Heavy quark skyrmions

The description of the heavy baryons as heavy-meson--soliton bound systems is reviewed. We outline how such bound systems arise from effective lagrangians that respect both chiral symmetry and heavy quark symmetry. Effects due to finite heavy quark masses are also discussed, and the resulting heavy baryon spectra are compared with existing quark model and empirical results. Finally, we address some issues related to a possible connection between the usual bound state approach to strange hyperons and that for heavier baryons.Comment: To appear in "The Multifaceted Skyrmion" (World Scientific) ed. G.E. Brown and M. Rh

Multibaryons in the Skyrme model

Low-lying multibaryon configurations are studied within the bound state approach to the SU(3) Skyrme model. We use approximate ansaetze for the static background fields based on rational maps which have the same symmetries of the exact solutions. To determine the explicit form of the collective Hamiltonians and wave functions we only make use of these symmetries. Thus, the expressions obtained are also valid in the exact case. On the other hand, the meson bindings, inertia parameters and hyperfine splitting constants we calculate do depend on the detailed form of the ansaetze and are, therefore, approximate. Using these values we compute the low-lying spectra of multibaryons with B =< 9 and strangeness 0 and -B. With these results the stability of some multilambda configurations is discussed.Comment: 7 pages. To be published in the Proc. of "Hadron Physics 99". Coimbra, Portugal. September 10- 15, 199

Decays of Non-Strange Positive Parity Excited Baryons in the 1/Nc Expansion

The decays of non-strange positive parity excited baryons via emission of a pseudo-scalar meson are studied in the framework of the 1/Nc expansion to order 1/Nc. In particular, the pionic decays of the l=0 Roper baryons and of the l=2 baryons in the mass interval 1680-1950 MeV are analyzed using the available partial decay widths. Decay widths by emission of an eta meson are shown to be suppressed by a factor 1/Nc^2 with respect to the pionic ones.Comment: 16 pages, 8 table

Light pseudoscalar mesons in a nonlocal SU(3) chiral quark model

We study the properties of the light pseudoscalar mesons in a three flavor chiral quark model with nonlocal separable interactions. We concentrate on the evaluation of meson masses and decay constants, considering both the cases of Gaussian and Lorentzian nonlocal regulators. The results are found to be in quite good agreement with the empirical values, in particular in the case of the ratio f_K/f_pi and the anomalous decay pi^0 --> gamma gamma. In addition, the model leads to a reasonable description of the observed phenomenology in the eta-eta' sector, even though it implies the existence of two significantly different state mixing angles.Comment: 18 pages, 3 figures. New subsections included, references added. Mixing angles eta - eta' reanalyzed. Final version to appear in Phys. Rev.