abstract

Solutions for two different models of non-static charged fluid distributions are given. One of them exhibits cylindrical symmetry, while the other may be considered to be plane symmetric. In both solutions it has been shown that once the contraction starts, the collapse to a singularity becomes accelerated and the entire collapse occurs within a finite proper time.

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The note presents the possible solutions for electromagnetic fields in a source-free region when the space-time admits an Abelian group of motions with three space-like generators (Bianchi Type I group). The entire set of solutions can be recovered by a simple transformation of an already known group of solutions.

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A simple procedure is described for expressing the generators of SU(\(n\)) as differential operators in the parameters of the group. It is then shown how recursion relations for the matrix elements of the “boost operator” leading from SU(\(n-1\)) to SU(\(n\)) can be obtained by treating the representation functions as basis functions and operating on them by the differential operators. The matrix elements of the “boost” appear in the present theory as solutions of ordinary differential equations. The operators for SU(3) and SU(4) are constructed, and some recursion relations and special matrix elements are derived by way of illustration.

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The problem of the discontinuities of the Feynman amplitudes is discussed. Kadyshevsky’s formalism is used to obtain the Cutkosky formula.

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The \(e^3\) contribution to the electromagnetic vertex function of spin-1 particles is calculated in the framework of source theory. A magnetic moment of arbitrary strength \(\kappa \) is included in the primitive interaction. In particular, the quadrupole form factor is shown to be finite with no need of adding any contact term if and only if \(\kappa =1\). A general discussion of the contact terms is included in the present work and the explicit expressions of the form factors are obtained along with their asymptotic behaviour, when \(\kappa =1\). The dynamically induced quadrupole moment, in that case, is calculated to be \(\alpha /18\pi \), and the associated spectral form is superconvergent.

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We show how correlations between missing mass and multiplicity in high energy reactions are easily explained by fire-ball production, and try in a simple manner to illustrate the properties of the fire-balls.

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The analysis of relativistic free-particle systems inclines us to define a set of non-equivalent Hamiltonians which imply the factorization of all degrees of freedom into groups corresponding to different “clustering” of the constituents of these systems. Within the quantum description all these Hamiltonians lead to selfconsistent solutions, although only one of them — call it \(H_1\) — respects the full relativistic symmetry of the laws of motion. In the classical framework the only consistent description of motion follows from \(H_1\), and thus the relativistic covariance is here unavoidable.

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The Illinois partial wave analysis program has been modified to study the dissociation of the proton into proton and two mesons. The formalism used in this modification is described in detail and a geometrical interpretation of all spin rotations and couplings is given.

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Assuming O(5) symmetry (pairing scheme of states for the system of protons and neutrons), the formulas for the probability of Gamov–Teller transition, the magnetic moment, and the probability of the (M1) transition were obtained as well as the relations between them. The comparison with the experimental data shows, except for few cases, quite good agreement in the region of light and very light nuclei.

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New isotope of \(^{148}\)Dy was found. The internal conversion electrons and gamma-rays spectra, following the decay of \(^{148,150,152}\)Dy were investigated. The decay schemes of these isotopes were proposed.

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The existence of the \(4.8 \pm 0.2\) min \(^{160}\)Yb activity has been established. Five gamma-transitions with energies (in keV) and their relative intensities (in parentheses): 132.23 (9.9), 140.35 (16.6), 173.76 (77.4), 215.78 (32.0), and 372.24 (3.5) were found and assigned to decay of this isotope.

abstract

The neutron deficient \(^{123}\)Ba and \(^{125}\)Ba isotopes obtained in the \(^{114}\)Sn(\(^{12}\)C,3n)\(^{123}\)Ba and \(^{117}\)Sn(\(^{12}\)C,4n)\(^{125}\)Ba reactions have been studied with Ge(Li) detectors. The most intense \(\gamma \)-rays assigned to \(^{125}\)Ba were confirmed in experiment perfomed with mass-separated sources obtained by spallation reaction from CeO\(_2\) (separation of barium fraction) and Ta (direct isobai s separation of A = 125) targets irradiated with 660 MeV protons. Beta-gamma delayed coincidence has been measured using NE 102 and Ge(Li) detectors. On the basis of gamma intensities and energy sums the decay schemes are proposed for \(^{123}\)Ba and \(^{125}\)Ba.

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The mean values \(\langle N_{\rm h}\rangle \) and the mean multiplicities \(\langle n_{\rm s}\rangle \) in the interactions of high-energy protons with two groups of nude (CNO and AgBr) were evaluated from the experimental emulsion data at different energies. The experimental data of \(\langle n_{\rm s}\rangle \) are well fitted by the dependence: \(\langle n_{\rm s}\rangle = C+DA^{1/3}\) (\(A\) — the mass number of target), which seems to be universal in a very wide interval of primary energies from 6.2 to thousands of GeV. A comparison of the experimental results with the predictions of theoretical calculations was made.

abstract

The effect of \({\mit \Lambda \Sigma }\) conversion on the binding energy, \(B_{\mit \Lambda }\), of \(^4_{\mit \Lambda }\)H and \(^4_{\mit \Lambda }\)He is calculated in the “hyperon + rigid 3\(N\) core” model. For a \({\mit \Lambda }\)N potential derived from \(^4_{\mit \Lambda }\)He, we obtain 1.6 MeV for the excitation energy of the \(J = 1\) state, and a very small negative contribution to \(B_{\mit \Lambda }(^4_{\mit \Lambda }\)He)–\(B_{\mit \Lambda } (^4_{\mit \Lambda }\)H) due to Coulomb interaction of \({\mit \Sigma ^+}\) and \({\mit \Sigma ^-}\).