[en] The search for the beta-delayed fission in neutron-rich nuclei has been performed at the IRIS mass-separator. The delayed fission has not been observed: The limits of probabilities for 228, 230, 232 Fr and 232 Ac precursors have been obtained. The new isotopes 232 Fr, 233, 234 Ra have been identified. (orig.)

[en] An approach for an estimation of the fusion cross section by combining the available experimental data with the statistical simulations is proposed. An important step is the correction of the experimental excitation functions for the noncompound contributions. The ratio of the corrected total evaporation excitation functions to the calculated ones allows to estimate the fusion cross section. The proposed scheme has been applied to the ⁴He+¹⁹⁷Au reaction data. The approach provides a basis for a consistent comparison between a particular complete-fusion model and experiment. (orig.)

[en] We identified two α-emitting isotopes of element 107 with masses of 261 and 262 respectively by parent-daughter correlations. For the isotope with mass 262 we found two transitions with (102±26) ms and (7.0±2.1) ms half-life, which we assign to the ground-state and to an isomeric transition, respectively. The half-life of the isotope with mass 261 is (11.8_-2.8^+5.3) ms. Spontaneous fission, which could be assigned to the decay of an isotope of element 107, was not detected in our experiments. This observation is in line with our previous results, indicating a region of nuclei with strong microscopic stabilisation in the trans-actinides. Both new isotopes were produced by complete fusion of ²⁰⁹Bi with ⁵⁴Cr. The production cross sections are (163±34) pb for ²⁶²107 and (36_-14⁺²²) pb for ²⁶¹107. (orig.)

[en] Energy shifts in the shallowest level of the muonic molecule dtμ are estimated by using an accurate wave function of the point-charge three-body system which gives ε⁰₁₁=-660.3 meV. Contributions of nuclear finite size, vacuum polarization, relativistic effect and internuclear interaction are evaluated to be +10.4 meV, +17.2 meV, +0.9 meV and ∝+10^-4 meV, respectively. These corrections to ε⁰₁₁ amount to 28.5 meV, which is significantly different from the corresponding value 20.6 meV of the Soviet group, with serious dependence on the dtμ formation rate. (orig.)

[en] In a recent article published in this journal it is stated that a specific three-pion effect is found in an experiment studying Au+Au collisions. The aim of this note is to show that these new data are compatible with two-pion effects leaving no room for a specific three-pion effect. This is in accordance with three-pion interferometry results from pp and e⁺e^- collisions at a high energy. (orig.)

[en] The neutron coherent scattering length b_c=9.26(13) fm of the lead isotope ²⁰⁸Pb was determined by neutron interferometry. (orig.)

[en] The properties of the two-body channels populated in the ³⁵Cl+¹²C reaction, at a bombarding energy of 180 MeV, have been studied by means of a kinematical coincidence technique. Binary reaction products show full energy equilibration and isotropic angular distributions in the center-of-mass frame. The asymmetrical elemental distribution of the fully-damped yields, similar to that observed previously in the ¹²S+²⁴Mg reaction, suggests the occurrence of fusion-fission rather than orbiting. (orig.)

[en] The chemical equilibrium is studied for the reaction A+B↔C, assuming that, initially, the particles B form a lattice and the particles A are statistically distributed on interstices. A mass action law is derived which defines the numbers n_A, n_B, n_C of particles A, B, C in the chemical equilibrium assuming the initial distribution to be known. It predicts a considerably larger number n_C of fused particles C compared to the mass action law for the gaseous phase. The result holds for an ordinary as well as for a nuclear lattice. Its possible relevance for the production of proton-rich isotopes in the universe is discussed. (orig.)

[en] The nuclear matrix elements of the 0νββ decay of ⁷⁶Ge, ⁸²Se, ¹⁰⁰Mo, ^128,130Te, ¹³⁶Xe and ¹⁵⁰Nd are calculated in the proton-neutron quasiparticle RPA with the G-matrix of the Paris potential. It is shown that the matrix elements are not sensitive to details of nuclear structure, in contrast to the 2νββ decay. We investigate effects of ground-state correlations and those of short-range correlations on the suppression of the nuclear matrix elements. We also discuss effective values of the neutrino mass which are deduced from experimental 0νββ decay half-lives. (orig.)

[en] In impulse approximation the calculated cross section of the reaction d+p → p+p+n at 9 GeV/c depends strongly on the spectator momentum distribution used. We compare the results of a conventional calculation to those of light-cone dynamics and propose to decide between the two approaches by measuring the angular distribution of the low-momentum recoil proton in coincidence with a high-momentum proton. (orig.)