REINA() DE TRABALHO SOBRE FiSICA NUCLEAR NO BRASIL

22 Estrutura Nuclear - XX RTFNB
collective in "Mo. No sign of proton subshell closure
is, therefore, further seen,
A simple pairing description of 'ILi
ETTORE BALDINI NETO, CELSO LUIZ LIMA
Finpe - Universidade de &in Paulo
MAIJRO KYOTOKU
Departamento de Fisica Universidade Federal da Pamela
The recent interest on nuclei near the neutron and protons
drip-lines which have been observed through the
use of radioactive nuclear beams has raised a new challenge.
to the theorists. It remains to be cleared whether
or not the well estabilished theories in the valley
of stability can be wilted to halo nuclei. In this work,
we treat the neutron rich nuclei 11Li using the BCS
approach slightly modilicated by the inclusion of the
self-energy term, usually riot considered [1]. This leads
to a new gap equation, which depends on the jth single
particle level,
E; GE(l; bij)ttivi.
Varying the pairing force strenght, we have calculated
the binding energy of 'Li using the calculated single
particle neutron levels available. We have also calculated
the first excited state energy through the use of
the quasi-spin method [2]. We expect this extension to
multi-level case to bring us some information about the
structure of the ground state of 14 Li.
M.Kyotoku, N.Teruya and C.L,Lima Phys.Lett.I3 377,1
(1996) A.K.Kennan Annals of Physics 12 300-3291),
(1.961)
Decay of 102Rhm
Ruv Moat:ADo DE CASTRO, VITO ROBERTO VANIN
IFUSP
The decay of 1°2111 has been studied for five years
through a Rh source, produced by the natRh(7,xn) reaction
using the Linear Acceleretor of LA L-IFUSP.
With single and coincidence gamma-ray spectroscopy
measurements, the known 1 °2Rh decay has been verified,"
and a new gamma-ray with energy 277.071(12)
keV and intensity 1.4(3) 10 -4 transitions per 1°2'nRh
decay, was observed and assigned to the transition between
the 4+, 1798.71 keV, and 3+, 1521.64 keV, levels
in 1°2Ru.
It was confirmed that the longer lived, 6+, level is the
isomeric state. The intensity of the isomeric transition
between the 6+ and 2 - levels of 1 °2R11 was measured
as 2.7(3) 10 -3 transitions per decay.
Statistical Methods of analysis of the decay data were
developed, taking into full account the experimental information
and the data covariances.
The isomeric states excitation energies and eletromag-
netic properties, were calculated within the single par-
tide model. In this framework, it is possible to assign
a configuration to the 2 - fundamental state but not to
the 6+ isomeric state.
Neutron Star Mass in Relativistic Mean -Field
Theory
L. Cank, M. L. CESCATO
UFPB
Relativistic Mean-Field (B.MF) Theory has been applied
iu recent years to a large number of problems
in nuclear structure. It has turned out to provide a
very simple mean to describe ground state properties
of nuclear matter and of finite nuclei in the entire periodic
table. In fact, the model is very successful around
the saturation region, but this does not assure that the
same is true at extreme conditions (very low or very
high densities).
Various applications of nuclear physics depend on the
behavior of nuclear matter under extreme conditions.
The properties of neutron stars depend on the neutron
matter equation of state at densities up to an order
of magnitude higher than those observed in ordinary
nuclei. This high-density behavior is essential for calculating
the balance between the attraction of general
relativity and the nuclear pressure; it determines under
what conditions gravity will cause the collapse of a
neutron star into a black hole.
In this work, we use several RMF models available in
the literature to obtain the neutron matter equation
of state. From this equation of state, we calculate the
neutron star maximum mass predicted in these models,
which compared to observational estimates, allows us
to test their validity at extreme conditions. We use the
Walecka o'-w - p-model, considering the most successful
parameterizations for the coupling constants, with
and without non-linear terms in the a-field. Density
dependent coupling constants approaches are also used.
Measurement of directional 7 - 7 angular
correlation in the beta- decay of 1"R,e
MARLETE PEREIRA MEDIA ASSUNcAO, IUDA
GOLDMAN, GARABED KENCHIAN
Institute de Fisica da Universidade de Seto Paulo
The energy levels of the nuclide 'Os, populated in the
beta-decay of 1"Re, are showing clearly the rotational
bands. There are several 0+ and 2 4 states and possible
states 1+ and 3+. Some negative parity states are also
present and definitively identified.
Nuclear reactions induced by HI have shown the existence
of high spin states.
Angular correlation measurement are difficult because
the predominance of gamma-ray transitions with 155
keV (2+ - 0+) [1].
In this work, at the automatic spectrometer Angular
Correlation device of the "Laboratorio do Acelerador