abstract

Energies and intensities of conversion spectra were measured with a magnetic beta-ray spectrometer. Gamma spectra were obtained by the use of a Ge (Li) detector. Schemes of the low excited states of \(^{98}\)Rh and \(^{99}\)Rh are suggested.

abstract

The problem of high energy \(p\)–\(p\) scattering is investigated in the approximation in which the colliding particles are treated classically. It is assumed that the interactions of these particles can be described in terms of some, (unspecified in detail), short range interactions and in terms of massive vector mesons exchanges. It is shown that for a reasonable choice of the classical world lines of the protons the high energy elastic differential cross-section is consistent with the Regge model predictions and with the experimental data. The amplitude of the inelastic \(\pi \)–\(p\) process with \(n\) vector mesons in the final state is also calculated. It is shown that, in general, the number of the produced vector particles is not governed by the Poisson distribution.

abstract

Tolman’s theorem concerning the expression for the energy of a stationary system in General Relativity, in terms of the Einstein canonical energy-momentum complex, is extended so as to apply to a general class of field theories. The general result is then criticised and a remedy is given which results quite naturally in an infinite number of different energy-momentum complexes. One of these complexes might reasonably be called “canonical” and for the special case of General Relativity, this “canonical” complex turns out to be the one proposed by Moller.

abstract

Instead of describing the scattering processes in terms of asymptotic fields at minus infinity and plus infinity in time, we express them in terms of ingoing and outgoing (concentric and excentric) waves from and to infinity in space. This involves a quite different boundary problem as compared to the traditional initial-condition-problem. The system consisting of fields streaming in (out) from (to) spatial infinity is not a well isolated physical system, hence a description in terms of a state obeying a Schrödinger equation is not applicable. The scattering problem is soluble in the Heisenberg Picture whereby the necessary boundary informations concern the ingoing fields crossing the surface of the domain. This type of information is subject to an uncertainty relation between energy and time.

abstract

The cross-section for excitation of the 3 min ground state of \(^{190}\)Re in (\(n,p\)) reaction on natural osmium is determined as (\(1.9\pm 0.3\)) mb at 14.8 MeV neutron energy.

abstract

A method of separating the centre of mass motion in two-particle shell-model wave function of the finite depth potential is suggested. The wave function of the centre of mass is represented as a superposition of the Sturm–Liouville wave functions, therefore the problem of taking into account the continuous spectrum influence does not arise.

abstract

The search for new exact solutions of the gravitational field equations for space filled with matter is pursued in isotropic coordinates. These solutions describe static and spherically symmetric distributions of a non-charged, perfect fluid; they may be applied in a general relativistic treatment of stellar structure. In analogy to the general formal solution of Einstein equations in canonical coordinates which was given by Eq. (8.2) in the first paper of this series (Kuchowicz 1968), another general solution for the present case of isotropic coordinates is obtained. The problem of solving a differential equation resulting from the isotropy of pressure is thus reduced to the much simpler task of performing several integrations. The least number of integrations which must be done if we wish to obtain expressions for the metric functions \(e^{\lambda }\) and \(e^v\) amounts to two. Some of the specific solutions of quite a simple form are presented.

abstract

Problems related with the field-theoretic description of unstable particles are studied. The Lee model is introduced with the \(V\)-particle replaced by a general unstable elementary object with continuous mass spectrum. The model is completely solved in the lowest \(N\theta \) sector. The analytic continuation on the second Riemann sheet of the scattering amplitudes and the analytically continued unitarity condition are considered. The derivation of the reduction formula with complex mass shell is presented. Finally the equivalence is shown of this model in \(N\theta \) sector with the conventional Lee model with four-leg direct interaction.

abstract

The application of the absorption model to many body reactions \(\pi +p\to n\pi +N\), with the group of n pions treated as a quasiparticle, with the variable mass, and spin zero, is presented. Predictions of this model are compared with the experimental data for reactions \(\pi ^++p\to 5\pi +p\) and \(\pi ^++p\to 6\pi +p\) at laboratory momentum of \(\pi ^+\) 8 GeV/\(c\). It is demonstrated that at a given energy the absorption model can roughly describe many body reactions if the absorption factor of Jackson and Gottfried is used. Oct the contrary the absorption factor of Dar, Weisskopf and Watts leads to a complete disagreement with the data.

abstract

The hyperon polarization resulting in high-energy meson–baryon strangeness-exchange processes is discussed. The general predictions of various Regge models are compared with experiment. It is shown that the absorption corrections to the strongly degenerate pair of \(K^*\)(890) and \(K^{**}\)(1420) trajectories describe correctly the observed polarization. The qualitative predictions for cross-sections are also discussed.

abstract

The level scheme of \(^{79}\)Kr was investigated from the decay of 23.8 min \(^{79}\)Rb. Using Ge(Li) detectors and scintillator NaJ(Tl) counters single, prompt coincidence and delayed coincidence spectra were measured. For the 146.8 keV state the value of the life time of (\(79.1 \pm 1.5\)) nsec was obtained, which is in good agreement with previous results, and for the 182.3 keV state the upper limit of 0.6 nsec was estimated. From the end-point energies of positron spectra in coincidence with prominent \(\gamma \)-rays the decay energy of (\(3726\pm 60\)) keV of \(^{79}\)Rb was determined. The proposed level scheme of \(^{79}\)Kr incorporates all the observed transitions except four weak ones. The log \(ft\) values (or their limits) were determined for \(\beta \) transitions to the excited states of \(^{75}\)Kr. The results of this work are compared with those of Lingemann et al. and differences in the spin assignments of some excited states of \(^{79}\)Kr and of the ground state of \(^{79}\)Rb are discussed. A comparison of the low-lying states of \(^{79}\)Kr and \(^{77}\)Se is made and a description of some excited states in the framework of the Nilsson model is also discussed.

abstract

Equilibrium pairing energy gaps for nuclei with \(42 \lt Z \lt 56\) and \(52 \lt N \lt 58\), \(68 \lt N \lt 88\) are calculated by the total energy minimum method. The results are compared with the experimental odd–even mass differences.

abstract

Neutron pairing in Ni, Sn and Pb isotopes is calculated by minimalization of the total energy under the condition of constant volume. Satisfactory overall agreement with experimental pairing parameters is found in all three cases.

abstract

It is shown that alpha-particles with energies \(T\geq 32\) MeV which are found in the interactions of 660 MeV protons with carbon, can be interpreted as alpha-clusters removed from the nucleus in the process of the development of the nuclear cascade. The study of the properties of these fast alpha particles may provide important information on the cluster structure of light nuclei.

abstract

In the paper the two-step model of the (\(d,t\)) direct reaction in rare-earth nuclei is investigated. The inclusion of the strong coupling in the entrance and exit channels improves the agreement of theoretical angular distributions with experimental data, although a discrepancy in absolute strengths remains.

abstract

A separable two-channel potential model is used to describe hyperon–nucleon reactions. The parameters of the potential are set to reproduce the low energy sigma (lambda) nucleon scattering, hypernuclear data and the virtual bound state of the sigma and nucleon.

abstract

The static baryon model with the symmetry group SU(2)\(_J\otimes \)SU(2)\(_I\otimes \)U(1)\(_Y\) is investigated in the strong coupling limit. In the algebraic (or — equivalently — in bootstrap) formulation of that model the reduced meson–baryon coupling constants can be found from the sum rules involving the static angular momentum and isospin crossing matrices, both proportional to \(6j\)-symbols. This fact enables one to use the identities between \(3nj\)-symbols of the group SU(2) in order to find two types of solutions (Eqs. (10) and (23)) for the coupling constants and the isobar states spectrum.

abstract

The distributions of the \(p\)–\(\alpha \) and \(d\)–\(\alpha \) relative energy of the \(^7_{{\mit \Lambda }}\)Li \(\to p+d+\alpha +\pi ^-\) decay products are calculated with the use of the \({\mit \Phi }(d-\alpha -{\mit \Lambda }\)) cluster wave function of \(^7_{{\mit \Lambda }}\)Li. For \(^7_{{\mit \Lambda }}\)Li \(\to ^4\)He \(+ ^3\)He \(+\pi ^-\) decay the distributions of the \(^3\)He–\(^4\)He relative energy and angular distribution of the \(^3\)He are calculated with the use of the \({\mit \Phi }(d-\alpha -{\mit \Lambda }\)) and \({\mit \Phi }(^3\)He \(-t-{\mit \Lambda }\)) cluster wave functions for the description of the \(^7_{{\mit \Lambda }}\)Li. It is shown that the mentioned angular distribution strongly depends on the structure of the \(^7_{{\mit \Lambda }}\)Li. The energy distributions for both models of the \(^7_{{\mit \Lambda }}\)Li decay agree with the experimental data.

abstract

In this letter a conjecture of Fishbane (P.M. Fishbane, Phys. Rev., 177(11), 2323 (1969)) is investigated in the framework of Gali–Lee model. It is found that this conjecture is true.