809 research outputs found
High-speed Hydrodynamic Characteristics of a Flat Plate and 20 Degrees Dead-rise Surface in Unsymmetrical Planing Conditions
Stochastic Variational Search for H
A four-body calculation of the bound state, $^{\
4}_{\Lambda\Lambda}NN\Lambda N\Lambda\Lambda\Lambda\Lambda_\Lambda^3{H}+\Lambda\Lambda\LambdaB_{\Lambda\Lambda}(^{6}_{\Lambda\Lambda}{He})d\Lambda\Lambda$ model in the Letter.Comment: Corrected typos, added addtional calculations regarding a truncated
to l=0 interaction model, 4 pages, 3 figure
The Lambda-Lambda Interaction and ^{6}_{Lambda Lambda}He
An OBE potential model for the ^{1}S_0 S = -2 interaction is analyzed with
emphasis on the role of coupling between the Lambda Lambda, N Xi, and Sigma
Sigma channels. Singlet scalar exchange, an approximation to two-pion exchange,
is significant in all channels; surprisingly, the one-pion exchange component
is almost negligible. The size of the channel coupling as a function of the
overall strength of the OBE model potential is examined. Implications of the
analysis for the binding energy of ^{6}_{Lambda Lambda}He are considered; the
new experimental datum may suggest a consistency between the extracted Lambda
Lambda matrix element and the relation implied by SU(3) among OBE baryon-baryon
interactions. \\Comment: 4 pages brief report to Physical Review
Brueckner Rearrangement Effects in He and He
Rearrangement effects in light hypernuclei are investigated in the framework
of the Brueckner theory. We can estimate without detailed numerical
calculations that the energy of the -core is reduced by more than 2.5
MeV when the adheres to He to form He. Similar
assessment of rearrangement contributions is essential to deduce the strength
of interaction from experimentally observed . The recently observed experimental value of 1 MeV
for the of \hll suggests that the matrix element of
in \hll is around -2 MeV.Comment: 7 pages, to appear in Phys. Rev.
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
Faddeev calculations for the A=5,6 Lambda-Lambda hypernuclei
Faddev calculations are reported for Lambda-Lambda-5H, Lambda-Lambda-5He and
Lambda-Lambda-6He in terms of two Lambda hyperons plus the respective nuclear
clusters, using Lambda-Lambda central potentials considered in past non-Faddeev
calculations of Lambda-Lambda-6He. The convergence with respect to the
partial-wave expansion is studied, and comparison is made with some of these
Lambda-Lambda hypernuclear calculations. The Lambda-Lambda Xi-N mixing
effect is briefly discussed.Comment: submitted for publicatio
The H-Dibaryon and the Hard Core
The H dibaryon, a single, triply magic bag containing two up, two down and
two strange quarks, has long been sought after in a variety of experiments. Its
creation has been attempted in , proton and most recently in relativistic
heavy ion induced reactions. We concentrate on the latter, but our conclusions
are more generally applicable. The two baryons coalescing to form the single
dibaryon, likely in the case of heavy ions, must penetrate
the short range repulsive barrier which is expected to exist between them. We
find that this barrier can profoundly affect the probability of producing the H
state, should it actually exist.Comment: 9 pages including 4 figure
Strangeness S=-2 baryon-baryon interactions using chiral effective field theory
We derive the leading order strangeness S=-2 baryon-baryon interactions in
chiral effective field theory. The potential consists of contact terms without
derivatives and of one-pseudoscalar-meson exchanges. The contact terms and the
couplings of the pseudoscalar mesons to the baryons are related via SU(3)
flavor symmetry to the S=-1 hyperon-nucleon channels. We show that the chiral
effective field theory predictions with natural values for the low-energy
constants agree with the experimental information in the S=-2 sector.Comment: 10 pages, 2 PostScript figure
Warm strange hadronic matter in an effective model with a weak Y-Y interaction
An effective model is used to study the equation of state of warm strange
hadronic matter with nucleons, Lambda-hyperons, Xi-hyperons, sigmastar and phi.
In the calculation, a newest weak Y-Y interaction deduced from the recent
observation of a He double hypernucleus is adopted. Employing this effective
model, the results with strong Y-Y interaction and weak Y-Y interaction are
compared.Comment: 9 pages, 9 figure
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