Outgoing nucleon polarization in exclusive deuteron electrodisintegration is studied at the quasielastic peak in the standard theory with emphasis on the effect of nucleonic and pionic relativistic corrections. The cases of polarized beams or/and polarized target are considered. Sizable relativistic effects are pointed out in several polarization components. The sensitivity of nucleon polarization to the neutron charge form factor ${\mathit{G}}_{\mathit{E}}^{\mathit{n}}$ is discussed. In particular, it is shown that the longitudinal component of neutron polarization with vector polarized deuterons is as sensitive to ${\mathit{G}}_{\mathit{E}}^{\mathit{n}}$ as the sideways beam polarization transfer.

The effects of the consideration of the ρ-meson effective mass, proposed in a number of previous papers, are investigated in medium nuclei by analyzing the electroexcitation of some low-lying magnetic states in ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$. It is found that the simple consideration of ${\mathit{m}}_{\mathrm{\rho }}^{\mathrm{*}}$/${\mathit{m}}_{\mathrm{\rho }}$ as a constant does not work properly in this nucleus, contrary to what happens in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$. If, in addition, the ${\mathit{f}}_{\mathrm{\pi }}^{\mathrm{*}}$ is included as given by the in-medium scaling law established by Brown and Rho, the available experimental data can be reasonably well described, provided ${\mathit{m}}_{\mathrm{\rho }}^{\mathrm{*}}$/${\mathit{m}}_{\mathrm{\rho }}$≊${\mathit{f}}_{\mathrm{\pi }}^{\mathrm{*}}$/${\mathit{f}}_{\mathrm{\pi }}$≊0.91. This value differs notably from the one found for ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ which is of 0.79. As predicted, ${\mathit{f}}_{\mathrm{\pi }}^{\mathrm{*}}$ does not strongly affect the conclusions drawn in lead for the ${\mathit{m}}_{\mathrm{\rho }}^{\mathrm{*}}$ calculations, the only effect being an increase of the quenching factor corresponding to the lower ${12}^{\mathrm{-}}$ state at 6.43 MeV up to a value near 0.9. The results obtained show a rather clear dependence of the scaling with the nucleus considered.

The effects of the struck nucleon-core binding potential on the first-order term of the Kerman, McManus, and Thaler (KMT) expansion of the nucleon-nucleus optical potential are calculated for the elastic scattering of protons from ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ at 200 MeV. The binding effects are expressed as a momentum-transfer-dependent energy shift in the off-shell nucleon-nucleon t matrix. Numerical results are based on the Paris nucleon-nucleon potential together with both harmonic oscillator or Woods-Saxon single-particle wave functions for the target. The calculations show that these binding effects introduce only small corrections to the optical potential and calculated observables in the intermediate energy region when compared with the impulse approximation.

The cross section of the charge-exchange ${(}^3$He,t) reaction in a Δ-isobar region was calculated for a finite nucleus in terms of a relativistic nuclear response function. The medium effects modifying a Δ and a pion propagation were considered for a finite size nucleus. The Glauber approach was used for distortion treatment of a ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ and a triton in the initial and final states. The effects determining the cross section, the peak position, and its width are discussed. A large displacement width for the Δ-hole excitations and a considerable contribution of coherent pion production were found for the reaction on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$.

In double charge exchange leading to residual nonanalog $0^{+}$ ground states, we examine the relative contribution of sequential charge exchange and delta-nucleon charge exchange. We conclude that the data cannot be quantitatively understood in terms of these two reaction mechanisms.

The role of unitary equivalence of relativistic corrections in elastic electron deutron scattering is studied, starting from a class of approximately, unitarily equivalent Hamiltonians and using consistent charge density operators. The connection of various formal approaches for deriving the relativistic corrections to wave functions and operators are discussed in detail. For reasons of simplicity, we have chosen a pure one-pion-exchange model and calculated the charge and quadrupole form factors of the deuteron. The numerical results show that the unitary equivalence holds at small momentum transfers, but breaks down rather soon with increasing momentum transfers (≲5 ${\mathrm{fm}}^{\mathrm{-}1}$).

A global model of transverse energy and multiplicity distributions in ultrarelativistic nuclear collisions is proposed in which the global observables are assumed to be determined simply by the geometrical and statistical properties of the collision process, while the dynamics appears only as a gross average. The overall fit to the CERN 200 GeV p+A and 60 GeV/nucleon B+A as well as 200 GeV/nucleon B+A experiments is satisfactory, and the fitted average transverse energy ${\mathrm{\varepsilon }}_{\mathit{T}}$ and multiplicity m per collision are as reasonable as 0.44–0.83 GeV and 1.3–1.5, respectively. This study shows that the collision number plays an important role in the B+A collisions through the collision geometry, while the details of the collision process are irrelevant for the global observables.

Spin-dependent inelastic electron scattering from polarized ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ is studied. The theoretical description uses the plane-wave impulse approximation. A spin-dependent spectral function, which summarizes all of the nuclear structure information on the process, is introduced. The formalism is developed for inclusive processes in all kinematic regimes of inelastic electron scattering. A comparison between theoretical predictions and experimental data is carried out in the region of quasifree scattering. The use of a polarized ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ target as a neutron spin target is discussed.

We consider two problems associated with the production of dileptons during collisions between heavy nuclei at the Brookhaven Relativistic Heavy Ion Collider energy. One is the difference in dilepton yield between an idealized Maxwell construction of phase coexistence and a dynamical phase transition with finite nucleation and phase conversion rates. The other is the contribution from dilepton-producing reactions involving free-streaming hadrons in the final state. We find that the mass spectrum in the range 2${\mathit{m}}_{\mathrm{\pi }}$<M<2 GeV is dominated by the mixed phase and the final hadron phase, is somewhat sensitive to the degree of supercooling, but is remarkably insensitive to the ‘‘freeze-out’’ temperature which delineates the passage from local thermal equilibrium to free streaming.

The exclusive ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(e,e’p)${\mathit{N}}^{\mathrm{*}}$ process at CEBAF energies, with the missing mass coincidence technique, offers the opportunity to reveal the baryon-baryon (BB) composition of the deuteron and to reconstruct the deuteron six-quark wave function. As an example, we project out two different kinds of currently discussed six-quark functions into various BB channels including such baryons as n, p, Δ, N(1440), N(1520), and N(1535). Spectroscopic factors and momentum distributions are calculated using the nonrelativistic quark model. The results are that the ΔΔ component in the deuteron is almost entirely connected with the six-quark configuration ${\mathit{s}}^6$ while the channels with N(1440), N(1520), and N(1535) display the configuration ${\mathit{s}}^4$${\mathit{p}}^2$.

The operator expansion method for the evaluation of the 2ν ββ decay nuclear matrix element is extended to include the Coulomb interaction and nuclear central and tensor interactions. It is shown that the Coulomb interaction, which represents a part of one-body terms of Hamiltonian, plays a decisive role in taking into account effects of ground-state correlations, and a significant improvement is achieved in simulating the ‘‘exact’’ calculation based on the quasiparticle RPA. However, this method does not reproduce the strong suppression of the nuclear matrix element, probably because of the two-body approximation.

Inspired by the model of Nambu and Jona-Lasinio, various Lagrangians are considered for a system of interacting quarks. Employing standard techniques of many-body theory, the scalar part of the quark self-energy is calculated including terms up to second order in the interaction. Results obtained for the single-particle Green’s function are compared with those which only account for the mean-field or Hartree-Fock term in the self-energy. Depending on the explicit form of the Lagrangian, the second-order contributions range between 4 and 90 percent of the leading Hartree-Fock term. This leads to a considerable momentum dependence of the self-energy and the effective mass of the quarks.

Because null tests of parity conservation exist in nuclear and particle reactions, it has been possible to measure very precisely the (weak-interaction) parity nonconserving contribution to the process. There is, however, a proof of the nonexistence of a comparable null test of time-reversal invariance. As a result, reaction tests of T symmetry have, at best, achieved precisions several orders of magnitude below that of the tests of P symmetry. Since transmission experiments are not included in the nonexistence proof, the existing formalism used to describe spin observables in neutron transmission experiments has been expanded to include explicitly the target spin. Through this formalism, the time-reversal-violating (and parity nonconserving) forward scattering amplitudes are identified, along with the corresponding spin observables. It is noted that new and more precise tests of T symmetry are provided in transmission experiments, and that such investigations are applicable more generally in nuclear and particle physics.

The beta-delayed alpha-particle emission of ${}_{}{}^{16}{}_{}{}^{}\mathrm{N}$ has been studied, with ${}_{}{}^{16}{}_{}{}^{}\mathrm{N}$ nuclei produced using 80 MeV/nucleon ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ beams on ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$ targets. The ${}_{}{}^{16}{}_{}{}^{}\mathrm{N}$ secondary nuclei were mass analyzed and separated from the reaction products using the Michigan State University A1200 isotope separator. A detector array, including four thin surface barrier detectors, a p-i-n diode, a Ge gamma-ray detector, and a two-dimensional position sensitive parallel plate avalanche counter, was used for implantation and study of the separated nuclei. A beta-decay branching ratio of (1.3±0.3)×${10}^{\mathrm{-}5}$ to the $1^{\mathrm{-}}$ state at 9.6 MeV and a centroid of 2.35±0.05 MeV for the beta-delayed alpha-particle emission were measured. These results are essential for the analysis of a high sensitivity measurement at Yale University of the low-energy beta-delayed alpha-particle emission of ${}_{}{}^{16}{}_{}{}^{}\mathrm{N}$, and for understanding the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(α,γ${)}^{16}$O reaction in the helium burning process in massive stars.

The half-life of the $2_1^{+}$ state of ${}_{}{}^{94}{}_{}{}^{}\mathrm{Zr}$ is measured as ${\mathit{T}}_{1/2}$=7.26±0.42 ps, which corresponds to B(E2)↑=0.060±0.004 ${\mathit{e}}^2$${\mathrm{b}}^2$.

The electron capture and ${\mathrm{\beta }}^{+}$-decay properties of ${}_{}{}^{145}{}_{}{}^{}\mathrm{Dy}$ (produced in ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ + ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$ irradiations) were investigated following mass separation of A=145 isobars. A new 6(2)-s activity was identified and assigned to the ν${\mathit{s}}_{1/2}$ ${}_{}{}^{145}{}_{}{}^{}\mathrm{Dy}$ ground state. Its decay to low-spin levels in ${}_{}{}^{145}{}_{}{}^{}\mathrm{Tb}$ indicates that the base state for low-spin levels in this N=80 odd-Z nucleus is probably π${\mathit{d}}_{3/2}$ rather than π${\mathit{s}}_{1/2}$, as is the case for terbium nuclei with N=82, 84, and 86.

The ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$(n,p${)}^{14}$C cross section was measured, relative to ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$(n,α${)}^3$H, from thermal energy to approximately 5 eV. The measured cross section has a shape indistinguishable from 1/v. The astrophysical implications of this result are discussed.

The differential cross section σ(θ), the vector analyzing power ${\mathit{A}}_{\mathit{y}}$(θ), and the tensor analyzing power ${\mathit{A}}_{\mathit{y}\mathit{y}}$(θ) have been measured for the ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$(d→,γ${)}^9$Be reaction at ${\mathit{E}}_{\mathit{d}}$(lab) =6.0 MeV. The angle-integrated cross section at this energy is estimated to be 4.8±1.0 μb. A transition matrix element analysis has been performed on the data. In addition, a direct-capture calculation has been performed, and is compared to the data.

In an investigation of A=146 isobars, produced in ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ bombardments of ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$, the electron capture and ${\mathrm{\beta }}^{+}$ decay of the previously unknown isotope ${}_{}{}^{146}{}_{}{}^{}\mathrm{Er}$ was identified. This nuclidic assignment was based on the observation of Ho K x rays in coincidence with β-delayed protons as well as in total-projected coincidence γ-ray spectra. From the time distribution of the x-ray events seen in these total-projected spectra the half-life of ${}_{}{}^{146}{}_{}{}^{}\mathrm{Er}$ was determined to be 1.7(6) s.

An improved microscopic calculation of the initial exciton number has been carried out on the basis of the original microscopic model—the so-called phase-space model. In our calculation the Vlasov or Boltzmann-Uehling–Uhlenbeck dynamics is used during the nucleus-nucleus collision instead of a simple dynamical process without friction. Our calculation reproduces the experimental results better than the original microscopic model.