The role of the continuity equation in the calculations usually performed in the context of the electron scattering from nuclei is analyzed. Special attention is paid to the uncertainty introduced in the theoretical predictions after this equation is considered in the calculation of the transverse electric multipoles, when the models are not gauge invariant. Quantitative analysis of this point is done for a simple model based on a harmonic oscillator Hamiltonian with a constant spin-orbit potential. © 1996 The American Physical Society.

We consider the problem of determining amplitudes from observables for the case of pseudoscalar meson photoproduction. We find a number of surprisingly simple constraints which give necessary conditions for a complete set of measurements. These results contradict one of the selection rules derived previously. © 1996 The American Physical Society.

The linear momentum transfer occurring in central heavy ion collisions is studied within the Landau Vlasov model. A sensitivity to the equation of state is found for this observable. Assuming the free nucleon-nucleon cross section, a soft compressibility modulus (around 210 MeV) is required to reproduce the large amount of data available for linear momentum transfer. This result stands for local and nonlocal effective potentials. © 1996 The American Physical Society.

Particle evaporation from excited nuclei is calculated with the Boltzmann-Uehling-Uhlenbeck equation, which is solved numerically using the test-particle method. If the collision integral is omitted, the resulting Vlasov dynamics is very sensitive to numerical noise inherent in the test-particle method. With the collision integral included, the numerical error can be reduced to a point where the system reaches a steady state of evaporative decay. The evaporation rate is found to be consistent with the Weisskopf statistical formula. © 1996 The American Physical Society.

In a recent publication Zheng, Vary, and Barrett reproduced the negative quadrupole moment of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ and the low-lying positive-parity states of ${}_{}{}^5{}_{}{}^{}\mathrm{He}$ by using a no-core shell model. In this Comment we question the meaning of these results by pointing out that the model used is inadequate for reproducing these properties. © 1996 The American Physical Society.

We reply to the preceding Comment. © 1996 The American Physical Society.

Definitions of the energy and width of an unbound level, which have more justification than those used by Fortune et al. [Phys. Rev. C 51, 3023 (1995)], are discussed and applied to low-lying levels of ${}_{}{}^{11}{}_{}{}^{}\mathrm{Be}$ and ${}_{}{}^{11}{}_{}{}^{}\mathrm{N}$. © 1996 The American Physical Society.

The rescattering mechanism with ${\mathit{K}}^{\mathrm{*}}$K¯ and K${\mathrm{¯}}^{\mathrm{*}}$K intermediate states gives a large enhancement for p¯p→φ${\mathrm{\pi }}^0$ from initial S states. This is consistent with experimental data. The problem is why p¯p→φ${\mathrm{\pi }}^0$ is not seen in the annihilation from initial P states. A recent paper suggested that possible destructive interference between l=0 and l=2 of the intermediate ${\mathit{K}}^{\mathrm{*}}$K¯ system may be the reason. Here I argue that there is another more solid and important reason, i.e., the small total decay width of I=1 ${}_{}{}^1{}_{}{}^{}$${\mathit{P}}_1$ protonium. © 1996 The American Physical Society.

We reply to the Comment by Bingsong Zou. © 1996 The American Physical Society.

Inclusive ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(\gamma , pp)$ cross sections have been measured with tagged photons in the range $E_{\gamma }=187-227\mathrm{}$ MeV using the Saskatchewan-Alberta Large Acceptance Detector (SALAD). The large angular acceptance allowed the measurement of noncoplanar $\mathrm{pp}$ emission. The cross sections were compared to a Monte Carlo intranuclear cascade calculation. Agreement was reasonable for the shapes of the cross sections but the calculated total cross section was 3.9 times larger than the data.

The cross section for the reaction ${}_{}{}^1{}_{}{}^{}\mathrm{H}(\gamma , {\pi }^0)$ has been measured using tagged photons in the threshold region (144.7-169.3 MeV). The total cross section, augmented by angular distribution information, is used to deduce the $S$-wave multipole $E_{0+}$. Extrapolation to threshold yields $E_{0+}=(-1.32\mathrm{}\pm 0.05\pm 0.06)\times {10}^{-3\mathrm{}}/m_{\pi }$, in disagreement with earlier estimates. Suppression of $E_{0+}$ near the ${\pi }^{+}$ threshold is confirmed, in approximate agreement with recent calculations.

Double ratios involving (6Li, 7Li, 3He, 4He) and (7Li, 8Li, 3He, 4He) isotope yields have been used to extract nuclear temperatures for the ${}_{}{}^{36}{}_{}{}^{}\mathrm{Ar}$+${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$ systems at $\frac{E}{A}=35\mathrm{}$ MeV. After correcting for sequential decays, these isotope temperatures are compared to corresponding temperatures obtained from excited state populations measured in the same experiment. Within experimental uncertainties, both techniques yield similar results.

The influence of the coupling of inelastic and transfer channels on the absorption cross section behind the barrier is discussed for reactions induced by weakly bound projectiles. It is shown that because of the prevailing positive $Q$ values a decrease of the absorption cross section may occur. The result is demonstrated for a ${}_{}{}^{11}{}_{}{}^{}\mathrm{Be}$+${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ system using the coupled reaction channel approach. The adiabatic potential energies of the asymptotic states which are subjected to strong coupling may give a natural explanation of this effect.

Using a recently developed method for the inclusion of fluctuation in the BUU dynamics we study the self-consistent propagation of inherent thermal noise of unstable nuclear matter. The large time behavior of the evolving system exhibits synergism between fluctuation and nonlinearities in a universal manner which manifest in the appearance of macroscopic structure in the average description.

The phenomenon of identical bands is studied by analyzing the distributions of fractional changes in the dynamical moments of inertia of pairs of bands in superdeformed (SD) nuclei. These distributions are found to exhibit a peak with a centroid at nearly zero. Their widths increase in going from the SD bands in the mass $A\sim 150$, to the SD bands in the mass ∼190, and to the normally deformed bands in the rare-earth region. Consequently, there exists a significant excess of identical bands in SD nuclei compared to the normally-deformed nuclei at low spins. This difference may be attributed to the weaker pairing correlations and the stabilizing role of intruder orbitals on the structures of SD bands.

The high spin levels in ${}_{}{}^{84}{}_{}{}^{}\mathrm{Zr}$ have been populated through the ${}_{}{}^{59}{}_{}{}^{}\mathrm{Co}$${(}^{28}$Si,p2n) reaction using 98 MeV ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ beam. Lifetime measurements for the ${20}^{+}$ and ${22}^{+}$ levels in the yrast positive parity band using the line-shape analysis method gave values nearly a factor of 2.5 larger compared to those reported earlier—indicating a smaller deformation at high spins for ${}_{}{}^{84}{}_{}{}^{}\mathrm{Zr}$. The transition quadrupole moments obtained from the present measurements show a decrease at I∼8ħ and an increase at I∼16ħ. Theoretical calculations using the Nilsson model with the Woods-Saxon potential show that this decrease (increase) is directly related to the 2p (2n) alignment in high (low) Ω orbitals. © 1996 The American Physical Society.

We have measured the analyzing power for elastic scattering of ${\mathrm{\pi }}^{+}$ from a target of polarized ${}_{}{}^1{}_{}{}^{}\mathrm{H}$. Data were taken for incident pion beam energies of 165 and 240 MeV at several pion scattering angles. The current data generally agree with previously existing measurements of ${\mathit{A}}_{\mathit{y}}$ for this reaction and also with results of the SAID phase-shift analysis program. In most cases the new data are of higher precision than previously existing data. © 1996 The American Physical Society.

The time differential perturbed angular distribution (TDPAD) technique has been utilized to measure the $g$ factor of the ${10}^{+}$ state of ${}_{}{}^{132}{}_{}{}^{}\mathrm{Ba}$. The ${}_{}{}^{132}{}_{}{}^{}\mathrm{Ba}$ nucleus was produced in the reaction ${}_{}{}^{124}{}_{}{}^{}\mathrm{Sn}({}_{}{}^{12}{}_{}{}^{}\mathrm{C}, 4n){}_{}{}^{132}{}_{}{}^{}\mathrm{Ba}$ using a pulsed carbon beam. The experimentally obtained value of the $g$ factor (= -0.159±0.005) compares well with the theoretical estimate for the neutron character of the state.

Prescission neutron multiplicities have been calculated in the framework of a simple, dynamical model of fission. The fission trajectories have been calculated by solving Euler-Lagrange equations with dissipation generated through two-body nuclear viscosity. Systematic study of the relationship between the prescission neutron multiplicities and nuclear viscosity has been made in the range of mass 150–200 and incident energy 4–13 MeV/nucleon. The values of the viscosity coefficients which are used to predict the observed prescission neutron multiplicities follow a global relation in the region of mass and energy studied.

Neutron halos and their relations to the structure of E1 resonances are examined in a microscopic random phase approximation continuum calculation of ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$. Our results predict the occurrence of small but distinct E1 peaks located in the low energy tail of the giant dipole resonance and consisting of highly coherent neutron particle-hole excitations whose energy and strength are found to correspond well to photoneutron and electron scattering data. This work suggests that the high current interest in the appearance of neutron halos in light exotic nuclei could constructively be channeled to investigate similar occurrences in heavier systems where model calculations have already been thoroughly tested. © 1996 The American Physical Society.