The double differential cross sections of the (p, p′) process are calculated for ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{120}{}_{}{}^{}\mathrm{Sn}$, ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$, and ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ targets at $E_{\mathrm{p}}=62\mathrm{}$ MeV based on the generalized exciton model. Finite nuclear size effects are treated for the scattering kernel. Our results indicate that even at backward angles the angular distribution of the preequilibrium reaction can be well reproduced within the framework of the generalized exciton model.

We calculate the longitudinal response for (e, e') reactions on ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ and ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$ at|q|=550 MeV/c and show that a large discrepancy between theory and experiment found in the impulse approximation can be resolved by using the medium-modified nucleon electromagnetic form factors we have calculated in an earlier work.

The continuum spectra of the (p,${\pi }^{\mathrm{-}}$) reaction on nuclei in the medium and heavy mass region at $E_{\mathrm{p}\mathrm{\sim }200}$ MeV are studied in terms of the standard pion-absorption-production model. The threshold energy and the linear rise of the pion cross section with the excitation energy are reproduced. By including the medium effect on the rescattering pion and rho meson fields we can also account for the absolute value of the cross section.

Optical model potentials with various forms of energy-dependent geometry have been considered for the description of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ + ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ elastic scattering. It is shown that the variation with energy of the imaginary radius leads to a reasonable fit of the cross-section data, throughout the energy range.

We report on the sensitivity of the triton binding energy to the $D$-state probability $P_D$ in the deuteron. Based on a recently proposed energy-dependent separable potential, the ${}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}-{}_{}{}^3{}_{}{}^{}D_1^{}{}_{}{}^{}$ interaction is constructed in such a way that while varying $P_D$, the off-shell and on-shell behavior of the nucleon-nucleon forces employed (phase shifts are taken directly from experiment) are independent of the choice of $P_D$. The increase of $P_D$ within the experimental bounds from 4% to 7% decreases the triton binding energy by ≈0.55-0.60 MeV. These values are in very good agreement with the results obtained for the Reid potential by Harms et al., which differ strongly from the results by Brady et al.

Various functional parametrizations of the equation of state of cold nuclear matter are considered with regard to both their degree of stiffness and their causal behavior at high density. We show that (i) the inferred nuclear compressibility $K$ is strongly parametrization dependent when the measured pion multiplicity in central heavy ion collisions is fitted, and (ii) most of the commonly used equations of state are acausal at high density.

The anomalous mean free path for 1500 secondary interactions of projectile fragments produced by 5000 primary collisions of ${}_{}{}^{84}{}_{}{}^{}\mathrm{Kr}$ beam tracks at $1.52A$ GeV has been observed at a length of $L<\mathrm{}1.5\mathrm{}$ cm from their production point in nuclear emulsion. At energy $E>\mathrm{}1.1A$ GeV, the anomalous mean free path is independent of the target size, i.e., light (CNO) or heavy (AgBr), but at low energy $0.5<E<~1.1A$ GeV, the anomalous mean free path seems to appear with heavy targets.

We assess the adequacy of folded diagrams as a practical method for determining a Hermitian, instantaneous potential derived from meson exchange. The nucleon-nucleon scattering amplitude calculated from this folded-diagram potential agrees quite favorably with model-exact results. We compare our results to those based on a recently proposed non-Hermitian folded-diagram description.

Calculations are performed for the excitation of the $2_1^{+}$ state in ${}_{}{}^{52}{}_{}{}^{}\mathrm{Cr}$ by the inelastic scattering of electrons, protons, and pions. The use of probe-dependent enhancement factors of the type proposed by Brown and Madsen provides good agreement with data. The regions of large & differences in the $2^{+}$ and $4^{+}$ spectra, predicted by f-p shell configuration, are greatly reduced with the inclusion of pion enhancement factors.

Results of a determination of the imaginary Lane potential $W_1$ are presented, based on a second-order calculation of the 25 MeV ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$(p,n${)}^{48}$Sc $0^{+}$ analog reaction. Inelastic (p,${\mathrm{p}}^{\mathrm{-}1}$), (n,${\mathrm{n}}^{\mathrm{-}1}$) and charge exchange (p,${\mathrm{n}}^{\mathrm{-}1}$) particle-hole intermediate nuclear states are used, and an exact treatment of the continuum and of second-order knockout exchange are included. A complex-energy intermediate-projectile Green’s function is used to account for energy averaging of the incident beam. The sign of $W_1$ is shown to be positive, in agreement with phenomenological results, but the calculated magnitude is about a factor of 2 weaker than the Becchetti-Greenlees phenomenological potential. The contribution from an intermediate ground-state deuteron projectile is calculated in the zero-range approximation for pickup and stripping and is found to be about (1/3) of the contribution from the sum of all intermediate particle-hole states.

Cross sections, vector analyzing powers, and tensor analyzing powers were measured for the breakup reaction ${}_{}{}^4{}_{}{}^{}\mathrm{He}$(d,p)${\mathrm{n}}^4$He at three bombarding energies near the $1^{+}$ resonance in ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$. These observables were measured to test predictions made by recent three-body calculations for this reaction in the vicinity of the $1^{+}$ resonance. The measurements were focused on the region of the proton spectrum corresponding to the formation of the ${}_{}{}^5{}_{}{}^{}\mathrm{He}$ ground state. In general the three-body calculations provide a good description of the data, but discrepancies exist with $T_{11}$ and $T_{20}$ measurements, particularly at the lowest energy studied. The effect of the $1^{+}$ resonance is not as pronounced in the data as in the three-body calculations, and the differences between measurements and predictions at the lowest energies seem to be a result of Coulomb effects.

The particle production (p,d,t${,}^3$He${,}^4$He) was studied for 400 and 650 MeV/nucleon Nb+Nb and 400 and 1050 MeV/nucleon Ca+Ca. The chemical freeze-out density of the participants and the entropy produced were deduced for each system. The chemical freeze-out densities are close to normal nuclear density. The entropy production extrapolated for infinite nuclear matter is independent of target-projectile combination at 400 MeV/nucleon and changes little with increasing bombarding energy, but the absolute values are strongly model dependent. The low entropy, when compared to fireball calculations, indicates that compression is present in the collisions. Therefore entropy values in principle can help in the determination of the equation of state for nuclear matter.

A new approach to calculation of the fusion cross section ${\sigma }_F$, based on the direct reaction concept, is presented. The method is to define a fusion potential $W_F$ [with r≤$R_F$=$r_F$($A_1^{1/3}$+$A_2^{1/}$ 3)] as a part of the imaginary potential of the usual optical model. The ${\sigma }_F$ is then obtained as that part, due to only $W_F$, of the total absorption cross section. It is seen that, if $r_F$ is chosen as 1.40–1.50 fm, the value of ${\sigma }_F$ computed as described fits the experimental ${\sigma }_F$ very well, in both sub- and above-barrier regions, and for a variety of fusing nuclear pairs $A_1$ and $A_2$. In most cases, it is sufficient to consider only the incident (elastic scattering) channel. In a few cases, in which some specific nuclear structure effects are involved, it is found necessary to perform coupled-channel calculations. Then absorption due to other channels is also taken into account explicitly. It is shown that adding these contributions is the key to getting good fits to data, under the above-mentioned special circumstances. A possible relation of what the present approach describes, particularly when it is used in the sub-barrier region, to (spontaneous) fission is also discussed.

The structure of ${}_{}{}^{215}{}_{}{}^{}\mathrm{Fr}$ has been studied via the ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ ${(}^{11}$B, 4nγ${)}^{215}$Fr reaction at beam energies from 45 to 66 MeV. In-beam γ-ray spectroscopy techniques, including γ-ray excitation function, x-ray-γ coincidence, γ-γ coincidence, γ-ray angular distribution, and γ-ray linear polarization measurements were used to construct a level scheme up to a spin value J=(41/2) at an excitation energy of 3405 keV. Definite parity assignments were made up to the ${\mathrm{}(39/2)\mathrm{}}^{\mathrm{-}}$ state. The structure of this nucleus is compared with that observed in the other N=128 isotopes and predictions of shell model calculations.

Light-particle (Z<eq2) inclusive and coincidence spectra have been measured for the reactions 30 MeV/nucleon ${}_{}{}^{12}{}_{}{}^{}$C+Al and ${}_{}{}^{12}{}_{}{}^{}$C+Au and 92 MeV/nucleon ${}_{}{}^{40}{}_{}{}^{}$Ar+Au at angles from 45° to 90°. Coincidence triggers for the light-particle spectra were intermediate rapidity fragments (3<eqZ<eq7) at -30° and projectilelike fragments (3<eqZ<eq18) at -13°. The Ar + Au inclusive spectra are compared to hydrodynamics and firestreak model calculations. Nonazimuthally averaged hydrodynamics calculations are compared to the light-particle spectra triggered by projectilelike fragments. A single moving source parametrization is employed throughout to extract the relevant trends in the inclusive and coincidence data. The coincidence spectra are compared with a model based on the moving source model but incorporating momentum conservation to account for kinematical biases. Little difference between inclusive and complex-fragment-triggered coincidence cross sections is observed, indicating that all the fragments have a common source.

The explanation of anomalous mean free paths, observed in relativistic heavy-ion collisions in emulsions, by the excitation of molecular configurations in projectile fragments, is discussed. The γ-decay half-life of molecular states in ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ and ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$ are calculated in a microscopic cluster model and compared with the inferred mean lifetimes of anomalous projectile fragments. While the half-life of the ${}_{}{}^{16}{}_{}{}^{}$O${+\mathrm{}}^{16}$O molecular states might be compatible with this explanation, an identification as anomalous projectile fragments can be ruled out for the ${}_{}{}^{12}{}_{}{}^{}$C${+\mathrm{}}^{12}$C molecular states. It is argued that because of nuclear structure effects, molecular configurations in neighboring nuclei have lifetimes similar to the ${}_{}{}^{12}{}_{}{}^{}$C${+\mathrm{}}^{12}$C molecular states.

Time-dependent Hartree-Fock calculations for head-on collisions of ${}_{}{}^4{}_{}{}^{}$He${+\mathrm{}}^{14}$C, ${}_{}{}^{12}{}_{}{}^{}$C${+\mathrm{}}^{12}$C${(0\mathrm{}}^{+}$), and ${}_{}{}^4{}_{}{}^{}$He${+\mathrm{}}^{20}$Ne have been performed at bombarding energies near the Coulomb barrier. The results are interpreted in terms of their classical quasiperiodic and chaotic behavior. The position of the time-dependent Hartree-Fock collective path with respect to the multidimensional energy surface of the compound nuclear system is shown. Dynamical collective degrees of freedom are identified and classical frequencies associated with each degree of freedom are calculated. For ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ we calculate molecular frequencies of about 0.8 and 1.0 MeV and a characteristic moment of inertia of 15 ${\mathrm{MeV}}^{\mathrm{-}1}$.

We have carried out a systematic investigation of $\gamma$ rays after thermal neutron capture by all stable sulfur isotopes (${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$, ${}_{}{}^{33}{}_{}{}^{}\mathrm{S}$, ${}_{}{}^{34}{}_{}{}^{}\mathrm{S}$, and ${}_{}{}^{36}{}_{}{}^{}\mathrm{S}$). The measurements were made at the internal target facility at the Los Alamos Omega West Reactor. We detected a larger number of $\gamma$ rays: ∼100 in ${}_{}{}^{33}{}_{}{}^{}\mathrm{S}$, ∼270 in ${}_{}{}^{34}{}_{}{}^{}\mathrm{S}$, ∼60 in ${}_{}{}^{35}{}_{}{}^{}\mathrm{S}$, and ∼15 in ${}_{}{}^{37}{}_{}{}^{}\mathrm{S}$. Before developing detailed level schemes, we culled and then consolidated the existing information on energies and $J^{\pi }$ values for levels of these nuclides. Based on the current data, we have constructed detailed decay schemes, which imply that there are significant populations of 26 excited states in ${}_{}{}^{33}{}_{}{}^{}\mathrm{S}$, 70 states in ${}_{}{}^{34}{}_{}{}^{}\mathrm{S}$, 20 states in ${}_{}{}^{35}{}_{}{}^{}\mathrm{S}$, and 7 states in ${}_{}{}^{37}{}_{}{}^{}\mathrm{S}$. By checking the intensity balance for these levels and by comparing the total intensity of primary transitions with the total intensity of secondary $\gamma$ rays feeding the ground state, we have demonstrated the relative completeness of these decay schemes. For strongly populated levels, the branching ratios based on the current measurements are generally better than those available from previous measurements. In all four cases, a few primary electric dipole ($E1\mathrm{}$) transitions account for a large fraction of the capture cross section for that particular nuclide. To understand and explain these transitions, we have recapitulated and further developed the theory of potential capture. Toward this end, we reviewed the theory relating off-resonance neutron capture to the optical-model capture. We studied a range of model-dependent effects (nature and magnitude of imaginary potential, surface diffuseness, etc.) on the potential capture cross section, and we have shown how experimental data may be analyzed using the expression for channel capture suitably modified by a factor that takes into account the model-dependent effects. The calculations of cross sections for most of the primary transitions in the sulfur isotopes are in good agreement with the data. Some discrepancies for weaker transitions can be explained well by an interfering compound-nucleus contribution to capture. This contribution is of the magnitude expected from statistical surveys of resonance capture data. Estimates of the cross section due to the valencecapture mechanism in $s$-wave resonances show that this cross section should dominate the more complicated compound-nucleus contributions.

Available data concerning nuclear-charge distribution for thermal-neutron-induced fission of ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$ have been evaluated for the region near symmetry (104≤A≤129, 42≤Z≤50). Evaluated data or averages are listed and are interpreted by the use of empirical $Z_P$ and $A_P^{\mathcal{’}}$ models. The parameters and functions derived for the two models are presented and are compared with each other and with the data. Both models represent most data satisfactorily, and they permit the calculation of more reliable estimates of unmeasured independent-fission-product yields near symmetry than has been possible in the past. The two models show the same major trends, so the physical phenomena deduced from the trends are not model dependent. The independent yields of fission products with Z values of 50 and 42 are much larger than those of products with Z values of 43 through 49. The yields for products with Z values of 49 and 43 are larger than those of products with Z values of 44 through 48. These yield differences indicate that the stable filled, or nearly filled, 50-proton shell in the heavy fragment causes the fission probability to increase rapidly with mass number in the range from 120 to 130 between improbable symmetric and probable asymmetric fission. The lack of even-odd-proton and -neutron effects near symmetry indicates that excitation energies are higher for ${}_{}{}^{236}{}_{}{}^{}\mathrm{U}$ nuclei undergoing symmetric fission than for those undergoing asymmetric fission.