allows an intriguing identification for the Theta^+ particle…
We examine several assignments of spin and parity for the pentaquark Theta+ state (J^P=1/2^{+,-}, 3/2^{+,-}) in connection with phenomenology of known baryon resonances, using a general framework based on the flavor symmetry. Assuming that…
Recent strong experimental evidence of a narrow exotic S = +1 baryon resonance, $\Theta^+$, suggests the existence of other exotic baryons. We discuss the prospects of confirming earlier experimental evidence of $\Theta^+$ and the…
Evidence for a narrow baryon state at 1528 +- 2.6(stat) +- 2.1(syst) MeV is presented in quasi-real photoproduction on a deuterium target through the decay channel p,K0 to p,pi+,pi-. The statistical significance of the peak in the p,K0…