Related papers: The Search for Pentaquark Baryon with Hidden Stran…
Experimental results of the SPHINX Collaboration on studying proton diffractive production processes are presented. Evidences for new baryon states with masses >1.8 GeV were obtained in hyperon-kaon effective mass spectra in several…
In the experiment with the SPHINX spectrometer in 1995-99 a new baryon state X(2000) -> Sigma^0K^+ was observed in the proton diffractive reactions p + N(C) -> Sigma^0K^+ + N(C). The main parameters of X(2000)^+ baryon are M = 1986 +- 6…
A narrow resonance peak was observed at 1.54 +/- 0.01 GeV as an exotic baryon with strangeness S = +1 in the gamma + n going to K^+ + K^- + n reaction on Carbon. The new state have a width smaller than 0.025 GeV and a Gaussian significance…
Several recent experiments have reported evidence for a narrow baryon resonance with positive strangeness ($\Theta^+$) at a mass of 1.54 GeV/$c^2$. Baryons with $S=+1$ cannot be conventional $qqq$ states and the reports have thus generated…
The pentaquarks are exotic baryons formed of four quarks and an antiquarks. Their existence has been discussed in the literature over the last 30 years or more, first in connection with kaon nucleon scattering data. The subject has been…
Since LEPS collaboration reported the first evidence of $\Theta^+$ pentaquark in early 2003, eleven other experimental groups have confirmed this exotic state while many other groups didn't see any signal. If this state is further…
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…
We study the possibility that four $\Xi$ resonances $(\Xi(1620)$, $\Xi(1690)$, $\Xi(1820)$, $\Xi(1950))$ could correspond to pentaquark states, in the form of meson-baryon bound systems. We also explore the possible existence of doubly…
Experimental evidence for and against the existence of pentaquarks has accumulated rapidly in the last three years. If they exist, they would be dramatic examples of hadronic states beyond our well-tested and successful particle models. The…
The pentaquark state recently discovered has been discussed based on various quark model calculations. Odd parity for the state can not be ruled out theoretically because contributions related to non-trivial color structures have not been…
The reaction $\gamma p \to \pi^+K^-K^+n$ was studied at Jefferson Lab using a tagged photon beam with an energy range of 3-5.47 GeV. A narrow baryon state with strangeness S=+1 and mass $M=1555\pm 10$ MeV/c$^2$ was observed in the $nK^+$…
The masses of cryptoexotic pentaquarks with hidden beauty are estimated phenomenologically using the results by the LHCb collaboration which discovered recently the cryptoexotic pentaquarks with hidden charm. The expected masses of the…
The existence of pentaquarks with strangeness content zero and one are major discoveries of the latest years in hadron physics. Most of these states can be understood as hadronic molecules and were predicted prior to their discovery within…
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 $\gamma p\to…
Pentaquark states have been extensively investigated theoretically in the context of the constituent quark model. In this paper results of an experimental search for pentaquarks in the \Xim\pim, \Xim\pip, \Xip\pim and \Xip\pip invariant…
Review for exotic strange multibaryon states were obseved in the effective mass spectra of: 1)$\Lambda \pi^+$, $\Lambda \pi^-$, $\Lambda p$, $\Lambda p p$, and $\Lambda K^0_S$, $K^0_S\pi^{\pm}$ and $K^0_Sp$ subsystems.The invariant mass of…
We report on searches in deep inelastic $ep$ scattering for narrow baryonic states decaying into $\Xi^-\pi^-, \Xi^-\pi^+, \KS p$ and their charge conjugates, at centre-of-mass energies of 300 and 318 GeV. No signal for a new narrow baryonic…
The classical quenched quark models with three constituent quarks provide a good description for the baryon spatial ground states, but fail to reproduce the spectrum of baryon excited states. More and more evidences suggest that unquenched…
We study, within the statistical hadronization model, the influence of narrow strangeness carrying baryon resonances (pentaquarks) on the understanding of particle production in relativistic heavy ion collisions. There is a great variation…
Narrow Xi-pi+- and Xi-bar+pi+- resonances produced by quasi-real photons have been searched for by the COMPASS experiment at CERN. The study was stimulated by the recent observation of an exotic baryonic state decaying into Xi-pi-, at a…