Table of contents

Presents approximate solutions of the MIT bag model for quarks in cylindrical bags. For a cylindrical bag surface it is found that Dirac's equation does not admit solutions corresponding to the linear boundary condition in psi = psi . It admits, nevertheless, solutions which satisfy the original confinement condition psi psi =0 exactly. The pressure balance condition is approximately satisfied through the variational minimisation of hadronic energy. These cylindrical quark bags to give not only the string limit of the bag model but also the correct slope of the leading Regge trajectory for baryons at the low angular momenta. States on a given trajectory differ from one another in axial-momentum excitations of a single quark.

The coupled Schrodinger equations for the KN and Sigma pi systems are solved for the case of a bound state to obtain the strong-interaction shift and width in kaonic hydrogen. The Coulomb force is simulated by a separable potential which gives the exact unperturbed wavefunction. The shift is the opposite sign to that obtained in two recent experiments.

The yrast line of well deformed nuclei in the actinide region is investigated within the framework of a cranked shell model. In agreement with results, the authors obtain only slight upbending for the cases measured to date. However, they predict that backbending will occur in the nuclei ²³⁸U and ²⁴⁸Cm for spins around 30h(cross) due to the alignment of a j_15/2 neutron pair.

The data for charged-pion photoproduction near the forward direction are analysed in conjunction with finite energy sum rules (FESR). It is found that the usual picture of pion exchange modified according to the poor man's absorption model (PMA) with A₂ cuts fails to fit the FESR and data, and that the pi -exchange term must be modified substantially.

For pt.II see ibid., vol.7, no.12, p.1611-20 (1981). Backward scattering data for the reactions K^-p to Xi ^-K⁺ and K^-p to Xi ⁰K⁰ are analysed as part of a unified study of hyperon-exchange reactions. An apparent gross violation of SU(3) is examined in detail and possible remedies suggested.

The authors predict the spin-spin correlations A_nn, A_SS, A_LS, A_SL and depolarisation parameter D_NN for the reaction pp to np pi ⁺ in the geometry for exclusive, in-plane kinematics. Calculations are based on a relativistic and unitary three-body isobar model. The partial-wave isobar amplitudes T_{N alpha from NN} (for alpha =P₁₁ and P₃₃ pi N quasiparticle interactions) are found by solving coupled Blankenbecler-Sugar integral equations with one-pion-exchange driver terms. Results are presented for several proton-pion angle pairs at T_lab=800 MeV and, for one angle pair, also at T_lab=500 and 1200 MeV. The correlations are typically large and change rapidly as kinematic conditions are varied. There is a moderate model-dependence in these predictions, as seen by comparing with calculations using heavy-boson-exchange modified partial-wave isobar amplitudes.

Improvements are made on previous work about the effect of NN bound states on the NN optical potential and the subsequent changes in the predicted widths of such bound states. These improvements include a more thorough search for the best form of optical potential when NN bound states are present, the effect of two bound states on a particular incident channel and, finally, a relativistic treatment of the pion.

It is shown that by performing an inverse Fourier transform of electron-scattering data with q_max>or=3.5 fm^-1, model-independent charge distributions and transition densities of longitudinal excitation in nuclei can be extracted out to a radius at which the density falls to about one per cent of its central value. The method is applied to obtain a charge density for about one per cent of its central value. The method is applied to obtain a charge density for ³²S. The advantages of this method are that it is easy to apply, it elucidates the relationship between experimental form factors and derived charge densities and provides a well defined procedure for determining uncertainties in the charge densities derived.

The fluidic integral form of the cranking model kinetic energy, originally obtained from the noninteracting single-particle Schrodinger fluid, is shown also to apply to the rotation of systems of interacting nucleons. An explicit example of its agreement with the well known incompressible irrotational limit for the case of strongly paired systems is exhibited.

Contracted expressions for the four-particle shell-model matrix elements between identical particles (protons, neutrons and bosons) are derived and applied to the nucleus ¹³⁶Xe. A comparison with experiment and with other shell-model calculations is performed, concentrating especially on effects due to configuration space truncation.

The results of many phenomenological analyses of bound proton single-particle states and of proton elastic scattering are analysed using a nonlocal formalism that provides a unified treatment over the whole energy range. The anomalous behaviour in the region of the Fermi surface is investigated.

On the basis of an adiabatic coupling model for heavy ions the intermediate structure in ¹²C-¹²C scattering is evaluated including quadratic coupling terms and higher excited states in ¹²C. The calculations reproduce semiquantitatively the structure found experimentally up to an energy of E_CM=35 MeV. A substantial cross section in the integrated (4₁⁺, GS) channel points to the necessity of considering the coupling to the 4₁⁺ (14.08 MeV) state of ¹²C.

The effect of density isomers on heavy-ion collisions is studied in a one-dimensional shock-wave model. A family of phenomenological equations of state, which include density isomers, is constructed. The thermodynamic properties resulting from these exotic equations of state are calculated, and some of the shortcomings of this conventional approach are pointed out. The nature of the phase transitions occurring in heavy-ion reactions is discussed in terms of the shock-wave model.

The problem of DWBA calculations for stripping to states just unbound or only very weakly bound is discussed with reference to the two procedures originating with Vincent and with Huby (1980), and the close correspondence of these procedures is further elucidated. A modification of Comfort's (1980) extension of DWUCK4 is presented, enabling DWBA calculations for proton transfer to be carried down even to the limit of zero binding energy. Model calculations are performed for the reaction ⁹²Mo(³He,d)⁹³Tc, in which the ⁹³Tc energy is supposed to vary from well bound, through zero binding energy, to very unbound, and it is shown that the DWBA differential cross section for the energy, to very unbound, and it is shown that the DWBA differential cross section for the level varies smoothly throughout this range. An outline is given for the equivalent calculations of neutron transfer.

The gamma gamma directional correlation method was used to determine the spins of levels in ¹⁴⁰Ce populated following the beta decay of ¹⁴⁰La. The multipolarities of gamma -ray transitions were measured and, on the basis of the dominant multiple and published ICC data parity assignments were made. Past ambiguities in the decay have been removed, and from the present measurements the authors make unique spin-parity assignments to the following levels: 2350.0 keV, 5⁺; 2516.1 keV, 3⁺; 2548.0 keV, 1⁺. The structure is well accounted for by the shell-model calculation of B.H. Wildenthal, (1969). The level systematics of nuclei in this region are examined and it is found that the change from a vibrational- to a rotational-like structure is not so well defined as in heavier isotopes such as Sm or Gd. The behaviour of the ^3- level energy as a function of Z value is examined for a ground of isotones in this mass region and is found to be linear.