相关论文: Theta+ formation in inclusive gamma D -> pK- X
We analyse Theta+ production in the gamma+D -> \Lambda+n+K+ reaction and study the dependence of the gamma+D -> \Lambda+n+K+ differential cross section on the nK+ invariant mass and on the momentum of the final neutron p_n. We examine the…
The \gamma d \to K^+K^-pn reaction has been studied to search for the evidence of the \Theta^+ by detecting K^+K^- pairs at forward angles. The Fermi-motion corrected nK^+ invariant mass distribution shows a narrow peak at 1.524 +- 0.002 +…
We analyze an effect of the coherent $\Theta^+\Lambda(1520)$ photoproduction in $\gamma D$ interaction near the threshold. We demonstrate that the coherence effect becomes manifest in a comparison of the $nK^+$ invariant mass distribution…
For the first time, the reaction gamma d -> Lambda n K+ has been analyzed in order to search for the exotic pentaquark baryon Theta+(1540). The data were taken at Jefferson Lab, using the Hall-B tagged-photon beam of energy between 0.8 and…
The Theta+ was searched for via the K+p -> pi+X reaction using the 1.2 GeV/c K+ beam at the K6 beam line of the KEK-PS 12 GeV Proton Synchrotron. In the missing mass spectrum of the K+p -> pi+X reaction, no clear peak structure was…
The gamma + D -> Lambda + Theta+ and gamma + D -> Sigma + Theta+ reactions can be used to determine the width of Theta+ almost model-independently. We calculate the differential cross sections of the gamma +D -> Lambda + Theta+, gamma + D…
We have searched for $\Theta^{+}$ via $\pi^{-}p \to K^{-}X$ reaction using 1.87 and 1.92 GeV/c $\pi^{-}$ beam at the K2 beam line of the KEK 12 GeV Proton Synchrotron. In the missing mass spectrum at beam momentum of 1.92 GeV/$c$, a bump…
We present a calculation of the $\gamma d \to K^+ K^- n p $ reaction with the aim of seeing if the experimental peak observed in the $K^+ n$ invariant mass around 1526 MeV, from where evidence for the existence of the $\Theta^+$ has been…
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…
The cross section for $\Theta^+$ production from the reaction $\gamma p\to\pi^+K^-\Theta^+$, which was observed in the CLAS experiment at the Jefferson National Laboratory, is evaluated in a hadronic model that includes couplings of…
We estimate the cross sections for the inclusive production of $\Theta^+$ and $\Lambda(1520)$ in $pp$ collisions at high energy using the $K$ exchange diagrams. We find that inclusive $\Theta^+$ production should be at the level of 1 $\mu$b…
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…
A search for the \thp in the reaction $\gamma d \to pK^-K^+n$ was completed using the CLAS detector at Jefferson Lab. A study of the same reaction, published earlier, reported the observation of a narrow \thp resonance. The present…
We study $\Theta^+(1540)$ productions in kaon-nucleon ($KN$) and nucleon-nucleon ($NN$) interactions by assuming that the $\Theta^+$ is an isosinglet with $J^P = \frac12^+$. Possible $t$-channel diagrams with $K^*$ exchange are considered…
We have studied the $\gamma d \to K^+ K^- n p$ reaction in which the LEPS collaboration found a signal in the $K^+ n$ invariant mass for the claimed $\Theta(1540)$ pentaquark peak. Our study reveal that the procedure used at LEPS to…
A search for narrow Theta(1540)^+, a candidate for pentaquark baryon with positive strangeness, has been performed in an exclusive proton-induced reaction p+C(N) \to Theta^+ \bar{K}^0 + C(N) on carbon nuclei or quasifree nucleons at…
We investigate theoretically the $K^{0} p$ invariant mass spectrum of the $K^{+} d \to K^{0} p p$ reaction and scrutinize how the signal of the "$\Theta ^{+}$" pentaquark, if it exists, emerges in the $K^{0} p$ spectrum. The most prominent…
The reaction $\gamma p \to pK^+K^-$ was studied at Jefferson Lab with photon energies from 1.8 to 3.8 GeV using a tagged photon beam. The goal was to search for a $\Theta^{++}$ pentaquark, a narrow doubly charged baryon state having…
Differential cross sections and photon beam asymmetries for the gamma p rightarrow K+ Lambda and gamma p rightarrow K+ Sigma0 reactions have been measured in the photon energy range from 1.5 GeV to 2.4 GeV and in the angular range from…
The K0s-p invariant mass spectrum was reconstructed in several kinematic regions with the main emphasis on the studies of the production mechanism of the Theta+ candidate recently observed by ZEUS. The candidate Theta+ signal was found to…