In the four-momentum-transfer range 0.05≤${\mathit{q}}_{\nu }^2$≤0.27 (GeV/c${)}^2$, longitudinal and transverse response functions have been determined by performing a Rosenbluth separation of ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(e,e’p) coincidence cross sections measured in parallel kinematics. The results are compared to nonrelativistic calculations that include the effects of final-state interaction, meson-exchange currents, and isobar configurations, and to relativistic calculations that include the effects of final-state interaction. The ratios of the response functions agree with both calculations; the absolute values are (16±3±8)% larger than predicted.

By using effective chiral Lagrangians with a suitable incorporation of the scaling property of QCD, we establish the approximate in-medium scaling law, ${\mathit{m}}_{\mathrm{\sigma }}^{\mathrm{*}}$/${\mathit{m}}_{\mathrm{\sigma }}$≊${\mathit{m}}_{\mathrm{N}}^{\mathrm{*}}$/${\mathit{m}}_{\mathrm{N}}$ ≊${\mathit{m}}_{\mathrm{\rho }}^{\mathrm{*}}$/${\mathit{m}}_{\mathrm{\rho }}$≊${\mathit{m}}_{\mathrm{\omega }}^{\mathrm{*}}$/${\mathit{m}}_{\mathrm{\omega }}$≊${\mathit{f}}_{\mathrm{\pi }}^{\mathrm{*}}$/${\mathit{f}}_{\mathrm{\pi }}$. This has a highly nontrivial implication for nuclear processes at and above nuclear-matter density. Some concrete cases are cited in this paper.

The first spin-transfer observables for the πd→pp reaction have been measured at a number of energies spanning the Δ resonance in this system. These parameters correspond to ${\mathit{K}}_{\mathit{S}\mathit{L}}$ and ${\mathit{K}}_{\mathit{S}\mathit{S}}$ of the pp→dπ reaction for incident proton energies ranging from 600 to 800 MeV. Such data can provide an important constraint on the determination of the partial-wave amplitudes describing this fundamental reaction. The discrepancies between our data, theoretical predictions, and values calculated from published partial-wave amplitudes demonstrate the need for further work in this area.

Kaon production from meson-meson annihilation is enhanced significantly because of the decrease of hadron masses in hot and dense matter as a result of the restoration of chiral symmetry. We show that this can lead to enhanced kaon yield in high-energy heavy-ion collisions.

Classical dynamics of heavy-ion scattering is investigated in the case of a collision between a supposed spherical nucleus, ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$, and a deformed one, ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$, at energies above the Coulomb barrier. Evidence of regular and irregular motion is found. The chaotic behavior justifies the presence of Ericson’s fluctuations observed for this reaction, while the presence of regular motion embedded in the chaotic region could be the crucial point to explain the nature of the observed isolated resonances, once the semiclassical theory is applied.

Data obtained by the associated production of Λ hypernuclei through the (${\mathrm{\pi }}^{+}$,${\mathit{K}}^{+}$) reaction are presented for a wide range of mass numbers. The special features which make this reaction useful are pointed out. The reaction is shown to be an excellent probe of Λ single-particle states, as demonstrated by the excitation of deeply bound states which are interpreted as the weak coupling of a Λ to neutron-hole states of the core. The Λ binding energies and ground-state production cross sections for ${}_{\mathrm{\Lambda }}{}^9{}_{}{}^{}\mathrm{Be}$, ${}_{\mathrm{\Lambda }}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{\mathrm{\Lambda }}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{\mathrm{\Lambda }}{}^{28}{}_{}{}^{}\mathrm{Si}$, ${}_{\mathrm{\Lambda }}{}^{40}{}_{}{}^{}\mathrm{Ca}$, ${}_{\mathrm{\Lambda }}{}^{51}{}_{}{}^{}\mathrm{V}$, and ${}_{\mathrm{\Lambda }}{}^{89}{}_{}{}^{}\mathrm{Y}$ are presented.

We have studied the β spectrum of ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ using a germanium detector containing a crystal with ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ dissolved in it. We find a feature in the β spectrum 17 keV below the end point which can be explained by the hypothesis that there is a heavy neutrino emitted in the β decay of ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ with a mass of 17±2 keV and an emission probability of (1.40±0.45±0.14)%.

It is shown that the continuum missing-mass spectra for the (${\mathrm{\pi }}^{\mathrm{-}}$,${\mathrm{\pi }}^{+}$) and (${\mathrm{\pi }}^{\mathrm{-}}$,p) reactions leading to extremely neutron-rich exotic nuclei can be explained in terms of phase-space distributions by invoking the presence of dineutrons as one of the products of the breakup. It is suggested that this indicates the presence of the dineutron as a cluster in these neutron-rich systems during their breakup. It is noted that these observations in weakly unbound systems may be analogs of the dineutron halos for which evidence has been found in weakly bound nuclei near the neutron drip line.

We have observed the excitation of the first excited state (${\mathit{E}}_{\mathit{x}}$=0.98 MeV, ${\mathit{J}}^{\mathrm{\pi }}$=$1^{+}$) of the radioactive, neutron-rich nucleus ${}_{}{}^8{}_{}{}^{}\mathrm{Li}$ (${\mathit{J}}_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{\mathrm{\pi }}$=$2^{+}$) from its inelastic scattering on ${}_{}{}^{\mathrm{nat}}{}_{}{}^{}\mathrm{Ni}$ at E${(}^8$Li)≃14.6 MeV. Cross sections measured out to large ${\mathrm{\theta }}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$ agree well with Coulomb-excitation probabilities and have been used to deduce an E2↑ transition rate for the $2_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{+}$→$1^{+}$ excitation in ${}_{}{}^8{}_{}{}^{}\mathrm{Li}_{}^{\mathrm{*}}{}_{}{}^{}$. The latter [B(E2↑)=55±15 ${\mathit{e}}^2$ ${\mathrm{fm}}^4$] is large relative to nearby stable nuclei, but comparable to the neighboring neutron-rich nucleus ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$. The relevance of the data to predicted ‘‘neutron-halo’’ giant dipole resonances in unstable nuclear projectiles is considered.

A magnetic dipole spin resonance around 6–8 MeV is described for rare-earth nuclei, ranging from ${}_{}{}^{142}{}_{}{}^{}\mathrm{Ce}$ to ${}_{}{}^{198}{}_{}{}^{}\mathrm{Pt}$. Starting from an unperturbed basis of ${\mathit{K}}^{\mathrm{\pi }}$=$1^{+}$ two-quasiparticle states, constructed within the Nilsson model and applying the BCS formalism, one can quantitatively estimate the total spin M1 strength. We include Coriolis mixing and residual quadrupole and spin separable forces and study the spin resonance in more detail for a few representative examples, ${}_{}{}^{148}{}_{}{}^{}\mathrm{Nd}$,${\mathrm{}}^{154}$Sm, ${}_{}{}^{164}{}_{}{}^{}\mathrm{Dy}$ and ${}_{}{}^{174}{}_{}{}^{}\mathrm{Yd}$. A double-humped structure in the spin M1 strength around 6–8 MeV results from the calculations, and is found to be related to separate proton and neutron spin-flip excitations.

It is explained that a large cross section and an increase with energy of diffractive production of nucleons (${\mathit{N}}^{\mathrm{*}}$, . . .) (${\mathit{E}}_{\mathit{N}}$,${\mathit{E}}_{\mathit{N}}^{\mathrm{*}}$≥${\mathit{E}}_{\mathit{A}}$/A) in central collisions of light (A) and heavy (B) nuclei would signal the color-screening phenomenon and large fluctuations of size in the nucleon wave function. In particular, we find that for ${\mathit{E}}_{\mathit{A}}$/A≥200 GeV and B∼240, the probability of diffractive nucleon production should increase by a factor >5 as compared to that observed at BNL energies.

We report a first measurement of the spin-correlation parameter ${\mathit{A}}_{\mathit{z}\mathit{z}}$ in neutron-proton scattering at 67.5 MeV. The results, obtained in the angular range 105°≤${\mathrm{\theta }}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$≤170° with typical accuracies of 0.008, are highly sensitive to the ${}_{}{}^3{}_{}{}^{}$${\mathit{S}}_1$${\mathrm{-}}^3$${\mathit{D}}_1$ mixing parameter ${\mathrm{\epsilon }}_1$. A phase-shift analysis based on the current world data yields a value of ${\mathrm{\epsilon }}_1$ significantly higher than predicted by modern potential models.

Results of the first pion single-charge-exchange experiment on a polarized nuclear target are reported. Analyzing powers ${\mathit{A}}_{\mathit{y}}$ for the (${\mathrm{\pi }}^{+}$,${\mathrm{\pi }}^0$) reaction at ${\mathit{T}}_{\mathrm{\pi }}^{+}$=163 MeV on a polarized ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ target were measured over an angular range between 20° and 60° in the laboratory system. Calculations in the distorted-wave impulse approximation do not reproduce these new data.

Analyzing powers ${\mathit{A}}_{\mathit{y}}$ were measured for ${\mathrm{\pi }}^{+}$ and ${\mathrm{\pi }}^{\mathrm{-}}$ elastic scattering from polarized ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ at energies near the ${\mathit{P}}_{33}$ resonance. At ${\mathit{T}}_{\mathrm{\pi }}$=132 MeV the values of ${\mathit{A}}_{\mathit{y}}$ are significantly different from zero for ${\mathrm{\pi }}^{\mathrm{-}}$. For ${\mathrm{\pi }}^{+}$ at 132 MeV and for both ${\mathrm{\pi }}^{\mathrm{-}}$ and ${\mathrm{\pi }}^{+}$ at all other energies, the ${\mathit{A}}_{\mathit{y}}$ are mostly consistent with zero. These data differ from the predictions of present pion-nucleus reaction theories, especially at large momentum transfers.

A shell-model study is made of first-forbidden β decay in A=205–212 nuclei. A least-squares fit for eighteen ΔJ=0 and 1 decays gave a scaling factor for the rank-one contributions of 0.97±0.06, i.e., agreement with experiment, and an enhancement factor ${\mathrm{\epsilon }}_{\mathrm{MEC}}$ for the rank-zero matrix element of ${\gamma }_5$ of 2.01±0.05, indicating an enhancement by 100% over the impulse approximation. A 40% effect is predicted from meson exchange. Thus, a deficiency in the meson-exchange calculation or some further unforeseen effect is suggested.

Nuclear transition rates in μ-catalyzed p-d fusion have been calculated using numerically converged ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ bound-state and p-d scattering wave functions for the first time. The transition rates for M1 radiative capture in both quartet and doublet initial states have been computed using a model of meson-exchange currents which reproduces the thermal n-d capture cross section, and are in excellent agreement with experiment. The muon internal-conversion rate is in very good agreement with a recent reanalysis of old bubble-chamber measurements. Furthermore, our nonvanishing quartet capture rate resolves the anomaly in the Wolfenstein-Gerstein effect.

A superdeformed band of twenty transitions has been found in ${}_{}{}^{142}{}_{}{}^{}\mathrm{Eu}$ following the reaction ${}_{}{}^{110}{}_{}{}^{}\mathrm{Pd}$${(}^{37}$Cl,5n${)}^{142}$Eu at 160 MeV. This is the first case to be found intermediate to the A∼135 and A∼150 regions. The ${\mathit{scrI}}^{\mathrm{}\left(2\right)\mathrm{}}$ dynamic moment of inertia remains remarkably constant, suggesting that the configuration is π$6^1$ν$6^3$, blocking both proton and neutron band crossings. The band has been estimated to have ∼3.6% of the channel intensity. This is remarkably intense, and is possibily due to a lowering of the odd-odd configuration by a strong residual n-p correlation.

Using laser-induced nuclear-orientation and optical-saturation techniques, we have produced sub-Doppler changes in the anisotropy of the angular distribution of the 514-keV γ rays from the 1-μs isomer ${}_{}{}^{85}{}_{}{}^{}\mathrm{Rb}_{}^{\mathit{m}}{}_{}{}^{}$. This permits high-resolution measurements of D1 and D2 hyperfine transitions of atoms of the isomer, which give the isomer’s nuclear electric quadrupole moment, -0.73±0.17 b, and its nuclear magnetic dipole moment, (6.043±0.005)${\mathrm{\mu }}_{\mathit{N}}$. The isomer shift, -113±8 MHz relative to the ground state of ${}_{}{}^{85}{}_{}{}^{}\mathrm{Rb}$, corresponds to a change in the mean-square charge radius of +0.174±0.008 ${\mathrm{fm}}^2$.

The production of ${\mathrm{\pi }}^{\pm }$,${\mathit{K}}^{\pm }$,p has been measured in p+Be and p+Au collisions for comparison with central Si+Au collisions. The inverse slope parameters ${\mathit{T}}_0$ obtained by an exponential fit to the invariant cross sections in transverse mass are found to be, ${\mathit{T}}_0^{\mathit{p},}$${\mathit{K}}^{+}$,${\mathrm{\pi }}^{\mathrm{\pi }}$∼140–160 MeV in p+A collisions, whereas in central Si+Au collisions, ${\mathit{T}}_0^{\mathit{p},}$${\mathit{K}}^{+}$∼200–220 MeV >${\mathit{T}}_0^{\mathrm{\pi }\mathrm{\pi }}$∼140–160 MeV at midrapidity. The ${\mathrm{\pi }}^{\pm }$ and ${\mathit{K}}^{+}$ distributions are shifted backwards in p+Au compared with p+Be. A gradual increase of (dn/dy${)}_{\mathit{K}}^{+}$ per projectile nucleon is observed from p+Be to p+Au to central Si+Au collisions, while pions show no significant increase.

An E/A=65 MeV ${}_{}{}^{78}{}_{}{}^{}\mathrm{Kr}$ beam has been used to produce six new isotopes near the proton-drip line. The newly commissioned A1200 beam-analysis device was used to observe the astrophysically interesting isotope ${}_{}{}^{65}{}_{}{}^{}\mathrm{As}$, as well as ${}_{}{}^{61}{}_{}{}^{}\mathrm{Ga}$, ${}_{}{}^{62}{}_{}{}^{}\mathrm{Ge}$, ${}_{}{}^{63}{}_{}{}^{}\mathrm{Ge}$, ${}_{}{}^{69}{}_{}{}^{}\mathrm{Br}$, and ${}_{}{}^{75}{}_{}{}^{}\mathrm{Sr}$. Implications of the observation of these nuclei are discussed in terms of the astrophysical rp process.