738 research outputs found
The strength of beta-decays to the continuum
The beta-strength in beta-delayed particle decays has up to now been defined
in a somewhat ad hoc manner that depends on the decay mechanism. A simple,
consistent definition is presented that fulfils the beta strength sum rules.
Special consideration is given to the modifications needed when employing
R-matrix fits to data. As an example the 11Be(beta-p) decay is investigated
through simple models.Comment: 18 pages, 4 figure
Classification of three-body quantum halos
The different kinds of behaviour of three-body systems in the weak binding
limit are classified with specific attention to the transition from a true
three-body system to an effective two-body system. For weakly bound Borromean
systems approaching the limit of binding we show that the size-binding energy
relation is an almost universal function of the three s-wave scattering lengths
measured in units of a hyperradial scaling parameter defined as a mass weighted
average of two-body equivalent square well radii. We explain why three-body
halos follow this curve and why systems appearing above reveal two-body
substructures. Three-body quantum halos 2-3 times larger than the limit set by
zero hypermoment are possible
The size of two-body weakly bound objects : short versus long range potentials
The variation of the size of two-body objects is investigated, as the
separation energy approaches zero, with both long range potentials and short
range potentials having a repulsive core. It is shown that long range
potentials can also give rise to very extended systems. The asymptotic laws
derived for states with angular momentum l=1,2 differ from the ones obtained
with short range potentials. The sensitivity of the asymptotic laws on the
shape and length of short range potentials defined by two and three parameters
is studied. These ideas as well as the transition from the short to the long
range regime for the l=0 case are illustrated using the Kratzer potential.Comment: 5 pages, 3 figures, submitted to Physical Review Letter
Unbound states in C populated by -decay of the 16.11 MeV state
The reaction has been used to populate the state at an excitation energy of 16.11 MeV in C. -decay
to unbound states in C are identified from analysis of the decay of the
populated daughter states. Due to a new technique, -decay to the 10.8
MeV 1 state is observed for the first time, and transitions to the 9.64 MeV
(3) and 12.71 MeV (1) are confirmed. Unresolved transitions to natural
parity strength at 10 MeV and 11.5-13 MeV are also observed. For all
transitions partial widths are deducedComment: Corrected small typographical errors and added more details on data
analysi
Assessing the accuracy of Hartree-Fock-Bogoliubov calculations by use of mass relations
The accuracy of three different sets of Hartree-Fock-Bogoliubov calculations
of nuclear binding energies is systematically evaluated. To emphasize minor
fluctuations, a second order, four-point mass relation, which almost completely
eliminates smooth aspects of the binding energy, is introduced. Applying this
mass relation yields more scattered results for the calculated binding
energies. By examining the Gaussian distributions of the non-smooth aspects
which remain, structural differences can be detected between measured and
calculated binding energies. Substructures in regions of rapidly changing
deformation, specifically around and , are clearly
seen for the measured values, but are missing from the calculations. A similar
three-point mass relation is used to emphasize odd-even effects. A clear
decrease with neutron excess is seen continuing outside the experimentally
known region for the calculations.Comment: 13 pages, 9 figures, published versio
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