Evidence for the J^p=1/2^+ narrow state at 1650 MeV in the photoproduction of KLambda

We have investigated the existence of the J^p=1/2^+ narrow resonance predicted by the chiral soliton model by utilizing the kaon photoproduction process gamma + p --> K^+ + Lambda. For this purpose we have constructed two phenomenological models based on our previous effective Lagrangian model, which are able to describe kaon photoproduction from threshold up to W = 1730 MeV. By varying the mass (width) of an inserted P_{11} resonance from 1620 to 1730 MeV (0.1 to 1 MeV and 1 to 10 MeV) a number of fits has been performed in order to search for the resonance mass. Our result indicates that the most promising candidate mass (width) of this resonance is 1650 MeV (5 MeV). Although our calculation does not exclude the possibility of narrow resonances with masses of 1680, 1700 and 1720 MeV, the mass of 1650 MeV is obtained for all phenomenological models used in this investigation. Variations of the resonance width and $K\Lambda$ branching ratio are found to have a mild effect on the chi^2. The possibility that the obtained result originates from other resonance states is also discussed.Comment: 27 pages, 19 figures, submitted to Phys. Rev.

1-loop correction to the SU(3) symmetric chiral soliton

Masses of the SU(3) chiral soliton in tree approximation turn out at much too high energies typically around 2 GeV. It is shown that 1-loop corrections reduce this value drastically with results in the region of the empirical nucleon mass.http://www.sciencedirect.com/science/article/B6TVN-3TX52TY-3/1/b94a13be7c59e68c61e01d2fc393d40

1-loop correction to the SU(3) symmetric chiral soliton

Masses of the SU(3) chiral soliton in tree approximation turn out at much too high energies typically around 2 GeV. It is shown that 1-loop corrections reduce this value drastically with results in the region of the empirical nucleon mass.http://www.sciencedirect.com/science/article/B6TVN-3TX52TY-3/1/b94a13be7c59e68c61e01d2fc393d40

Collective Resonances in the Soliton Model Approach to Meson--Baryon Scattering

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 large-Nc consistency conditions. As an application I discuss hadronic pentaquark decays and show that predictions based on axial current matrix elements are erroneous.Comment: Contribution to QNP06 (Madrid, June 2006), 3 pages epja styl

The Low-Energy Theorem of Pion Photoproduction in Soliton Models of the Nucleon

We derive an analytic expression for the Kroll-Ruderman amplitude up to the order 1/N_C for general Skyrme-type models of the nucleon. Due to the degeneracy of intermediate N- and Delta-states we find deviations from the standard low-energy theorem for the photoproduction of neutral pions.Comment: 17 pages, LATEX, SI-93-TP3S

Optimización Técnico-Ecónomica de sistemas discontinuos de tintura.

En la actualidad, no es posible hablar sólo de métodos rápidos de tintura o de optimización de sistemas de tintura, sino que debemos introducir también el concepto de balance técnico-económico para que cada decisión que tomemos signifique una aportación positiva a la solución de los problemas.Peer Reviewe