A comparison of differential cross sections for inelastic scattering of 130 MeV positive and negative pions has been made for studying the giant resonance region in ${}_{}{}^{118}{}_{}{}^{}\mathrm{Sn}$ and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$. In addition, several of the low-lying collective states in each target were examined. Comparison to distorted wave impulse approximation calculations allowed collective deformation lengths βR and fractions of the energy-weighted sum rules to be extracted. For bound collective states, the strengths for ${\pi }^{+}$ and ${\pi }^{\mathrm{-}}$ were nearly equal, as has been found for other scattering probes. Giant quadrupole and dipole excitations in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ (T=0) had nearly equal ${\pi }^{+}$ and ${\pi }^{\mathrm{-}}$ sum rule strengths. Quadrupole and monopole excitations in ${}_{}{}^{118}{}_{}{}^{}\mathrm{Sn}$ near 14 MeV show about twice the ${\pi }^{\mathrm{-}}$ transition strengths compared to those for ${\pi }^{+}$, contrary to expectations from simple isoscalar models.

The magnetic hyperfine splitting frequencies ${\nu }_M$=‖g${\mu }_{\mathrm{N}}$$B_{\mathrm{hf}}$/h‖ of ${}_{}{}^{107}{}_{}{}^{}\mathrm{Ag}_{}^{\mathrm{m}}{}_{}{}^{}$ (E=93 keV; $I^{\pi }$${=(7/2)\mathrm{}}^{+}$; $T_{1/2}$=44.3 s) and ${}_{}{}^{109}{}_{}{}^{}\mathrm{Ag}_{}^{\mathrm{m}}{}_{}{}^{}$ (E=88 keV; $I^{\pi }$${=(7/2)\mathrm{}}^{+}$; $T_{1/2}$=39.8 s) as dilute impurities in Fe and Ni have been measured with nuclear magnetic resonance on oriented nuclei at temperatures of ∼10 mK as ${\nu }_M$(${}^{107}$${\mathrm{Ag}}^{\mathrm{m}}$ Fe)=428.09(9) MHz, ${\nu }_M$(${}^{107}$${\mathrm{Ag}}^{\mathrm{m}}$ Ni)=103.19(12) MHz, and ${\nu }_M$(${}^{109}$${\mathrm{Ag}}^{\mathrm{m}}$ Ni) =103.26(4) MHz. With the magnetic hyperfine fields, $B_{\mathrm{hf}}$(AgFe)=-446.9(5) kG, $B_{\mathrm{hf}}$(AgNi) =-107.8(2) kG, the magnetic moments of ${}_{}{}^{107}{}_{}{}^{}\mathrm{Ag}_{}^{\mathrm{m}}{}_{}{}^{}$ and ${}_{}{}^{109}{}_{}{}^{}\mathrm{Ag}_{}^{\mathrm{m}}{}_{}{}^{}$ are deduced to be (+)4.398(5) ${\mu }_{\mathrm{N}}$ and (+)4.400(6) ${\mu }_{\mathrm{N}}$, respectively. The reorientation of short-lived nuclear states due to spin lattice relaxation is discussed.

Measurements have been made with curved crystal x-ray spectrometers of the natural line widths of the $L_1$$M_2$ (Γ=12.1±2 eV), $L_1$$M_3$ (Γ=12.7±1 eV), and $M_1$$N_3$ (Γ=19±3 eV) atomic transitions in Tm. These results are combined with published results to determine $M_1$, $M_2$, and $M_3$ internal conversion line widths for ${}_{}{}^{169}{}_{}{}^{}\mathrm{Tm}$. These lines have been used in the calibration of a beta spec- trometer for recent measurements of the electron antineutrino mass from the tritium beta decay spectrum. A reanalysis of these results suggests that there is no conclusive evidence for a finite mass for the electron antineutrino.

A variational method inspired by the Hartree-Fock approximation but not restricted to a single Slater determinant trial space is investigated. The physical motivation is that a method should attempt to find a subspace of collective states which are most strongly coupled to the ground state. This method attempts to do this by providing a systematic technique to generate basis states from the collective Hartree-Fock type of state. In the resulting basis space a residual diagonalization is easily performed. Results of a test with the four-nucleon problem with realistic effective nuclear Hamiltonians are shown.

We present a model of nucleon structure that is fully covariant. We begin with a Lagrangian that describes quarks coupled to various mesonic fields (σ,π,ρ,ω) and an additional field, χ, which is required to bind the quarks into a nucleon. The couplings of the σ, π, ρ, and ω fields to the quarks are fixed so as to reproduce the empirically determined coupling of these mesons to the nucleon. The latter couplings are taken from fits to nucleon-nucleon scattering data made using one-boson-exchange models. Therefore the free parameters of the model are the mass and coupling constant of the χ field and the quark mass, $m_q$. In order to simplify the problem, the nucleon is assumed to virtually decay into a quark and a diquark. Equations which specify this amplitude are found by using the equations for the quark and meson field operators obtained from our Lagrangian. The equations which we solve are fully covariant and nonlinear and are solved by iteration. In this model the quark dynamics is governed by the mesonic fields whose source is the nucleon itself. The amplitudes for the emission of these fields by the nucleon depend upon the (nucleon)→(quark + diquark) amplitudes whose structures we are attempting to determine. This model therefore requires a self-consistent solution and leads to the nonlinear equations noted above. At this point we have not calculated mesonic corrections to the nucleon observables such as the magnetic moments, form factors, and $g_A$, although we have included the effects of all the mesonic fields in the calculation of the nucleon mass. However, the calculation of nucleon observables, using current operators which contain only quark fields, yields a surprisingly good fit to electromagnetic form factors, magnetic moments, $g_A$, etc. (It is possible that some aspects of these results will be less satisfactory when mesonic corrections are calculated.) The model has the further virtue of generalizing the SU(6) quark model of the nucleon so as to be consistent with the covariance requirements of the theory of special relativity. It is clear that the major limitation of the model, other than the use of the diquark approximation, is the lack of a satisfactory description of the confinement mechanism as the χ field serves to bind the system but does not actually confine the quarks.

We propose a model of nuclear structure in which the degrees of freedom are quarks and mesonic fields. The quarks are organized into nucleons which interact via the exchange of mesons (σ,π,ρ,ω). The model is so structured as to reproduce the results of recently developed relativistic models of nuclear structure in which the degrees of freedom are nucleons and mesons. The model used to describe nucleon structure is taken from a previous work in which a fully covariant (soliton) model of the nucleon was developed. The model also allows one to consider the dynamics of solitons in the presence of the fields generated by other solitons. This feature enables us to investigate the modification of nucleon properties when the nucleon is inside a nucleus. Our central result is the prediction that nucleons will be bigger in the nucleus than in free space. Evidence for this modification of nucleon properties is discussed. We consider deep inelastic electron scattering from nuclei: We discuss the European-Muon-Collaboration effect and some recent (e,e’) experiments and relate the experimental results to our prediction of modified nucleon radii and form factors.

The isotope shift, magnetic moment, and quadrupole moment of the radioactive transitional nucleus ${}_{}{}^{151}{}_{}{}^{}\mathrm{Sm}$ has been measured using the atomic-beam resonance-fluorescence technique. The hyperfine structure of the 591.6 nm transition was observed with an energy resolution of 20 MHz. The isotope shift of this line is found to be δ${\nu }_i^{151}$,152=-1472.2± 2.9 MHz. We have constructed a King plot of muonic atom δ〈$r^2$〉 versus optical isotope shifts to determine electronic parameters, and obtain δ〈$r^2$${〉}^{151}$,152=0.279±0.012 ${\mathrm{fm}}^2$.

Medium energy (40–65 MeV) γ rays following radiative capture of 50 MeV polarized protons on ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$ were studied for the first time by using a NaI detector ensemble with good energy resolution and small background counts. Discrete γ rays feeding the ground $0^{+}$, 4.44 MeV $2^{+}$, and 9.64 MeV $3^{\mathrm{-}}$ states, and prominent γ peaks feeding the 19 and 22 MeV excitations region in ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ were identified. The analyzing powers of the radiative capture were found to depend on the microscopic configurations of the final states.

The ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(d,pn)pn reaction has been measured in the two-spectator quasifree scattering condition by using a 108 MeV deuteron beam. Its cross sections are about 1.5 times as large as those of the ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(d,pp)nn reaction under similar kinematical conditions. The energy spectra are reasonably reproduced by a calculation based on the four-body scattering theory derived by Sloan.

The reaction ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$(e,e’d${)}^4$He, carried out with quasifree kinematics, is ideally suited for mapping out the ${}_{}{}^6{}_{}{}^{}\to \mathit{\alpha }+\mathrm{d}$ momentum distribution in the region where Pauli effects from the underlying $S_{1/2}$ αN interaction are manifest. Data for the ${}_{}{}^6{}_{}{}^{}\to \mathit{\alpha }+\mathrm{d}$ momentum distribution in the range of alpha-particle recoil momenta of 0.0 to 1.4 ${\mathrm{fm}}^{\mathrm{-}1}$ are important to understanding three-body models of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ in general and the $S_{1/2}$ αN interaction in particular. In anticipation of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$(e,e’d${)}^4$He coincidence measurements, the cross section is calculated with three-body models of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ under the assumptions of one-photon exchange and deuteron-pole dominance. The required kinematical conditions that make the theory applicable are emphasized.

Proton elastic scattering from ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ at 398 MeV is studied in terms of a phenomenological nonrelativistic optical potential. It is shown that cross-section and polarization data alone lead to a discrete ambiguity in the potential. The sign of the real central and imaginary spin-orbit term can be changed simultaneously. Measurement of the spin-rotation function resolves this ambiguity. Analyses of inelastic scattering do not give clear preference for either sign.

The possible existence of stable bound states of two neutrons and a negative pion is investigated in all three-body channels with angular momentum J≤2, by solving the relativistic Faddeev equations at threshold with all the S- and P-wave pion-nucleon channels and all the S-, P-, and D-wave nucleon-nucleon channels as input. It is shown that the most likely configuration to have in a bound state is that with angular momentum and parity quantum numbers $J^P$${=2\mathrm{}}^{+}$.

Giant pairing resonances, i.e., collective two-particle excitations built upon high-lying single-particle states, are studied in the lead region. Two-particle $0^{+}$ states (T=1) outside the ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ core are found to be clustered in the nuclear surface. Our calculation shows that these states are the most excited in two-particle transfer reactions.

The kinematics for the (γ,${\pi }^0$) reaction near threshold is discussed. The pion formed in this reaction decays into two gammas whose angular distribution can be calculated from the pion differential cross section. The sensitivity of the angular distribution of the two gammas to various models of the reaction on ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ is shown.

The narrow widths of highly excited Λ single-particle states are discussed in comparison with large widths of nucleon deep hole states.

In a fluid-dynamical model, the extra entropy production which arises from a nonequilibrium phase transition from nuclear to quark-gluon matter is calculated.

The volume integrals of the central real part of the empirical optical model potentials are used to study the isospin dependent term. Results for neutron and proton elastic scatterings are found to be consistent with each other and also consistent with results from quasi- elastic scattering if the density dependence of the effective interaction is taken into consideration.

A simple relation between total inclusive neutrino-scattering cross sections and total muon-capture rates in nuclei is derived. The calculation makes use of the closure and the nonrelativistic impulse approximations. The relation is used to predict neutrino cross sections in ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ for $E_{\nu }$=150–250 MeV.

We investigate numerically the predictions of a formula, proposed recently by Balian and Vénéroni, for evaluating fluctuations of one-body observables in a mean-field framework.

Coulomb sum rules are evaluated in those nuclei where experimental data are available. The role of the high energy tail of the excitation spectrum and of dynamical correlations, explicitly included in the calculation, is discussed. They seem to be essential for reaching an agreement between theory and experiments.