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[en] Fine structure, intermediate structure and some aspects of isobaric analog states are discussed mainly from the experimental point of view. An example of intermediate based on examining isobaric analogue resonances in the even-germanium plus proton system is given. Quite different approach to study of the nuclear structure, made possible by nuclear lifetimes measurements in the region of 10-17 sec, is shown. As there are no nuclear states in existence, whose electromagnetic transition rates exceed about 1015 sec -1 and as soon as nucleon emission becomes energetically possible it will usually be the preferred mode of decay over electromagnetic decay, the competition with electromagnetic decay can be overcome in this region. Phenomena of channeling and blocking of charged particles in crystal make it possible to determine interaction times between incident particles and the nuclei of the crystal lattice which are of the desired order. Since the absolute lifetime is very difficult to obtain, differences in lifetimes have been estimated and their dependence on certain nuclear conditions as: 1/ whether the proton bombarding energy is on or off an isobaric analog resonance, 2/ spin of the state of the residual nucleus to which the inelastic scattering takes place, has been shown. (S.B.)
[en] A semi-microscopic Hartree-Fock-Bogolubov (HFB) calculation which reproduces in a correct qualitative manner the changes in the deformation that occur upon the addition of a proton to the even-even nuclei sup(70,72)Ge and sup(80)Kr has been done and the results are presented. (author)
[en] With the advent of high technology in analyzing the Gamow-Teller (GT) excited states beyond the one nucleon emission threshold, the quenching of the GT strength to the Ikeda sum rule can be recovered by using the high-lying GT states. Moreover, in some nuclei, GT peaks that are stronger than any other peaks appear explicitly in the high-lying excited states. In the current study, we have addressed these high-lying GT (–) excited states within a framework of the deformed quasi-particle random-phase approximation (DQRPA). These high-lying GT (–) excited states are generated due to an increase in particle numbers around the Fermi surface due to an increase in the chemical potential owing to a certain deformation of the nuclei. On the contrary, among the GT(+) excited states, the low-lying ones were favored by an increase in the deformation. The main GT(+/–) transitions were also changed drastically by the deformation. A detailed mechanism leading to the changes in the GT transitions is discussed by studying the shell evolution and the consequent change in the particle numbers in the smearing region caused by the deformation in typical doublebeta-decay nuclei, 76Ge and 76Se.
[en] The nucleus 70Ge has been studied via the 68Zn(α, 2nγ)70Ge reaction at E/sub alpha/approx. =30 MeV using different in-beam γ spectroscopic techniques. Levels up to 5.5 MeV have been identified and spins up to 8+ have been established
[en] A very low background Ge detector used to search for double beta decay has yielded new restrictions on candidates for cold dark matter particles in the halo of our galaxy. Particles with β = 10-3c with respect to the earth and having spin-independent interactions would scatter coherently from Ge nuclei. From the observed counting rate at low energies Dirac neutrinos constituting all of dark matter are excluded for masses between 12 GeV/c2 and 1.4 TeV/c2. Better limits are set on magninos (<11 GeV/c2) and cosmions (<9 GeV/c2), proposed massive particles which also explain the solar neutrino problem and which interact more strongly with Ge. In addition, millicharged shadow matter is ruled out as the main form of dark matter