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

Quark matter under strong magnetic fields in SU(2) NJL-type models: parameter dependence of the cold dense matter phase diagram

The phase structure of magnetized cold quark matter is analyzed in the framework of the two-flavor Nambu-Jona-Lasinio models paying special attention to its dependence on the model parameters as different values within the phenomenological allowed range are considered. We first discuss the simpler chiral limit case, and then the more realistic situation of finite current masses. We show that in spite of the difference in the nature of some transitions, both cases are alike and exhibit a rather rich phase structure for a significant range of acceptable parameters. A simplification of the phase structure is obtained as parameters leading to larger values of the dressed quark mass in the vacuum are considered. Finally, we consider the so-called "inverse catalysis effect" showing that in some phases it implies an actual decrease of the order parameter as the magnetic field increases.Comment: 15 figure

Cold magnetized quark matter phase diagram within a generalized SU(2) NJL model

We study the effect of intense magnetic fields on the phase diagram of cold, strongly interacting matter within an extended version of the Nambu-Jona-Lasinio model that includes flavor mixing effects and vector interactions. Different values of the relevant model parameters in acceptable ranges are considered. Charge neutrality and beta equilibrium effects, which are specially relevant to the study of compact stars, are also taken into account. In this case the behavior of leptons is discussed.Comment: 25 pages, 7 figure

Magnetized color superconducting cold quark matter within the SU(2)f_f NJL model: a novel regularization scheme

The influence of intense magnetic fields on the behavior of color superconducting cold quark matter is investigated using an SU(2)$_f$ NJL-type model for which a novel regulation scheme is introduced. In such a scheme the contributions which are explicitly dependent on the magnetic field turn out to be finite and, thus, do not require to be regularized. As a result of this, nonphysical oscillations that might arise in the alternative regularization schemes previously used in the literature are naturally removed. The sensitivity of our results to the model parametrization is analyzed.Comment: 28 pages, 7 figure

ΔS=1\Delta S = 1 Hadronic Weak Decays of Hyperons in a Soliton Model

We study the parity violating hyperon non-leptonic weak decays in the three flavor Skyrme model. We follow the approach in which the symmetry breaking terms in the action are diagonalized exactly within the collective coordinate approximation. We show that although this method introduces some configuration mixing, the $\Delta I =1/2$ rule is numerically well satisfied. In addition, and in contrast to previous calculations, we show that not only the relative amplitudes are in good agreement with the empirical values but also their absolute values. The issue of whether the strong interaction enhancement factors should be included in soliton calculations is also addressed.Comment: 8 pages, LaTeX, no figure