Position-sensitive detectors have been used to measure the angular correlation of the two protons de-exciting the $4^{+}$, $T=2\mathrm{}$ isobaric analog state in ${}_{}{}^{22}{}_{}{}^{}\mathrm{Mg}$ fed in the ${\beta }^{+}$ decay of ${}_{}{}^{22}{}_{}{}^{}\mathrm{Al}$. The observed isotropy indicates a predominantly sequential decay mechanism. However, a 15% admixture of correlated di-proton (${}_{}{}^2{}_{}{}^{}\mathrm{He}$) emission cannot be excluded.

The cross sections for the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(\pi , {\pi }^{\prime }){}_{}{}^{12}{}_{}{}^{}\mathrm{C}_{}^{*}{}_{}{}^{}$ ($2^{+}$, 4.44 MeV; $3^{-}$, 9.64 MeV) reactions at 800 MeV/c are calculated in the distorted-wave impulse approximation. Distortion effects are taken through the eikonal form. Data are reproduced with realistic transition densities and the $\pi \mathrm{N}$ scattering amplitudes fitted to $\pi \mathrm{N}$ data, except for the region of low momentum transfers.

We investigate the propagation of virtual particles in a medium with anticorrelations. We show that it obeys an analog of the Beg-Agassi-Gal theorem, namely, that the medium effects disappear at high momentum. The relevance to pion exchange interactions is discussed.

A one-boson-exchange NN potential with mesonic vertices obtained from bag model quark wave functions is extended to short distances by a separable potential for a six quark core which is fitted to the NN $S$-wave data. Core parameters are extracted.

We show that the folding model with a density-dependent effective $\Lambda \mathrm{N}$ interaction satisfactorily explains the available $\Lambda$ binding energy data of $p$ shell and heavier hypernuclei.

The ${}_{}{}^{163}{}_{}{}^{}\mathrm{Ho}$ nucleus decays by electron capture with the lowest $Q$ value of any known $\beta$-decay process and is sensitive to the effects of a finite electron neutrino mass. Low energy $N$ and $M$ orbital-electron capture events have been observed from a gaseous form of ${}_{}{}^{163}{}_{}{}^{}\mathrm{Ho}$ internally dispersed in a heated gas counter. The ratio $\frac{{\lambda }_N}{{\lambda }_M}=3.86\mathrm{}\pm 0.12$ provides a constraint on $Q_{\mathrm{ec}}$ and $m_{\nu }$. For $m_{\nu }=0\mathrm{}$, we find $Q_{\mathrm{ec}}=2600\mathrm{}\pm 30$ eV. Using independent $Q_{\mathrm{ec}}$ values, the range for $m_{\nu }$ is discussed.

We report results from neutron coincidences with projectile-like fragments in collisions of 35 MeV/nucleon ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ with ${}_{}{}^{165}{}_{}{}^{}\mathrm{Ho}$. Quasi-elastic events show a clear left-right asymmetry, decreasing with fragment $Z$, which gives more high energy neutrons on the side of the beam opposite the detected fragment, while strongly damped events are left-right symmetric. A moving-source fit to the spectra in quasi-elastic events requires a source with a velocity near half the beam velocity and moving on the side of the beam opposite the projectile-like fragment. The fitted temperature and kinetic energy of this source are consistent with previous analyses of charged particle emission data which involved an intermediate-velocity moving source, except that in our case the source is not moving along the beam axis. Recoil effects in the framework of two moving sources cannot account for both the asymmetry and angular distribution observed.

Energies of muonic x rays of the Lyman series of the even sulphur isotopes ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$, ${}_{}{}^{34}{}_{}{}^{}\mathrm{S}$, and ${}_{}{}^{36}{}_{}{}^{}\mathrm{S}$ and of natural phosphorus have been determined with absolute precisions up to 23 parts/${10}^6$. Equivalent Barrett charge radii $R_{k,\alpha }$ have been deduced. Their differences between the sulphur isotopes amount to $\Delta R_{k,\alpha }({}_{}{}^{34}{}_{}{}^{}\mathrm{S}-{}_{}{}^{32}{}_{}{}^{}\mathrm{S})=29.7\mathrm{}\left(1.4\right)\mathrm{}$ am and $\Delta R_{k,\alpha }({}_{}{}^{36}{}_{}{}^{}\mathrm{S}-{}_{}{}^{34}{}_{}{}^{}\mathrm{S})=18.7\mathrm{}\left(1.5\right)\mathrm{}$ am. Combining these results with recent elastic electron scattering data, we obtain in a model-independent way $\Delta {〈r^2〉}^{\frac{1}{2}}({}_{}{}^{34}{}_{}{}^{}\mathrm{S}-{}_{}{}^{32}{}_{}{}^{}\mathrm{S})=23.1\mathrm{}\left(1.2\right)\mathrm{}$ am and $\Delta {〈r^2〉}^{\frac{1}{2}}({}_{}{}^{36}{}_{}{}^{}\mathrm{S}-{}_{}{}^{34}{}_{}{}^{}\mathrm{S})=13.0\mathrm{}\left(1.2\right)\mathrm{}$ am.

Energy levels and electromagnetic properties of the N=27 and 28 nuclei are studied systematically in terms of the shell model within the $f_{7/2}^n$+$f_{7/2}^{n\mathrm{-}1}$($p_{3/2}$,$p_{1/2}$,$f_{5/2}$${)}^1$ configurations. The effective interactons are made up of empirical matrix elements and phenomenological potentials superposed with two and three central interactions. Least-squares fitting calculations of selected energy levels are performed to fix some of the matrix elements and the strength parameters of the potentials. It is shown that some states with a collective nature appear in ${}_{}{}^{51}{}_{}{}^{}\mathrm{Cr}$ and ${}_{}{}^{53}{}_{}{}^{}\mathrm{Fe}$ which are connected to each other by the enhanced E2 transitions, whereas no such states appear in ${}_{}{}^{47}{}_{}{}^{}\mathrm{Ca}$ and ${}_{}{}^{49}{}_{}{}^{}\mathrm{Ti}$. The anomalously large B(E2) values observed in the transitions between the intruder states can be reproduced very well. The hindrance of the E2 transitions between the intruder state and the normal $f_{7/2}^n$ state is obtained in the present model, being in qualitative agreement with the experiments. Both of the proton-neutron (p-n) interactions (1) among the $f_{7/2}$ nucleons and (2) between the $f_{7/2}$ and the other fp nucleons are very important in order to obtain proper understanding of the nuclei in this mass region.

The problem of collective rotational parameters is studied using a new expansion of the good angular momentum states ‖${\Psi }_J$〉 and linearization procedure. It is shown that the approximation correctly reproduces Skyrme’s formula. The approximation is applied to parametrize the value of the matrix element ‖〈${\Psi }_{J\mathrm{-}2}$‖$Q_{20}$‖${\Psi }_J$〉‖. The agreement with the values deduced from experimental data on the nuclei ${}_{{\mathrm{}}^1{\mathrm{}}_{64}^{56}}{}^{}{}_{}{}^{}\mathrm{Gd}_{92}^{}{}_{}{}^{}$ and ${}_{{\mathrm{}}^1{\mathrm{}}_{70}^{76}}{}^{}{}_{}{}^{}\mathrm{Yb}_{106}^{}{}_{}{}^{}$ is fairly good.

The reaction ${}_{}{}^{13}{}_{}{}^{}\mathrm{N}$(p,γ${)\mathrm{}}^{14}$O is important in the hot-CNO cycle. At the energies of astrophysical interest, the rate of this reaction is dominated by capture through an l=0 resonance corresponding to the 5.17 MeV $J^{\pi }$${=1\mathrm{}}^{\mathrm{-}}$ excited state in ${}_{}{}^{14}{}_{}{}^{}\mathrm{O}$. The contribution of this resonance to the total cross section can be determined from a measurement of the total width, Γ, and the γ-decay branching ratio, ${\Gamma }_{\gamma }$/Γ, for this state. This method does not require the use of radioactive ${}_{}{}^{13}{}_{}{}^{}\mathrm{N}$ as either a beam or a target, neither of which is at present technically feasible. Using the ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$${(}^3$He,t${)}^{14}$O reaction, the total width of this state has been measured to be Γ=38.1±1.8 keV.

The total β-decay energies of the three isomers of ${}_{}{}^{130}{}_{}{}^{}\mathrm{In}$ have been studied. The ground state $Q_{\beta }$ was determined to be 10.12±0.18 MeV resulting in a mass excess of -70.05±0.20 MeV for ${}_{}{}^{130}{}_{}{}^{}\mathrm{In}$. The relative excitation energies of the three β-decaying isomers have been determined, resulting in the first level scheme information for the ${\pi }^{\mathrm{-}1}$${\nu }^{\mathrm{-}1}$ nucleus neighboring ${}_{}{}^{132}{}_{}{}^{}\mathrm{Sn}$. Arguments on β- and γ-ray selection rules permit unique assignments of $J^{\pi }$${=1\mathrm{}}^{\mathrm{-}}$ and $5^{+}$, respectively, for the low and medium spin isomers of ${}_{}{}^{130}{}_{}{}^{}\mathrm{In}$.

A new delayed neutron precursor with a half-life of 1.3±0.1 s has been observed at mass 75. The delayed neutron emission probability is 3.5±0.6%. Mass formula and fission yield predictions indicate that ${}_{}{}^{75}{}_{}{}^{}\mathrm{Cu}$ is the most likely precursor.

The nuclide ${}_{}{}^{118}{}_{}{}^{}\mathrm{In}$ has for the first time been studied via a nuclear reaction: ${}_{}{}^{119}{}_{}{}^{}\mathrm{Sn}$(t,α${)}^{118}$In, at a bombarding energy of 18 MeV. By comparing the ‘‘ground-state’’ Q value of this reaction with those of the well-known ${}_{}{}^{118}{}_{}{}^{}$,120Sn(t,α${)}^{117}$, ${}_{}{}^{119}{}_{}{}^{}\mathrm{In}$ reactions, the mass excess of ${}_{}{}^{118}{}_{}{}^{}\mathrm{In}$ was determined to be -87.234(12) MeV. Sixteen excited states of ${}_{}{}^{118}{}_{}{}^{}\mathrm{In}$ were observed below 1.3 MeV excitation.

The existing ${\pi }^{\mathrm{-}}$p radiative scattering data are reanalyzed in a simple model which allows the study of structure effects at high photon energies. Off-shell effects are included in terms of πNΔ form factors, and various models and parameter values are discussed.

A semiclassical method of evaluating the path integral over collective (Bose) and independent-particle (Fermi) fields is represented. As an illustration, the schematic two-level model is adopted. The semiclassical calculations of the energy spectra is performed and the result obtained is compared with the exact one.

Abstract exchange effects and Δ creation entering the transverse response function in (e,e’) in the region above the quasi elastic peak are described by a common mechanism as electroproduction of a pion interacting with the nucleus via its optical potential. Predictions compare favorably with experiment.

Galilean noninvariant terms in an often cited expression of the two-pion exchange three-nucleon interaction are shown to arise from the subtraction of the forward propagating Born term π-N amplitude chosen in a form which is not consistent with the sequence of two pair interactions between three nucleons.