The cross section and transverse polarization transfer for the ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(p,n)2p reaction at $E_{\mathrm{p}=160\mathrm{}}$ MeV and theta=0° have been measured with good energy resolution (1 MeV). An asymmetric peak shape characteristic of the ${}_{}{}^1{}_{}{}^{}\mathrm{S}_0^{}{}_{}{}^{}$ final-state interaction of the residual two-proton system has been clearly observed. The measured transverse polarization transfer coefficient for this peak is $D_{\mathrm{NN}}$(0?(de)=-0.43±0.04. A simple impulse approximation calculation including the ${}_{}{}^1{}_{}{}^{}\mathrm{S}_0^{}{}_{}{}^{}$ final-state interaction reproduces the main features of the observed peak shape and polarization transfer. Small discrepancies observed in the peak tail region can be accounted for by including the ${}_{}{}^3{}_{}{}^{}\mathrm{P}_0^{}{}_{}{}^{}$,1,2 final state interaction.

Two-dimensional γ-γ transition energy correlation measurements were made in ${}_{}{}^{144}{}_{}{}^{}\mathrm{Gd}$ using Compton-suppressed Ge detectors in the spin spectrometer. A ridge-valley structure was observed and shown to originate from discrete, fast transitions. The deduced moment of inertia is less than that of the superdeformed collective bands that have been predicted by Strutinsky cranking calculations.

The vector analyzing power has been measured for ${\pi }^{+}$d elastic scattering at 0.74 GeV/c in the angular range of ${\mathrm{theta}}_{\mathrm{c}.\mathrm{m}.\mathrm{}=40\mathrm{}\mathrm{?}(\mathrm{de}–}$105°, using a polarized deuteron target in a large aperture spectrometer. A comparison with calculations based on the Glauber model was made.

The pion angular distribution for the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$(γ,${\pi }^{+}$${)\mathrm{}}^{16}$N reaction leading to the lowest quartet of states in ${}_{}{}^{16}{}_{}{}^{}\mathrm{N}$ has been measured at 320 MeV photon energy. The results are compared with a distorted-wave impulse approximation calculation.

It is shown that the Landau-Zener transition mechanism due to the formation of molecular orbitals of the active neutron exists in the inelastic scattering ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$${(}^{12}$C, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${)}^{13}$${\mathrm{C}}^{\mathrm{*}}$ (3.086 MeV, ${\mathrm{}(1/2)\mathrm{}}^{+}$). The evidence stems from characteristic changes of the angular distributions observed as a function of the incident energy.

We calculated the differential cross sections as well as the total cross sections for the ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$(p,γ${)}^8$B at low energies in the radiative direct capture model including the E1, M1, and E2 transitions. The astrophysical S factor at the solar temperature of 20 keV is found to be 0.024 keV? which agrees well with a recent measurement by Filippone et al. We show that the d-wave capture plays an important role in determining the magnitude and shape of S(E) at low energies of astrophysical interest.

We study the effect of the elastic transfer process on sub-barrier fusion reactions between similar nuclei. The coupling to the elastic transfer channel is described in terms of a parity dependent potential, directly obtained from the transfer form factor. Within the simple barrier penetration model, we find that this effect can account for a considerable part of the sub-barrier enhancement of the ${}_{}{}^{16}{}_{}{}^{}$O${+\mathrm{}}^{18}$O fusion cross section over the ${}_{}{}^{16}{}_{}{}^{}$O${+\mathrm{}}^{16}$O case.

Recoil corrections are incorporated into the coordinate space Dirac equation. Numerical calculations with and without the recoil corrections are performed.

Differential cross sections, (dσ/dΩ)(theta), and analyzing powers, $A_y$(theta), have been measured for the reaction ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(p→,γ${)\mathrm{}}^3$He at laboratory energies of 99.1, 150.3, and 200.7 MeV. The cross sections obtained are found to be in very good agreement with those of other authors. Both the size and shape of the angular distributions for the cross sections are found to be well accounted for by a simple ‘‘quasideuteron’’ model. Further support for this model is provided by the measured analyzing powers. Both the shape and size of the angular distributions for $A_y$ are found to be very similar to those predicted for n(p→,γ)d at the same $E_{\gamma }^{\mathrm{c}.\mathrm{m}.\mathrm{}}$.

We have measured energy spectra and angular distributions of ${}_{}{}^1{}_{}{}^{}\mathrm{H}$ and ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ from 190–MeV ${}_{}{}^{40}{}_{}{}^{}$Ar${+\mathrm{}}^{27}$Al reactions. Comparisons with statistical model calculations show that evaporation from spherical nuclei cannot account for both the energy spectra and angular distributions, using entrance channel spins and evaporation barriers derived from fusion data. Alterations are required in both the emission barriers and the moments of inertia. Extensive nuclear deformation could explain the ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ data but discrepancies remain with the ${}_{}{}^1{}_{}{}^{}\mathrm{H}$ spectra, suggesting that additional effects are needed in the models.

Experimental studies of the energy dependence of the (${\pi }^{+}$${\pi }^{\mathrm{-}}$) reaction may reveal the presence of six-quark bags in nuclei.

Total cross sections have been measured for the ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$(p,n${)}^{26}$Al reaction from threshold at $E_{\mathrm{p}=4.988\mathrm{}}$ MeV to $E_{\mathrm{p}=5.820\mathrm{}}$ MeV and for the ${}_{}{}^{23}{}_{}{}^{}\mathrm{Na}$(α,n${)}^{26}$Al reaction from threshold at $E_{\alpha }$=3.483 MeV to $E_{\alpha }$=4.597 MeV, including separate measurements to the ground and first two excited states of ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$. Thermally averaged reaction rates are tabulated over the temperature range 0.1≤$T_9$≤10 for the respective inverse reactions ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$(n,p${)}^{26}$Mg and ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$(n, α${)}^{23}$Na, leading to the ground state of the exit-channel nuclide with the three lowest states of ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ as ‘‘targets.’’ These rates are compared to rates calculated on a statistical model. Astrophysical implications with respect to ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ nucleosynthesis are discussed.

The mean-field approximation to the many-body Green’s function (E-H${)}^{\mathrm{-}1}$ is derived by the use of products of single particle orbitals for trial functions in a variational formalism. It is shown that the matrix elements of the Green’s function behave smoothly as ImE is varied towards the on-shell limit ImE=0.

It is shown that in a reaction in which a spin j particle is produced, the tensor parameters $t_q^{2j}$ are sufficient to determine the reaction amplitudes in spin space. Choosing the initial particles in a pure (spin) state ‖i〉 and keeping the spin state ‖α〉 of all other coproduced particles fixed, the subset of reaction amplitudes $A_m^j$(α,i) characterized by (α,i) is completely characterized by 2j axes and a complex scalar which may be determined (except for an overall phase and the discrete ambiguities) by measuring the tensor parameters $t_q^k$ with k=2j and the differential cross section. Additional measurements to fix the relative phases between subsets with different (α,i) are also suggested.

We study inclusive cross sections for backscattered protons in proton-nucleus collisions at the incident energies of 35–300 MeV. We evaluate the contributions from the two-nucleon cluster reaction as well as from the single scattering mechanism. Realistic Fermi momentum distributions are considered for both reaction mechanisms. It is found that, at 300 MeV, the two-nucleon cluster reaction dominates the inclusive cross section while, below 200 MeV, the two processes are in competition with each other and depend on the observed energy of the backscattered proton. We present the incident energy dependences of the cross sections at fixed energies of the backscattered protons to clarify the reaction mechanisms.

Production cross sections for ${}_{}{}^{94}{}_{}{}^{}\mathrm{Nb}$(2.03×${10}^4$ yr) have been measured from enriched ${}_{}{}^{94}{}_{}{}^{}\mathrm{Mo}$ and ${}_{}{}^{\mathrm{nat}}{}_{}{}^{}\mathrm{Mo}$. The samples were irradiated by 14.5–14.8 MeV neutrons and the cross sections were measured by gamma spectroscopy. The cross section for the ${}_{}{}^{95}{}_{}{}^{}\mathrm{Mo}$(n,np+d${)}^{94}$Nb reaction was deduced from the difference in ${}_{}{}^{94}{}_{}{}^{}\mathrm{Nb}$ activity in the natural and enriched Mo samples. Cross sections were also determined for the ${}_{}{}^{95}{}_{}{}^{}\mathrm{Mo}$(n,p${)}^{95}$Nb, ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$(n,x${)}^{91}$${\mathrm{Nb}}^{\mathrm{m}}$, and ${}_{}{}^{98}{}_{}{}^{}\mathrm{Mo}$(n,α${)}^{95}$Zr reactions, all being in good agreement with previous data. Our data can also be used to estimate the production of the long-lived (700 yr) ground state of ${}_{}{}^{91}{}_{}{}^{}\mathrm{Nb}_{}^{\mathrm{g}}{}_{}{}^{}$ from ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$.

The nuclide ${}_{}{}^{231}{}_{}{}^{}\mathrm{Th}$ was investigated with the reactions ${}_{}{}^{230}{}_{}{}^{}\mathrm{Th}$(n,γ${)\mathrm{}}^{231}$Th, ${}_{}{}^{230}{}_{}{}^{}\mathrm{Th}$(n,γe${)}^{231}$Th, and ${}_{}{}^{230}{}_{}{}^{}\mathrm{Th}$(d,p${)}^{231}$Th. Gamma rays from average resonance capture were measured, in addition to the usual thermal neutron capture spectroscopy. From these data, 70 excited levels in ${}_{}{}^{231}{}_{}{}^{}\mathrm{Th}$ were identified and, of these, 57 were placed in 18 rotational bands with assigned configurations. Candidates have been proposed for all expected Nilsson states below 750 keV, albeit with varying degrees of confidence, including the ${\mathrm{}(5/2)\mathrm{}}^{+}$[622], ${\mathrm{}(7/2)\mathrm{}}^{+}$[624], ${\mathrm{}(3/2)\mathrm{}}^{\mathrm{-}}$[761], ${\mathrm{}(1/2)\mathrm{}}^{\mathrm{-}}$[770], ${\mathrm{}(1/2)\mathrm{}}^{+}$[640], and ${\mathrm{}(5/2)\mathrm{}}^{\mathrm{-}}$[503] configurations. Several vibrational states have been identified; a special feature of these is the observation of greater fragmentation of single-particle-$0^{+}$ phonon-mixed states than expected theoretically. Assuming degenerate parity doublets indicate the existence of stable octupole deformation, no evidence was found for a tendency toward this phenomenon in ${}_{}{}^{231}{}_{}{}^{}\mathrm{Th}$. The neutron binding energy was determined to be 5118.13±0.20 keV.

The electromagnetic field representation of the nuclear electromagnetic interaction is developed, by extending previous work on the nuclear current (one-photon amplitude) to the nuclear Compton amplitude. The resulting form of the Compton amplitude is gauge invariant and, in transverse gauge, manifests the low-energy theorems for the $0^{+}$→$0^{+}$ case, which is discussed in detail. Deuteron forward photodisintegration is also studied numerically, and it is shown that the generalized Siegert form of the retarded electric dipole interaction efficiently incorporates pion-exchange currents implicitly, while large explicit forms of these currents are needed in the standard representation of the interaction. Gauge invariance and Reiss’s strong-field momentum-translation approximation are also discussed.

Vector analyzing powers, tensor analyzing powers, and relative differential cross sections have been measured for the ${}_{}{}^2{}_{}{}^{}(\mathrm{d}\to$,γ${)\mathrm{}}^4$He reaction at an incident energy of 10 MeV. Multipole decomposition and partial-wave analysis reveal that about 15% of the cross section involves processes in which the tensor force plays a role, either in the entrance or exit channel. Contrary to earlier claims, the reaction cannot be used to determine the D-state admixture in the ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ wave function unless the D state of the deuteron and other tensor-force effects in the entrance channel are taken into account.

The ${}_{}{}^{36}{}_{}{}^{}\mathrm{S}$(t,pγ${)\mathrm{}}^{38}$S reaction was used to populate levels in ${}_{}{}^{38}{}_{}{}^{}\mathrm{S}$ up to 3-MeV excitation. A definite $2^{+}$ assignment to the 1292-keV first-excited state was obtained from a (t,pγ) angular correlation. Doppler shift information provided lower limits of 0.45 and 0.2 ps for the mean lifetimes of the 1291→0 and 2825→1291 transitions. Evidence for a possible new level at 2805 keV was obtained from p-γ coincidence data. The known level spectrum of ${}_{}{}^{38}{}_{}{}^{}\mathrm{S}$ is compared to predictions of a shell-model interaction utilizing the full sdpf model space. The E2 and M1 transition rates predicted by this calculation are also presented.