Brute-force nuclear magnetic resonance on oriented nuclei (BF-NMRON) experiments have been performed with 12 T maximum field and at 10 mK. The resonances for ${}^{95,96}\mathrm{Tc}Nb,$ ${}^{106}{\mathrm{Ag}}^{m}Ag,$ and ${}^{110}{\mathrm{Ag}}^m\mathrm{Ag}$ have been observed. The magnetic moment of ${}^{106}{\mathrm{Ag}}^m$ was determined to be 3.705(4) ${\mu }_N.$ Comparing the resonance frequencies of BF-NMRON and those of the known NMR-ON results in Fe, the hyperfine anomalies in Fe were determined: ${}^{95}{\Delta }^{96}\left(\mathrm{Tc}\right)=-0.026\left(17\right)\%,$ ${}^{106m}{\Delta }^{110m}\left(\mathrm{Ag}\right)=0.10\mathrm{}\left(6\right)\%.\mathrm{}$ The measured hyperfine anomalies are interpreted in terms of a microscopic theory including core polarization and exchange current effects.

The new neutron deficient nuclide ${}^{195}\mathrm{Rn}$ and the nuclide ${}^{196}\mathrm{Rn}$ have been produced in fusion evaporation reactions using ${}^{56}\mathrm{Fe}$ ions on ${}^{142}\mathrm{Nd}$ targets. A gas-filled recoil separator was used to separate the fusion products from the scattered beam. The activities were implanted in a position sensitive silicon detector. The isotopes were identified using spatial and time correlations between implants and decays. Two $\alpha$ decaying isomeric states, with $E_{\alpha }=7536\mathrm{}\left(11\right)\mathrm{}\mathrm{keV}\left[T_{1/2}{=(6\mathrm{}}_{-2}^{+3\mathrm{}}\right)\mathrm{ms}]$ for the ground state and $E_{\alpha }=7555\mathrm{}\left(11\right)\mathrm{}\mathrm{keV}\left[T_{1/2}{=(5\mathrm{}}_{-2}^{+3\mathrm{}}\right)\mathrm{ms}]$ for an isomeric state were identified in ${}^{195}\mathrm{Rn}.$ In addition, the half-life and $\alpha$ decay energy of ${}^{196}\mathrm{Rn}$ were measured with improved precision. The reduced widths deduced for the neutron deficient even-mass Rn isotopes suggest an onset of substantial deformation at $N=110.\mathrm{}$

The liquid-gas phase transition is studied in a multicomponent nuclear system using a local Skyrme interaction with Coulomb and surface effects. Some features are qualitatively the same as the results of Müller and Serot where a relativistic mean field was used without Coulomb and surface effects. Surface tension brings the coexistence binodal surface to lower pressure. The Coulomb interaction makes the binodal surface smaller and causes another pair of binodal points at low pressure and large proton fraction with fewer protons in the liquid phase and more protons in the gas phase.

We consider the interaction of two Skyrmions in the framework of the sudden approximation. The widely used product Ansatz is investigated. Its failure in reproducing an attractive central potential is associated with terms that violate G parity. We discuss the construction of alternative Ansätze and identify a plausible solution to the problem.

The appearance of bound states with large binding energies of several hundred MeV in the three-body system, known as bound state collapse, is investigated. For this purpose three classes of two-body potentials are employed; local potentials equivalent to nonlocal interactions possessing a continuum bound state, in addition to the usual negative-energy bound state; local potentials with a strong attractive well sustaining a forbidden state; and supersymmetric transformation potentials. It is first shown that local potentials equivalent to the above nonlocal ones have a strong attractive well in the interior region which supports, in addition to the physical deuteron state, a second bound state (usually called a pseudobound state) with a large binding energy, which is responsible for the bound state collapse in the three-body (and in general to the N-body) system. Second, it is shown that local potentials with a forbidden state also generate a three-body bound state collapse, implying that the role played by the forbidden state is similar to the one played by the pseudobound state. Finally, it is shown that the removal of the forbidden state via supersymmetric transformations also results in the disappearance of the collapse. Thus one can safely argue that the presence of unphysical bound states with large binding energies in the two-body system is responsible for the bound state collapse in the three-body system.

We investigate isospin breaking in low-energy pion-nucleon scattering in the framework of chiral perturbation theory. This work extends the systematic analysis of Fettes et al. [Phys. Lett. B 451, 233 (1999)] to the energy range above threshold. Various relations, which identically vanish in the limit of isospin symmetry, are used to quantify isospin breaking effects. We study the energy dependence of the $S-$ and P-wave projections of these ratios and find dramatic effects in the S waves of those two relations which are given in terms of isoscalar quantities only. This effect drops rather quickly with growing center-of-mass energy.

Using a previously established effective Lagrangian model we describe anti-kaon induced reactions on the nucleon. The dominantly contributing channels in the c.m.-energy region from threshold up to 1.72 GeV are included $(\overline{K}N,\pi \Sigma ,\pi \Lambda ).\mathrm{}$ We solve the Bethe-Salpeter equation in a unitary K matrix approximation.

We discuss the available data for the differential and the total cross section for the photodisintegration of ${}^3\mathrm{He}$ and ${}^3\mathrm{H}$ and the corresponding inverse reactions below $E_{\gamma }=100\mathrm{}$ MeV by comparing with our calculations using realistic $\mathrm{NN}$ interactions. The theoretical results agree within the error bars with the data for the total cross sections. Excellent agreement is achieved for the angular distribution in the case of ${}^3\mathrm{He},$ whereas for ${}^3\mathrm{H}$ a discrepancy between theory and experiment is found.

The longitudinal asymmetry due to $Z^0$ exchange is calculated in quasielastic electron-deuteron scattering at momentum transfers $|Q^2|\simeq 0.1{\mathrm{GeV}}^2$ relevant for the SAMPLE experiment. The deuteron and $\mathrm{pn}$-scattering-state wave functions are obtained from solutions of a Schrödinger equation with the Argonne $v_{18}$ potential. Electromagnetic and weak neutral one- and two-nucleon currents are included in the calculation. The two-nucleon currents of pion range are shown to be identical to those derived in chiral perturbation theory. The results indicate that two-body contributions to the asymmetry are small $(\simeq 0.2\%)$ around the quasielastic peak, but become relatively more significant $(\simeq 3\%)$ in the high-energy wing of the quasielastic peak.

The tilted axis cranking model is used in combination with the random phase approximation and particle number projection to analyze the influence of dynamical pair correlations in the $\mathrm{h}\mathrm{i}\mathrm{g}\mathrm{h}-K$ bands of ${}^{178}\mathrm{W}$ and their effect on relative energy and angular momentum. The calculations show the importance of dynamical pair correlations to describe the experiment as well as advantages and problems with the different models in the superfluid and normal state regions.

The dynamics of light charged particle emission in the cold fission of ${}^{252}\mathrm{Cf}$ is studied in terms of spheroidal coordinates. This system of coordinates provides a more adequate description for a hyperdeformed fissioning nucleus than the standard spherical variables. We derive the system of coupled differential equations describing the motion of the emitted light cluster and we give a generalization of the Fröman matrix. The phase-shift analysis predicts long half-lives with respect to the characteristic particle nuclear time, but shorter than the cold fission transient time for those fissioning configurations that are emitting $\alpha$ particles and ${}^{10}\mathrm{Be}.$ Consequently, such configurations could be interpreted as ternary nuclear molecules.

The $\gamma$-ray strength function for $\gamma$ energies in the 1–7 MeV region has been measured for ${}^{161,162}\mathrm{Dy}$ and ${}^{171,172}\mathrm{Yb}$ using the ${(}^3\mathrm{He},\alpha \gamma )$ reaction. Various models are tested against the observed $\gamma$-ray strength functions. The best description is based on the Kadmenskiĭ, Markushev, and Furman $E1\mathrm{}$ model with constant temperature and the Lorentzian $M1\mathrm{}$ model. A $\gamma$-ray bump observed at $E_{\gamma }\sim 3$ MeV is interpreted as the so-called pygmy resonance, which has also been observed previously in $(n,\gamma )$ experiments. The parameters for this resonance have been determined and compared to the available systematics.

It has been a long-standing question whether momentum space integral equations of the Faddeev-type are applicable to reactions of three charged particles, in particular above the three-body threshold. The presence of long-range Coulomb forces has been thought to give rise to such severe singularities in their kernels that the latter may lack the compactness property known to exist in the case of purely short-range interactions. Employing the rigorously equivalent formulation in terms of an effective-two-body theory, we have proved in a preceding paper [Phys. Rev. C 61, 064006 (2000)] that, for all energies, the nondiagonal kernels occurring in the integral equations that determine the transition amplitudes for all binary collision processes, possess on and off the energy shell only integrable singularities, provided all three particles have charges of the same sign, i.e., all Coulomb interactions are repulsive. In the present paper we prove that, for particles with charges of equal sign, the diagonal kernels, in contrast, possess one, but only one, nonintegrable singularity. The latter can, however, be isolated explicitly and dealt with in a well-defined manner. Taken together these results imply that modified integral equations can be formulated, with kernels that become compact after a few iterations. This concludes the proof that standard solution methods can be used for the calculation of all binary [i.e., (in)elastic and rearrangement] amplitudes by means of momentum space integral equations of the effective-two-body-type.

Spectroscopic properties of nuclei are accessible with projectile fragmentation reactions, but approximations made in the reaction theory can limit the accuracy of the determinations. We examine here two models that have rather different approximations for the nucleon wave function, the target interaction, and the treatment of the finite duration of the reaction. The nucleon-target interaction is treated differently in the eikonal and the transfer-to-continuum model, but the differences are more significant for light targets. We propose a new parametrization with that in mind. We also propose a new formula to calculate the amplitudes that combines the better treatment of the wave function in the eikonal model with the better treatment of the target interaction in the transfer-to-continuum model.

γ-ray transitions have been identified for the first time in the near-drip-line nucleus ${}^{126}\mathrm{Pr},$ making it the lightest odd-odd praseodymium nucleus in which excited states have been reported. Evidence is presented for two rotational bands in ${}^{126}\mathrm{Pr},$ one strongly coupled and the other doubly decoupled. In addition, the preliminary reports of a band in ${}^{128}\mathrm{Pr}$ are confirmed. The signature inversion phenomenon and trends in the energy staggering of the $\pi h_{11/2}\nu h_{11/2}$ bands are discussed for the Cs, La, and Pr nuclei.

We study the properties of the ${}^1{S}_0$ pairing gap in low-density neutron matter. Different corrections to the lowest-order scattering length approximation are explored, resulting in a strong suppression with respect to the BCS result.

In heavy-ion fusion reactions involving a well-deformed nucleus, one often assumes that the orientation of the target nucleus does not change during the reaction. We discuss the accuracy of this procedure by analyzing the excitation function of the fusion cross section and the fusion barrier distribution in the reactions of ${}^{154}\mathrm{Sm}$ target with various projectiles ranging from ${}^{12}\mathrm{C}$ to ${}^{40}\mathrm{Ar}.$ It is shown that the approximation gradually loses its accuracy with increasing charge product of the projectile and target nuclei because of the effects of finite excitation energy of the target nucleus. The relevance of such inaccuracy in analyzing the experimental data is also discussed.

The moments of inertia (MoI) of odd-$A$ and even-even rare-earth nuclei are calculated using the Nilsson + BCS method with and without the blocking effect taken into account. The calculated MoI’s with blocking considered is smaller than that without blocking considered. The MoI of an odd-$A$ nucleus depends strongly on which orbital is occupied by the odd nucleon. Although the calculated MoI’s are systematically smaller than the data, the large fluctuations in the experimental odd-even differences in MoI’s can be reproduced qualitatively. This is contrary to the common assertion that the MoI of an odd-$A$ nucleus is some 15% larger than those of its neighboring even-even nuclei with the BCS theory and is helpful to understand the appearance of normally deformed identical bands in an odd-$A$ nucleus and its even-even neighbors under the mean-field (BCS) approximation.

The central two-pion exchange $\mathrm{NN}$ potential at large distances is studied in the framework of relativistic chiral symmetry and related directly to the nucleon scalar form factor, which describes the mass density of its pion cloud. This relationship is well supported by phenomenology and allows the dependence of the asymptotic potential on the nucleon mass to be assessed. Results in the heavy baryon limit are shown to be about 25% larger than those corresponding to the empirical nucleon mass in the region of physical interest. This indicates that it is very important to keep this mass finite in precise descriptions of the $\mathrm{NN}$ system and supports the efficacy of the relativistic chiral framework. One also estimates the contribution of subleading effects and presents a simple discussion of the role of the quark condensate in this problem.

We suggest that the ultrarelativistic collisions of heavy ions provide the simplest situation for the study of strong interactions which can be understood from first principles and without any model assumptions about the microscopic structure of the colliding nuclei. We argue that the boost-invariant geometry of the collision, and the existence of hard partons in the final states, both supported by the data, make a sufficient basis for the quantum theory of the phenomenon. We conclude that the quantum nature of the entire process is defined by its global geometry, which is enforced by a macroscopic finite size of the colliding objects. In this paper, we study the qualitative aspects of the theory and review its development in two subsequent papers. Our key result is that the effective mass of the quark in the expanding system formed in the collision of the two nuclei is gradually built up reaching its maximum by the time the quark mode becomes sufficiently localized. The chromo-magneto-static interaction of the color currents flowing in the rapidity direction is the main mechanism which is responsible for the generation of the effective mass of the soft quark mode and, therefore, for the physical scale at the earliest stage of the collision.