A possible explanation is given of the experimentally observed differences between the the fission cross-sections in the reactions induced by the intermediate energy (hundreds MeV) neutrons and protons.

All results on the production cross sections of the lightest hypernuclei and the life-times of the hydrogen hypernuclei obtained in Dubna streamer chamber experiments are presented.

The method and the results of an experiment on the study of relativistic Λ 4 H and Λ 3 H production in interactions of 18 GeV/c4He nuclei with CH2 target nuclei are presented. The experiment was performed using the HYBS-spectrometer. The main registering part of the spectrometer is a (2×0.6×1)m3 streamer chamber placed in a magnetic field of 0.9 T. The streamer chamber was triggered when the beam4He nucleus lost one charge unit in the target and then again became double-charged inside the chamber fiducial volume according to the selection criteria for Λ 3,4 H hypernucleus production and its mesonic decay with the He nucleus in the final state. After scanning of the pictures, measurements of two-prong events and careful analysis, events of the decays Λ 4 H→4He+π− and Λ 3 H→3He+π− were identified. The estimates of the Λ 4 H production cross-section (∼0.4 µb) and its mean lifetime (∼2.2·10−10s) were obtained. A comparison with the results of other experiments and theoretical calculations is made. By the way, the cross-section of the charge exchange reaction3H+Ne→3He+π−++...(∼1 mb) was estimated. The work has been performed at the Laboratory of High Energies, JINR, Dubna.

Experimental data on the yields of low-energy /sup 1//sup ,//sup 2//sup ,//sup 3/H and /sup 3//sup ,//sup 4/He obtained in interaction of protons and deuterons with respective energies 7.5 and 6.7 GeV with /sup 58//sup ,//sup 64/Ni are compared with calculations according to the cascade-evaporative model. It is shown that the experimentally observed characteristics of the secondary particles are described by the model, and that the model correctly predicts the isotropic effects arising as a consequence of the formation in the cascade of evaporating nuclei for which Z and N depend on the nucleonic composition of the target nucleus.

Experimental data are presented on the energy spectra of protons, deuterons, and tritons emitted at 160/sup 0/ in interactions of /sup 12/C (3.6 GeV/nulceon) with nuclei of C, Al, Cu, and Pb. The characteristics of the spectra obtained are compared with the corresponding characteristics of the spectra of p, d, and t in hadron-nucleus reactions. The data are compared with the predictions of the coalescence model. Estimates are given of the radius of the regions of deuteron formation, obtained in the framework of a thermodynamic model.

The cross section for the (d,p2n) reaction in carbon 12 was measured at 4.45 GeV/nucleon. A value 46 +- 6 mb was obtained. This value will be useful for calibration of the intensity of beams of high-energy charged particles. (AIP)