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The reactions ¹⁶O(⁷Li, 2n) and ¹⁶O(⁷Li, np) populating ²¹Na and ²¹Ne have been studied at E_L &equal; 27 MeV using the GASP γ-detector array. The level scheme for ²¹Na and ²¹Ne has been extended to higher excitation energy. Spins and parities of the observed levels are assigned tentatively supporting the identification of opposite parity structures connected by strong dipole transitions. The structure of these bands is interpreted as based on a reflection asymmetric cluster structure.

The mean life of the lowest 21/2(+ level of89Zr has been measured with a pulsed7Li beam and the85Rb(7Li, 3n)89Zr reaction.

A procedure to evaluate the transition amplitude for isospin-forbiddenE1 transitions is proposed and the experimental data on self-conjugate nuclei from14N to40Ca are compared with the theoretical order-of-magnitude estimate. This procedure can be useful for the investigation of parity mixing in18F, as it provides a means for fixing the sign relation between the circular polarization of the 1081 keV γ-ray and the coupling constants which determine the parity mixing.

The Eötvös method to investigate the dependence of the Earth attraction on the substance considered is diseussed in terms of the recently proposed interaction of intermediate range. A null result of the Eötvös experiment is to be expected in a flat, horizontal and symmetric environment. Significant results can, however, be expected in the presence of a steep slope of the soil or of other sizeable asymmetries. The comparison of the Eötvös results with other geophysical information is rediscussed accordingly.

Interference between parity-allowed and parity-forbidden transition amplitudes is considered for the special case of two overlapping resonances having equalJand opposite π. Parity mixing between states in the continuum is discussed with a modified version of theR-matrix theory. The interference effects of the first order in the parity mixing, which can be observed in polarization experiments, are calculated for the (, α) reaction. The specific case of the 13 482 keV level in20Ne is discussed in detail.

A study of fast baryons emitted from 12 150 K−meson interactions at rest in emulsion has been made in order to determine the nature and extent of K−meson-multinucleon capture processes. Fast Σ hyperons are produced in at least 9 per cent of all interactions while direct fast Λ0hyperon production is indicated by the presence of 3 protons with energies exceeding 200 MeV. An upper limit of 30% is obtained for multinucleon processes (not producing π mesons) from consideration of π meson emission. The energy spectra for fast Σ hyperons and fast protons are given and mass determinations on a sample of so-called fast protons have revealed about 10% of deuterons and tritons. The suggestion in K−European Collaboration Part II of an apparent infrequency of the reaction K−+n+n→Σ−+n has been confirmed and anα-particle model of K−meson multinucleon interaction has been put forward to explain both this and the emission of deuterons and tritons.

Some results on 25 GeV proton interactions in nuclear emulsions are obtained. We find a total m.f.p. for elastic and non elastic events of (33.6±1.5) cm. But if we take into account the beam contamination from electrons and μ-mesons we find (32.6±1.4) cm. We give the distribution innh; from the examination of it, it is found that the generally accepted hypotesis that all the stars withnh≤4 are due to the interactions with light nuclei seems in disagreement with the results. We give also the distribution innsfor separated classes ofnh. The correlationdoes not show any discontinuity like that found by Friedländer at 9 GeV.

Photometric measurements of track widths have been carried out in the thin-down region on12C and16O tracks and also on tracks ofαand singly charged particles stopping in the emulsion. An appropriate model for the process of track formation in the thin-down region is proposed, and successfully tested on the experimental material.

A new version of the “recoil distance method”, making use of a gas target, has been used to determine the lifetime of the 871 keV level in17O and of the 495 keV level in17F. The measured values of the lifetimes are (2.32±0.08) · 10-10 sec and (3.96±0.10) · 10-10 sec for17O and17F, respectively.

High spin states of146Dy above the 10+ isomer have been identified by means ofγ- recoil andγ}-γ coincidences through the reaction90Zr(58Ni, 2pat a bombarding energy of 250 Me V. The level scheme is discussed in terms of the coupling of 2h11/2protons to the N=80 core vibrations.

Two new isomers with half- lives of 0.67(6) µs and 2.8(3) µs have been identified in the odd-odd nucleus144Tb. A partial decay scheme is presented. An interpretation in the framework of the shell model is discussed for the low lying energy states.

High-spin states up to I=22h have been observed for the first time in the odd-odd nucleus142Eu above the 8- ß+ -decaying isomer. A new isomer of mean life tm=9.0± 0.6 ns and Jp=8+ has been identified. The low energy part of the level scheme is interpreted in terms of single-particle excitations in the 2d5/2 and h11/2 orbitals and of the N=80 core excitations.