Table of contents

Starting from the density of states of an ideal Bose-Einstein gas, the authors have formulated an uncorrelated jet model with Bose-Einstein statistics. The transition to continuum is based on the Touschek invariant measure. It has been shown that in this model average multiplicity increases logarithmically with total energy, while the inclusive distribution shows ln s violation of scaling.

The authors estimate trimuon production nu N to mu ^- mu ^- mu ⁺X by the internal Drell-Yan processes nu d to mu ^-u, uu to mu ⁺ mu ^- and nu u to mu ^-d, dd to mu ⁺ mu ^-, for d and u quarks in the same target nucleon, using a parton-model approach. This mechanism predicts energetic trimuons with little hadronic excitation at rates of order (3 mu )/( mu ) approximately 10^-6.

Using multishell-model wavefunctions obtained from a fit to spectroscopic data for (f,p)-shell nuclei, the authors calculated elastic and inelastic cross sections and analysing powers for proton scattering on ⁵⁸Ni at E_p=20.4 MeV and 30.3 MeV respectively. The experimental data are described fairly well by these calculations.

The importance of coincidence experiments in radiative pion capture reactions is discussed and supported by a detailed numerical calculation of the expected effects in the ¹⁶O( pi ^-, gamma n)¹⁵N process.

The radiative pion capture by light nuclei is discussed in the framework of the unified theory of direct and resonance reactions. For the target nucleus ¹⁶O the spectrum of hard gamma rays and the gamma -n angular correlation function of the ( pi ^-, gamma n) reaction are calculated in a particle-hole continuum shell-model version.

With the concept of redundant spaces a reduction scheme is proposed which makes the generator coordinate method with two conjugate parameters tractable. By means of that, a collective Schrodinger equation is derived which proves to be identical to the one obtained by consistent quantisation of the classical adiabatic time-dependent Hartree-Fock Hamiltonian.

Measured values of the full width at half maximum of atmospheric Cerenkov pulses from extensive air showers have been used to study the dependence of the parameter on shower development. This pulse width shows a strong dependence on the height of the shower maximum and a functional form of the dependence is presented.

An exact finite-energy solution in three spatial dimensions is constructed to a modified nonlinear SU(2)/U(1) theory. The solution has a 'twisted ring' structure but spherically symmetric energy density. It has unit Hopf index.

The NN pi system is studied in a semi-relativistic model (non-relativistic nucleons and relativistic pions) where a Chew-Low Hamiltonian acts in the restricted space spanned by free N+N, N+N+ pi and N+N+2 pi states. The N+N ('absorption') and N+N+2 pi ('production') channels can be eliminated exactly, leaving an effective three-particle problem whose energy-dependent, absorptive interactions are known analytically. These represent a simple but non-trivial example of a mutually consistent set of forces for the NN pi problem, free of overcounting difficulties.

For pt.I see ibid., vol.4, no.9, p.1371 (1978). A complete solution is presented to the novel disconnectedness problem encountered in a recent study of a simple field-theory model of the NN pi system. The five disconnectedness classes of the problem, coupled through a non-Abelian 'disconnectedness-multiplication' law, are summed by a system of coupled equations, which in the framework of the model also provides a complete account of the connection between the renormalisation and disconnectedness problems. A 5*5 system of generalised Fadde'ev equations is derived which acquires a connected kernel after one iteration. On the basis of these equations, modified, effective transition operators between two-cluster channels are constructed and shown to obey integral equations of a generalised Alt-Grassberger-Sandhas type.

An approximate description of a system of three composite particles in terms of the Saito orthogonality condition model is proposed. The orthogonalising pseudopotential technique is used to derive a modified set of Faddeev equations where the two- and three-body exchanges due to the Pauli principle are included by orthogonalising to two- and three-body forbidden states. The scope of applicability of and the method for solving the derived equations are discussed briefly.

Based on recent microscopic multichannel calculations for the ⁸Li system, excitation functions and integrated cross sections for the reactions ⁷Li(n,n)⁷Li and ⁷Li(n,n')⁷Li* have been calculated. Results are displayed from the ⁷Li-n and ⁷Li*-n thresholds, respectively, up to 5 MeV excitation energy.

A self-consistent RPA method is presented for N-particle Fermi systems with two- and three-body forces. The RPA equations for the generalised 'particle-hole' and 'particle-particle' problem, respectively, are derived by minimising the mean excitation energies defined analogously to mean single-particle energies. This corresponds to the equation-of-motion method. For the generalised 'one-particle/two-particle-one-hole problem' the Green-function scheme is used in order to establish a connection between two possible ways of treating the problem. It is shown that the RPA Hamiltonians have almost the same structure as in the case of pure two-body forces, and that Rowe's general RPA equations are contained as a special case of the treatment.

A method of treating antisymmetrisation in calculations on alpha decay is presented and is compared with the method proposed recently by Fliessbach (1975). The application of these methods to alpha transfer is also discussed.

Jackson and Rhoades-Brown (ibid., vol.4, no.9, p.1441 (1978)) (JR) have criticised the treatment of alpha decay made by Fliessbach and Mang (1976) (FM). This criticism is based on a misinterpretation of both the bound-state functions introduced by FM and the reduced alpha amplitude as used by many authors. A simple analytic example is presented in which all the quantities occurring are given explicitly.

Exact penetrability calculations through a double-humped barrier, a portion of which is taken to be biharmonic in nature, have been performed. It is shown that a family of fission barrier shapes exist which give roughly the same penetrability as that through a double-humped barrier made up of harmonic wells and barriers. This leads to an uncertainty in the position of the barrier extrema as determined from an analysis of the experimental data on fission probability and angular distributions.

In the ²²Ne(³He,p)²⁴Na reaction at 18 MeV, excitation energies and angular distributions have been measured for 28 levels below 4.7 MeV in excitation. A distorted-wave analysis identifies the L value for most of these, resulting in J^pi assignments for a number of levels and J^pi restrictions for most levels.

The ⁵⁹Co(d,p) reaction has been studied at E_d=14 MeV using a single-channel magnetic spectrograph. The energy levels in ⁶⁰Co have been obtained up to E_x approximately 6.2 MeV and the angular distributions have been measured for the levels over an angular range 7 degrees -45 degrees . The data up to E_x approximately 6 MeV have betn analysed in terms of the nonlocal finite-range DWBA method and the l_n values and spectroscopic factors are derived. A sum-rule analysis of the spectroscopic factors has been carried out.

The ⁷⁶Se(³He,d)⁷⁷Br and ⁷⁸Se(³He,d)⁷⁹Br reactions have been studied at a bombarding energy of 41 MeV with a magnetic spectrograph. In ⁷⁷Br, 23 levels were resolved, and in ⁷⁹Br, 26 levels were resolved. The l-transfer values and spectroscopic strengths for most of these levels were determined from DWBA analyses. The results are compared with the predictions of the Coriolis coupling model with pairing residual interaction of Scholz and Malik.

The authors have studied the decay of ¹²⁰In using an isotopically-separated source. Two isomers with very close half-lives were established. One, decaying with a 47.3+or-0.5 s half-life, has a proposed J^pi of (8^-). The other, with a half-life of 46.2+or-0.8 s, has a possible J^pi =(3⁺, 4⁺, 5⁺). Separated decay schemes were obtained. The resultant level structure of ¹²⁰Sn is compared with a two-quasiparticle calculation.

The K-shell internal ionisation during beta decay has been treated relativistically on the basis of the wavefunction proposed by Greenland and Irvine (1972). The total ionisation probabilities are calculated and compared with those from the hydrogenic wavefunctions. Comparison with experimental data indicates that a discrepancy still remains between theory and experiment. A possible reason for this discrepancy is discussed.