The Bloom-Gilman local duality of the inelastic structure function of the proton, the deuteron, and light complex nuclei is investigated using available experimental data in the squared four-momentum transfer range from $0.3$ to $5\hspace{0.5em}(\mathrm{GeV}{/c)}^2$. The results of our analysis suggest that the onset of the Bloom-Gilman local duality is anticipated in complex nuclei with respect to the case of the proton and the deuteron. A possible interpretation of this result in terms of a rescaling effect is discussed with particular emphasis on the possibility of reproducing the damping of the nucleon-resonance transitions observed in recent electroproduction data off nuclei.

Relativistic corrections in the electromagnetic transition operators for the $E2/M1\mathrm{}$ ratio in the $\gamma \overrightarrow{N}\Delta$ process are investigated based on a chiral quark model. The improved result shows that the effect of the relativistic corrections plays a desirable role in the ratio when compared with our previous calculation.

The photon energy spectrum from the elementary process ${\mu }^{-}\overrightarrow{p}{\nu }_{\mu }n\gamma$ was measured using a photon pair-spectrometer at the TRIUMF cyclotron. Various sources of backgrounds are discussed in detail and evaluated. From the final spectrum the partial branching ratio $R_{\gamma }$ and the pseudoscalar coupling $g_p$ were extracted. The values obtained are $R_{\gamma }(k>\mathrm{}60\mathrm{}$ MeV$)=(2.10\mathrm{}\pm 0.21)\times {10}^{-8}$ and $g_p{(q}^2=-{0.88m}_{\mu }^2)=(9.8\mathrm{}\pm 0.7\pm {0.3)g}_a\mathrm{}\left(0\right)\mathrm{}$, respectively. The first error is the quadrature sum of statistical and systematic errors, while the second error is due to the uncertainty in ${\lambda }_{\mathrm{op}},$ the transition rate of the $p\mu p$ molecule from ortho to para states. This measurement of $g_p,$ the most precise to date, agrees with all but one of the previous measurements. However it is 1.46 times the value predicted by the partially conserved axial current hypothesis and pion pole dominance.

Effects of final state interaction on asymmetries in inclusive scattering of polarized electrons on polarized ${}^3\mathrm{He}$ are investigated using a consistent ${}^3\mathrm{He}$ bound state wave function and $3N$ continuum scattering states. Significant effects are found, which influence the extraction of the magnetic neutron form factor from $A_{T^{\prime }}.$ The enhancement found experimentally for $A_{{\mathrm{TL}}^{\prime }}$ near the $3N$ breakup threshold, which could not be explained in calculations carried through in plane wave impulse approximation up to now, occurs now also in theory if the full final state interaction is included.

The neutron capture cross sections of ${}^{142}$Nd, ${}^{143}$Nd, ${}^{144}$Nd, ${}^{145}$Nd, ${}^{146}$Nd, and ${}^{148}$Nd have been measured in the energy range from 3 to 225 keV at the Karlsruhe 3.75 MV Van de Graaff accelerator. Neutrons were produced via the ${}^7$Li$\mathrm{}(p,n)\mathrm{}$${}^7$Be reaction by bombarding metallic Li targets with a pulsed proton beam. Capture events were registered with the Karlsruhe 4$\pi$ Barium Fluoride Detector. The cross sections were determined relative to the gold standard. The experiment was difficult due to the small cross sections of the even isotopes at or near the magic neutron number $N$=82, and also since the isotopic enrichment of some samples was comparably low. The necessary corrections for capture of scattered neutrons and for isotopic impurities could be determined reliably thanks to the high efficiency and the spectroscopic quality of the BaF${}_2$ detector, resulting in a consistent set of $(n,\gamma )$ cross sections for the six stable neodymium isotopes involved in the $s$ process with typical uncertainties of 1.5–2 %. From these data, Maxwellian averaged cross sections were calculated between $kT=10\mathrm{}$ and 100 keV. The astrophysical implications of these results were investigated in an $s$-process analysis, which deals with the role of the $s$-only isotope ${}^{142}$Nd for the $N_s〈\sigma 〉$ systematics near the magic neutron number $N=82\mathrm{}$, the decomposition of the Nd abundances into the respective $r$-, $s$-, and $p$-process components, and the interpretation of isotopic anomalies in meteoritic material.

In this work we calculate the ${}^1{S}_0$ gap energies of Λ hyperons in neutron star matter. The calculation is based on a solution of the BCS gap equation for an effective $G$-matrix parametrization of the Λ-Λ interaction with a nuclear matter background, presented recently by Lanskoy and Yamamoto. We find that a gap energy of a few tenths of a MeV is expected for Λ Fermi momenta up to about $1.3{\mathrm{fm}}^{\mathrm{-}1}.$ Implications for neutron star matter are examined, and suggest the existence of a Λ ${}^1{S}_0$ superfluid between the threshold baryon density for Λ formation and the baryon density where the Λ fraction reaches 15–20 %.

The new neutron-deficient nuclide ${}^{206}$Ac was produced by bombarding a ${}^{175}$Lu target with 5.5 MeV/nucleon ${}^{36}$Ar ions. The evaporation residues were separated in flight by a gas-filled separator and subsequently identified by the $\alpha$-$\alpha$ position and time correlation method. ${}^{206}$Ac was found to have two $\alpha$ particle emitting isomeric levels with half-lives of (22${}_{-5}^{+9\mathrm{}})$ ms and (33${}_{-9}^{+22\mathrm{}})$ ms, and with $\alpha$ particle energies of (7790$\pm$30) keV and (7750$\pm$20) keV, respectively. The former isomer is tentatively assigned to a $J^{\pi }{=3\mathrm{}}^{+}$ level and the latter to a $J^{\pi }{=10\mathrm{}}^{-}$ level, both of which are also seen in the daughter and granddaughter nuclides ${}^{202}$Fr and ${}^{198}$At. Improved values of ${(27\mathrm{}}_{-6}^{+11\mathrm{}})$ ms and (7693$\pm$25) keV for the half-life and $\alpha$ particle energy of ${}^{207}$Ac are also reported.

The analyzing power $A_{y0\mathrm{}}$ of the reaction $\mathrm{H}(\overrightarrow{p},d){\pi }^{+}$ has been measured at a fixed value of the Mandelstam variable $u_d=-0.17{\mathrm{GeV}}^2$ for nine proton energies between 1000 and 1300 MeV. The experiment was performed at SATURNE with the SPES1 spectrometer. The data exhibit structure around $\sqrt{s}\simeq 2.37\mathrm{GeV}.$ The origin of this structure could be related to a resonancelike behavior of the ${}^1{S}_{0}P$ or ${}^1{G}_{4}F$ partial amplitudes.

We consider constraints on the isoscalar $S$-wave $\pi$-$N$ scattering length $a^{+}$ from $\pi$-deuteron scattering, to third order in small momenta and pion masses in chiral perturbation theory. To this order, the $\pi$-deuteron scattering length is determined by $a^{+}$ together with three-body corrections that involve no undetermined parameters. We extract a novel value for a combination of dimension two low-energy constants which is in agreement with previous determinations.

The evolution of nuclear structure along the Xe and Ba isotopes with $N<\mathrm{}82\mathrm{}$ is studied in comparison with that in the Pt-Os isotopes and with interacting boson approximation calculations. As is well known, the Pt isotopes from ${}^{188-196}$Pt exhibit a stable structure very close to O(6), the lighter Pt isotopes and the Os nuclei evolve towards a rotor, and the heaviest Pt nuclei, ${}^{198,200}$Pt, show a tendency towards vibrational character. In contrast, we show that the Ba nuclei are best described by a trajectory from U(5) towards SU(3) that passes through an intermediate structure that resembles O(6) for $N\sim$72–76. The Xe appears to evolve from U(5) to O(6)-like.

Average angular momenta of compound nuclei were deduced from measured evaporation-residue cross sections on the basis of statistical model calculations. We have applied this method to the following systems: ${}^4$He+${}^{197}$Au, ${}^{16}$O+${}^{147,149,152,154}$Sm, ${}^{32}$S+${}^{138}$Ba, and ${}^{48}$Ti+${}^{122}$Sn. For some of these systems, the average angular momenta were compared with those extracted from early $\gamma$-multiplicity measurements. A reasonable agreement was found between the values of the deduced average angular momentum obtained from both methods, giving support to the validity of the present method. The average angular momenta for all the systems exhibit the energy dependence predicted by a standard fusion model calculation.

Kaon production cross sections in nucleon-nucleon, nucleon-$\Delta$, and $\Delta$-$\Delta$ interactions are studied in a boson exchange model. For the latter two interactions, the exchanged pion can be on-mass shell; only contributions due to a virtual pion are included via the Peierls method by taking into account the finite $\Delta$ width. With these cross sections and also those for pion-baryon interactions, subthreshold kaon production from heavy-ion collisions is studied in the relativistic transport model.

We investigate possible consequences of resonant scalar interactions for dilepton production from a quark plasma at the chiral phase transition. It is found that this production mechanism is strongly suppressed compared to the Born process and has no significance for present experiments.

Two superdeformed bands have been observed in the nucleus ${}^{145}$Sm in an experiment performed with the Gammasphere multidetector array. One of these bands demonstrates a sudden rise in its dynamic moment of inertia at low frequency which may be related to the interaction between $N=6\mathrm{}$ Nilsson orbitals at the Fermi surface. The other band has a moment of inertia identical to the yrast band of ${}^{149}\mathrm{Gd}$, making it the fourth case in the $A\simeq 150$ mass region of identical bands in nuclei differing by an $\alpha$ particle.

We evaluate the full one-photon-exchange Born amplitude for $\mathrm{Nd}$ scattering. We include the contributions due to the magnetic moment of the proton or neutron, and the magnetic moment and quadrupole moment of the deuteron. It is found that the inclusion of the magnetic-moment interaction in the theoretical description of the $\mathrm{Nd}$ scattering observables cannot resolve the long-standing $A_y$ puzzle.

Based on the relativistic plane-wave impulse approximation for quasielastic $(\overrightarrow{p},p^{\prime })$ and $(\overrightarrow{p},\overrightarrow{n})$ polarization observables, we provide quantitative estimates of nuclear medium modifications of the $\mathrm{NN}$ interaction. We employ a ${}^{40}$Ca target for proton energies ranging from 135 to 300 MeV at a momentum transfer of 1.97 fm${}^{-1}$. Compared to former calculations, we have generated new meson-exchange parameters for the relativistic $\mathrm{NN}$ amplitudes between 80 and 200 MeV. Finally, the results are compared to the limited available data.

The Efimov effect for a three-body system was studied previously in an adiabatic representation, where the distance between two “heavy” particles was represented by x, and the third “light” particle was described by coordinate y relative to the center of mass of the heavy ones. When x is held fixed, an exact solution for the light particle can be obtained if the interaction is assumed to be of separable form. The resulting adiabatic potential between the heavy particles shows the critical $-{1/x}^2$ behavior that leads to an infinite number of bound states. However, subsequently the leading nonadiabatic effect was shown to generate an undesirable correction of $1/x$ type, the pseudo-Coulomb disease (PCD). To remedy the PCD, the Efimov effect is reexamined in the adiabatic state representation, but with the new Jacobi coordinates (r,R), where r describes the distance between one of the heavy particles and the light one and R is the position of the other heavy particle with respect to the center of mass of the subsystem of light-heavy particles. It is then shown that the adiabatic potential in this distorted cluster state representation behaves as $-{1/R}^2$ at large R if the pair described by r has a zero-energy bound state. Moreover, in this case the leading nonadiabatic correction term does not manifest the PCD, thus explicitly showing that the PCD is due to the “wrong” choice of coordinates (x,y). Alternatively, a particle boost factor is introduced to eliminate the PCD in the treatment with the original (x,y) coordinates. This is shown to be equivalent to the change in coordinates, described above. Such a factor is usually associated with high energy collisions, but for the first time shown here to play also an important role in near zero-energy situations.

We use the method of QCD sum rules in the presence of an external point field to investigate isospin symmetry breakings in pion-nucleon couplings. Possible manifestations of such isospin symmetry breakings are examined in the context of low-energy nucleon-nucleon scattering. We discuss numerical results in relation to both the existing data and other theoretical predictions.

We investigate the size of potential higher pseudoscalar resonance contaminations of the estimates of isospin-conserving and isospin-violating $\pi \mathrm{NN}$ couplings obtained using the three-point function method in QCD sum rules. For the isospin-conserving case it is shown that conventional models of the isovector pseudoscalar spectral function imply resonance decay constants large enough to create significant contaminations, and that assuming these models are incorrect, and that the decay constants are actually much smaller, implies physically implausible values for the flavor-breaking quark condensate ratios. For the isospin-violating case it is shown explicitly that such resonance contamination is unavoidably present and precludes using the three-point function method as a means of estimating the at present unmeasured isospin-violating $\pi \mathrm{NN}$ couplings.

Measurements of Coulomb excitation probabilities of the first $2_1^{+}$ state of ${}^{100,102,104}$Ru were carried out using back-scattered ions of ${}^4$He and ${}^{16}$O. The static quadrupole moments $Q_{2_1^{+}}$ and the reduced transition probabilities ${B(E2;0\mathrm{}}_1^{+}\to 2_1^{+})$ have been determined using the reorientation effect. The quadrupole moments $Q_{2_1^{+}}$ deduced for the positive sign of the $2_2^{+}$ interference term are $-0.54\pm 0.07$ $e\mathrm{b}$, $-0.64\pm 0.05$ $e\mathrm{b}$, $-0.62\pm 0.08$ $e\mathrm{b}$ for ${}^{100}$Ru, ${}^{102}$Ru, and ${}^{104}$Ru, respectively. The reduced transition probabilities ${B(E2;0\mathrm{}}_1^{+}\to 2_1^{+})$ are $0.493\pm 0.003$ $e^2{\mathrm{b}}^2$, $0.614\pm 0.004$ $e^2{\mathrm{b}}^2$, and $0.809\pm 0.006$ $e^2{\mathrm{b}}^2$, respectively. A compilation of the available experimental results for the reduced eletric quadrupole transition probability ${B(E2;0\mathrm{}}_1^{+}\to 2_1^{+})$ and for the static quadrupole moments $Q_{2_1^{+}}$ for the even ruthenium stable isotopes $(96\mathrm{}<~A<~104)$ are presented.