Existing ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ ${(}^3$He, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$${)}^6$Li elastic scattering data at 34, 50, 60, and 72 MeV have been reanalyzed with a microscopic potential in an elastic plus elastic triton-exchange model. The effects of the renormalization of the potential and the importance of the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ + t bound-state wave function are discussed.

The nonunitary character of the Dyson boson mapping is explored in a model case with the monopole pairing interaction. It is shown that because of the very special form of this interaction, the calculations in the intrinsic state formalism with the particle-particle representation of the Hamiltonian reproduce the exact results of the original fermion space. In contrast, we show that with the particle-hole representation of the Hamiltonian the intrinsic state approach produces erroneous results. Of course, upon employing the physical boson states we recover the exact results in the particle-hole represenation as well.

Chatterjee et al. [Phys. Rev. C 44, R2249 (1991)] report that the sharing of dissipated energy in the ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ + ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ reaction at E/A=6.5 MeV is not influenced appreciably by the direction and magnitude of net charge (and mass) transfer. We point out that neither this conclusion nor one arguing for a correlation between mass flow and excitation energy division is supported by the data and analysis presented in their communication.

It is pointed out that the Comment by Viola et al. does not contest the conclusions stated in our Rapid Communication [Phys. Rev. C 44, R2249 (1991)]. Instead, the Comment offers and disputes an interpretation of our data, which is more extensive than warranted, given the actual uncertainties associated with our data and method of analysis.

We comment on a recent paper by Rahman, Sen Gupta, and Rahman [Phys. Rev. C 41, 2305 (1990)]. We demonstrate that the theoretical results presented in that paper based on the strong absorption model of Frahn and Venter are at variance with those reported in this Comment. This in turn raises serious doubts regarding their stated conclusions.

The neutron decay of ${}_{}{}^{10}{}_{}{}^{}\mathrm{Li}$, produced in the reaction of 80 MeV/nucleon ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ + ${}_{}{}^{\mathrm{nat}}{}_{}{}^{}\mathrm{C}$, was studied by the coincidence detection of neutrons and ${}_{}{}^9{}_{}{}^{}\mathrm{Li}$ nuclei in a collinear geometry. An analysis of the relative velocity spectrum indicates the presence of a ${}_{}{}^{10}{}_{}{}^{}\mathrm{Li}$ state which decays by very low energy neutron emission. This state corresponds to either the ground state of ${}_{}{}^{10}{}_{}{}^{}\mathrm{Li}$, in which case it is probably an s-wave resonance, or an excited state at ${\mathit{E}}_{\mathit{x}}$≊2.5 MeV.

High-spin states in the nucleus ${}_{}{}^{196}{}_{}{}^{}\mathrm{Hg}$ were populated in the reaction ${}_{}{}^{192}{}_{}{}^{}\mathrm{Os}$${(}^9$Be,5n) at a beam energy of 65 MeV. A regular rotational-like ΔI=1 band has been observed up to an excitation energy of ${\mathit{E}}^{\mathrm{*}}$≊8.7 MeV and spin I≊30ħ. This is the second observation of a band of this character in a mercury isotope. The experimental results are compared with mean field calculations and semiclassical estimates based on the Dönau-Frauendorf formalism. The mercury bands show significantly lower B(M1)/B(E2) branching ratios as compared with similar bands in light lead nuclei. This difference may be more readily explained by a difference in single-particle structure rather than by large differences in deformation between the lead and mercury configurations.

The nucleus ${}_{}{}^{141}{}_{}{}^{}\mathrm{Gd}$ was investigated at high spins for the first time via the reactions ${}_{}{}^{112}{}_{}{}^{}\mathrm{Sn}$${(}^{32}$S,2pn${)}^{141}$Gd at 155 MeV and ${}_{}{}^{112}{}_{}{}^{}\mathrm{Sn}$${(}^{33}$S,2p2n${)}^{141}$Gd at 170 MeV. The methods of in-beam γ-ray spectroscopy were used to establish a number of different structures. These include a band assigned as the ν${\mathit{i}}_{13/2}$[660]1/$2^{+}$ intruder in the Nilsson scheme. This is the heaviest nucleus thus far in which this type of intruder band has been identified, and is the first case in which the 13/$2^{+}$ bandhead has been clearly observed. Cranked shell model (CSM) calculations predict the occurrence of backbends due to ${\mathit{h}}_{11/2}$ proton and ${\mathit{h}}_{9/2}$ neutron band crossings. Gradual upbends are observed in the experimental alignments, which suggests the interaction strengths are stronger than those predicted by the CSM.

An excess amount of ${}_{}{}^{96}{}_{}{}^{}\mathrm{Mo}$ found in a 1.7×${10}^9$ yr zircon sample from Cable Sands’ Western Australia, yielded a half-life of (3.9±0.9)×${10}^{19}$ yr for the double beta decay of ${}_{}{}^{96}{}_{}{}^{}\mathrm{Zr}$ to ${}_{}{}^{96}{}_{}{}^{}\mathrm{Mo}$.

Complete two-fragment velocity systematics have been measured over the entire range of fragmentation products for the system ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$ ${+}^{197}$Au at 50 and 100 MeV per nucleon. Fragment emission lifetimes are estimated from the reduced velocity (${\mathit{V}}_{\mathrm{rel}}$/ √${\mathit{Z}}_1$+${\mathit{Z}}_2$ ) correlation functions by a direct comparison with results from a classical three-body trajectory calculation. Furthermore, we examine the validity of the reduced velocity, ${\mathit{V}}_{\mathrm{red}}$, as a scaling parameter for constructing mixed-fragment (${\mathit{Z}}_1$≠${\mathit{Z}}_2$) correlation functions over the full measured range (5≤${\mathit{Z}}_{\mathit{i},}$j≤53) of fragment pairs excluding fission.

We calculate the momentum dependence of the ρ-ω mixing amplitude in a purely hadronic model. The basic assumption of the model is that the mixing amplitude is generated by NN¯ loops and thus driven entirely by the neutron-proton mass difference. The value of the amplitude at the ω-meson point is expressed in terms of only the NNω and NNρ coupling constants. Using values for these couplings constrained by empirical two-nucleon data we obtain a value for the mixing amplitude in agreement with experiment. Extending these results to the spacelike region, we find a ρ-ω contribution to the NN interaction that is strongly suppressed and opposite in sign relative to the conventional contribution obtained from using the constant on-shell value for the mixing amplitude.

We analyze the formation and decay properties of nucleon resonances formed in heavy-ion collisions at 1–2 GeV/u within a microscopic transport approach. In case of Au+Au reactions the density of Δ resonances reaches 0.15 ${\mathrm{fm}}^{\mathrm{-}3}$ in the central cell for a time period of the order of 10 fm/c such that one can legitimately speak about resonance matter. The lifetime of the Δ’s is found to be shortened at high density by only 20% due to the in-medium channel Δ+N→N+N.

We discuss the effect of breakup on heavy-ion fusion reactions induced by a halo nucleus ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ based on a semiclassical method. Our formula leads to a smaller effect of breakup than that calculated in a recent paper using unitarity. We show that although the large enhancement of the fusion cross section is moderated by the breakup, the halo nucleus ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ still leads to a larger fusion cross section than the other Li isotopes. This trend is especially significant at low energies, but occurs also at energies near the Coulomb barrier where experimental study is feasible.

A new phase-shift analysis of NN scattering in the energy range 15–160 MeV is presented. The analysis is based on the carefully reviewed world pp+np data, including recent results for higher-order spin observables in n-p scattering. The latter are essential to determine the mixing parameter ${\mathrm{\varepsilon }}_1$ which is directly related to the isoscalar tensor force. ${\mathrm{\varepsilon }}_1$ displays a high trend, in agreement with recent analyses above 140 MeV, and is only reproduced by potential models with a strong tensor force. The prediction of the full Bonn potential is too low by 20% for energies above 40 MeV. All other I=0 phase shifts show agreement with potential models; in particular, the notorious problem with ${}_{}{}^1{}_{}{}^{}$${\mathit{P}}_1$ around 50 MeV has disappeared. Around 25 MeV a ten parameter fit based purely on np data agrees with the corresponding fit to the pp data and reveals no indication of anomalous charge independence breaking.

The effect of the force range ${\mathit{r}}_0$ on an effective long-range interaction in a system of three resonantly interacting particles is considered. By employing a boundary-condition approach, it is explicitly shown that the account of the force range gives rise to a correction ${\mathit{r}}_0$/${\mathit{R}}^3$ in the effective long-range interaction. The correction is universal (i.e., independent of detail structure of the force), and is attractive for symmetric $0^{+}$ three-particle states. The effect of the correction on the well-known correlation between the three-particle binding energy and the particle-pair scattering length is calculated.

The variational method, within the Hamiltonian formalism of quantum field theory, is used to derive momentum space wave equations for any number of fermions interacting via a massive scalar field. These coupled equations are shown to be exactly solvable in the limit of fixed fermions. Approximate solutions are given in the two- and three-particle bound state case for various mass combinations and various strengths of the coupling of the fermion and scalar fields.

We consider the P- and Q-shape parameters in the eigenphase and ‘‘bar’’ phase shift representations for the two Reid potentials and the more recent Moscow potential. The values of these parameters were obtained from integrals of the zero-energy wave function in a similar manner to that for the effective range. Such expressions for the shape parameters yield more reliable numerical values of the shape parameter than those obtained by least-mean-squares or polynomial fits. We show that the eigenphase representation is more meaningful than the ‘‘bar’’ phase shift representation and that the variation in the values of ${\mathit{P}}_{\mathrm{\alpha }}$ in the models may be of significance.

The completeness properties of the discrete set of bound states, virtual states, and resonant states characterizing the system of a single nonrelativistic particle moving in a central cutoff potential are investigated. We do not limit ourselves to the restricted form of completeness that can be obtained from Mittag-Leffler theory in this case. Instead we will make use of the information contained in the asymptotic behavior of the discrete states to get a new approach to the question of eventual overcompleteness. Using the theory of analytic functions we derive a number of completeness relations in terms of discrete states and complex continuum states and give some criteria for how to use them to form resonant state expansions of functions, matrix elements, and Green’s functions. In cases where the integral contribution vanishes, the discrete part of the expansions is of the same form as that given by Mittag-Leffler theory but with regularized inner products. We also consider the possibility of using the discrete states as basis in a matrix representation.