Table of contents

A new generalization of Pade approximants to power series in two (or more) variables is given, along with an example of its application.

Estimates are presented for the magnetic specific heat of an infinite chain of spins with isotropic nearest-neighbour exchange. The calculations are performed for S=¹/₂, 1, ³/₂, 2 and ⁵/₂. The results are presented graphically. A simple expression is used to represent the results for ferromagnetic as well as for antiferromagnetic interaction.

Evidence is presented that the arrival direction distribution of cosmic rays with energies above 10¹⁹ eV is not isotropic. Harmonic analyses indicate that there is, prima facie, a first harmonic (amplitude=44%, chance probability=2.6%, phase (in right ascension)=13.3+or-1.5 h) at declinations above 0 degrees , and that there is a significant second harmonic (amplitude=101%, chance probability=0.2%, phase 7.8, 19.8+or-1 h) at declinations below -30 degrees . Supporting evidence from low energy data is also discussed.

Graphs associated with the Gel'fand-Yaglom equations for arbitrary spin are used in a simple method to find the number of conditions which a good quantizable free-field theory must satisfy. The number of conditions is seen to be simply related to the line independence numbers of the s block subgraphs of the theory. This provides a rough guide as to whether a particular theory is possibly quantizable. Some examples are given. Also a general result is given which enables quick elimination of a range of 'bad' theories by visual examination of their graphs.

By extensive use of methods developed by Rieckers it is shown that power series of the free field, while not strictly localizable in general, are essentially local with respect to all those Gel'fand spaces S^alpha on which they can be defined at all.

The contributions of 'shadow poles' to the nonrelativistic S-wave scattering by the exponential and the Hulthen potentials are calculated and the implications of these results in the theory based on 'shadow poles' in particle physics are discussed.

Relativistic eikonal physics is applied to Coulomb scattering and bound states. It is shown that the eikonal approximation can accommodate the impact factor result as well as the non-relativistic Balmer spectrum. It is argued that relativistic corrections are outside this realm of approximation. This will be confirmed by eikonalizing the high-energy scattering amplitude of an electron in a static Coulomb field which is generated by a proton.

The nuclear emulsion method has been used to examine neutrons from ⁹Be(d,n)¹⁰B reaction at a deuteron energy of 600 KeV on a ⁹Be target of 4 mm thickness. The well known energy levels of ¹⁰B have been verified but our data strongly suggest that the 2.9 MeV level, which is the subject of some dispute, is composed of two levels, one at 2.75 MeV and the other at 3.17 MeV.

The g factor of the 235 keV, 2^- state in ⁴⁴Sc has been measured by observing the time-integrated perturbation of the de-exciting gamma ray angular distributions under the influence of an externally applied magnetic field. The result, g=+0.29+or-0.07 supports the assignment of this state as a member of the K=0 rotational band.

The shape of the continuous internal bremsstrahlung accompanying the beta decay of the radioactive nuclide ¹⁴⁷Pm is experimentally measured with a NaI(Tl) scintillation spectrometer and compared with the Knipp, Uhlenbeck and Block (KUB) theory as well as with the Coulomb-corrected theories due to Lewis and Ford, and Nilsson. The experimental distribution is found to agree fairly well with the KUB theory in the energy region from 60 to 85 keV and beyond 85 keV the experimental distribution is in excess over KUB theory, the excess being 13% at 95 keV, 32% at 130 keV and 80% at 155 keV. However, the authors find very good agreement between the experimental distribution and the theoretical one due to Lewis and Ford throughout the investigated energy region.

Using the eikonal approximation of Yennie the authors give a general expression for the cross section for fast-electron scattering from oriented nuclei and a corresponding simpler expression for nuclei fully oriented along the direction of momentum transfer. The branching ratios of quadrupole transition probabilities to different rotational levels of aligned nuclei are also obtained. Using Petkov's analytic method for the Fermi charge density and taking different forms of nuclear charge distributions they calculate in the eikonal approximation the cross section and the effect of nuclear alignment on it for electron scattering from oriented ¹⁶⁵Ho nuclei.

The reduced resonance integrals were measured by an activation technique using cadmium ratios, relative to two standard materials, manganese and gold. The use of two reference standards corrects for small deviations in the neutron slowing down spectrum from a 1/E dependence per unit neutron energy E. Results obtained were ⁶³Cu:2.79+or-0.18 b, ⁶⁵Cu:1.22+or-0.06 b, ¹⁰⁷Ag:79+or-4 b, ¹⁵⁹Tb:390+or-24 b, ¹⁶⁴Dy:-514+or-115 b and ¹⁶⁵Ho:618+or-33 b, where the uncertainties are estimated at approximately the 99% confidence level, and include an uncertainty of +or-4% in the reference standards. It was necessary to measure the half-lives of the activities produced, giving ⁶⁴Cu:12.704+or-0.006 h, ⁶⁶Cu:5.13+or-0.03 min, ¹⁰⁸Ag:2.37+or-0.01 min and ^116gHo:26.83+or-0.03 h, and also the 2200 ms^-1 neutron capture cross sections of ¹⁵⁹Tb:23.2+or-0.5 b, ¹⁶⁵Ho:61.2+or-1.1 b and ¹⁰⁷Ag:37.6+or-1.2 b (re-evaluated from the new half-life).

During the period 1965 to 1971 a set of absolute muon intensity data available at stations having low vertical cut-off rigidities show a small disagreement with our latitude corrected muon intensity and this could possibly be due to the maximum increase in the Zurich sun spot number which intensifies the electric tension of earth, i.e. the Ehmert potential. The decrease of muon intensity at around 1 GeV/c during the years 1965 to 1969 is in accord with the theoretical results calculated after O'Brien when multiplied by a factor 1.085 but lies below the theoretical values calculated after Allkofer and Dau. The decrease of muon intensity is in agreement with the Deep River integral muon intensity data during the same period.