Beta decay strengths from four $T_z$=-(3/2) nuclei ${(}^{21}$Mg, ${}_{}{}^{25}{}_{}{}^{}\mathrm{Si}$, ${}_{}{}^{29}{}_{}{}^{}\mathrm{S}$, and ${}_{}{}^{41}{}_{}{}^{}\mathrm{Ti}$) to levels above the isobaric analog states have been measured by beta-delayed proton emission. At least seven new levels have been identified in the daughter nuclei. Logft values indicate allowed beta decay strengths dominate and show good agreement in general with model comparisons.

In a previous work we showed that the use of medium-modified electromagnetic form factors of the nucleon, obtained from our theory of covariant soliton dynamics, led to a significant improvement in the agreement between theory and experiment for the charge density of ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$. Here we show that the addition of corrections to the charge density obtained in the random-phase approximation leads to a further improvement when comparing the theoretical predictions and the charge distributions extracted from the experimental data.

It is shown that P-wave medium polarization corrections to the second-order rescattering contribution to the S-wave isovector strength (b${¯}_1$) in the pion-nucleus optical potential follow the trend of recent pionic atom fits. In particular, the net effect of medium polarization corrections is to increase the effective magnitude of b${¯}_1$ some 10% to 20%.

Dyson’s boson expansion theory is known to allow one to calculate eigenenergies much easier than does the Hermitian boson expansion theory. New methods of calculating transition probabilities with the Dyson theory have also been developed recently. Here we show that these new methods can further be extended so as to give eigenstates of the Hermitian problem, via a very simple numerical procedure, by first obtaining Dyson’s eigenstates.

A microscopic estimate of the inelastic cross section ratio σ(${\pi }^{\mathrm{-}}$)/σ(${\pi }^{+}$) to the isoscalar giant quadrupole resonance in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ is given. Based on an extended random phase approximation including 1p1h as well as 2p2h excitations we conclude that the calculated ratio is in agreement with the hydrodynamical scaling for the transition densities δ${\rho }_{\mathrm{n}=\mathrm{N}/\mathrm{Z}\mathrm{\delta }{\rho }_{\mathrm{p}}}$. For the surface quadrupole vibration however the theory predicts a deviation from the hydrodynamical estimate.

Reaction theory expressions are used to prove that the tensor analyzing powers $T_{20}$(θ) and $T_{22}$(θ) for the ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(darrow,γ${)\mathrm{}}^4$He reaction are isotropic if the reaction is pure E2 and terms quadratic in channel-spin-2 matrix elements are neglected. Experimental departures from isotropy can be expected near θ-0°, 90°, and 189°.

It is noted that in a single j shell ($f_{7/2}$) calculation in the titanium isotopes one obtains M1 rates of about one single particle unit in strength to states at about 4 MeV excitation. This is systematically consistent with the recently discovered collective excitations in ${}_{}{}^{156}{}_{}{}^{}\mathrm{Gd}$, and neighboring nuclei. In the single j shell case, though, the spin and orbital contributions to the M1 matrix element are nearly the same.

The effects of external and internal Coulomb corrections on the asymmetry between ${\pi }^{+}$ and ${\pi }^{\mathrm{-}}$ deuteron elastic scattering have been calculated at a pion energy of 180 MeV.

Using a semirelativistic theory previously developed by the author, we have computed the total probability per K-capture event for the ionization of the remaining K electron for a dozen nuclides of interest. Based on hydrogenic wave functions and accurate to relative order (Zα${)}^2$, the theory takes into account the correlation between the two initial K electrons and permits adjustments for screening. Numerical results exhibiting the effects of screening are presented. A comprehensive comparison of the predictions of this theory, as well as those of other theoretical models, with recent experimental data is also given.

A systematic analysis of the imaginary part of the light projectile ($A_p$=1–6) phenomenological optical potentials has been carried out. As a result of this analysis a global formula has been found which describes successfully the volume integrals of the imaginary potential in terms of the projectile energy in the range 0–50 MeV/nucleon and the target and the projectile mass numbers.

We calculate the effect of the neck degree of freedom on subbarrier fusion reaction cross sections. The potential energy and mass tensor are calculated on the basis of a two-dimensional representation of the liquid drop model. The WKB and Hill-Wheeler approximations are used to calculate the tunneling amplitudes for motion along the direction of the neck size degree of freedom. The resulting cross section for collisions between two identical Ni isotopes show a marked enhancement at low energies compared with the standard one-dimensional radial penetration calculations.

Few nucleon pickup and stripping reactions have been analyzed in terms of direct surface transfer reactions leading to continuum states. Excellent agreements were obtained with the prediction of the diffractional model.

The level structure of ${}_{}{}^{219}{}_{}{}^{}\mathrm{Ac}$ up to a spin of J=(31/2) and $E_x$=2.2 MeV has been studied via the ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$${(}^{13}$C,3nγ) reaction. The dominant γ-ray deexcitation sequence consists of two parallel cascades, each containing alternating positive and negative parity states. In addition, there is a sideband probably built on the π$i_{13/2}$ single particle state. The most striking feature of this level scheme is the appearance of parity doublets similar to those seen in the heavier actinides.

We have measured the sub-barrier fusion cross sections for the ${}_{}{}^{16}{}_{}{}^{}$O${+\mathrm{}}^{16}$O and ${}_{}{}^{16}{}_{}{}^{}$O${+\mathrm{}}^{18}$O systems from $E_{\mathrm{lab}=13.5\mathrm{}–}$25 MeV. We find no significant enhancement of the ${}_{}{}^{16}{}_{}{}^{}$O${+\mathrm{}}^{18}$O cross section compared with the ${}_{}{}^{16}{}_{}{}^{}$O${+\mathrm{}}^{16}$O cross section; this is quite different from the sub-barrier fusion of the calcium isotopes which exhibit a strong isotope dependence.

Using polyethylene terephthalate track-recording films, which are sensitive only to particles with Z>6, we have detected for the first time the exotic radioactive decay mode in which an energetic ${}_{}{}^{24}{}_{}{}^{}\mathrm{Ne}$ nucleus is emitted. For ${}_{}{}^{232}{}_{}{}^{}\mathrm{U}$ the branching ratio for ${}_{}{}^{24}{}_{}{}^{}\mathrm{Ne}$ relative to alpha decay is (1.00±0.25)×${10}^{\mathrm{-}12}$. We point out that the spontaneous fission rates reported for ${}_{}{}^{232}{}_{}{}^{}\mathrm{U}$ and several other nuclides based on early measurments of energetic pulses in ionization chambers may actually have been rates for emission of ${}_{}{}^{24}{}_{}{}^{}\mathrm{Ne}$ or other heavy clusters.

The angular distribution and the magnitude of the cross section of the ${}_{}{}^4{}_{}{}^{}\mathrm{He}$(${\pi }^{\mathrm{-}}$,n${)}^3$H reaction for pion kinetic energies from 100 to 250 MeV are reasonably well reproduced in the framework of the Δ-hole model with an improved overlap function 〈${\psi }_{{\mathrm{}}^3\mathrm{H}\mathrm{\Vert }{\psi }_{{\mathrm{}}^4\mathrm{He}\mathrm{〉}}}$. It is pointed out that the Δ-hole formation dominates the reaction in the forward region while the one nucleon mechanism becomes more important at larger angles.

It is shown that an underlying SU(3) structure of the interacting boron approximation is exhibited by nuclei near neutron number 104 in the rare earth region. This is particularly evident in Yb and Hf and to a lesser extent in the heavy Er and light W nuclei. Although the structure and mixing effects are complex, this region seems to represent the closest approach to the SU(3) limit yet observed in heavy nuclei.

The region of excitation in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ near 9.85 MeV has been investigated for evidence of a doublet, expected from tetrahedral symmetry arguments, by using the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^4$He,${\gamma }_3$${)}^{16}$O and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^4$He${,}^4$He${)}^{12}$C reactions. Energy-matched measurements of the pair of reactions show no evidence for cascade gamma-ray decay of any but the known D-wave resonance observed in the elastic channel. The gamma-ray decay width of a possible second nondegenerate level to the $2_1^{+}$ state is determined to be less than 5×${10}^{\mathrm{-}4}$ eV.

The ${}_{}{}^{31}{}_{}{}^{}(\gamma$,p${)}^{30}$Si reaction was studied at seven angles for nine bremsstrahlung end point energies varying from 17 to 25 MeV in 1 MeV steps. Absolute (γ,${\mathrm{p}}_0$) and (γ,${\mathrm{p}}_1$) angular cross sections for ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}$ in the excitation energy interval between 14.6 and 25 MeV were extracted and angular distribution factors were deduced by fitting a sum of Legendre polynomials to the data. Absolute cross sections for various other photoproton reaction channels were determined using an artificially constructed pseudo-monoenergetic photon spectrum. The total (γ,p) cross section was evaluated up to 24 MeV excitation energy. About 53% of this cross section is due to a direct-semidirect reaction mechanism. The angular distribution factors in the (γ,${\mathrm{p}}_0$) channel were used to estimate the contribution of E2 photon absorption in this channel. It was found that between 48% and 63% of the isoscalar E2 energy-weighted sum rule is exhausted by this (γ,${\mathrm{p}}_0$) channel.