In the case of massless current quarks we find that the breaking of chiral symmetry usually triggers the generation of an anomalous magnetic moment for the quarks. We show that the kernel of the Ward identity for the vector vertex yields an important contribution. We compute the anomalous magnetic moment in several quark models. The results show that it is hard to escape a measurable anomalous magnetic moment for the quarks in the case of spontaneous chiral symmetry breaking.

We have measured the $\beta -\gamma$ directional correlation coefficient $A_{22}$ in the decay of ${}^{22}\mathrm{Na}$ to the $2^{+}$ 1275 keV excited state of ${}^{22}\mathrm{Ne}.$ We find $A_{22}=(5.3\mathrm{}\pm 2.5)\times {10}^{-4}.$ This measurement has higher precision but disagrees with most previous experiments. The value for $A_{22},$ combined with other experimental inputs, gives recoil-order form factors in disagreement with theoretical estimates. This experiment demonstrates the capabilities of Gammasphere as an instrument for precise $\beta -\gamma$ correlation measurements.

Parity nonconservation (PNC) was studied in p-wave resonances in Ag by measuring the helicity dependence of the neutron total cross section. Transmission measurements on natural Ag were performed in the energy range 32 to 422 eV with the time-of-flight method at the Manuel Lujan Neutron Scattering Center at Los Alamos National Laboratory. A total of 15 p-wave neutron resonances were studied in ${}^{107}\mathrm{Ag}$ and nine p-wave resonances in ${}^{109}\mathrm{Ag}.$ Statistically significant asymmetries were observed for eight resonances in ${}^{107}\mathrm{Ag}$ and for four resonances in ${}^{109}\mathrm{Ag}.$ An analysis treating the PNC matrix elements as random variables yields a weak spreading width of ${\Gamma }_w{=(2.67\mathrm{}}_{-1.21}^{+2.65\mathrm{}})\times {10}^{-7}\hspace{0.5em}\mathrm{eV}$ for ${}^{107}\mathrm{Ag}$ and ${\Gamma }_w{=(1.30\mathrm{}}_{-0.74}^{+2.49\mathrm{}})\times {10}^{-7}\hspace{0.5em}\mathrm{eV}$ for ${}^{109}\mathrm{Ag}.$

A new search has been performed for parity violation in the compound nuclear states of ${}^{94}\mathrm{Nb}$ by measuring the helicity dependence of the neutron total cross section. Transmission measurements on a thick niobium target were performed by the time-of-flight method at the Manuel Lujan Neutron Scattering Center with a longitudinally polarized neutron beam in the energy range 32 to 1000 eV. A total of 18 p-wave resonances in ${}^{93}\mathrm{Nb}$ were studied with none exhibiting a statistically significant parity-violating longitudinal asymmetry. An upper limit of $1.0\times {10}^{-7}$ eV (95% confidence level) was obtained for the weak spreading width ${\Gamma }_w$ in ${}^{93}\mathrm{Nb}.$

Neutron transmission experiments for neutron-electron interaction are discussed. The contribution of the coherent elastic scattering cross section to the attenuation cross section is reconsidered. Some uncertainties in interference correction to the coherent elastic scattering cross section, which leave some room for doubting the reliability of the number $1.3\times {10}^{-3}$ fm for n-e-scattering amplitude, are pointed out. Some corrections to the real part of the scattering amplitude, which should be taken into account in measurements of the neutron polarizability, are found.

The ${}^{16}\mathrm{O}{(}^3\mathrm{He}{,d)}^{17}\mathrm{F}$ reaction has been used to determine asymptotic normalization coefficients for transitions to the ground and first excited states of ${}^{17}\mathrm{F}.$ The coefficients provide the normalization for the tails of the overlap functions for ${}^{17}{\overrightarrow{\mathrm{F}}}^{16}\mathrm{O}+p$ and allow us to calculate the S factors for ${}^{16}\mathrm{O}(p,\gamma {)}^{17}\mathrm{F}$ at astrophysical energies. The calculated S factors are compared to measurements and found to be in very good agreement. This provides a test of this indirect method to determine astrophysical direct capture rates using transfer reactions. In addition, our results yield $S\left(0\right)\mathrm{}$ for capture to the ground and first excited states in ${}^{17}\mathrm{F},$ without the uncertainty associated with extrapolation from higher energies.

The neutron capture cross sections of ${}^{141}\mathrm{Pr}{,}^{160}\mathrm{Dy}{,}^{161}\mathrm{Dy}{,}^{162}\mathrm{Dy}{,}^{163}\mathrm{Dy},$ and ${}^{164}\mathrm{Dy}$ 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 ${}^7\mathrm{Li}{\mathrm{}(p,n)\mathrm{}}^7\mathrm{Be}$ 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. For the first time the correction for undetected capture events was completely obtained from experimental information, using capture cascades derived from measurements with an analog-to-digital converter system. The cross section ratios could be determined with an overall uncertainty of 1–1.5 %, an average improvement compared to previous measurements by a factor 4. Maxwellian averaged neutron capture cross sections were calculated for thermal energies between $kT=8\mathrm{}\hspace{0.5em}\mathrm{keV}$ and 100 keV. For most of the isotopes there is reasonable agreement with recent evaluations, but discrepancies of $\sim 20\%$ were obtained for ${}^{160}\mathrm{Dy}$ and ${}^{164}\mathrm{Dy}.$ The experimental data were complemented by statistical model calculations in order to describe the cross section enhancements in the stellar environment. The astrophysical implications of the present data include the quest for the origin of ${}^{160}\mathrm{Dy},$ the decomposition of the Dy abundances in the respective s- and r-process contributions, branchings of the s-process chain at the terrestrially stable isotopes ${}^{157}\mathrm{Gd}$ and ${}^{163}\mathrm{Dy},$ and the isotopically anomalous dysprosium in meteoritic inclusions.

High-spin states in the doubly-odd nuclei ${}^{154,156}\mathrm{Tb}$ have been populated in two separate experiments using the ${}^{36}\mathrm{S}{+}^{124}\mathrm{Sn}$ reaction at different beam energies (160 and 175 MeV). The yrast structures of both nuclei were extended to much higher spin $(I<~48ħ)$ than previously known and several quasiparticle alignments have been identified. These include the second neutron alignment and a clear delineation of the second proton crossing in ${}^{156}\mathrm{Tb}.$ Systematics of these crossings for odd-$Z$ nuclei and comparisons with results of cranked shell model calculations are discussed.

High-spin states in ${}^{75}\mathrm{Se}$ were populated via the ${}^{48}\mathrm{Ti}{(}^{30}\mathrm{Si}{,2pn)}^{75}\mathrm{Se}$ thin-target reaction at 90 MeV and studied using $\gamma -\gamma$ techniques. The $\pi =+$ band was extended to the $\left({\frac{41}{2}}^{+}\right)$ level, and a return was observed to the larger signature splitting characteristic of the lower-spin states. Two separate band structures were observed above the band crossing in the negative-parity bands, as in ${}^{77}\mathrm{Kr}.$

The energy spectra of $\alpha$ particles have been measured in coincidence with the evaporation residues for the decay of the compound nucleus ${}^{31}\mathrm{P},$ produced in the reaction ${}^{19}\mathrm{F}(96\mathrm{}\hspace{0.5em}\mathrm{MeV}{)+}^{12}\mathrm{C}.$ The data have been compared with the predictions of the statistical model code CASCADE. It has been observed that significant deformation effects in the compound nucleus need to be considered in order to explain the shape of the evaporated $\alpha$-particle energy spectra.

The ${}^{20}\mathrm{Ne}\mathrm{}(p,t)\mathrm{}{}^{18}\mathrm{Ne}$ reaction has been studied in order to investigate the properties of ${}^{18}\mathrm{Ne}$ excited states. A missing $3^{+}$ state of ${}^{18}\mathrm{Ne},$ which could have a great influence on the ${}^{17}\mathrm{F}(p,\gamma ){}^{18}\mathrm{Ne}$ reaction rate, was searched for, but the existence of this state was not clearly verified. The spins and parities of the 5.11- and 5.15-MeV states were assigned tentatively by angular distribution measurements, as $2^{+}$ and $3^{-},$ respectively. We were able to resolve the doublets at 4.5, 5.1, and 6.3 MeV clearly for the first time due to our high precision system, which allowed us to determine the widths of some critical states above the proton threshold of ${}^{18}\mathrm{Ne}$ more precisely.

The six-$\alpha$ decay of ${}^{24}\mathrm{Mg}$ has been studied via the reaction ${}^{13}\mathrm{N}{+}^{11}\mathrm{B}$ at two beam energies, 29.5 MeV and 45 MeV. Large detector arrays allowed this reaction to be studied with low intensity radioactive ${}^{13}\mathrm{N}$ beam. The excitation energy in the ${}^{24}{\mathrm{Mg}}^{*}$ was in the region of the 46 MeV resonance in ${}^{12}\mathrm{C}{+}^{12}\mathrm{C}$ scattering. From the six-$\alpha$ particles, events of interest were selected by associating two of the $\alpha$ particle pairs as the decay products of ${}^8\mathrm{Be}.$ The c.m. energy spectra for two ${}^8\mathrm{Be}+\mathrm{two}\hspace{0.5em}\alpha$ events have been extracted. The analysis revealed that most of these events originate from ${}^{12}{\mathrm{C}}_{3_1^{-}}{+}^{12}{\mathrm{C}}_{3_1^{-}}.$ The total cross section for these six-$\alpha$ events has been extracted at the two beam energies.

We have conducted tests of two changes to the formalism of the dispersive optical model (DOM) by making use of a large ${n+}^{208}\mathrm{Pb}$ database. One change relaxes the constraint, conventional in DOMs, that the real- and imaginary-volume potentials share the same geometrical parameters. The second change adopts a different functional form for the energy dependence of the surface imaginary potential, which allows its strength to drop off rapidly in the 30–80 MeV region. Radial shapes of the total imaginary potentials for the new DOMs are compared to each other and to those of a microscopic optical model. We also present an improved DOM analysis which models elastic scattering data for ${n+}^{208}\mathrm{Pb}$ and ${n+}^{209}\mathrm{Bi}$ simultaneously, and which incorporates a newer set of ${n+}^{208}\mathrm{Pb}$ total cross-section data.

The baryon rapidity (or pseudorapidity) distributions in nucleus-nucleus collisions in the SPS energy region have been described by the thermalized cylinder picture. The calculated results are in agreement with the experimental data of the reactions ${}^{32}\mathrm{S}+\mathrm{S}$ at $200A\mathrm{GeV},$ ${}^{16}\mathrm{O}+\mathrm{A}\mathrm{u},\mathrm{}\mathrm{Ag},$ Cu at 60 and $200A\hspace{0.5em}\mathrm{GeV}$ bombarding energy. The limiting fragmentation of the target spectator is achieved for a given projectile in the concerned energy region.

The recent $\mathrm{}(p,n)\mathrm{}$ spin experiments on various nuclear targets at forward angles suggest that the Gamow-Teller strength is almost exhausted by nucleon excitations, which limit the Landau-Migdal parameter for the delta nucleon to $g_{\Delta }^{\prime }<~\mathrm{0.2.}$ This small $g_{\Delta }^{\prime }$ makes the nucleus in or very close to the condition for pion condensation and produces, if close, the precritical phenomena, which have been proved to be not occurring in the nucleus. One solution for reducing the pionic correlation is to take the relativistic description of the nuclear many-body system, which reduces the nonrelativistic pionic Lindhard function by about a factor of 2. This relativistic Lindhard function is also consistent with no enhancement of the longitudinal spin-response function against the transverse one as seen as $R_L{/R}_T<~1$ extracted in ${(p,p}^{\prime })$ and $\mathrm{}(p,n)\mathrm{}$ experiments at large angles. These observations, when combined, indicate that the relativistic description is necessary to understand the low-energy properties of nucleus.

Spectral averaging methods have been used in nuclear physics for many purposes but always using spherical symmetry. We demonstrate its use in calculating the state density and level density of deformed nuclei using Nilsson model single-particle scheme. The calculated results are compared with statistical Fermi-gas model to evaluate standard Fermi-gas parameters; these are then compared with experimental data. The spin-cutoff factors and parity ratios have also been calculated.

Using the Walecka model, we investigate theoretically whether an $\omega$ meson is bound to finite nuclei. We study several nuclei from ${}^6\mathrm{He}$ to ${}^{208}\mathrm{Pb},$ and compare the results with those in the quark-meson coupling (QMC) model. Our calculation shows that deeper $\omega$-nucleus bound states are predicted in the Walecka model than in QMC. One can expect to detect such bound states in the proposed experiment involving the ${(d,}^3\mathrm{He})$ reaction at GSI.

The $d+N$ systems are studied in a three-body model, using phenomenological $N-N$ interactions. The scattering matrices are calculated by using the Kohn-Hulthén variational method. Then, they are analytically continued to complex energies and their singularities are localized. We find a virtual state at $E=-1.66$ MeV in ${}^3\mathrm{H}$ and a pair of states at $E=(-0.42\pm i0.52)$ MeV in ${}^3\mathrm{He}$ relative to the $d+N$ thresholds, respectively. In addition, we discuss some general aspects and problems of virtual states which may be useful also in the study of other systems, like ${}^{10}\mathrm{Li}.$

The deuteron stripping reactions are presented as a method of determining particle distribution within possible halo nuclei. Distributions of the last proton in ${}^{17}\mathrm{F}$ and the last neutron in ${}^{17}\mathrm{O}$ are extracted from a comparison of experimental and theoretical reaction cross sections. It is found that the first excited state of ${}^{17}\mathrm{F}$ is a proton halo state and that the halo behavior can be explained purely in terms of binding-energy effects.

Earlier fits to a large set of deuteron total reaction cross sections, ${\sigma }_R,$ using a Glauber model, were improved by including correlations between nucleon positions in the deuteron. Glauber predictions (without correlations) for an equally large set of α-particle ${\sigma }_R$ data were too high, especially for light targets. Both calculations changed by less than 1% when the projectiles were assumed to have classical trajectories, determined by Coulomb and nuclear forces, rather than eikonal trajectories.