3,162 research outputs found
Addendum: Triton and hypertriton binding energies calculated from SU_6 quark-model baryon-baryon interactions
Previously we calculated the binding energies of the triton and hypertriton,
using an SU_6 quark-model interaction derived from a resonating-group method of
two baryon clusters. In contrast to the previous calculations employing the
energy-dependent interaction kernel, we present new results using a
renormalized interaction, which is now energy independent and reserves all the
two-baryon data. The new binding energies are slightly smaller than the
previous values. In particular the triton binding energy turns out to be 8.14
MeV with a charge-dependence correction of the two-nucleon force, 190 keV,
being included. This indicates that about 350 keV is left for the energy which
is to be accounted for by three-body forces.Comment: 4 pages, 1 figur
Quark-Model Baryon-Baryon Interaction and its Applications to Hypernuclei
The quark-model baryon-baryon interaction fss2, proposed by the Kyoto-Niigata
group, is a unified model for the complete baryon octet (B_8=N, Lambda, Sigma
and Xi), which is formulated in a framework of the (3q)-(3q) resonating-group
method (RGM) using the spin-flavor SU_6 quark-model wave functions and
effective meson-exchange potentials at the quark level. Model parameters are
determined to reproduce properties of the nucleon-nucleon system and the
low-energy cross section data for the hyperon-nucleon scattering. Due to the
several improvements including the introduction of vector-meson exchange
potentials, fss2 has achieved very accurate description of the NN and YN
interactions, comparable to various one-boson exchange potentials. We review
the essential features of fss2 and our previous model FSS, and their
predictions to few-body systems in confrontation with the available
experimental data. Some characteristic features of the B_8 B_8 interactions
with the higher strangeness, S=-2, -3, -4, predicted by fss2 are discussed.
These quark-model interactions are now applied to realistic calculations of
few-body systems in a new three-cluster Faddeev formalism which uses
two-cluster RGM kernels. As for the few-body systems, we discuss the
three-nucleon bound states, the Lambda NN-Sigma NN system for the hypertriton,
the alpha alpha Lambda system for 9Be Lambda, and the Lambda Lambda alpha
system for 6He Lambda Lambda.Comment: 20 pages, 12 figures, 18th Nishinomiya Yukawa Memorial Symposium on
Strangeness in Nuclear Matter, 4 - 5 December 2003, Nishinomiya, Japan. (to
be published in Prog. Theor. Phys. Suppl.
Three-Cluster Equation Using Two-Cluster RGM Kernel
We propose a new type of three-cluster equation which uses two-cluster
resonating-group-method (RGM) kernels. In this equation, the orthogonality of
the total wave-function to two-cluster Pauli-forbidden states is essential to
eliminate redundant components admixed in the three-cluster systems. The
explicit energy-dependence inherent in the exchange RGM kernel is
self-consistently determined. For bound-state problems, this equation is
straightforwardly transformed to the Faddeev equation which uses a modified
singularity-free T-matrix constructed from the two-cluster RGM kernel. The
approximation of the present three-cluster formalism can be examined with more
complete calculation using the three-cluster RGM. As a simple example, we
discuss three di-neutron (3d') and 3 alpha systems in the harmonic-oscillator
variational calculation. The result of the Faddeev calculation is also
presented for the 3' system.Comment: 12 pages, no figur
P-wave Lambda N - Sigma N coupling and the spin-orbit splitting of 9 Lambda Be
We reexamine the spin-orbit splitting of 9 Lambda Be excited states in terms
of the SU_6 quark-model baryon-baryon interaction. The previous folding
procedure to generate the Lambda alpha spin-orbit potential from the
quark-model Lambda N LS interaction kernel predicted three to five times larger
values for Delta E_{ell s}=E_x(3/2^+)-E_x(5/2^+) in the model FSS and fss2.
This time, we calculate Lambda alpha LS Born kernel, starting from the LS
components of the nuclear-matter G-matrix for the Lambda hyperon. This
framework makes it possible to take full account of an important P-wave Lambda
N - Sigma N coupling through the antisymmetric LS^{(-)} force involved in the
Fermi-Breit interaction. We find that the experimental value, Delta
E^{exp}_{ell s}=43 pm 5 keV, is reproduced by the quark-model G-matrix LS
interaction with a Fermi-momentum around k_F=1.0 fm^{-1}, when the model FSS is
used in the energy-independent renormalized RGM formalism.Comment: 5 pages, no figure
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