A fully microscopic calculation for pion inelastic excitation of giant resonances in which random phase approximation transition densities are used is presented for the first time. The mixing of isoscalar and isovector modes is incorporated in the random phase approximation calculations and its effect on σ(${\pi }^{\mathrm{-}}$) vs σ(${\pi }^{+}$) is discussed. Comparison with existing data is made and reasonable agreement is achieved.

The influence of strong relativistic nuclear dynamics on weak nuclear processes is examined. The constraint of partial conservation of the axial current is shown to render the weak nuclear amplitudes insensitive to the relativistic nuclear dynamics.

A microscopic description of the recent data on the Coulomb form factors for the $0_{\mathrm{g}.\mathrm{s}.\mathrm{}{}^{+}\to 2_2^{+}}$ transitions in the nuclei ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ti}$ and ${}_{}{}^{50}{}_{}{}^{}\mathrm{Cr}$ is attempted in terms of the prolate and oblate intrinsic states resulting from realistic effective interactions operating in the 2p-1f shell. The results for the higher momentum-transfer region show significant improvements compared to the form factor estimates obtained in some recent shell model calculations involving the $f_{7/2}^n$+$f_{7/2}^{n\mathrm{-}1}$$p_{3/2}$ configurations.

The barrier region resonances of the ${}_{}{}^{12}{}_{}{}^{}$C${+\mathrm{}}^{12}$C system have been analyzed by Erb and Bromley in terms of the O(4) dynamical symmetry of the nuclear vibron model. Using the general Hamiltonian of the model based on δ and π bosons, we have reanalyzed these data. With parameters characterizing a situation close to the U(3) dynamical symmetry good agreement was also achieved.

A transformation is used to obtain sets of equivalent Lorentz scalar, Lorentz four-vector, and tensor optical potentials. These potentials are used in the Dirac equation for describing elastic scattering observables.

Data obtained by scattering 29.8 MeV protons and 21.7 MeV neutrons from ${}_{}{}^{34}{}_{}{}^{}\mathrm{S}$ are used in a consistent analysis to obtain values and relative signs for proton ($M_{\mathrm{p}}$) and neutron ($M_{\mathrm{n}}$) multiple matrix elements for E2 transitions to the first three $2^{+}$ states in ${}_{}{}^{34}{}_{}{}^{}\mathrm{S}$. The data for the $0^{+}$(g.s.)→$2_2^{+}$(3.30 MeV) transition are consistent only with the assumption of the same relative sign of $M_{\mathrm{p}}$ and $M_{\mathrm{n}}$. .AE

It is shown that the statistical model of fission fragment angular distributions predicts a variation of the fragment spins with angle. This provides a simple test which can be used to establish the range of validity of the statistical model.

The production of intermediate rapidity complex fragments up to A=14 from the reactions of Ar incident on Au and Ca targets at 92 and 137 MeV/nucleon has been described using the coalescence model. The resulting coalescence radii are independent of observed fragment mass which indicates that these fragments are emitted from a common source. Extracted interaction region radii agree with recent proton-proton correlation results.

A discussion of tensor analyzing powers of the ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(d→,γ${)\mathrm{}}^4$He reaction at low energy ($E_{\mathrm{d}<20\mathrm{}}$ MeV), where the process is predominantly E2, is presented. The inclusion of the ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ D state generates transitions from the ${}_{}{}^5{}_{}{}^{}\mathrm{S}_2^{}{}_{}{}^{}$, ${}_{}{}^5{}_{}{}^{}\mathrm{D}_2^{}{}_{}{}^{}$, and ${}_{}{}^5{}_{}{}^{}\mathrm{G}_2^{}{}_{}{}^{}$ initial states. It is shown that the tensor analyzing powers depend linearly on the D/S ratio ρ of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ for angles near (1/4)π and (3/4)π. Using scattering wave functions with phase shifts obtained from resonating group calculations good agreement with recent $T_{20}$ data at $E_d$=9.7 MeV is obtained for -0.5<ρ<-0.4.

Charge-exchange spectra for the ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$(p,n) reaction at 200 MeV are calculated over the range -70≤$Q_{\mathrm{pn}}$ (MeV)≤0, in an effort to assess the degree of quenching and/or redistribution of Gamow-Teller strength. Comparison with the data suggests that the mixing of 1p-1h with 2p-2h states provides the most plausible explanation of the missing Gamow-Teller strength. Predicted spectra for anticipated (n,p) data are also presented and it is indicated how such data may provide additional insight into the issue of missing Gamow-Teller strength.

Differential cross sections and analyzing powers are presented for ${}_{}{}^{16}{}_{}{}^{}$O(p→,p${)}^{16}$O elastic scattering at $E_{\mathrm{p}=200\mathrm{}}$ MeV, extending over a large range of momentum transfer (up to q∼6 ${\mathrm{fm}}^{\mathrm{-}1}$). The data were analyzed in the framework of the nonrelativistic optical model. In addition to standard Woods-Saxon potentials, nonstandard radial shapes for the central and the spin-orbit potentials were investigated. The data are not adequately described over the entire angular range using a Woods-Saxon real central potential, but two distinct parametrizations (not simply related by the usual discrete or continuous parameter ambiguities which maintain a rough phase-shift equivalence) were found which provide a far superior representation. The similarity in the angular distributions given by these two potentials can be attributed to the fact that the non-spin-flip partial-wave scattering amplitudes $a_L$ differ by only a simple rotation in the complex $a_L$ plane. This rotation has a negligible effect on the predicted cross section and the analyzing power angular distributions, but leads to sizable differences in the predicted spin-rotation function Q(θ).

Differential cross sections for the elastic scattering of 14.6 MeV neutrons from ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$, C, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, Fe, ${}_{}{}^{59}{}_{}{}^{}\mathrm{Co}$, ${}_{}{}^{89}{}_{}{}^{}\mathrm{Y}$, ${}_{}{}^{93}{}_{}{}^{}\mathrm{Nb}$, In, ${}_{}{}^{140}{}_{}{}^{}\mathrm{Ce}$, ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$, ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$, ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$, and ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ have been measured using a time-of-flight facility. The measured cross sections cover the angular range from 9.2° to 159°. Calculations have been carried out using two local microscopic optical potentials, based on the work of Jeukenne, Lejeune, and Mahaux, and of Brieva and Rook. Reasonably good agreement with the measurements is found over the whole mass range, with the Jeukenne-Lejeune-Mahaux potential giving systematically better agreement with the data. The quality of the results with the Jeukenne-Lejeune-Mahaux potential compares well with that obtained from phenomenological optical model calculations using global parameters.

The elastic scattering in the ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$${+}^{12}$C system was measured at c.m. energies of 5.43, 6.47, and 7.60 MeV in the angular range from 13° to 160° c.m. The analysis, taking into account the interference between potential scattering and direct elastic transfer, led to the value of the asymptotic magnitude of the 1$p_{3/2}$ proton wave function in ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, C¯=12.9±1.0. A proton spectroscopic factor equal to 2.75±0.4 is obtained for a binding potential with geometrical parameters $r_0$=1.25 fm and a=0.65 fm.

A marked variation of the analyzing power A(θ) with incident proton energy for the ground-state ($0_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{+}$) transition of ${}_{}{}^{92}{}_{}{}^{}\mathrm{Zr}$(p,t${)}^{90}$Zr($0_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{+}$ was observed over a proton-energy range from 17.0 to 28.5 MeV in the angular region around θ≊20° where the corresponding (p,t) cross section σ(θ) yields the first minimum. On the other hand, no such an energy variation was observed at all in the analyzing power for the ground-state transition of ${}_{}{}^{138}{}_{}{}^{}\mathrm{Ba}$(p,t${)}^{136}$Ba($0_{\mathrm{g}.\mathrm{s}.\mathrm{}}$ ${}_{}{}^{+}{}_{}{}^{}$) over the same energy range. The former analyzing power shows an ‘‘anomalous’’ angular distribution which deviates essentially from the derivative rule {A(θ)=[dσ(θ)/dθ]/σ(θ)}, while the latter analyzing power shows a ‘‘normal’’ angular distribution. In contrast to the analyzing-power angular distributions, the cross-section angular distributions of the two reactions are quite similar and do not show any remarkable energy variation. All these characteristic features of the two reactions are explained by taking account of strong, sequential (p,d) (d,t) two-step processes in addition to a (p,t) one-step process in terms of the first- and second-order distorted-wave Born approximation. The nuclear-shell orbit dependence ( j dependence) of the analyzing powers for the (p,d) (d,t) two-step process plays an essential role in producing the distinguished difference in the energy dependence of the observed analyzing powers for the two reactions. When two neutrons are picked up sequentially from a $j_{>}$=l+(1/2) ( $j_{<}$=l-(1/2)) orbit, such as a $d_{5/2}$ ($d_{3/2}$) orbit in the case of the ${}_{}{}^{92}{}_{}{}^{}\mathrm{Zr}$(p,t${)}^{90}$Zr ${[}^{138}$Ba(p,t${)}^{136}$Ba] reaction, the two-step analyzing power is quite different from (similar to) the one-step analyzing power so that the total analyzing power shows a completely different (similar) angular distribution from (to) the one-step analyzing power in the forward angles. The interference effect between the one- and two-step processes is thus quite sensitive to (quite stable against) the relative phase between the transition amplitudes of the two processes. Therefore ${}_{}{}^{92}{}_{}{}^{}\mathrm{Zr}$(p,t) ${[}^{138}$Ba(p,t)] analyzing power shows a marked (no marked) change with incident energy. The nuclear structure involved in the reaction ${}_{}{}^{138}{}_{}{}^{}\mathrm{Ba}$(p,t${)}^{136}$Ba is calculated on the basis of the monopole-pairing vibrational model. The cross section of the (p,d) (d,t) two-step processes is as large as that of the one-step process, so that the resultant total cross section obtained from the coherent sum of the two processes can reproduce the absolute magnitude of the experimental cross sections for the $0_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{+}$→$0_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{+}$(p,t) reactions well. The derivative rule for $0_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{+}$→$0_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{+}$(p,t) reactions is derived within the framework of the first-order distorted-wave Born approximation.

The particle-inclusive doubly differential cross section, $d^2$σ/dE dθ, for ejectiles with atomic numbers Z=4 to 15 from 100 MeV ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$${+}^{48}$Ti, was measured over a large angular range. From a semiclassical analysis of the angular distributions we obtain the mean values and the dispersion widths of the deflection angles and the contributions from orbiting around 180°. A mean prolate deformation with β=0.37 is derived from the most probable Q values in the fully damped processes at large angles. Using the surprisal technique, the shapes of the energy spectra are well reproduced by constrained phase-space distributions. If the measured correlation of the angular momentum transfer and the reaction Q value is taken into account, only the mean Q values of the quasielastic and of the deep-inelastic reaction component are required as constraints.

Collective flow effects associated with bounceoff and side splash recently seen in Nb+Nb collisions are investigated. The nuclear bounceoff effect is studied using a folded optical potential. The velocity dependence of the two-body interaction is found to be important for bounceoff. The side-splash effect is studied using linear transport theory. Based on a relaxation time approximation to the Boltzmann equation, we are able to explicitly isolate two separate contributions to the kinetic flow tensor. Specifically, the kinetic flow tensor is related to the collective velocity field and the pressure tensor. In turn, the pressure tensor is related to the nuclear viscosity. The two contributions to kinetic flow interfere destructively. Assuming laminar flow, the viscous term is found to be important in the nuclear side-splash effect.

From the energy spectra of light particles produced in light-heavy-ion-induced reactions, level densities of the final nuclei as well as the critical angular momenta for fusion may be obtained. The ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$, ${}_{}{}^{16}{}_{}{}^{}$,18O${+\mathrm{}}^{12}$C reactions were investigated in the energy range 30 MeV<$E_{\mathrm{lab}<60\mathrm{}}$ MeV. Detailed angular distributions of the light particles (p,d,t${,}^3$He,α) emitted in the process were obtained. Fits of the magnitude and shape of the spectra by means of statistical model calculations were used to extract final nuclei level densities. The shape of the spectra and the ratio σ(α)/σ(p) are shown to be sensitive to the fusion critical angular momentum ($J_{\mathrm{cr}}$), offering an alternative method for the total fusion cross-section determination.

We obtain an explicit approximate expression for the nucleon knockout form factor at small momentum transfer induced by a scalar probe in a single particle model in terms of the momentum space bound state wave function. Our form preserves the orthogonality constraint without using explicitly the final state scattering wave function. We examine the leading large momentum behavior of the momentum space wave function and of correction terms to our expression for the form factor in the case where the bound state is an s state.

The microscopic model of the distorted-wave Born approximation theory for (p,α) reactions formulated in the isospin representation is compared with a semimicroscopic analysis using cluster form factors and SU(3) spectroscopic amplitudes. The differential cross sections of α particles emitted in the reaction ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$(p,α${)}^{24}$Mg have been measured at the bombarding energies 20, 24, 30.5, and 45 MeV. The microscopic as well as the semimicroscopic distorted-wave Born approximation analysis reproduces the angular distributions in a large range of incident energies when using energy-dependent optical potentials. The relative intensities of the transitions to the ground state and excited states up to $E_x$=6 MeV are described quite well in the semimicroscopic analysis.

The amplitudes $F_{21}$(0)=1/2[F(0)-F(0)¯] for the coherent ${\mathrm{K}}_{\mathrm{L}}^0$→${\mathrm{K}}_{\mathrm{S}}^0$ regeneration on Cu in the momentum region of 600≤$P_{\mathrm{K}}$≤1400 MeV/c are calculated in the optical model. The many-body corrections for $Y^{\mathrm{*}}$ resonances in the nuclear medium are taken into account in the calculations of the strangeness -1 component F(0)¯ in $F_{21}$(0). Within the framework of the phenomenological isobar-doorway model, the many-body corrections for the resonances are expressed in terms of the resonance energy shifts and width-modification factors. The optical potentials for the scattering of K¯ ${}_{}{}^0{}_{}{}^{}$ and ${\mathrm{K}}^0$ on the nucleus are constructed with the K¯ ${}_{}{}^0{}_{}{}^{}$- and ${\mathrm{K}}^0$-nucleon partial wave amplitudes parametrized by Gopal et al. and by Nakajima et al., respectively. The calculated results are compared with the experimental data measured by Birnbaum et al. The inclusion of the many-body effects on the $Y^{\mathrm{*}}$’s is successful in explaining the striking energy dependence of the data around $P_{\mathrm{K}}$=1250 MeV/c.