A method is proposed to provide an absolute calibration of analyzing powers for spin-(1/2 particles. The method makes use of elastic scattering of a polarized beam from a spin-zero target at an angle where the analyzing power is large. In this case the polarization of the scattered beam is nearly complete and very accurately known. A measurement of the left-right asymmetry in a second scattering or reaction determines the analyzing power of the second process to an accuracy much below 0.005.

The pairing interaction is solved exactly in the ${}_{}{}^{114}{}_{}{}^{}\mathrm{Sn}$ nucleus using a realistic strength parameter as well as standard energy levels for the shell seniority zero states. The same single-particle and two-body Hamiltonian is treated with finite-temperature BCS and the thermal random-phase approximation. The results obtained through these calculations are compared to obtain insight about the suitability of the thermal approach to the description of nuclear phenomena.

Antiproton production from the secondary process ρρ→pp¯ is studied for nucleus-nucleus collisions at energies which are below the threshold for its production from the nucleon-nucleon reaction in the free space. In an expanding fireball model, we determine the ρ abundance from the fusion of pions and find that for collisions at 2.1 GeV/nucleon the antiproton to negative pion ratio is ≊5.5×${10}^{\mathrm{-}7}$ and has a similar magnitude to that of the data.

Data from complementary experiments on the members of the ($3^{\mathrm{-}}$ν$f_{7/2}$) multiplets in ${}_{{}_{60}{}^{143}{}_{}{}^{}}{}^{}{}_{}{}^{}\mathrm{Nd}_{83}^{}{}_{}{}^{}$, ${}_{{}_{62}{}^{145}{}_{}{}^{}}{}^{}{}_{}{}^{}\mathrm{Sm}_{83}^{}{}_{}{}^{}$, and ${}_{{}_{64}{}^{147}{}_{}{}^{}}{}^{}{}_{}{}^{}\mathrm{Gd}_{83}^{}{}_{}{}^{}$ are summarized and the particle-vibration coupling is investigated. It is shown that for odd N=83 nuclei the quadrupole-quadrupole interaction gives the leading contribution in the energy displacements of the multiplet members and that it can essentially explain the spin order and the absolute values for the splitting of the observed particle-octupole multiplets.

The response function of nuclear matter is determined from experimental data on inclusive electron scattering from finite nuclei.

The assumptions underlying several quadrupole collective models are tested by a comparison with results of self-consistent Hartree-Fock plus BCS calculations using the Skyrme SIII interaction. We analyze the deformed states of ${}_{}{}^{128}{}_{}{}^{}\mathrm{Ba}$ in terms of condensates of fermion pairs which have been introduced in the interacting boson model and in the quadrupole phonon model, and in terms of multipole components of the density suggested by the Bohr and Mottelson model. We compare the deformation energy curves obtained by using (i) several multipole truncations of the Hartree-Fock plus BCS pairs, (ii) pairs obtained by a variation after truncation, and (iii) truncated series of multipole correlation energies. The influence of the core and vacuum polarization effects on the structure of the fermion pairs is found to be fairly strong.

Describing an assembly of an infinite number of nucleons in interaction via a two-body potential as a nonrelativistic many-body problem in the first place, we envisage corrections to this picture due to suppressed degrees of freedom at the level of the two-body potential. At variance with relativistic many-body theory, the solution of the nonrelativistic problem with a two-body potential only is sufficiently under control at present so that evaluating corrections in this framework is of particular interest. These corrections come primarily from additional three-body forces either due to finite-density effects (Pauli blocking of fermions) or are of genuine origin: relativistic dynamical processes and effects from the intrinsic structure of the nucleon. Recalling the successful treatment of electromagnetic interactions in nuclei in terms of meson-exchange currents, we establish novel consistency requirements between the initial two-body force and the well-identified residual three-body force. In this way no new parameters enter in the three-body force, save for the controversial mass of the fictitious scalar ‘‘σ’’ meson. We show further that the nucleon-antinucleon pair term required in the analysis of meson-exchange currents has a genuine three-body counterpart resulting from time-ordered diagrams containing a single Z branch. Its contribution to the energy per particle is repulsive and varies with a high power of the density. Thereby we obtain the important saturating effect present in relativistic mean-field approaches. We envisage next the role of the first radial nucleon resonance $N^{\mathrm{*}}$((1/2,1)/2) (Roper resonance) in inducing a specific three-body force. The meson-nucleon-Roper coupling constants and form factors are evaluated in a relativistic quark model. Gathering all self-consistent corrections to the binding energy per particle of infinitely many nucleons, we find that the final equation of state is solely governed by the density dependence of medium corrections to the free σ-meson mass. We discuss a first attempt to extract this density dependence from an empirical equation of state.

A decay scheme of ${}_{}{}^{74}{}_{}{}^{}\mathrm{Zn}$ to levels in ${}_{}{}^{74}{}_{}{}^{}\mathrm{Ga}$ is presented in which 39 γ rays are placed, deexciting 11 states up to 1085 keV. Five levels are postulated to have $J^{\pi }$${=1\mathrm{}}^{+}$ based on β feedings but much uncertainty still exists concerning $J^{\pi }$ assignments for levels below 300 keV.

The $K^{\pi }$${=1\mathrm{}}^{\mathrm{-}}$ and $0^{\mathrm{-}}$ bands from the ((1/$2^{+}$[411]±(1/$2^{\mathrm{-}}$[521]) configuration, and the $K^{\pi }$${=1\mathrm{}}^{\mathrm{-}}$ and $2^{\mathrm{-}}$ bands from the ((3/$2^{+}$[411]±(1/$2^{\mathrm{-}}$[521]) configuration have been identified for the first time largely using known but previously unused gamma transitions from the ${}_{}{}^{165}{}_{}{}^{}\mathrm{Ho}$(n,γ) reaction. A remarkable similarity is shown to exist between the level structures of the $K^{\pi }$${=1\mathrm{}}^{\mathrm{-}}$ and $0^{\mathrm{-}}$ bands from the ((1/$2^{+}$[411]±(1/$2^{\mathrm{-}}$[521]) configurations in ${}_{}{}^{170}{}_{}{}^{}\mathrm{Tm}$ and ${}_{}{}^{166}{}_{}{}^{}\mathrm{Ho}$.

The angular correlation of the (${\pi }^{+}$,pp) and (${\pi }^{\mathrm{-}}$,pp) cross sections for ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, and C was measured in a wide angular range. We analyzed the structure of the (${\pi }^{+}$,pp) angular correlation comparing cross sections between the two reactions. It was found that the broad component of the (${\pi }^{+}$,pp) angular correlation is mainly due to the two-step processes associated with the two-nucleon absorption.

Zamick et al. recently reported on a series of Hartree-Fock calculations of light nuclei with Skyrme interaction in which they observed a near degeneracy of states corresponding to different fillings of the single-particle levels. We will present here a possible explanation for these facts using very simple arguments based on the liquid drop model.

On the basis of perturbative quantum chromodynamics, we consider the bremsstrahlung energy losses of partons traversing parton matter using the well-known quantum electrodynamical formulas. We find the transport equation describing the energy distribution of partons as a function of thickness of a target. The equation is solved numerically and we briefly discuss the relevance of our results for hadron-nucleus and nucleus-nucleus collisions at high energies.

Charged pion production induced by 201 MeV protons on ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ and ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ni}$ has been studied. The double differential cross sections have been measured over a wide angular range. Different behavior of the angular distribution is observed for low and high energy pions. The yield of positive pions shows a pronounced forward peaked component. The deduced total production yields are about the same for (p,${\pi }^{+}$) on both isotopes whereas that for ${}_{}{}^{64}{}_{}{}^{}(\mathit{p}$,${\pi }^{\mathrm{-}}$) is twice as large as for ${}_{}{}^{58}{}_{}{}^{}(\mathit{p}$,${\pi }^{\mathrm{-}}$).

Certain types of ring diagrams of the thermodynamic potential Ω can be summed up to all orders using two apparently very different methods—the eigenvalue method and the transition-amplitude method. A relatively simple derivation of these methods is given, and we show that these two methods are exactly equivalent to each other. To study their numerical applications we have calculated the particle-particle, hole-hole ring diagrams of Ω for nuclear matter with both methods, using a modified Gogny interaction. Our results suggest that the strength-parameter integration involved in the transition-amplitude method can be accurately performed using a small number of mesh points and both methods seem to be suitable for numerical calculations.

We perform S-matrix–to–potential inversion calculations for recently published phase shift fits for protons scattering from ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ at 64.9-MeV laboratory energy. Certain features of the local potential corresponding to these phase shifts appear to be well determined and are unexpected. These include a ‘‘tail’’ in the surface of the real potential, and conspicuous regions of emissivity. We also present the equivalent scalar plus vector Dirac potentials.

Two independent measurements of the ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$(γ,n) reaction cross section have been made using both an enriched-gas target, and one of ${(}^{15}$${\mathrm{NH}}_4$${)}_2$${\mathrm{SO}}_4$. The results are self-consistent, but reveal discrepancies with an earlier measurement of this cross section, particularly in the giant dipole resonance region, and with a measurement of the ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$(γ,$n_0$) cross section. These discrepancies are discussed and in general resolved. The results are used in conjunction with other isospin-selective reactions data on ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$ to elucidate the isospin distribution of E1 states in ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$.

The most recent data for the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(α,γ${)}^{16}$O reaction are parametrized in terms of a K matrix in order to derive the astrophysical S(E) factor at stellar energies. This straightforward parametrization introduces neither boundary condition constants nor channel radii. To constrain the free parameters, all the available data for the phase shifts ${\delta }_l$(l=1,2) of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(α,α${)}^{12}$C were simultaneously fitted with those for the E1 and E2 radiative captures. For each of the three sets of capture data we have analyzed, ${\chi }^2$ tests have been performed with different types of energy-dependent background terms, namely, polynomials and nonresonant echo poles (in the sense of McVoy). The introduction of such poles is motivated by the falling of the ${\delta }_l$ phase shift at higher energies. On the basis of the present analysis, it is concluded that, from the data available, one can derive an allowed range for S(0.3), from 0.00 to 0.17 MeV b. No confidence can be given to a so-called best value of S(0.3) within this range because such a value is dependent on both the data set analyzed and the type of background terms introduced into the parametrized K matrix.

Branching ratios for radiative alpha capture by tritium and ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ have been studied in a kinematical direct capture model for the purpose of obtaining an independent derivation of the ${}_{}{}^3{}_{}{}^{}\mathrm{H}$(α,γ${)}^7$Li branching ratio and possibly resolving an apparent discrepancy in the experimentally measured value. From the mirror symmetry between ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ and ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$, and the observed branching ratio R(0)=0.38±0.04(1σ) for the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$(α,γ${)}^7$Be reaction, the branching ratio for the ${}_{}{}^3{}_{}{}^{}\mathrm{H}$(α,γ${)}^7$Li reaction is constrained to be R(0)=0.47±0.07, which agrees best with the higher measured value. The implication of these results for big-bang nucleosynthesis in standard and nonstandard models is discussed.

Polarization effects in ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(γ,n${)}^1$H are considered in the low photon energy domain. We discuss linear photon polarization, one-nucleon polarization, and vector target asymmetry.

The energy spectra of neutrons emitted from 25 MeV (p,n) reactions on nuclei in the Cr-Ni region have been analyzed in terms of the preequilibrium exciton model introducing effective Q values, the pairing correlation, and the modified uniform spacing model in which the uniform spacing model is modified so as to have a wide spacing at the magic number. The calculated energy spectra using the above model are in fairly good agreement with the observed spectra with pronounced structures.