An analysis of isospin symmetry breaking in the case of pure spectral observables is made within the recently developed deformed Gaussian orthogonal ensemble. The low-energy spectrum of ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ recently studied by Mitchell et al. is used to perform the analysis. Both the spacing and eigenvector distributions are considered. The value of the Coulomb matrix elements that causes the isospin breaking is extracted and found to be consistent with other measurements.

We present the results of our calculations for the elastic scattering of 800 MeV/c charged pions from the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ nuclei using a strong absorption approximation. These results are found to be in excellent agreement with the experimental data. We also discuss the validity of this approximation within the context of high energy pion-nucleus elastic scattering.

Particle-rotor model calculations have been performed for the B(M1)/B(E2) ratios in ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ir}$, the lightest-mass Ir nucleus for which the spins and parities are firmly established experimentally. Remarkable agreement with experimental data is observed for a fixed, well-deformed shape, in contrast with suggestions of multiple shapes at low spins in the light-mass Ir nuclei.

The use of summation methods, to deal with the calculation of matrix elements involved in the microscopic description of nuclear double beta decay processes, is discussed. The analysis focuses on the accuracy of a procedure which formally expresses the matrix elements of the standard current-current weak interaction, starting from the second-order perturbation treatment of the standard weak Lagrangian, as divergent power series of energy denominators. It is shown that, when properly treated, the summation method leads to results which coincide with the numerical sum of contributions due to virtual intermediate states.

Sensitivity of proton-nucleus scattering is studied to the off-shell behavior of the nucleon-nucleon (NN) effective interaction, particularly to the presence of the NN bound state. The effect is found to be negligible in a kinematical region where an optimal factorization approximation is justified. A sensitivity can be seen below 100 MeV of beam energy and for the light nuclei ${(}^{12}$C${,}^{16}$O). The effect is more pronounced for a tensor part of the NN t matrix which is shown in the charge-exchange cross section of proton scattering from ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$.

We discuss and interpret the numerical results obtained by Zheng, Sprung, and Flocard [Phys. Rev. C 46, 1355 (1992)] in a two-level pairing model. It is shown that a violation of applicability limits of the Kamlah projection method is at the origin of results obtained for a weak pairing strength.

The atomic masses of neutron-deficient isotopes with $N-Z=19\mathrm{}$, $N-Z=18\mathrm{}$, $N-Z=17\mathrm{}$, and $N-Z=16\mathrm{}$ have been determined by linking measured $\alpha$-decay energies to the known masses of ${}_{}{}^{145}{}_{}{}^{}\mathrm{Eu}$, ${}_{}{}^{146}{}_{}{}^{}\mathrm{Gd}$, ${}_{}{}^{147}{}_{}{}^{}\mathrm{Tb}$, and ${}_{}{}^{148}{}_{}{}^{}\mathrm{Dy}$, respectively. The results are compared to model predictions. The deviations between model predictions and experimental data show an odd-even effect, which indicates that the pairing energy in this region is not fully explained by most of the mass models.

Excitation functions for sub-barrier one- and two-neutron pickup reactions were measured for ${\mathit{E}}_{\mathrm{lab}}$≤106 MeV in ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$${+}^{93}$Nb, ${}_{}{}^{98,100}{}_{}{}^{}\mathrm{Mo}$ systems by detecting targetlike recoils at 0° using a recoil mass spectrometer. The slopes of transfer probability vs distance of closest approach are in good agreement with binding energies, indicating the absence of a ‘‘slope anomaly.’’ Angle-integrated transfer cross sections derived from measured 180° yields are consistent with enhancements in previously measured fusion yields for the ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$${+}^{98,100}$Mo systems.

Neutron spectra in coincidence with fission fragments have been measured for the 190 MeV ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$${+}^{76}$Ge populating ${}_{}{}^{104}{}_{}{}^{}\mathrm{Pd}$ compound nucleus at ${\mathit{E}}_{\mathit{x}}$∼133 MeV excitation energy. The extracted prescission multiplicity for symmetric splitting is ${\nu }_{\mathrm{pre}}$=1.1±0.2. The average fission time ${\mathrm{\tau }}_{\mathit{F}}$=$6_{\mathrm{-}2}^{+3\mathrm{}}$×${10}^{\mathrm{-}20}$ s is determined, in good agreement with the systematics of Hinde et al. for heavier systems (A≥125 compound nuclei).

Exclusive events for central collision of ${}_{}{}^{94}{}_{}{}^{}\mathrm{Kr}$ on Ag/Br emulsion at a bombarding energy of 70–120 MeV per nucleon point to an extremely large flow energy of the order of 10 MeV per nucleon for intermediate mass fragments. We show that this large radial flow energy is associated with an explosive breakup of the excited matter in the very early stage of the collision process.

In this paper we present a model based solely on isospin for the determination of ratios of pion absorption cross sections on three nucleons. We then compare the results with the available experimental data for pion absorption on ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, at the energies 120 and 165 MeV, and for ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ and ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ at 50, 100, 140, and 180 MeV. Good agreement was found between this simple model and experiment, suggesting that pion absorption on three nucleons in light nuclei may be described as a one step process.

The α-cluster structure of the ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ nucleus is investigated by studying the properties of a global optical model potential which describes ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$(α,α) elastic scattering at 28, 40, and 54 MeV on the whole angular range. This calculation does not support the existence of the negative-parity molecular dipole states which have been proposed to coexist with the positive-parity four-particle–two-hole (4p-2h) deformed band built on the ${\mathit{J}}^{\mathrm{\pi }}$=$0^{+}$, ${\mathit{E}}_{\mathit{x}}$=3.63 MeV state. It suggests that the broad ${\mathit{J}}^{\mathrm{\pi }}$=$1^{\mathrm{-}}$ state recently seen around ${\mathit{E}}_{\mathit{x}}$=9 MeV in the β-delayed α-particle spectrum from ${}_{}{}^{18}{}_{}{}^{}\mathrm{N}$ is the bandhead of the negative-parity inversion-doublet partner band of the 4p-2h band.

The neutron rich Zr isotopes are studied in a relativistic mean-field approach. A transition from spherical to strongly deformed shapes is obtained around A≃100 and ground state deformations are found, which are in size close to superdeformed shapes. Furthermore, very large radii are predicted in the vicinity of the neutron drip line due to the combined effects of deformation and neutron excess.

Ratios of inclusive electron-nucleus cross sections are studied at incoming electron energies of 1 GeV to 25 GeV and (Bjorken) variable ${\mathit{x}}_{\mathit{B}\mathit{j}}$>1 where many of the present theoretical speculations and the available and forthcoming experimental data are focused on. An alternative analysis which accounts for nuclear target mass effects is proposed.

Polarized proton beams and a liquid-deuterium target were used to measure the analyzing power for quasifree p→-n and p→-p scattering in the forward direction at 643 and 797 MeV. Alternate use of a liquid-hydrogen target provided a comparison of free and quasifree p→-p scattering. The precision of the data is in general ±0.01 to ±0.02, although some of the p→-p data for 797 MeV are at the precision level of ±0.005. For c.m. angles ${\mathrm{\theta }}^{\mathrm{*}}$≥22° there is no difference between quasifree and free results at either energy. The data are compared with the predictions of several phase-shift analyses. In a search for more pronounced quasifree scattering effects, a small amount of p→-‘‘p’’ data were taken with a carbon target.

The Harvard noncoplanar geometry is used to specify calculations of the different and integrated cross sections and of the component analyzing powers from pp bremsstrahlung. This geometry is equivalent to spherical polar coordinates for coplanar scattering. A wide range of incident energies and symmetric proton emission angles are considered in studying various properties of the reaction. Emphasis is placed on an energy of 280 MeV and for forward proton angles, at which results are most sensitive to specific off-of-the-energy-shell properties of the two nucleon t matrices. Those t matrices are generated with various interactions. The importance of the NN t-matrix off-diagonal tensor contributions for the coplanar observables as demonstrated in the pioneering work of Brown is clearly shown. Photon cross sections vary with the noncoplanarity of the reaction due in part to changes in relative importance of diverse NN channel t matrices. The analyzing powers likewise vary with azimuthal angle and reveal a particular sensitivity to the tensor coupled ${}_{}{}^3{}_{}{}^{}$${\mathit{P}}_{2\mathrm{-}}^3$${\mathit{F}}_2$ channels and to the ${}_{}{}^3{}_{}{}^{}$${\mathit{P}}_0$ channel.

For the purpose of addressing catastrophic phenomena in nuclear dynamics, we explore the possibility of simulating the stochastic part of the collision integral in the Boltzmann-Langevin model by the numerical noise associated with the finite number of test particles in the ordinary Boltzmann-Uehling-Uhlenbeck (BUU) treatment. Considering idealized two-dimensional matter, for which it is practical to simulate the Boltzmann-Langevin equation directly, we demonstrate that the number of test particles per nucleon can be adjusted so that the corresponding BUU calculation yields a good reproduction of the spontaneous clusterization occurring inside the spinodal region. This approximate method may therefore provide a relatively easy way to introduce meaningful fluctuations in simulations of unstable nuclear dynamics.