1,208 research outputs found
Efimov universality with Coulomb interaction
The universal properties of charged particles are modified by the presence of
a long-range Coulomb interaction. We investigate the modification of Efimov
universality as a function of the Coulomb strength using the Gaussian expansion
method. The resonant short-range interaction is described by Gaussian
potentials to which a Coulomb potential is added. We calculate binding energies
and root mean square radii for the three- and four-body systems of charged
particles and present our results in a generalised Efimov plot. We find that
universal features can still be discerned for weak Coulomb interaction, but
break down for strong Coulomb interaction. The root-mean-square radius plateaus
at increasingly smaller values for strong Coulomb interaction and the
probablity distributions of the states become more concentrated inside the
Coulomb barrier. As an example, we apply our universal model to nuclei with an
alpha-cluster substructure. Our results point to strong non-universal
contributions in that sector.Comment: 18 pages, 9 figures, final version (with small orthographical
corrections
Constituent quark model for baryons with strong quark-pair correlations and non-leptonic weak transitions of hyperon
We study the roles of quark-pair correlations for baryon properties, in
particular on non-leptonic weak decay of hyperons. We construct the quark wave
function of baryons by solving the three body problem explicitly with
confinement force and the short range attraction for a pair of quarks with
their total spin being 0. We show that the existence of the strong quark-quark
correlations enhances the non-leptonic transition amplitudes which is
consistent with the data, while the baryon masses and radii are kept to the
experiment.Comment: 4 pages, 2 figures, talk presented at KEK-Tanashi International
Symposium on Physics of Hadrons and Nuclei, Tokyo, Japan, 14-17 Dec. 199
Role of quark-quark correlation in baryon structure and non-leptonic weak transitions of hyperons
We study the role of quark-quark correlation in the baryon structure and, in
particular, the hyperon non-leptonic weak decay, which is sensitive to the
correlation between quarks in the spin-0 channel. We rigorously solve
non-relativistic three-body problem for SU(3) ground state baryons to take into
account the quark-pair correlation explicitly. With the suitable attraction in
the spin-0 channel, resulting static baryon properties as well as the parity
conserving weak decay amplitudes agree with the experimental values. Special
emphasis is placed also on the effect of the SU(6) spin-flavor symmetry
breaking on the baryon structure. Although the SU(6) breaking effects on the
local behavior of the quark wave functions are considerable due to the spin-0
attraction, the calculated magnetic moments are almost the same as the naive
SU(6) expectations
Tensor correlation, pairing interaction and deformation in Ne isotopes and Ne hypernuclei
We study tensor and pairing effects on the quadruple deformation of neon
isotopes based on a deformed Skyrme-Hartree-Fock model with BCS approximation
for the pairing channel. We extend the Skyrme-Hartree-Fock formalism for the
description of single- and double-lambda hypernuclei adopting two different
hyperon-nucleon interactions. It is found that the interplay of pairing and
tensor interactions is crucial to derive the deformations in several neon
isotopes. Especially, the shapes of Ne are studied in details in
comparisons with experimentally observed shapes. Furthermore the deformations
of the hypernuclei are compared with the corresponding neon isotopic cores in
the presence of tensor force. We find the same shapes with somewhat smaller
deformations for single -hypernuclei compared with their core
deformations. It is also pointed out that the latest version of hyperon
interaction, the ESC08b model, having a deeper potential makes
smaller deformations for hypernuclei than those of another NSC97f model.Comment: 13 pages, 5 figures, Physical Review C 2013 in pres
Four-body cluster structure of double- hypernuclei
Energy levels of the double- hypernuclei
He, Li,
Li, Li,
Be and Be are predicted on
the basis of the four-body model with He and , respectively.Comment: 27 pages (preprint style), 12figures submitted to Phys. Rev.
-- coupling in He with the Nijmegen soft-core potentials
The -- coupling in
He is studied with the [ + +
] + [ + + ] + [ + + ] model,
where the particle is assumed as a frozen core. We use the Nijmegen
soft-core potentials, NSC97e and NSC97f, for the valence baryon-baryon part,
and the phenomenological potentials for the parts (=,
, and ). We find that the calculated of He for NSC97e and NSC97f are,
respectively, 0.6 and 0.4 MeV in the full coupled-channel calculation, the
results of which are about half in comparison with the experimental data,
MeV.
Characteristics of the sector in the NSC97 potentials are discussed in
detail.Comment: 18 pages, 4 figure
Consistency of Lambda-Lambda hypernuclear events
Highlights of Lambda-Lambda emulsion events are briefly reviewed. Given three
accepted events, shell-model predictions based on p-shell Lambda hypernuclear
spectroscopic studies are shown to reproduce the Lambda-Lambda (LL) binding
energies of LL10Be and LL13B in terms of the LL binding energy of LL6He.
Predictions for other species offer judgement on several alternative
assignments of the LL13B KEK-E176 event, and on the assignments LL11Be and
LL12Be suggested recently for the KEK-E373 HIDA event. The predictions of the
shell model, spanning a wide range of A values, are compared with those of
cluster models, where the latter are available.Comment: Based on talk given by Avraham Gal at EXA 2011, Vienna, September
2011; Proceedings version prepared for the journal Hyperfine Interactions;
v2--slight changes, matches published versio
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