40 research outputs found
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) 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) 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
Quarkonium baryons in the topological soliton model
Abstract We show that the bound state version of the topological soliton model for the baryons, which is consistent with both chiral symmetry in the light quark sector and heavy quark spin symmetry in the heavy flavour sector, implies that the c c and b b pseudoscalar mesons form bound states with nucleons, the binding energy increasing with the heavy meson (quark) mass. The result qualitatively agrees with the earlier QCD-based results that heavy quarkonia should bind to nuclei, although the prediction that the binding energy grows with the heavy quark mass disagrees with the (approximate) QCD-based results