A simple estimate, based on the quark model, is made of the effect of the odd parity baryon resonances ${\mathrm{N}}^{*}$ and ${\Delta }^{*}$ on the vector dipole excitations in the nucleus. Although the coupling between the nuclear and baryon $L=1\mathrm{}$ degrees of freedom seems to be much more relevant for the vector dipole fields than for the corresponding axial-vector ones, it still represents a minor effect.

We calculate the pion-deuteron $2^{+}$ dibaryon vertex function and the influence on $\pi \mathrm{d}$ elastic scattering of a strong baryon-baryon interaction in the intermediate state. The general results of our investigation are the following. Near the $\Delta \mathrm{N}$ threshold, the contribution to the $\pi \mathrm{d} B_2$ vertex function is largely dominated by the $\Delta \mathrm{N}$ intermediate state. The vertex function falls off rapidly for energies above the $\Delta \mathrm{N}$ threshold. The coupling of a possible $2^{+}$ dibaryon resonance at 2.15 GeV to the $\pi \mathrm{d}$ system occurs mainly in an $l=1\mathrm{}$ wave. We evaluate the contributions to $\pi \mathrm{d}$ helicity scattering amplitudes due to explicit $\Delta \mathrm{N}$ interaction in the intermediate state.

The elastic scattering of protons from ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ is calculated with a microscopic, momentum space optical potential which incorporates the full spin dependence of the NN and p ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ interactions. The theory includes antisymmetrized NN amplitudes, realistic neutron and proton distributions, nucleon recoil and binding energy shifts, Lorentz invariant angle transformations, $t$ matrices with on-shell behavior from NN phase shifts, and off-shell behavior from a realistic separable potential model. Qualitative agreement is found with differential cross section and polarization data for $100<\mathrm{}{T}_{\mathrm{p}}<1000\mathrm{}$ MeV.

The ${}_{}{}^{16}{}_{}{}^{}\mathrm{N}$ and ${}_{}{}^{15}{}_{}{}^{}\mathrm{C}$ spectra measured by Alburger, Gallmann, and Wilkinson were reanalyzed to obtain more accurate branching ratios as well as a shape factor for the first-forbidden, nonunique ${}_{}{}^{15}{}_{}{}^{}\mathrm{C}\left({\frac{1}{2}}^{+}\right)\to {}_{}{}^{15}{}_{}{}^{}\mathrm{N}\left({\frac{1}{2}}^{-}\right)$ decay. ${}_{}{}^{16}{}_{}{}^{}\mathrm{N} {\beta }^{-}$ branches were derived to the levels at 0 and 6.13 MeV of 27.9(5)% and 66.3(6)%, respectively; ${}_{}{}^{15}{}_{}{}^{}\mathrm{C} {\beta }^{-}$ branches were found to ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$ levels at 0 and 5.30 MeV of 36.8(8)% and 63.2(8)%, respectively. The ${}_{}{}^{15}{}_{}{}^{}\mathrm{C}$ shape factor was found to deviate significantly from the allowed shape. Analysis of the shape factor results in the determination of the rank zero component of the transition and determination of the two independent matrix elements which contribute to the rank one component. The possible role of muon capture in determining the rank zero matrix elements is considered. Comparisons, for both the ${}_{}{}^{15}{}_{}{}^{}\mathrm{C}\left({\frac{1}{2}}^{+}\right)\to {}_{}{}^{15}{}_{}{}^{}\mathrm{N}\left({\frac{1}{2}}^{-}\right)$ and ${}_{}{}^{16}{}_{}{}^{}\mathrm{N}\left(0^{-}\right)\to {}_{}{}^{16}{}_{}{}^{}\mathrm{O}\left(0^{+}\right)$ transitions, are made to shell-model calculations with particular emphasis on the sensitivity of the nuclear matrix elements to the choice of the single particle wave function. It is found that rank zero rates calculated with Woods-Saxon wave functions are much smaller than those calculated with harmonic oscillator wave functions. Possible meson-exchange contributions to the rank zero rates are discussed in light of this finding.

The transition probability for enhancement of forbidden nuclear beta decay by an applied plane-wave electromagnetic field is calculated in a nonrelativistic spinless approximation by a Green's function method. The calculation involves a stationary-phase approximation. The stationary phase points in the presence of an intense field are located in very different positions than they are in the field-free case. In order-of-magnitude terms, the results are completely consistent with an earlier, much more complete wave-function calculation which includes spin and relativistic effects. Both the present Green's function calculation and the earlier wave function calculation give electromagnetic contributions in first-forbidden nuclear beta decay matrix elements which are of order ${\left(\frac{R_0}{{\lambda }_C}\right)}^2$ with respect to allowed decays, where $R_0$ is the nuclear radius and ${\lambda }_C$ is the electron Compton wavelength.

A. 4.25-kg sample of vanadium metal was counted with a high purity Ge detector for 135.5 d. Ninety-six peaks were observed in the $\gamma$-ray spectrum between 220 and 2615 keV, all but one of which could be assigned to known contaminant radioactivities mostly contained in the V sample itself. After making a 4.0% calculated correction for the intensity of a ${}_{}{}^{234}{}_{}{}^{}\mathrm{Pa}_{}^m{}_{}{}^{} \gamma$ ray of 1554.1(5) keV, the unassigned peak had an energy of 1553.77(6) keV and contained 1020(70) counts. This energy agrees with a recent precision determination of 1553.768(8) keV for the $\gamma$ ray from the first excited state of ${}_{}{}^{50}{}_{}{}^{}\mathrm{Ti}$ following the ${\beta }^{-}$ decay of ${}_{}{}^{50}{}_{}{}^{}\mathrm{Sc}$. The 1554-keV $\gamma$ ray from the V sample is assigned to the electron capture decay of ${}_{}{}^{50}{}_{}{}^{}\mathrm{V}$ to ${}_{}{}^{50}{}_{}{}^{}\mathrm{Ti}$. Based on an absolute $\gamma$-ray efficiency calibration of the system, a partial half-life $T_{\frac{1}{2}}=1.5\mathrm{}\left(3\right)\mathrm{}\times {10}^{17}$ yr and $log{f}_{0}t=23.4\mathrm{}\left(1\right)\mathrm{}$ were derived for the ${}_{}{}^{50}{}_{}{}^{}\mathrm{V}$ e.c. branch. The expected 783.3-keV $\gamma$ ray, which would follow the ${\beta }^{-}$ decay of ${}_{}{}^{50}{}_{}{}^{}\mathrm{V}$ to ${}_{}{}^{50}{}_{}{}^{}\mathrm{Cr}$, was in an unresolved region of contaminant peaks allowing only an upper limit of < 560 counts to be placed on its intensity. This corresponds to $T_{\frac{1}{2}}>4.3\mathrm{}\times {10}^{17}$ yr and $log{f}_{0}t>\mathrm{}24.0\mathrm{}$ for the ${\beta }^{-}$ branch. The total half-life derived for ${}_{}{}^{50}{}_{}{}^{}\mathrm{V}$ is $T_{\frac{1}{2}}={1.5}_{-0.7\mathrm{}}^{+0.3\mathrm{}}\times {10}^{17}$ yr.

Based on a recently proposed method of incorporating quark degrees of freedom in nuclei, we estimate the probability of the six-quark compound state of deuteron using the experimental data and quantum chromodynamics prediction for the deuteron form factor, and also using the partial width of the dibaryon resonance of Kamae et al. Both estimates are consistent with each other.

The effect of the delta resonance on the magnetic dipole properties of the $1p$-shell nuclei with $A\ge 11$ has been investigated. When the quark model phasing between the central and tensor transition potentials is used, the delta has little effect on the magnetic moments of the yrast ${\frac{3}{2}}^{-}$ and ${\frac{1}{2}}^{-}$ states. The effect on $M1\mathrm{}$ transition matrix elements is to reduce them by about 6% with some tendency towards a smaller reduction for the lighter nuclei. For seven transitions this quenching improves the agreement between theory and experiment. However, three transitions in the $A=11\mathrm{}$ and 12 nuclei already have shell model values which are too small so that the suppression worsens the agreement between theory and experiment. Thus the almost state independent reduction in $M1\mathrm{}$ transition rates predicted when the effect of the delta is included does not resolve some of the discrepancies between calculation and experiment.

A new approximate projection method is proposed to treat the spurious state problem in the Dyson boson description of nuclear collective motion. In this method, successive orders of approximate projection are used to construct the various physical states in the Dyson boson representation of the shell model. Even in the lowest orders of approximation, the approximately projected boson states obtained turn out to be quite accurate in producing physical quantities. Furthermore, this approximate projection method is applicable not only to vibrational or transitional nuclei but also to rotational nuclei.

The implications of representing the $S_{\frac{1}{2}}\alpha -\mathrm{N}$ interaction by an attractive potential with an excluded bound state, rather than by a repulsive potential, are explored with three-body models of the ${}_{}{}^6{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ ground states. After an introduction to the underlying theory, comparisons are made between the predictions of the two models for ${}_{}{}^6{}_{}{}^{}\mathrm{He}$ $\beta$ decay, the shell structure of ${}_{}{}^6{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, and the $\alpha$-deuteron properties of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$. A major conclusion is that the appropriate choice for the $S_{\frac{1}{2}}\alpha -\mathrm{N}$ interaction should be extractable from electron coincidence experiments of the ${}_{}{}^6{}_{}{}^{}\mathrm{Li}(\mathrm{e},{\mathrm{e}}^{\prime }\mathrm{d}){}_{}{}^4{}_{}{}^{}\mathrm{He}$ or ${}_{}{}^6{}_{}{}^{}\mathrm{Li}(\mathrm{e},{\mathrm{e}}^{\prime }\alpha ){}_{}{}^2{}_{}{}^{}\mathrm{H}$ type.

A reanalysis of old data removes the ($0^{+}$,$2^{+}$) ambiguity for a very narrow state at $E_x\left({}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}\right)=11.55\mathrm{}$ MeV and gives a unique $0^{+}$ assignment. Such a $0^{+}$ state corresponds well to a predicted state at 11.494 MeV of unusually small reduced widths for decay to both the ground and first excited state of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$. This new $0^{+}$ state is a better $0_6^{}{}_{}{}^{+}$ band head for the 8p-4h states at 15.159 MeV ($6^{+}$) and 18.538 MeV ($8^{+}$) than the currently accepted $0^{+}$ state at 12.44 MeV. Possible $2^{+}$ and $4^{+}$ members are considered. The higher $0^{+}$ level at $E_x=12.44\mathrm{}$ starts a new $0_7^{}{}_{}{}^{+}$ band, and candidates for this band are critically discussed.

An ultralow-energy $K$-capture branch in the decay of ${}_{}{}^{158}{}_{}{}^{}\mathrm{Tb}$ has recently been suggested as a favorable transition for determination of the electron neutrino mass. The present work describes new measurements of several reaction $Q$-value differences which imply that the ${}_{}{}^{158}{}_{}{}^{}\mathrm{Tb}$ decay energy is not large enough for the reported $K$ capture to take place.

The ${}_{}{}^{65}{}_{}{}^{}\mathrm{Cu}$(${}_{}{}^3{}_{}{}^{}\mathrm{He}$, t)${}_{}{}^{65}{}_{}{}^{}\mathrm{Zn}$ and ${}_{}{}^{71}{}_{}{}^{}\mathrm{Ga}$(${}_{}{}^3{}_{}{}^{}\mathrm{He}$, t)${}_{}{}^{71}{}_{}{}^{}\mathrm{Ge}$ reaction $Q$ values have been directly compared. Problems with a ${}_{}{}^{65}{}_{}{}^{}\mathrm{Zn}$ source for calibration of the proposed gallium solar neutrino detector are presented.

Absolute photofission cross sections of ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$ and ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ have been measured with quasimonoenergetic photons from ${\mathrm{e}}^{+}$ annihilation and direct fragment detection between 11.5 and 30 MeV. The results obtained in the energy range of the giant dipole resonance (up to 18 MeV) are compared with those from previous experiments.

The angular dependence of the polarization of neutrons from the ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$(d,n)${}_{}{}^8{}_{}{}^{}\mathrm{Be}$ reaction leaving ${}_{}{}^8{}_{}{}^{}\mathrm{Be}$ in the ground state was determined from the asymmetry in the scattering by ${}_{}{}^4{}_{}{}^{}\mathrm{He}$. Mean deuteron energies of 400 and 460 keV in the LiF target were used. Differential cross sections were also determined as well as the energy dependence of the neutron yield from 100-500 keV incident deuteron energy. Fitting of the data by distorted-wave Born approximation calculations is discussed and an approximate fit obtained. The polarization of 0.25 ± 0.03 at 35° with 400 keV deuteron energy indicates a possible interest in the reaction as a polarized neutron source for scattering studies.

Recently published data and optical model analysis of polarized triton scattering near 10 MeV show important variations of the spin-orbit potential. It is shown here that they appear to be correlated with giant multipole resonances of the compound nucleus.

The possibility of "universal" effective forces for the particle-hole and particle-particle problem in the renormalized random-phase approximation approach is analyzed using Green's function theory. A numerical comparison in the lead region for a simple semiphenomenological force and a more microscopic force deduced from the bare nucleon-nucleon interaction is given and discussed.

A semiclassical method is applied to the problem of quantum tunneling in the presence of internal oscillator degrees of freedom. Comparison with coupled channel calculations verifies the accuracy of the semi-classical method. Providing the coupling has a physically reasonable form factor, the coupling produces an enhancement in the tunneling rate. The enhancement becomes larger when the tunneling degree of freedom couples with a harmonic oscillator with lower frequency. The semiclassical method is found to be quite useful in situations where the coupled channel method becomes numerically difficult.

The energy and momentum dissipations of a few GeV incident hadron in the nucleus are studied in terms of multiple hadronic excitation processes. The incident momentum and target mass dependences of moving source parameters are explained with decay products of these hadronic excitations. It is found that the velocity and temperature of the moving source increase and then saturate with the increasing incident momentum.

Two-step amplitudes in which the Coulomb interaction of the ejected $\beta$ electron excites the bound atomic electron into $S$ and $P$ states are calculated. Probabilities for excited states of the residual helium ion are changed by less than 0.24% from the sudden approximation.