[en] The theory of multistep nuclear reactions due to Feshbach, Kerman and Koonin (1980) is reviewed with particular attention to recent developments. These include the latest analyses of multistep compound and multistep direct reactions that have established the dependence of the effective interaction strength V₀ on the incident nucleon energy and on the atomic weight of the target, and the study of P to Q-chain transitions. (Author)

[en] We first generalize the Fulton-Gouterman transformation to a multi-band and exponential form. While the exponential form admits the consideration of multiparticle systems, which will be done in future papers, here we treat the multi-band form in its application to an archetypical electron-phonon Hamiltonian, which contains the Froehlich one as a particular limiting case. Several generalizations will be outlined. (author)

[en] Short communication. 2 refs

No abstract available

[en] The massive transfer reaction is viewed as a process in which a light fragment breaks away from the projectile without being absorbed by the target, but a heavy fragment is captured by the target by a compound capture process. The process is formulated theoretically, and the reaction cross section and the distribution of angular momenta in residual nuclei calculated

[en] The fusion reactions between heavy ions are used for the production of very heavy elements but this method has reached its limit: it is almost impossible to go beyond the 118 element unless the intensities of the ion beams are strongly increased. The S3 project at GANIL aims at producing Ti⁵⁰ and Cr⁵⁴ beams with an intensity 100 times as higher as before. Another way to produce very heavy elements is the possibility of a massive transfer of nucleons between a U²³⁸ and a Cm²⁴⁸ nucleus when they are colliding. (A.C.)

[en] In recent experiments, α-decay has been indispensable for the identification of new nuclides. Because the experimentalists have to evaluate the values of the α-decay half-lives, during the experimental design, it is quite important and necessary to investigate the α decay of SHN theoretically. Besides the role of shell effects in the stability of SHN, the α-decay or spontaneous fission(SF) took important role. SHN with atomic number beyond 110 predominantly undergo sequential α-decay and long α-decay chains usually terminate by the SF. In experiment the measurement is mainly α- decay Q values and half-lives, while the major goal of the theory is to predict the half-lives to serve the experimental design. Q-value, one of the crucial quantity for a quantitative prediction of decay half-life, affects strongly the calculation of the half-life due to the exponential law, i.e., α- decay rates exhibit an exponential dependence (Geigger-Nuttall) on emission energy. Therefore it is extremely important and necessary to obtain an accurate theoretical Q-value in a reliable half life prediction during the experimental design

[en] A model for describing three-cluster configurations of nuclei is formulated in terms of the algebraic version of the resonating-group method. The model is applied to six-nucleon systems represented as an α particle and two nucleons. The results indicate the importance of three-cluster modes in both bound and continuum states of ⁶He and ⁶Li. In particular, a neutron halo in ⁶He is revealed

[en] 'Diogene' is the name of a 4π solid angle detector, based on a Time Projection Chamber (TPC), designed to perform exclusive measurements of charged particles emitted in central collisions of relativistic heavy ions. Exclusive measurements of all charged particles emitted in central collisions of relativistic heavy ions are becoming more and more necessary in this field of nuclear physics in order to answer some crucial questions such as: what is the degree of compression achieved in these collisions. What is the behavior of nuclear matter at high degree of excitation as well as compression. The possibility of handling high multiplicities up to 40 or 60; a momentum measurement of all particles, with not too bad a resolution, up to about 1.5 GeV/c; a good particle identification between π^+-, p, d, t ..

[en] Some microscopic treatments of the nuclear vibrational spectra are analyzed in terms of a model allowing an exact solution for a many-body nucleon system interacting via pairing plus quadrupole force. The multi-phonon approach -exact diagonalization in the restricted space of 1, 2, 3, .. collective phonons- appears satisfactory for the few lowest lying vibrational Ksup(π)=0⁺ states in deformed nuclei. The non conservation of the number of particles and coupling between collective and non collective states seem to be main sources of the discrepancies, that occur for the higher states. On the other hand, the lowest order contributions suggested by nuclear field theory lead to serious disagreement as compared with the exact solutions