The Glauber model approach for the description of the heavy-ion reaction cross section is extended to lower energies. A simple analytic expression for the transparency function is obtained by evaluating the overlap integral of the nuclear densities over the hyperbolic trajectory. Using this transparency function the reaction cross section of a large number of heavy-ion systems is predicted reasonably well at low energies.

We propose here a practical projection method to make non-gauge-invariant amplitudes for N(γ,π)N and N(e,e’π)N gauge invariant.

We show that a major part of the neutron and charged-fragment multiplicity distributions measured in the collision of ${}_{}{}^{136}{}_{}{}^{}\mathrm{Xe}$ on ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ at an incident energy of 28.2A MeV can be reproduced by assuming that the colliding nuclei decay independently after a highly dissipative process.

A simple and yet useful model for deriving sdg interacting boson model (IBM) Hamiltonians is to assume that single-boson energies derive from identical particle (pp and nn) interactions and proton, neutron single-particle energies, and that the two-body matrix elements for bosons derive from pn interaction, with an IBM-2 to IBM-1 projection of the resulting p-n sdg IBM Hamiltonian. The applicability of this model in generating sdg IBM Hamiltonians is demonstrated, using a single-j-shell Otsuka-Arima-Iachello mapping of the quadrupole and hexadecupole operators in proton and neutron spaces separately and constructing a quadrupole-quadrupole plus hexadecupole-hexadecupole Hamiltonian in the analysis of the spectra, B(E2)’s, and E4 strength distribution in the example of ${}_{}{}^{150}{}_{}{}^{}\mathrm{Nd}$.

The production of several massive fragments in the decay of a very excited compound nucleus is studied using simultaneous and sequential mechanisms of fragment production. The calculated massive-fragment multiplicities exhibit remarkably similar behaviors as functions of the excitation energy, thus ruling out using this observable as an experimental signature of the dominant fragmentation mechanism.

We propose a novel decomposition of the scattering amplitude appropriate for a qualitative understanding of angular distributions in elastic collisions of neutron-rich nuclei. This decomposition allows one to isolate the contributions of the nuclear attraction to the elastic scattering amplitude.

We investigate ground-state properties of the superheavy nucleus with N=184 and Z=114, ${}_{}{}^{298}{}_{}{}^{}114$, using conventional relativistic mean-field theory and density-dependent mean-field theory, which reproduces Dirac-Brueckner calculations in nuclear matter. Our calculations provide support for N=184 and Z=114 being magic numbers. Density-dependent mean-field theory does not predict ${}_{}{}^{298}{}_{}{}^{}114$ to be stable against β decay.

We examine a recent suggestion for an energy dependence of the pion-nucleon coupling in pp scattering. Hoshizaki and Tanaguchi find that this coupling increases from 13.5 at low energies to 18.5 at 800 MeV, using a pp partial-wave analysis method. We find large errors associated with such an extraction and no evidence for a rapid variation. The influence of a coupled NΔ channel complicates such studies.

The extremely neutron-deficient Ba isotopes close to the proton drip line are studied in a relativistic mean field approach. The charge radii and the deformations are found to be in good agreement with the known experimental values. An interesting crossing between the proton and neutron root mean square radii is predicted around ${}_{}{}^{116}{}_{}{}^{}\mathrm{Ba}$.

We demonstrate that the cross sections derived from the ‘‘shadow model’’ for reactions between light nuclei disagree with low-energy laboratory data and exhibit unphysical behavior at energies below those for which data exist. As a consequence, the large thermonuclear reaction rates obtained by Scalia and Figuera [Phys. Rev. C 46, 2610 (1992)] are incorrect.

Recently a method was proposed by which one can obtain rank-1 (for uncoupled channels) and rank-2 (for coupled channels) energy-dependent separable t-matrix representations which are exact on and half off of the energy shell. Fully off shell, this representation, though accurate at low energies, is flawed. For uncoupled channels, if the phase shift passes through zero, the representation has a pathology. Here we investigate two methods which overcome this; one due to Haberzettl which we extend to coupled channels, and the second which is based upon selective combination of the elements of Sturmian expansions. We investigate and compare all methods of separation over a range of energies up to 250 MeV for the ${}_{}{}^1{}_{}{}^{}$${\mathit{S}}_0$ and ${}_{}{}^3{}_{}{}^{}$${\mathit{S}}_1$ channels with the Paris interaction. Special attention is paid to the convergence of the higher-order Haberzettl expansion and to the comparison of the extended methods for energies around the zero-phase-shift pathology for the ${}_{}{}^1{}_{}{}^{}$${\mathit{S}}_0$ channel.

Mean-field approximation results emerging from Hartree-Fock calculations with Skyrme-type forces are compared with those obtained within the natural orbital representation of the Jastrow correlation method in its lowest order approximation for ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$. The influence of short-range correlations on the single-particle wave functions and occupation probabilities is analyzed. A two part decomposition of the one-body density matrix which is obtained in the method reflects both the low- and high-momentum components of the correlated ground state.

${\mathrm{He}}^4$-ion-induced fission excitation functions of terbium (Z=65) and ytterbium (Z=70) were obtained by measuring fission cross sections in the energy range of 40–65 MeV using lexan polycarbonate plastic as the fission fragment track detector. The present measurements extend the range of low-Z elements in the deformed region for which ${\mathrm{He}}^4$-ion-induced fission excitation functions were obtained at moderate energies. The analysis of the ratio of ${\mathrm{\Gamma }}_{\mathrm{f}}$/${\mathrm{\Gamma }}_{\mathrm{n}}$≈${\mathrm{\sigma }}_{\mathrm{f}}$/${\mathrm{\sigma }}_{\mathrm{R}}$, which is a measure of the competition between fission and neutron emission widths, in terms of the statistical model expression, indicates the fission thresholds for ${\mathrm{Ho}}^{163}$ and ${\mathrm{Hf}}^{177.1}$ to be 31.5±3.5 and 26.7±3.0 MeV, respectively. The corresponding value for the fission level density parameter ${\mathrm{a}}_{\mathrm{f}}$ was found to be A/12 ${\mathrm{MeV}}^{\mathrm{-}1}$ for both the compound nuclei. ${\mathrm{Ho}}_{67}^{163}$ represents the lightest compound nucleus for which fission barrier has been determined experimentally. The measured fission barriers compare very well with the theoretical fission barriers obtained by liquid-drop-based models. The present data have been used along with similar data available in the literature to bring out some systematics in the fission properties of low-Z elements. A systematic trend was observed in the ${\mathrm{a}}_{\mathrm{f}}$/${\mathrm{a}}_{\mathrm{n}}$ ratio of preactinide elements ranging from ${\mathrm{Ho}}^{163}$ to ${\mathrm{At}}^{213}$ (16 nuclei). A linear dependence of ${\log }_{10}$${\mathrm{\Gamma }}_{\mathrm{f}}$/${\mathrm{\Gamma }}_{\mathrm{n}}$ with ${\mathrm{Z}}^2$/A at constant excitation energies was observed extending over 8 orders of magnitude for low Z-compound nuclear systems from ${\mathrm{Ho}}^{163}$ to ${\mathrm{At}}^{213}$ all of which are characterized by a predominance of symmetric fission. A linear dependence was also observed in the variation of ${\log }_{10}$${\mathrm{\Gamma }}_{\mathrm{f}}$/${\mathrm{\Gamma }}_{\mathrm{n}}$ with ${\mathrm{E}}_{\mathrm{f}}^{\prime }$–${\mathrm{B}}_{\mathrm{n}}^{\prime }$ where ${\mathrm{E}}_{\mathrm{f}}^{\prime }$ is the effective fission barrier and ${\mathrm{B}}_{\mathrm{n}}^{\prime }$, neutron binding energy including 50% shell correction and pairing energy term, at constant excitation energies (40 MeV) for these 16 low-Z compound nuclear systems. The results suggest that shell effects tend to persist even at excitation energies of 40 MeV. An analysis was also done to separate the symmetric and asymmetric fission barriers. It is observed that asymmetric fission barrier ${\mathrm{E}}_{\mathrm{f}}$(asym) is much higher than symmetric fission barrier ${\mathrm{E}}_{\mathrm{f}}$(sym) for A⩽200 clearly suggesting that symmetric fission is the only observable mode below compound nuclear mass A=200.

Cross sections and analyzing powers have been measured for the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$(p,d${)}^{39}$Ca reaction with polarized proton beams of 65 MeV incident energy. The data analysis with a standard distorted-wave Born approximation theory provides transferred angular momenta l, j, and spectroscopic factors for 58 transitions mainly to the 1${\mathit{d}}_{3/2}$, 2${\mathit{s}}_{1/2}$, and 1${\mathit{d}}_{5/2}$ hole states in ${}_{}{}^{39}{}_{}{}^{}\mathrm{Ca}$. The occupation probabilities of the surface shells in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ and the spreading widths of the hole states are determined. The damping mechanism of the single hole states is discussed.

We have measured the electron β data spectrum of ${}_{}{}^{35}{}_{}{}^{}\mathrm{S}$ with an iron-free magnetic spectrometer. In particular, we have searched for the 17-keV neutrino claimed by various authors to exist at the 0.8–1.1 % level. We have successfully fit our data over a large portion of the spectrum (40–166 keV) and find no evidence for the 17-keV neutrino. The branch is determined to be (0.01±0.15)%, which is in serious disagreement (5σ) with the (0.84±0.06)% branch claimed by Hime and Jelley.

The recent finding that yrast B(E2) values and yrast energy ratios behave differently in nuclear transitional regions suggests that these two observables reflect collectivity in rather different ways. In this paper, these observables are systematically studied over most of the nuclear chart with a Nilsson-Strutinsky-BCS method, leading to a rather simple, qualitative distinction between them, namely that B(E2:$2_1^{+}$→$0_1^{+}$) values are primarily sensitive to the location of the minimum in the potential energy surface, while energies seem to reflect the detailed shape and anharmonicities of the potential.

Magnetic moment measurements in odd nuclei directly probe the distribution of fermion states and hence provide one of the most critical tests for multi-j supersymmetries in collective nuclei. Due to complexity of calculations and lack of data, such tests have not been performed in the past. Using the mathematica software, we derive analytic expressions for magnetic moments in the ${\mathrm{SO}}^{\left(\mathit{B}\mathit{F}\right)}$(6)×${\mathrm{SU}}^{\left(\mathit{F}\right)}$(2) limit of the U(6/12) supersymmetry and compare the results with recent measurements in ${}_{}{}^{195}{}_{}{}^{}\mathrm{Pt}$.

The large polarization recently measured in the annihilation reactions pp¯→${\mathrm{\pi }}^{+}$${\mathrm{\pi }}^{\mathrm{-}}$ and pp¯→${\mathit{K}}^{+}$${\mathit{K}}^{\mathrm{-}}$ seems to be due to the strong spin dependence of the initial state interaction. The nonlocality of the annihilation operator might also play an important role.

It is shown that the experimental in-band energy ratios for the even-even nuclei obey universal systematics similar to those observed by Mallmann for the quasiground band. Systematic correlations between energy ratios belonging to different bands are also found in certain cases. Finally, correlations between mixed energy ratios are shown to be useful in characterizing the evolution of the nulcear collectivity.