The electromagnetic inclusive responses of polarized ${}^3$He and ${}^3$H are thoroughly investigated at the quasielastic peak for squared momentum transfers up to 2 $(\mathrm{GeV}{/c)}^2$, within the plane wave impulse approximation. Great emphasis is put on the effects in the bound state due to different two- and three-body nuclear forces, and to the Coulomb interaction as well. A careful analysis of the polarized responses allows one to select possible experiments for minimizing the model dependence in the extraction of the neutron electromagnetic form factors. In particular, the relevant role played by the proton in the transverse-longitudinal response of polarized ${}^3$He, at low momentum transfer, can be utilized for obtaining valuable information on the proton contribution to the total polarized response and eventually on the neutron charge form factor.

The nucleon-nucleon potential is analyzed using the ${1/N}_c$ expansion of QCD. The $\mathrm{NN}$ potential is shown to have an expansion in ${1/N}_c^2,$ and the strengths of the leading order central, spin-orbit, tensor, and quadratic spin-orbit forces (including isospin dependence) are determined. Comparison with a successful phenomenological potential (Nijmegen) shows that the large-$N_c$ analysis explains many of the qualitative features observed in the nucleon-nucleon interaction. The ${1/N}_c$ expansion implies an effective Wigner supermultiplet symmetry for light nuclei. Results for baryons containing strange quarks are presented in an appendix.

We study possible bound states of the $\Delta \Delta$ and $\Delta \Delta \Delta$ systems by using a two-body interaction derived from the chiral quark cluster model. The systems of two and three deltas, which will appear in nature as dibaryon and tribaryon resonances with zero strangeness, have large similarities with the corresponding two- and three-nucleon systems. The two deepest bound $\Delta \Delta$ states are those with angular momentum and isospin $\mathrm{}(j,i)=(1,0)\mathrm{}$ and $\mathrm{}(j,i)=(0,1)\mathrm{}$ which have the same quantum numbers as the ${}^3{S}_1$-${}^3{D}_1$ (deuteron) and ${}^1{S}_0$ (virtual) $\mathrm{NN}$ states. Similarly, the more strongly bound $\Delta \Delta \Delta$ state is that with angular momentum and isospin $\mathrm{}(J,I)=(\frac{1}{2},\frac{1}{2})$ which has precisely the same quantum numbers as the triton.

Parity violation has been observed in a number of previously unreported neutron resonances in silver. Analysis of these parity violation data requires improved neutron resonance spectroscopy. The neutron total cross section for natural silver was measured for $E_n=10\mathrm{}$–800 eV with the time-of-flight method at the Los Alamos Neutron Scattering Center. The neutron capture reaction was studied with both a natural silver target and a highly enriched sample (98.29%) of ${}^{107}$Ag. A total of 38 previously unreported resonances were observed. The combination of the two measurements allowed assignment of the newly observed resonances to ${}^{107}$Ag or to ${}^{109}$Ag. Resonance parameters were determined for almost all of the neutron resonances observed.

High-spin states of $T_z=1\mathrm{}$ nuclei were studied with the reactions ${}^{58}$Ni${(}^{28}$Si,$3\alpha )$${}^{74}$Kr, ${}^{58}$Ni${(}^{28}$Si,$2\alpha )$${}^{78}$Sr, and ${}^{58}$Ni${(}^{28}$Si,$2p2n)$${}^{82}$Zr at 130 MeV beam energy. The Gammasphere array in conjunction with the $4\pi$ charged-particle detector array Microball was used to detect $\gamma$ rays in coincidence with evaporated light charged particles. The known $\pi =+$, $\alpha =0\mathrm{}$ yrast bands were extended to $I=28\mathrm{}ħ$ at 20 MeV excitation energy. For all three nuclei, a number of positive- and negative-parity sidebands were established; altogether 15 new rotational bands were found. The data are discussed using the pairing-and-deformation self-consistent total Routhian surface (TRS) model: High-spin structures of ${}^{74}$Kr and ${}^{78}$Sr are governed by the shell gaps at large prolate deformation while ${}^{82}$Zr seems to exhibit shape coexistence. Nearly identical bands were established which may be explained as arising from the $\mathrm{fp}$ orbits acting as spectators at very elongated shapes. The experimental data in these $T_z=1\mathrm{}$ nuclei are in good agreement with predictions of the TRS model using conventional $T=1\mathrm{}$ like-nucleon pairing correlations.

An exotic beam of ${}^{11}\mathrm{Be}$ at 57–60 MeV/nucleon has been used for a study of the excitation cross section of the 320 keV first excited state in collisions with targets of Pb, Au, C, and Be. The deexcitation $\gamma$ rays were observed in an array of position-sensitive NaI(Tl) detectors in coincidence with the scattered fragment. The reduced transition strengths $B$($E$1) extracted for the heavy targets suggest a predominantly electric excitation mechanism. Although the $B$($E$1) value is marginally in agreement with that obtained from the lifetime of the state, the deviation is of the size expected from higher-order Coulomb and nuclear effects. Excitations on the lighter targets have sizable nuclear contributions.

We outline an elegant way of deducing the spin structure of any reaction $A(a,b)B$ with arbitrary spins $s_A{,s}_a{,s}_b{,s}_B$ and apply the same to $\mathrm{NN}\to N\Delta$, taking into consideration the Pauli exclusion principle. This method, based on irreducible tensor techniques is then extended to $\Delta$ excitation in ${A(N,N}^{\prime }\pi )B$ by considering the target excitation process (TDP) as ${A(N,N}^{\prime }{)B}_{\Delta }^{*}$ followed by $B_{\Delta }^{*}\to B+\pi$ and the projectile excitation process (PDP) as $A(N,\Delta )B$ followed by $\Delta \to N^{\prime }\pi$. Expressions for the double differential cross section and inelastic nucleon spin observables are given, which are of current experimental interest.

Recent studies have provided new experimental information on neutron-rich nuclei around doubly magic ${}^{132}\mathrm{Sn}.$ We have performed shell-model calculations for the two- and three-proton $N$=82 isotones ${}^{134}\mathrm{Te}$ and ${}^{135}\mathrm{I}$ using a realistic effective interaction derived from the Bonn A nucleon-nucleon potential. The results are in remarkably good agreement with the experimental data evidencing the reliability of our realistic effective interaction.

The Efimov effect in the halo nucleus ${}^{14}$Be, considered as a three-body (${n-n-}^{12}$Be) system, is studied employing separable potential for the binary systems. Assuming a possibility for the existence of a low lying $s$-orbital state for the halo neutrons with ${}^{12}$Be as core, we investigate its effect on the possibility of occurrence of the Efimov states by computing the three-body integral equations. A virtual state of 2 to 4 keV for the $n$-${}^{12}$Be binary system predicts not only the ground state energy for ${}^{14}$Be, which is in reasonable agreement with the experimental value, but also shows excited states close to about zero binding energy for the halo neutrons.

A light front treatment of the nuclear wave function is developed and applied, using the mean field approximation, to infinite nuclear matter. The nuclear mesons are shown to carry about a third of the nuclear plus momentum $p^{+};$ but their momentum distribution has support only at $p^{+}=0,$ and the mesons do not contribute to nuclear deep inelastic scattering. This zero mode effect occurs because the meson fields are independent of space-time position.

The electric polarizability and logarithmic mean-excitation energy are calculated for the deuteron using techniques introduced in atomic physics. These results are then used to improve limits on the atomic-deuterium frequency shift due to nuclear polarization in the unretarded dipole limit, as well as confirming previous results.

The level structure and configurations of ${}^{217}$Rn have been studied following the $\alpha$ decay of mass separated ${}^{221}$Ra (30 s). A number of new levels and $\gamma$-ray transitions have been observed. A group of low-energy states populated with low $\alpha$ decay hindrance factors is interpreted as intermediate between the $g_{9/2}$ shell model configuration and the 5/2(0.2;0.2) quadrupole-octupole deformed configuration. A second group of states populated with high hindrance factors is interpreted as intermediate between the $i_{11/2}$ shell model configuration and the mixed 1/2(-0.1;0.5;-2)+3/2(-0.1;0.6) quadrupole-octupole configuration.

Elastic electron scattering off ${}^{30}$Si and ${}^{31}$P was studied in an effective momentum-transfer range of 1.8–3.0 fm${}^{-1}$. The form-factor data were analyzed together with existing data sets for these nuclei and for ${}^{32}$S in a model-independent Fourier-Bessel expansion. For ${}^{31}$P the $M1\mathrm{}$ contribution was subtracted following an established parametrization. Results of Hartree-Fock (HF) calculations, performed for these three nuclei in a spherical basis and in an axially deformed basis, are compared to experiment. Occupancies have been determined which, when used in the spherical-basis HF calculations, lead to a good description of the elastic form-factor data. The deformed-basis calculations have been used to study the influence of the deformation on the calculated binding energies and ground-state charge densities. In all calculations the influence of using different effective nucleon-nucleon interactions was investigated. The resulting differences in ${2s}_{1/2}$ in occupancy are combined with results from previous existing ${(e,e}^{\prime }p)$ experiments to yield “absolute occupancies” for the ${2s}_{1/2}$ orbital. The deduced ${2s}_{1/2}$ occupancies for ${}^{30}$Si and ${}^{32}$S are 0.24(4) and 1.35(19), respectively.

The ${}^{105}$Rh nucleus has been studied by in-beam $\gamma$ spectroscopy with the heavy-ion fusion-evaporation reaction ${}^{100}$Mo${(}^{11}$B, $\alpha$2$n\gamma )$ at 39 MeV. Gamma-gamma-$t$ coincidences and directional correlation ratios were measured. Four rotational bands have been identified with similar characteristics to those in other $A$≈100 odd-proton nuclei. The positive-parity yrast band based on the $\pi g_{9/2}$ configuration and the negative-parity $\pi p_{1/2}$ band, showing large signature splittings, exhibit band crossings at the frequencies of 0.38 MeV and 0.48 MeV, respectively. Experimental Routhians and alignments as well as $B\left(M1\mathrm{}\right)/B\left(E2\mathrm{}\right)\mathrm{}$ ratios were extracted. The structure of the bands was interpreted within the framework of the cranked shell model and total Routhian surface calculations.

Lifetimes of low-lying states in ${}^{125,127}$La nuclei were measured using the recoil distance method. The nuclei were produced by the ${}^{94}$Mo${(}^{35}$Cl,$2p2n)$ and ${}^{112}$Cd${(}^{19}$F,$4n)$ reactions, respectively. Experimental results were described in the framework of the core quasiparticle coupling model. It was found that the observed bands can be reasonably well described as $\pi g_{7/2},$ $\pi g_{9/2},$ and $\pi h_{11/2}$ quasiparticle configurations coupled to elongated $({\beta }_2\approx 0.28)$ triaxial cores. No evidence for a rapid change of the nuclear shape in the $\pi h_{11/2}$ band in ${}^{127}$La is seen in our data.

Cross sections have been measured up to 35 MeV excitation for the ${}^{76}$Se($n,p$)${}^{76}$As reaction at five laboratory angles between $0°$ and $15°$. The incident neutron energy was 198 MeV. The distribution of Gamow-Teller (GT) strength at excitation energies less than 10 MeV was deduced by carrying out a multipole decomposition of the data. The GT strength below 6 MeV excitation was found to be less than 0.9 units, in qualitative agreement with a quasiparticle random-phase approximation calculation. The present results have been compared with data from the ${}^{76}$Ge($p,n$)${}^{76}$As reaction to obtain an estimate of a lower limit for the lifetime of ${}^{76}$Ge for $\beta \beta$ decay. The estimate is in qualitative agreement with the measured lifetime.

The giant resonance region in ${}^{40}\mathrm{Ca}$ was studied with inelastic scattering of 240 MeV α particles at small angles including 0°. A peak at $E_x=17.5\mathrm{}\pm 0.4\mathrm{MeV}$ with $\Gamma =4.95\mathrm{}\pm 0.25\mathrm{MeV}$ was found to contain $33\pm 4\%$ of the isoscalar $E0\mathrm{}$ energy-weighted-sum-rule (EWSR) strength and $57\pm 6\%$ of the isoscalar $E2\mathrm{}$ EWSR. Evidence was found for $92\pm 15\%$ of the isoscalar $E0\mathrm{}$ EWSR between $8<\mathrm{}{E}_x<29\mathrm{}\mathrm{MeV}$ with a centroid of $18.9\pm 0.4\mathrm{MeV}$ and a rms half width of 11.1 MeV but a definitive $L=0\mathrm{}$ assignment could not be made. The resulting $E_{\mathrm{GMR}}$ is in agreement with systematics from heavier nuclei.

The yrast superdeformed band in ${}^{194}$Pb has been populated using the ${}^{174}$Yb${(}^{25}$Mg,5n)${}^{194}$Pb reaction at $E_{\mathrm{beam}}=130\mathrm{}$ MeV. Decay $\gamma$ rays were detected using the GAMMASPHERE array at the 88-Inch Cyclotron. Twelve $\gamma$-ray transitions have been observed directly linking three members of the ${}^{194}$Pb yrast superdeformed band to low-lying normal deformed levels. Anisotropy measurements indicate that these linking decays include $E$1, $M$1, and mixed $M1/E2\mathrm{}$ multipolarities. The radiative widths deduced are very inhibited, typically $B\left(E1\mathrm{}\right)\mathrm{}\sim {10}^{-8}$ Weisskopf units (W.u.) and $B\left(M1\mathrm{}\right)\mathrm{}\sim {10}^{-5}$ W.u. Without recourse to a priori assumptions $J^{\pi }{=6\mathrm{}}^{+}$ and $E_x=4878.4\mathrm{}\left(3\right)\mathrm{}$ keV have been unambiguously assigned to the lowest-lying observed superdeformed state (the state populated by the 170-keV intraband transition). The intensity of the observed primaries accounts for 21(2)% of the superdeformed band population.

Electron and intermediate energy proton scattering data from ${}^6$Li and ${}^7$Li, both elastic and inelastic, have been analyzed using wave functions obtained from shell model calculations involving spaces ranging from the conventional $0ħ\omega$ space to the $\mathrm{}(0+2+4)\mathrm{}ħ\omega$ one. The results, along with those of the static and dynamic properties of the low-lying spectra of the nuclei, allow for a strict assessment of the wave functions, as well as giving an indication of possible clusterlike behavior in those systems.

The nucleon mean free path is obtained based on the relativistic $\sigma$-$\omega$ model, the thermofield dynamics and the relativistic Dirac-Brueckner-Hartree-Fock results which includes the important medium effects at finite temperature in nuclear matter. The temperature and density dependence of the nucleon self-energy in nuclear matter is derived from the effective Lagrangian taking diagrams up to fourth order into account. The calculated results of the nucleon mean free path at zero temperature are in good agreement with the experimental data in normal nuclear matter.