Table of contents

An anomaly-free SU(7) grand unification model which unifies two conventional (V-A) generations of quarks and leptons with a third (V+A), all within 49 chiral fields, is presented.

Without demanding that the functions f(q²) and g(q²) in the structure function xF₃(x,q²)=Cx¹mf/(1-x)^ng be slowly varying, upper and lower bounds are obtained for the slope of the graph for 1g M_N against 1g M_N', where M_N is the Nth moment of xF₃(x,q²). The bounds obtained here also include the predictions of scalar gluon theories which is not the case for Harari's bounds (1979). Further, it is observed that the bounds are sensitive to the way in which the q² dependence is introduced in xF₃(x,q²).

The self-consistent version of the energy density formalism is used to study the variations of the neutron skin thickness near and far from the stability line. The shell effects in the differences between RMS radii and neutron and proton density distributions are found to be weak. Approximate droplet model sharp radii are also defined for the self-consistent densities, in order to compare the results with the droplet model predictions. Important differences with this model are found. In particular, the values obtained far from the stability line for the neutron skin thickness seem to be incompatible with the droplet model.

It is shown that the differential cross section of (p,n) reactions with 1 GeV protons corresponding to a Fermi-type transition between mirror nuclei is sensitive to the isovector component of the nuclear quadrupole moment because of the nuclear spin-re-orientation effect.

An unusual mass dependence of the vector analysing powers iT₁₁( theta ) observed experimentally for the ^76,78,80,82Se(d_pol,d) elastic scattering at 12 MeV incident deuteron energy is now explained as being due mainly to the contributions from a two-step scattering process via the first J^pi =2₁⁺ excited states.

An explicit expression for the kinetic energy of the mass transfer in heavy-ion collisions has been developed and compared with hydrodynamical and microscopic calculations.

High-spin states in ⁷⁸Br which decay into the previously known 4⁽⁺⁾ isomer at 180.8 keV were observed using the ⁷⁷Se( alpha ,2np) reaction. Two new isomeric states of 9+or-1 ns at 337.8 keV and 84+or-8 ns at 227.6 keV are reported.

The ¹⁰⁶Cd(³He,3n)¹⁰⁶Sn reaction is studied and three gamma rays assigned to ¹⁰⁶Sn through coincidence experiments. A preliminary level scheme is proposed.

Some consequences new experimental data on pp to e⁺e^- have for the rho -meson type contributions to the isovector magnetic nucleon form factor are studied.

A method relating the sigma term to scattering lengths is described. This formulation provides a rigorous basis for the Altarelli-Cabibbo-Maiani methods (see ibid., vol.B34, p.621, 1971).

A systematic method to evaluate the pi N sigma term using only very low-energy data is discussed. An s-wave 'curvature parameter' is used to recast the Altarelli-Cabibbo-Maiani relation (see ibid., vol.B34, p.621, 1971) into a more useful form.

The reaction NN to B_i pi is studied when NN are T=1 scattering states with E_lab(N)<or approximately=600 MeV and the B_i are NN quasinuclei bound by 183, 216 or 420 MeV which have been tentatively seen in a gamma -ray experiment at CERN.

The pairing force strength constants were adjusted to the experimental mass differences for rare-earth and actinide nuclei. To this end the quadrupole and hexadecapole equilibrium deformations were also calculated by means of the Strutinsky method using parameters of the deformed Woods-Saxon potential optimised by Dudek et al. (see ibid., vol.5, p.1359, 1979); pairing was treated in the usual BCS approximation. The results of the modified oscillator (Nilsson) and Woods-Saxon potential calculations were compared indirectly by comparing the nuclear moments of inertia (l^pi =2⁺ rotational energy levels obtained within the cranking model) which are known to be very sensitive functions of the pairing force strength. For comparison, the corresponding experimental data are also given, and the advantages of the Woods-Saxon model are discussed.

The influence of an isospin-dependent N-N interaction on the critical density for pion condensation is considered. The authors use the technique of lowest-order constrained variational calculations to predict the influence of a realistic N-N interaction on the properties of pion-condensed neutron matter, including the explicit allowance for N*(1236) excitations in intermediate states in the ¹S₀ channel in the N-N potential. They find a reduction in the critical density, but an increase in the energy density for high densities compared with that obtained using a pure neutron matter potential energy.

A proportionality between the average kinetic energy and the inverse of the mean-square radius is shown to be valid to a good approximation for a wide range of single-particle energies and RMS radius in the Hartree-Fock and Brueckner-Hartree-Fock theories.

The reactions ⁹²Zrp_pol, alpha )⁸⁹Y and ²⁷Al(p, alpha )²⁴Mg are analysed by applying the exact finite-range distorted-wave Born approximation theory to the three-particle transfer reactions. The finite-range calculations are compared with the zero-range distorted-wave Born approximation. Using a cluster-model form factor good fits to the angular distributions and to the analysing powers have been obtained for the transitions to the four low-lying states of ⁸⁹Y and ²⁴Mg.

A six-parameter spin-orbit potential is used to fit proton scattering from ¹²C in the energy range 49-156 MeV in conjunction with a central potential derived by the authors (see ibid., vol.5, p.1699, 1979). The imaginary spin-orbit potential is similar in shape to the prediction of the impulse approximation but the real spin-orbit potential has a markedly different shape with diffuseness parameter a_SR approximately 0.2 fm.

The elastic scattering cross sections for 88 MeV ⁷Li ions have been measured for targets of ^24,26Mg and ^40,48Ca. Analyses using both phenomenological and microscopic optical potentials provide information on the energy dependence of optical parameters, and the extent to which the potentials are determined for these light ions. The use of a double-folding microscopic model demonstrates the need for normalisation of the real potential by a factor of 0.5 in contrast to measurements at lower energies. The contribution of exchange effects density dependence and break-up are discussed.

Three high-spin precursors of the ^19-/₂ isomeric level at 3.12 MeV in ⁴³Sc have been studied using the ²⁹Si(¹⁶O,pn)⁴³Sc reaction at beam energies of 40 and 42 MeV. The decay scheme was established with the aid of gamma - gamma coincidence experiments. These previously unreported levels have excitation energies of 5517, 6429 and 7355 keV with probable spins and parities of ¹⁹⁺/₂, ²³⁺/₂ and ²⁵⁺/₂ respectively. The mean lifetimes of these levels have been found to be <90 fs for the 5517 keV level, 23.5+or-2.2 ps for the 6429 keV level and 600+or-160 fs for the 7355 keV level. Definite spin and parity assignments of ^11-/₂ and ^15-/₂ have also been made for the 1830 keV and 2987 keV levels respectively. The data are compared with the results of a simple shell-model calculation.

The K-shell capture fractions in the electron-capture decay of ¹⁹⁵Au to the 130 keV and 99 keV excited levels, and to the ground state in ¹⁹⁵Pt, have been measured using coincidence techniques. Observations were made on coincidence counting rates of K X-rays with 31, 99 and 130 keV gamma rays and with L and M internal conversion electrons from the 99 and 130 keV transitions. NaI(Tl) scintillation counters were used to detect the K x-rays and the 99 and 130 keV gamma rays. The 31 keV gamma rays were detected in a Si(Li) counter, and a 300 mu m depletion depth silicon surface-barrier detector was used to record the internal conversion electrons.

The energy distributions of primary cosmic-ray nucleons responsible for muons detected at sea level and underground have been calculated using a phenomenological model. The Feynman scaling hypothesis of nucleon-nucleon interactions has been employed using cross sections determined from high-energy scattering experiments.