The analyzing power ${\mathit{A}}_{\mathit{y}}$ for proton elastic scattering on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ has been precisely and absolutely determined at three scattering angles (${\mathrm{\theta }}_{\mathrm{lab}}$=16.3°, 17.3°, and 18.3°) at an incident proton energy of 188.9 MeV. The technique employed requires statistically high quality polarization transfer measurements, combined with the constraints imposed on polarization observables for reactions with the spin structure 1/2+0→1/2+0. These results represent some of the most accurately known spin observables at intermediate energies and serve as calibration points for secondary standards.

Cross sections have been measured for proton emission following ${\mathrm{\pi }}^{+}$ absorption on ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$, ${}_{}{}^{118}{}_{}{}^{}\mathrm{Sn}$, ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$, and ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ for pion kinetic energies of 50, 100, 150, and 200 MeV by using a large-solid-angle bismuth germanate detector array. An increasing fraction of transitions to states of large missing energy and with particles other than protons is observed as the energy and mass increase.

One-body contributions to parity mixing in compound nuclear states are discussed, with reference to the recent polarized neutron transmission experiments. The role of the J=$0^{\mathrm{-}}$ giant spin-dipole resonance as a mediator of parity mixing in complex nuclear states is pointed out, and an expression of the parity violating spreading width derived. The collective nature of the mixing mechanism is stressed, and an analogy with isospin mixing in nuclei is drawn.

Inclusive ${\mathit{K}}^{+}$ production cross sections in the collision ${}_{}{}^{96}{}_{}{}^{}\mathrm{Ar}$${+}^{48}$Ti at ${\mathit{E}}_{\mathrm{beam}}$=92 MeV/nucleon are calculated in the framework of a cooperative mechanism which had earlier been successful in explaining the subthreshold pion production cross sections. The calculated total cross section is 162 pb which is in agreement with the recent experimental evaluation ${\mathrm{\sigma }}_{\mathit{K}}^{+}$=(240±150) pb. Our work appears to imply that like other subthreshold particles, subthreshold kaon productions also are governed mainly by phase space constraints.

The saturation of the B(E2,$0_1^{+}$→$2_1^{+}$) strengths in the actinide nuclei is described very well by an analytical formula using shell closures at Z=82,126 and N=126,184. The transition towards saturation is much more gradual than in the rare earth nuclei and reaches a saturation value of 325±10 W.u. By assuming a similar correlation between B(E2) and summed B(M1) strengths as observed in the rare-earth region we predict for actinide nuclei a saturation of the summed B(M1,$0_1^{+}$→$1^{+}$) strengths below about 3 MeV of 3.7±0.4 ${\mathrm{\mu }}_{\mathit{N}}^2$. We compare our estimates for (${\mathit{g}}_{\mathrm{\pi }}$-${\mathit{g}}_{\nu }$${)}^2$ with values obtained from extrapolations of averaged regional boson g factors.

Correlations were found between the first level ($2^{+}$) isomeric half-lives and the atomic number. These correlations were found for actinide nuclei with a constant value of 2Z-N. The correlations were for 2Z-N=38, 40, 42, and 44. These correlations serve to predict the first energy level isomeric half-lives of some not yet measured actinide.

The ${}_{}{}^{169}{}_{}{}^{}\mathrm{Tm}$${(}^{16}$O,4n${)}^{181}$Ir reaction has been employed to investigate the high spin states of ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ir}$ using in-beam γ spectroscopy. A well-developed system of levels built on the ${\mathit{h}}_{9/2}$ subshell was identified up to a maximum spin of (41/$2^{\mathrm{-}}$). Two rotational bands built on the isomeric states with ${\mathrm{\tau }}_{1/2}$=0.33 μs (${\mathit{E}}_{\mathit{x}}$=289.2 keV) and 0.13 μs (${\mathit{E}}_{\mathit{x}}$=366.2 keV), respectively, were observed. The deduced ${\mathit{g}}_{\mathit{K}}$ values of 1.19±0.11 and 1.50±0.12 indicate Nilsson assignments of 9/$2^{\mathrm{-}}$[514] and 5/$2^{+}$[402], respectively, for the bandheads of these bands. A high spin (I≥19/2) isomer with ${\mathrm{\tau }}_{1/2}$=22 ns was found at an excitation energy above 1.96 MeV. The experimental results are discussed in terms of rotational models including Coriolis coupling and providing for a stable triaxial shape of the ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ir}$ nucleus.

Differential cross sections for elastic and inelastic α- scattering on ${}_{}{}^{36}{}_{}{}^{}\mathrm{Ar}$ have been measured at 40, 48, and 54 MeV. The data have been analyzed in the coupled-channel approach using double-folded optical α${\mathrm{-}}^{36}$Ar potentials considering the model of the symmetric rotator and the harmonic vibrator. The octupole transition probability deduced in the harmonic-vibrator model is almost identical to the value obtained from electromagnetic probes. In the symmetric-rotator model only the choice of negative ${\mathrm{\beta }}_2$ and ${\mathrm{\beta }}_4$ deformation parameters results in consistent fits to the data at all incident energies. This unambiguously proves the oblate shape of ${}_{}{}^{36}{}_{}{}^{}\mathrm{Ar}$. The volume integrals and rms radii of the extracted optical potentials fit well into the systematics obtained for lighter sd-shell nuclei.

The relative populations of particle-unstable states of intermediate-mass fragments were measured for the ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$+Ag reaction at E/A=35 MeV with a position-sensitive hodoscope. These measurements were compared to the predictions of statistical calculations which include the sequential decay of heavier particle unstable nuclei. The best overall agreement between the calculated and measured excited-state populations was obtained with calculations which assume emission temperatures of about 3–4 MeV for the primary distributions of the particle unstable intermediate-mass fragments. However, a detailed comparison between calculated and measured excited state populations assuming ${\mathit{T}}_{\mathrm{em}}$=4 MeV reveals significant discrepancies for about one-third to one-half of the measured quantities. Calculations that include rotational effects do not satisfactorily account for this discrepancy. These results suggest the possibility of a breakdown in the assumption of local thermal equilibrium at freezeout.

The nuclear magnetic moments of ${}_{}{}^{124}{}_{}{}^{}\mathrm{I}$, ${}_{}{}^{126}{}_{}{}^{}\mathrm{I}$, and ${}_{}{}^{130}{}_{}{}^{}\mathrm{I}$ have been measured by the techniques of low-temperature nuclear orientation and nuclear magnetic resonance on oriented nuclei. The magnetic hyperfine splitting frequency ‖g${\mathrm{\mu }}_{\mathit{N}}$${\mathit{B}}_{\mathrm{HF}}$/h‖ for ${}_{}{}^{124}{}_{}{}^{}\mathit{Fe}$ was determined to be 630.2(2) MHz from a field-shift analysis of the measured resonances at the external field of 0.1, 0.2, 0.4, 0.6, and 0.8 T. The resonances for ${}_{}{}^{126}{}_{}{}^{}\mathit{Fe}$ and ${}_{}{}^{130}{}_{}{}^{}\mathit{Fe}$ were observed in an external magnetic field of 0.2 T at ν${(}^{126}$IFe)=627.7(2) MHz and ν${(}^{130}$IFe)=585.7(2) MHz, respectively. Using the recalculated hyperfine field of ${\mathit{B}}_{\mathrm{HF}}$${(}^{131}$IFe)=114.50(5) T, the magnetic moments were deduced: ‖μ${(}^{124}$I,$2^{\mathrm{-}}$)‖=1.444(4)${\mathrm{\mu }}_{\mathit{N}}$, ‖μ${(}^{126}$I,$2^{\mathrm{-}}$)‖=1.436(5)${\mathrm{\mu }}_{\mathit{N}}$, and ‖μ${(}^{130}$I,$5^{+}$)‖=3.349(7)${\mathrm{\mu }}_{\mathit{N}}$. The present value of the magnetic moment of ${}_{}{}^{124}{}_{}{}^{}\mathrm{I}$ is very different from the value of 1.14(8)${\mathrm{\mu }}_{\mathit{N}}$ reported previously. The measured values of the magnetic moments are discussed using Landé formula.

The magnetic moment of the 19/$2^{\mathrm{-}}$ state in ${}_{}{}^{39}{}_{}{}^{}\mathrm{K}$ has been measured by the transient field technique. The state was excited by the inverse reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{32}$S,pα${)}^{39}$K and the recoil nucleus traversed a thin Gd foil. Its absolute g factor, g=0.35(3), was obtained by an internal calibration, which makes use of the magnetic moment of the 15/$2^{+}$ state in ${}_{}{}^{41}{}_{}{}^{}\mathrm{Ca}$ also excited in the same reaction. A mean g factor for the states $3^{\mathrm{-}}$, $5^{\mathrm{-}}$ in ${}_{}{}^{36}{}_{}{}^{}\mathrm{Ar}$, g=0.52(6), determined in a simultaneous measurement is consistent with the self-conjugate nature of the nucleus, giving further support to the validity of the field calibration. The experimental result agrees with shell-model predictions.

The giant dipole resonance (GDR) in ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$ has been studied with the reaction ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$(γ,p${)}^{16}$N from ${\mathit{E}}_{\gamma }$=13.50 to 43.15 MeV using quasimonoenergetic photons. The measured cross section shows major peaks at 15.1, 18.1, 19.3, 20.3, 22.2, 23.1, 24.4, and ∼26.5 MeV. The intermediate structure in the main GDR region is remarkably similar to that observed in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, indicating that the valence neutron outside the doubly magic ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ core perturbs the core-excited states minimally, in support of the weak-coupling hypothesis. We correlate the trends in GDR structure of ${}_{}{}^{16,17,18}{}_{}{}^{}\mathrm{O}$ with changes in ground-state properties related to static deformation. The (γ,p) reaction selects strength predominantly from two-particle–one-hole configurations formed via E1 transitions from the 1${\mathit{p}}_{1/2}$ subshell; comparison with other reactions (photoneutron and radiative capture) provides information on the microscopic structure of E1 states. The peak observed near threshold at 15.1 MeV is remarkably strong; we infer that it originates from photoexcitation of a few narrow T=3/2 states and that M1 transitions contribute to the measured strength. The total absorption cross section is approximated by summing the (γ,p) cross section and the previously published photoneutron cross section; comparison with particle-hole shell-model calculations shows that the main cross-section features, including isospin distribution, are well predicted. Evidence is found for isospin splitting in ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$. Systematics of the integrated cross sections for the carbon, nitrogen, and oxygen isotopes are delineated.

A generalization of the continuum open-shell r-space linear response random-phase approximation method to finite temperatures (i.e., TDRPA method) is applied in a study of the systematics of the electric double giant dipole resonance (DGDR) in magic and open-shell nuclei covering a wide range of nuclear masses. Viewing the DGDR as a single-phonon vibration in a hot nucleus, whose temperature corresponds to the centroid energy of the ground-state (zero-temperature) GDR, the TDRPA equation has been solved for the eleven nuclei whose DGDR state has recently been investigated in pion double-charge-exchange (DCX) experiments. The expected general features of a collective vibration in hot nuclei, particularly the broadening and the downshift of the GDR excitation energy due to increase in temperature, were found to be small, yet quite distinguishable. Except for the lighter nuclei, a reliable estimate for the DGDR energy would be ${\mathit{E}}^{\mathrm{DGDR}}$≊2${\mathit{E}}^{\mathrm{GDR}}$ and the estimate for its width would be ${\mathrm{\Gamma }}^{\mathrm{DGDR}}$≊ √2 ${\mathrm{\Gamma }}^{\mathrm{GDR}}$. However, the changes in the integrated cross sections of the DGDR due to finite temperature are found to be much more significant. An exact ${\mathit{A}}^{\mathrm{-}1/6}$ power law for the DGDR energy is suggested by the TDRPA solutions. A gratifying agreement between the TDRPA predictions and experiment has been established for the Q values of the relevant pion DCX reactions after taking into account the proper Coulomb and symmetry energy corrections.

We report results of covariant calculations of density-dependent polarization processes in relativistic nuclear matter. We consider the polarization induced by those mesons that play an important role in the boson-exchange model of nuclear forces (σ,π,ρ,ω). After obtaining the polarization operators, we construct the propagators for these mesons. The covariant nature of the calculation greatly clarifies the structure of the polarization operators and associated Green’s functions. (In addition to the meson momentum, these quantities depend upon another four-vector, ${\mathrm{\eta }}^{\mathrm{\mu }}$, that describes the uniform motion of the medium.) In the case of the pion, we show that the same results are obtained for pseudovector or pseudoscalar coupling to the nucleon, if the associated Lagrangians are related by chiral transformations. Of particular interest are the extremely large values found for the polarization operators of the omega and sigma mesons. It is also found that the coupling of the sigma and omega fields through the polarization process is also extremely large. (Because of these results one cannot usefully consider the sigma and omega fields as independent degrees of freedom in nuclear matter.) We describe methods for reorganizing the calculation of ring diagrams in which we group those diagrams that exhibit strong cancellations. We also comment on the implication of our results for nuclear structure studies.

23 p-d elastic scattering spin observables, most of them in linear combinations of two observables, were measured at 794 MeV over a range of four-momentum transfer t from -0.257 to -0.630 (GeV/c${)}^2$. By changing the beam polarization between S, N, and L type and by alternating the target vector polarization between negative and positive, six independent combinations of beam and target polarization were obtained. The target was dynamically polarized deuterated ammonia. An average target polarization of 30% was achieved. Transverse polarization components of the scattered protons (S and N type) were measured directly by using a polarimeter. The longitudinal polarization component (L type) was measured after precessing it to N type. Typical uncertainties for two-spin coefficients were 0.02 and for three-spin coefficients 0.1–0.2. The data are compared with the theoretical predictions calculated by fitting the previously available data to a relativistic multiple-scattering model with derivative couplings. Although relativistic impulse approximation calculations do not predict the data well, they are also included in the comparisons.

The experimental data on two-quasiparticle rotational bands of doubly-even nuclei in the rare-earth region are analyzed; both the ${\mathit{K}}_{\mathrm{-}}$=‖${\mathrm{\Omega }}_1$-${\mathrm{\Omega }}_2$‖ and many of the ${\mathit{K}}_{+}$=(${\mathrm{\Omega }}_1$+${\mathrm{\Omega }}_2$) bands exhibit an odd-even staggering in energy. A formalism for Coriolis coupling within the framework of the two-quasiparticle plus axially symmetric rotor model is presented. A detailed application of the model is made to the 27 known two-quasiparticle bands in ${}_{}{}^{168}{}_{}{}^{}\mathrm{Er}$. The odd-even staggering in all the bands is reproduced very well. A discussion of the mixing effects in some of the bands is also presented. The Coriolis mixing is able to resolve the apparent violation of the Gallagher rule in the configuration {5/2[642${]}_{\mathit{n}}$⊗1/2[521${]}_{\mathit{n}}$}.

Various wave functions that have been used to describe the ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ system are examined. In particular it is shown that while the ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$(γ,${\mathrm{\pi }}^{+}$${)}^{14}$${\mathrm{C}}_{\mathrm{g}.\mathrm{s}.\mathrm{}}$ reaction data at 173 and 200 MeV suggest that the Cohen and Kurath wave functions are inappropriate, the variations that these data imply can be explained in terms of core polarization effects.

Self-consistent axial Hartree-Fock plus BCS calculations have been performed in order to analyze the superdeformed single-particle orbitals near the chemical potentials in Hg and Pb nuclei. The influence of an approximate restoration of the particle-number symmetry is investigated. A discussion of available data is made, taking stock of our results, in the framework of the strong coupling model.

A survey of the kinematic moments of inertia of A≊80 nuclei shows a tendency to converge toward the rigid-body values of 20 to 25 ${\mathrm{ħ}}^2$/MeV at rotational frequencies above 0.6 MeV/ħ. The moments of the even-even isotopes approach the convergence zone from much lower values. The farther from the center of the shell, the lower the initial values are and the more rapid is the rise. By contrast, the moments of inertia of the odd-odd nuclei start from higher values and decrease into the convergence zone. The values for odd-A nuclei are generally intermediate, usually starting somewhat below the final value and increasing into the 20 to 25 ${\mathrm{ħ}}^2$/MeV region. The quadrupole deformations inferred from lifetimes in the even-even nuclei show no systematic change with spin, in contrast to the moments of inertia.

We discuss the problem of inclusion of quantum corrections in the semiclassical theory of adiabatic large amplitude collective motion for many-fermion systems. We concentrate on deriving a formula for the leading quantum correction to the classical collective potential energy function in this theory. This is an extension of the usual calculation of the quantum corrections to the static Hartree-Fock energy using the random phase approximation. The answer can be expressed in terms of those solutions of a local random phase approximation that describe oscillations orthogonal to the collective surface. Because of the strict enforcement of the Pauli principle, however, the answer differs from the usual quasiboson approximation, yielding the correct ground-state corrrelation energy for a static solution to the Hartree-Fock equations. The result is applied, approximately, to help improve a previous treatment of the low energy spectrum of ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$.