Related papers: The isotensor pentaquark
In the search for the pentaquark $\Theta^+$ baryon, the world data on $K^+n\to K^+n$ and $K^+n\to K^0\,p$ reactions on the deuteron target and $K^0\,p\to K^+n$ and $K^0_L\,p\to K^0_S\,p$ reactions on the hydrogen target are revisited to…
We search for the strange pentaquark $\Theta^+$ using kaon interactions in the material of the Belle detector. No signal is observed in the $p K_S$ final state, while in the $p K^-$ final state we observe $\sim 1.6 \cdot 10^4$…
If the number of colors Nc is taken large, baryons and their excitations can be considered in a mean-field approach. We argue that the mean field in baryons breaks spontaneously the spherical and SU(3) flavor symmetries, but retains the…
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 pentaquark $\Theta^+$ has been searched for via the $\pi^-p \to K^-X$ reaction with beam momenta of 1.92 and 2.01 GeV/$c$ at J-PARC. A missing mass resolution of 2 MeV (FWHM) was achieved but no sharp peak structure was observed. The…
I discuss recent results on the electroproduction and photoproduction of mesons in the region of non-strange baryon resonances. Results on the quadrupole transition from the ground state nucleon to the Delta(1232) show the importance of…
The three pentaquark candidates Theta^+(1530), Xi(1862) and Theta^0_c(3100) have been studied in ep collisions at a centre-of-mass energy sqrt{s}=300-318 GeV using the full luminosity of the HERA-I data. Searches for narrow baryonic states…
Re-analyzing the old pi N --> K Lambda data, the additional proof is given for the existence of the N(1710) P11 state, critically needed in light of reported observations of exotic Theta(1539) and Xi(1862) pentaquarks. An existing…
A systematic lowering in mass of strangeness ambiguous $pK^0_S$ peaks relative to the $nK^+$ is noted. We discuss how measurement of $\gamma p\to \Theta^+ K^0_S\to p K^0_S K^0_S \to p\pi^+\pi^-\pi^+\pi^-$ in association with $\gamma p\to…
We have searched for a bound state of kaon and pion denoted by $X$. The $X$ was conjectured to explain the so-called $\Theta^+$ resonance as a bound state of kaon, pion and nucleon. This model explains almost all properties of the…
We consider a $[ud]^2\bar{s}$ current in the QCD sum rule framework to study the mass of the recently observed pentaquark state $\Theta^+(1540)$, obtaining good agreement with the experimental value. We also study the mass of the pentaquark…
We investigate light meson bound state contributions to six quark Green's functions and establish that the latter has poles corresponding to baryon bound states. We estimate light baryon masses including the Roper resonance. Constituent…
The reaction pp->p K0 pi+ Lambda has been studied with the ANKE spectrometer at COSY-Juelich at a beam momentum of 3.65 GeV/c in order to search for a possible signal of the pentaquark Theta+(1540), decaying into the p K0 system. By…
Incoherent $\eta$-photoproduction on the deuteron is studied for photon energies from threshold up to 720 MeV. The elementary $\gamma N \to \eta N$ amplitude is constructed in the frame of a conventional isobar model. Effects of final state…
Very recent eta and K+ photoproduction data on the proton from threshold up to E = 2.6 GeV are interpreted within a chiral constituent quark formalism, which embodies all known nucleon and hyperon resonances. Possible contributions from an…
A study of the decay B+->ppbarK+ is performed using 81fb-1 of data collected at the Upsilon(4S) with the BaBar detector at PEP-II. The branching fraction of B+->ppbarK+ is measured to be (6.7+/-0.9+/-0.6)x10^-6. An upper limit on the…
Recent results on light hadron spectroscopy are reported, with special emphasis on the evidence for a narrow baryonic state decaying to Ks p and Ks pbar, compatible with the pentaquark state theta^+ observed by fixed target experiments. The…
We discuss the implications of the suggested interpretation of the recently reported narrow pi N resonance (width \approx 25 MeV at 1680 MeV) as a pentaquark in the same multiplet as the Theta+. We consider a diquark-triquark pentaquark…
The proton analyzing power Ay0 and the deuteron tensor analyzing power T20 are evaluated for the pd <-> pi+ t process, in the energy region around and above the Delta resonance. These calculations extend a previous analysis of the…
The exclusive reaction $\gamma p \to \bar K^0 K^+ n$ was studied in the photon energy range between 1.6-3.8 GeV searching for evidence of the exotic baryon $\Theta^+(1540)\to nK^+$. The decay to $nK^+$ requires the assignment of strangeness…