We reply to the preceding comment.

The optimum Q-value model of Siemens et al. is reformulated on the basis of the participant-spectator scheme. With this extension, the partition of excitation energy in bidirectional transfer reactions can be predicted.

The properties of ${}_{}{}^{158}{}_{}{}^{}\mathrm{Yb}$ are calculated for a path which begins at spin 60ħ with a temperature of 1.0 MeV, and cools down to join the yrast line at spin 10ħ. The moment of inertia scrI and angular velocity ω both suggest a transition from quasirotational structures for spins above 40ħ to quasivibrational structures for spins 18–36ħ. This transition occurs in mean-field calculations as well as in calculations which include the thermal fluctuations in scrI and ω. .AE

The tensor analyzing power $A_{\mathrm{yy}}$(θ), vector analyzing power $A_y$(θ), and cross section σ(θ) of the ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(d→,γ${)}^4$He reaction have been measured for the angular range of 55°–149° in the center of mass system at an incident deuteron energy of 95 MeV. The reaction is dominated by the ${〈}^1$$D_2$‖E2${\Vert }^1$$S_0$〉 transition involving the S-state component of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, as indicated by the approximately ${\sin }^2$2θ angular distribution of the cross section. The observed deviation of σ(θ) from this shape is due to either M2 strength, tensor force effects, or both. The tensor analyzing power $A_{\mathrm{yy}}$(θ) is nearly isotropic, with a typical value of approximately 0.3±0.1. The vector analyzing power $A_y$ is zero within the statistical precision (typically ±0.2) of this data set, indicating a reduced contribution from E1 and M2 transitions compared to lower energies. Direct capture calculations in the plane-wave Born approximation do not reproduce even the sign of $A_{\mathrm{yy}}$.

Within the context of three-body (alpha particle plus two nucleons) models, and by assuming that the ground state of ${}_{}{}^6{}_{}{}^{}\mathrm{He}$ ($0^{+}$) and the lowest $0^{+}$ excited state of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ are members of the same isospin multiplet, the M1 transition form factor of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ for the inelastic electron scattering from the ground state ($J^{\pi }$T${=1\mathrm{}}^{+}$0) to the ω=3.56-MeV excited state ($J^{\pi }$T${=0\mathrm{}}^{+}$1) is calculated. From the inelastic form factor evaluated at ‖q‖=ω, the radiative width for the deexcitation of the 3.56-MeV $0^{+}$ state of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ is given. It is suggested that the calculations of this work serve as a starting point for future investigations where refinements are made to the three-body models and more details of the electromagnetic interaction, e.g., meson exchange currents, are taken into account.

This paper investigates the nonstatistical effects in radiative neutron capture cross sections for nuclides at the 2p size resonance region of neutron strength function, specifically ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$(n,γ) and ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$(n,γ) reactions. The neutron energies studied range from thermal up to 2 MeV. The calculated results show that in comparison with medium and heavy nuclei, the nonstatistical fractions in the total capture cross sections for the two lighter nuclides are extremely large. In the thermal energy region, the fractions are about 50%. In the resonance energy region, the averaged contributions from the nonstatistical processes are considerably larger than that from the statistical mechanism. The physical significance of the results was briefly discussed. It was also indicated that this conclusion is qualitatively consistent with the fact that the measured capture data show significant correlations in both nuclides.

The properties of the type-c nucleon-exchange term in a resonating-group formulation that takes into account the clustering nature of the nuclei involved are investigated. The results indicate that these properties are weakly affected by the degree of clustering, and the one-exchange term makes the dominant contribution among all class-A exchange terms. The equivalent type-1c, or knockon, exchange potential is found to have a characteristic range shorter than the direct potential and a characteristic energy that has a large value around 50 MeV/nucleon.

The ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(γ,p)n cross section was measured simultaneously at ${\theta }_p^{\mathrm{c}.\mathrm{m}.\mathrm{}=0\mathrm{}}$°, 90°, and 180°. The photon energy range was 98–243 MeV. A quasimonochromatic photon beam was used and the photon spectrum measured on line by a pair spectrometer. The results are in good agreement with the existing measurements of the 0° and of the 180° cross sections and confirm the consistency among all experimental data from monochromatic photon beams. At all measured energies, angular distributions were extracted and compared with theory. The data agree moderately well with recent calculations which include relativistic effects.

Two methods of discretization of the s-wave n-p breakup continuum are compared, and their effect on the elastic deuteron-nucleus scattering matrix elements is numerically investigated. In one of the methods, the continuum eigenstates of the n-p Hamiltonian are averaged over discretized momentum bins of size Δk. In the other, which is a form of the $L^2$ diagonalization method, the continuum is expanded in a set of normalizable basis functions, which physically correspond to placing the n-p potential into a box. It is found, in the case of ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$(d,d) at incident deuteron energies $E_d$=21.6 and 45 MeV, that those two discretization techniques consistently display the same physics and yield the same results. However, the lower the incident deuteron energy, the less well do the momentum discretized answers converge to a final result. The diagonalization method is found to perform better in this respect. The theoretical expectation that the long range tails of the potentials in breakup space do not sensitively affect the elastic S-matrix elements is demonstrated numerically. This result provides the mathematical reason why the discretization of the breakup continuum is a viable and practical procedure of including the breakup effects.

The degree of parity mixing in the 0.734-eV neutron resonance in ${}_{}{}^{139}{}_{}{}^{}\mathrm{La}$ was measured in a two-sample transmission experiment. An unpolarized neutron beam was weakly polarized in the longitudinal direction at energies near the resonance by transmission through a ${\mathrm{La}}_2$${\mathrm{O}}_3$ sample. The beam was passed through a spin flipper and then through a second sample of ${\mathrm{La}}_2$${\mathrm{O}}_3$. The difference in transmission for the two spin directions was then measured to determine the longitudinal asymmetry. We obtain 9.2±1.7 % s-wave mixing into this p-wave resonance, which is consistent with earlier measurements using polarized beams in single transmission experiments. Because parity mixing is an attribute of the weak force, the experiment demonstrates the remarkable enhancement in the weak force in neutron resonances—an effect large enough to allow polarization of a neutron beam. Experiments of this class are described which should permit the first systematic study of the manifestation of the weak force in complex nuclei.

Using the microscopic optical model of Jeukenne, Lejeune, and Mahaux we have calculated the absolute neutron total cross sections and cross section differences of ${}_{}{}^{140}{}_{}{}^{}\mathrm{Ce}$, ${}_{}{}^{139}{}_{}{}^{}\mathrm{Ce}$, ${}_{}{}^{141}{}_{}{}^{}\mathrm{Ce}$, ${}_{}{}^{142}{}_{}{}^{}\mathrm{Ce}$, and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ca}$ from 6–60 MeV and have made comparisons with experimental data. Except for ${}_{}{}^{142}{}_{}{}^{}\mathrm{Ce}$, reasonable agreement with the mass 140 data was achieved with proton densities ${\rho }_p$ of the nuclei determined by ${\mu }^{\mathrm{-}}$ data and neutron densities determined by the relationship ${\rho }_n$=(N/Z)${\rho }_p$ which implies Δ$r_{\mathrm{np}}$ =〈$r_n^2$${〉}^{1/2}$ -〈$r_p^2$${〉}^{1/2}$=0. Satisfactory agreement with the ${}_{}{}^{142}{}_{}{}^{}\mathrm{Ce}$ data was obtained by choosing a ${\rho }_n$ for ${}_{}{}^{142}{}_{}{}^{}\mathrm{Ce}$ with Δ$r_{\mathrm{np}}$=0.05 fm and by a 10% increase in the strength of the ${}_{}{}^{142}{}_{}{}^{}\mathrm{Ce}$ imaginary potential. Similar choices of Δ$r_{\mathrm{np}}$ and imaginary potential strength were made for ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ca}$ in trying to fit the ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ca}$ data. Previous phenomenological analyses carried out for this data are in qualitative agreement with our results, which imply that the addition of a few neutrons to a nucleus with a closed neutron shell yields a nucleus with a slightly thicker neutron skin and a larger neutron reaction cross section when compared to their closed shell isotopes.

Differential cross sections for the inelastic scattering of 66.5 MeV protons from ${}_{}{}^{148}{}_{}{}^{}\mathrm{Sm}$ and ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}$ were measured over an angular range 8°–90° (c.m.). For ${}_{}{}^{148}{}_{}{}^{}\mathrm{Sm}$, data were obtained for the ground and the first excited states. Using the first-order vibrational model, coupled-channel calculations reproduce both states rather well. Data for the $J^{\pi }$${=0\mathrm{}}^{+}$–$6^{+}$ members of the roatational band of ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}$ were also obtained. ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}$ was treated as a rigid rotor and coupled-channel calculations were carried out in terms of the deformation of the ${}_{}{}^{148}{}_{}{}^{}\mathrm{Sm}$ spherical optical-model potential. Deformation parameters ${\beta }_2$, ${\beta }_4$, and ${\beta }_6$ have been extracted. Contrary to results of (α,α’)scattering at 50 MeV and proton inelastic scattering at 800 MeV, the data show preference for a positive value of ${\beta }_6$, in agreement with (p,p’) studies at 35 and 135 MeV and the calculations of Nilsson et al.

Gamma-ray decay of levels in the stable isotope ${}_{}{}^{53}{}_{}{}^{}\mathrm{Cr}$ has been studied using ${}_{}{}^{53}{}_{}{}^{}\mathrm{Cr}$(n,n’γ) reactions for incident neutron energies between threshold and 10 MeV. Measured gamma-ray production cross sections have been compared with earlier measurements and with cross sections calculated using precompound-compound-nucleus theory. Some of the present results are at variance with earlier experimental or evaluated results. For example, for the decay of the $E_x$=1537-keV level we are unable to explain variations in the measured branching ratios of the transition gamma rays as a function of incident neutron energy. The experimental data were analyzed within the framework of several theoretical model calculations of the level structure of ${}_{}{}^{53}{}_{}{}^{}\mathrm{Cr}$. Quantitative discrepancies are discussed.

A model for inclusive proton-nucleus scattering which covers the preequilibrium region is developed based on (1) single-step quasifree scattering and (2) the exciton model, which describes emission from 3p2h and higher configurations. Results are compared to data for various nuclei at incident energies from 60 to 200 MeV. The systematics of angle-dependent energy spectra are well reproduced by the model, except in the large-energy-loss region at very forward angles. We find the single-step quasifree scattering constitutes 60% to 80% of the reaction cross section in medium-heavy nuclei, and about 50% in heavy nuclei. The preequilibrium region is therefore dominated by direct single-step reactions.

The reaction ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}$(α,α’p) at $E_{\alpha }$=172.5 MeV is studied by measuring in-plane correlations at large angles. The data show the presence of two different reaction mechanisms: a direct proton knockout which was analyzed under the assumption of a quasifree process in terms of the distorted-wave impulse approximation and deep inelastic processes which were reproduced by exciton coalescence model calculations.

Fast neutron scattering cross section and analyzing power measurements have been performed for ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{\mathrm{nat}}{}_{}{}^{}\mathrm{Cu}$, and ${}_{}{}^{\mathrm{nat}}{}_{}{}^{}\mathrm{Cr}$ at incident neutron energies of $E_n$=7.62 MeV (Al) and $E_n$=7.75 MeV (Cu,Cr). Elastic scattering and inelastic scattering to the first excited states has been measured at angles from 21° to 124°. The scattering data obtained from the unfolded proton-recoil scintillation spectra were corrected for multiple scattering effects. Optical model parameters could be deduced by applying the excited-core weak-coupling model for a coupled channels analysis.

Based on neutron differential cross section and analyzing power measurements at $E_n$=7.75 MeV, optical-model parameters were deduced via spherical optical-model and coupled-channel calculations for the odd-even-nuclei ${}_{}{}^{89}{}_{}{}^{}\mathrm{Y}$, ${}_{}{}^{139}{}_{}{}^{}\mathrm{La}$, and ${}_{}{}^{169}{}_{}{}^{}\mathrm{Tm}$. For the strongly deformed thulium (${\beta }_2$=0.31), good fits to the sum of the angular distributions of the experimentally unresolved states could be achieved by coupling the ground-state rotational band.

${}_{}{}^{78}{}_{}{}^{}\mathrm{Sr}$ was produced in the reaction ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$${(}^{24}$Mg, 2p2n) with a relative cross section of less than 2.5% of the total fusion cross section at 110 MeV, but high spin states up to 16ħ were firmly identified. Fifteen neutron detectors and fifteen Compton suppressed Ge detectors were used in a large solid angle arrangement. 2nγγ and nγγ coincidences were recorded. A small irregularity in the dynamic moment of inertia $J^{\mathrm{}\left(2\right)\mathrm{}}$/${ħ}^2$ is evidence for a strongly mixed band crossing at ħω≊0.55 MeV in agreement with what is observed in ${}_{}{}^{80}{}_{}{}^{}$,82Sr.

We have examined the fragmentation of relativistic lanthanum and gold nuclei incident on targets of polyethylene, carbon, aluminum, and copper. Attention has been concentrated on those fragments whose atomic numbers were only changed by +1 to -3 from those of the incident nuclei. The cross section for the production of fragments with increased charge is about 10% that for fragments that have lost one charge, or about 1% of the total interaction cross section. We find that the velocity distributions of these fragments can be explained by assuming that they also lose significant numbers of neutrons when they pick up or lose charge, without a need to invoke any energy or momentum loss in the interaction, although we cannot exclude small losses. In particular, we cannot confirm the recent report of large energy losses during the charge pickup process. The relative numbers of neutrons lost can be represented by a simple Gaussian model, and, for those fragments with decreased charge, are much larger than the proton losses. These fragments consequently have large proton excesses and will be highly unstable.