Comment on `Two-body random ensembles: from nuclear spectra to random polynomials

In PRL 85, 3773 (2000) it was suggested to use random polynomials to analyze and understand the properties of two-body random ensembles. In this comment we point out that for the vibron model the random polynomial is not quadratic, but has a more general form. We make a comparison for the percentage of ground states with L=0 in the vibron model with random interactions.Comment: 2 pages, 1 figure, Phys. Rev. Lett., in pres

Flavor content of nucleon form factors in a VMD approach

The strange form factors of the nucleon are studied in a two-component model consisting of a three-quark intrinsic structure surrounded by a meson cloud. A comparison with the available experimental world data from the SAMPLE, PVA4, HAPPEX and G0 collaborations shows a good overall agreement. It is shown that the strangeness contribution to the electric and magnetic form factors is of the order of a few percent. In particular, the strange quark contribution to the charge radius is small (0.005 fm**2) and to the magnetic moment it is positive (0.315 n.m.).Comment: 5 pages, 6 figures, 1 table, invited talk at PAVI06, Milos, Greece, May 16-20, 200

Regular spectra in the vibron model with random interactions

The phenomenom of emerging regular spectral features from random interactions is addressed in the context of the vibron model. A mean-field analysis links different regions of the parameter space with definite geometric shapes. The results that are, to a large extent, obtained in closed analytic form, provide a clear and transparent interpretation of the high degree of order that has been observed in numerical studies.Comment: 19 pages, 8 figures, 2 tables. Physical Review C, in pres

Algebraic model of baryon structure

We discuss properties of baryon resonances belonging to the Nucleon, Delta, Sigma, Lambda, Xi and Omega families in a collective string-like model for the nucleon, in which the radial excitations are interpreted as rotations and vibrations of the string configuration. We find good overall agreement with the available data. The main discrepancies are found for low lying S-wave states, in particular N(1535), N(1650), Sigma(1750), Lambda*(1405), Lambda(1670) and Lambda(1800).Comment: 6 pages, 2 tables, invited talk Bologna 2000: Structure of the Nucleus at the Dawn of the Centur