630 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
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
Nuclear halo and its scaling laws
We have proposed a procedure to extract the probability for valence particle
being out of the binding potential from the measured nuclear asymptotic
normalization coefficients. With this procedure, available data regarding the
nuclear halo candidates are systematically analyzed and a number of halo nuclei
are confirmed. Based on these results we have got a much relaxed condition for
nuclear halo occurrence. Furthermore, we have presented the scaling laws for
the dimensionless quantity of nuclear halo in terms of the
analytical expressions of the expectation value for the operator in a
finite square-well potential.Comment: 14 pages, 3 figure
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