Angular distributions of the differential cross section of α elastic scattering by ${}^{24}\mathrm{Mg},$ ${}^{28}\mathrm{Si},$ and ${}^{30}\mathrm{Si}$ nuclei have been studied for various incident energies. The observed enhancement of differential cross sections at back angles, usually known as anomalous large angle scattering (ALAS), cannot be explained in terms of the normal optical model potential. A molecular type or squared Woods-Saxon optical potential can account for the ALAS and produce satisfactory fits to the angular distributions. A mass dependence of the potential parameters in the range $A=24\mathrm{}–30$ and energy variation in the region $E_{\alpha }=15\mathrm{}–45\mathrm{MeV}$ for the ${}^{28}\mathrm{Si}$ target and 22–120 MeV for the ${}^{24}\mathrm{Mg}$ target have been investigated.

Peripheral reactions of ${}^{28}\mathrm{Si}$ with ${}^{112}\mathrm{Sn}$ and ${}^{124}\mathrm{Sn}$ at 30, 40, and 50 MeV/nucleon were used to elucidate the effect of the neutron content of the target on the process of projectile fragmentation. It is demonstrated that the fragments that result from these projectile fragmentation reactions can be divided into those which are the result of statistical emission of the quasiprojectile and those that are part of a direct component. The statistical part is independent of the target whereas the isotopic composition of fragments from the direct component is dependent on the neutron content of the target.

The first complete set of analyzing powers for the ${}^{12}\mathrm{C}{(}^6\mathrm{Li}\to {,d)}^{16}{\mathrm{O}}_{\mathrm{g}.\mathrm{s}.\mathrm{}}$ reaction at ${E(}^6\mathrm{Li})=50\mathrm{}$ MeV is reported. It was possible to simultaneously describe ${}^6\mathrm{Li}{+}^{12}\mathrm{C}$ elastic scattering and its analyzing powers, ${d+}^{16}\mathrm{O}$ elastic scattering, and the ${}^{12}\mathrm{C}{(}^6\mathrm{Li}\to {,d)}^{16}{\mathrm{O}}_{\mathrm{g}.\mathrm{s}.\mathrm{}}$ transfer data. This $0^{+}\to 0^{+}$ transfer is used to probe the role of spin-dependent interactions in this reaction, including the ${}^6\mathrm{Li}\hspace{0.5em}D$ state, with finite-range-distorted-wave-Born-approximation calculations. It is found that the exit channel spin-orbit ${d+}^{16}\mathrm{O}$ interaction produces the transfer analyzing powers, but that the shape and magnitude of the transfer angular distribution is determined by the central ${}^6\mathrm{Li}{+}^{12}\mathrm{C}$ and ${d+}^{16}\mathrm{O}$ interactions. The limited knowledge of the size of the $\alpha {+}^{12}\mathrm{C}$ system is shown to be the major uncertainty in using the ${}^{12}\mathrm{C}{(}^6\mathrm{Li}{,d)}^{16}\mathrm{O}$ reaction to determine absolute $\alpha {+}^{12}\mathrm{C}$ spectroscopic factors.

Fission fragment folding angle distributions have been measured for the systems ${}^{11}\mathrm{B}{+}^{237}\mathrm{Np},$ ${}^{12}\mathrm{C}{+}^{236}\mathrm{U},$ and ${}^{16}\mathrm{O}{+}^{232}\mathrm{Th},$ populating the same compound nucleus ${(}^{248}\mathrm{Cf})$ and at similar excitation energies ${(E}_x$ 45–100 MeV). The full momentum transfer and incomplete momentum transfer fusion-fission components have been separated over the bombarding energy range $1.1<\mathrm{}{E}_{\mathrm{c}.\mathrm{m}.\mathrm{}}{/V}_B<\mathrm{2.1.}\mathrm{}$ It is observed that the largest value of the ratio of the transfer fission to the total fission is around 10 to $15\%$ at the highest energy investigated. Over the energy range mentioned above, it is found that the transfer fission corrected fission fragment anisotropies are not significantly different from the values already obtained from the analysis of the total fission data reported earlier and hence the conclusions reached from the inclusive data remain unchanged. The anisotropy data were analyzed for the two cases corresponding to fission events with sizable fission barriers ${(B}_f>T)$ and with smaller fission barriers ${(B}_f<T).\mathrm{}$ It was interesting to find that the effective moment of inertia ${(J}_{\mathrm{eff}})$ values deduced from the latter component were consistent with the values from Sierk prescription used in the former case.

Total and differential cross sections for the reaction ${}^6\mathrm{Li}(\gamma ,{\pi }^0)$ have been measured within 23 MeV of threshold using the tagged photon facility at SAL in conjunction with the ${\pi }^0$ spectrometer IGLOO. The differential measurements are the first to be reported in the threshold region, while the quality of the total cross section far surpasses previous investigations. The electric dipole amplitude for ${\pi }^0$ photoproduction has been deduced at threshold, and the relation to the corresponding free-deuteron amplitude as recently measured is examined within the context of an $\alpha -d$ cluster model of ${}^6\mathrm{Li}.$ The reduced P-wave amplitude $P_3^{\mathrm{}(+)\mathrm{}}/kq$ is deduced at threshold and is consistent with previous estimates from both the nucleon and nuclear sectors. The apparent stability of this amplitude as a function of environment remains a puzzle. Finally, the present cross sections compare favorably with the recent distorted-wave impulse approximation calculations of Kamalov et al.

We investigate the extent to which the nuclear transverse response to electron scattering in the quasielastic region, evaluated in the random-phase approximation, can be described by ring approximation calculations. Different effective interactions based on a standard model of the type $g^{\prime }{+V}_{\pi }{+V}_{\rho }$ are employed. For each momentum transfer, we have obtained the value of $g_0^{\prime }$ permitting the ring response to match the position of the peak and/or the non-energy-weighted sum rule provided by the random-phase approach. It is found that, in general, it is not possible to reproduce both magnitudes simultaneously for a given $g_0^{\prime }$ value.

A model for the $d\overrightarrow{d}\alpha \pi \pi$ reaction, based on two parallel $N\overrightarrow{N}d\pi$ reactions, is extended to incorporate a complete set of input amplitudes. While low-energy cross sections are underestimated, the rich structure observed in the $\alpha$-particle momentum distributions for $0.8<\mathrm{}{T}_d<1.9\mathrm{}\hspace{0.5em}\mathrm{GeV}$ (the Abashian-Booth-Crowe effect) is extraordinarily well reproduced. In addition, a recent measurement of deuteron analyzing powers agrees quite well with our predictions, both in frequency and magnitude of the oscillations.

We solve the in-medium T-matrix equation at finite temperature including the off-shell propagation of nucleons. In this way a self-consistent spectral function for the nucleons is obtained. The results are compared to a calculation using the quasiparticle approximation in the T-matrix equation. Also the effective in-medium cross sections for the two cases are compared.

A density expansion of the $K^{+}$-nucleus optical potential is used within a momentum-space approach to analyze the experimental total and elastic differential cross section data. We add to the microscopic first-order optical potential a phenomenological higher-order term proportional to the nucleon density raised to a power $\alpha .$ A fit to the total cross section data yields a value for $\alpha$ of $2.85\pm 0.25$ and a strength for the potential that decreases slightly faster than the inverse of the kaon laboratory momentum. To obtain a higher-order potential compatible with all the data and with parameters that are target independent, a renormalization of the differential cross section data by 30%, consistent with our estimate of systematic errors, is made. The need for such a large renormalization is explained.

A relatively simple model which reproduces the measured formation cross sections of deformed superheavy nuclei synthesized in cold fusion reactions is proposed. Within this model, optimal bombarding energies and formation cross sections of the hypothetical spherical superheavy nuclei are predicted.

The Yukawa-plus-exponential mass formula is generalized to describe the Gibbs free energy of hot, finite nuclei. The temperature dependence is obtained by fitting the results of former temperature-dependent Thomas-Fermi calculations with a finite-range mass formula. The temperature dependence of the pairing and Wigner terms in the mass formula is also given.

The cross sections for the ${(}^8{\mathrm{B},}^7\mathrm{Be}-p)$ breakup reaction on ${}^{58}\mathrm{Ni}$ and ${}^{208}\mathrm{Pb}$ targets at the beam energies of 25.8 MeV and 415 MeV have been calculated within a one-step prior-form distorted-wave Born approximation. The relative contributions of Coulomb and nuclear breakup of dipole and quadrupole multipolarities as well as their interference have been determined. The nuclear breakup contributions are found to be substantial in the angular distributions of the ${}^7\mathrm{Be}$ fragment for angles in the range of $30°–80°$ at 25.8 MeV beam energy. The Coulomb-nuclear interference terms make the dipole cross section larger than that of quadrupole even at this low beam energy. However, at the incident energy of 415 MeV, these effects are almost negligible in the angular distributions of the ${(}^7\mathrm{Be}-p)$ coincidence cross sections at angles below $4°.$

Following earlier one-step calculations, we explore the contributions of multistep effects for the breakup of low energy ${}^8\mathrm{B}$ on ${}^{58}\mathrm{Ni}$ and ${}^{208}\mathrm{Pb}$ within a coupled discretized continuum channels (CDCC) formalism. The Coulomb multistep differential cross section is significantly reduced for all angles, the largest effect being the destructive interference of nuclear couplings. The nuclear peak, at around $80°$ in the one-step calculations for ${}^{58}\mathrm{Ni},$ virtually disappears.

Isotope ratios are examined for several inclusive studies of light-ion and ${}^{14}\mathrm{N}$-induced reactions that involve significantly different reaction dynamics and bombarding energies. For adjacent isotope pairs that have one nuclide with $N<Z$, the ratios show a strong dependence on emission angle. Pairs with only $N>~Z$ isotopes depend weakly on $N/Z$ of the colliding system, but are otherwise not sensitive to angle of observation or beam energy. The double isotope-ratio method of Albergo has been used to determine apparent nuclear temperatures from these data. When empirically corrected for secondary decay effects, values in the range $T_{\mathrm{iso}}\approx 4.0\pm 0.4$ MeV are found for forward-angle measurements and $T_{\mathrm{iso}}\approx 2.4\pm 0.4$ MeV for backward angles. The double isotope-ratio temperatures are found to be systematically lower than temperatures derived from spectral shape analyses and Fermi gas estimates. This difference suggests the importance of time evolution in the application of temperature gauges. Relative emission-time differences between neutron-deficient and heavier isotopes arise from both nonequilibrium emission processes and cooling of the system during statistical decay. The importance of secondary feeding is also pointed out. These effects are illustrated by expanding, emitting source calculations.

To test the model dependence of the extracted asymptotic parameters, we reanalyze published $\mathrm{}(d,t),$ ${(d,}^3\mathrm{He}\left)\hspace{0.5em}\right(d,\alpha ),$ and ${(d,}^6\mathrm{Li})$ reactions, comparing recent variational Monte Carlo (VMC) microscopic vertex form factors with those used previously. In the $\mathrm{}(d,t)\mathrm{}$ reactions studied the tensor observables are found to be proportional to $\eta ,$ in ${(d,}^3\mathrm{He})$ and $(d,\alpha )$ transfers there is some sensitivity to the vertex shape, while for ${(d,}^6\mathrm{Li})$ there is a strong shape dependence. Comparisons with data show that the D states in the three- and four-body VMC vertex functions are slightly too weak. In the ${(d,}^6\mathrm{Li})$ reaction the polarization data are not reproduced, clearly indicating that the D-state components of the new ${}^6\mathrm{Li}$ models are too strong.

We investigate the reactions ${D(e,e}^{\prime }p)n$ and $D\left(\overrightarrow{e}{,e}^{\prime }p\right)n$ at GeV energies and discuss the opportunities to distinguish between different models for the nuclear ground state by measuring the response functions. In calculating the final-state interaction (FSI) we employ Glauber theory, and we also include relativistic effects in the electromagnetic current. We include not only the central FSI, but also the spin-orbit FSI which is usually neglected in ${(e,e}^{\prime }p)$ calculations within the Glauber framework, and we show that this contribution plays a crucial role for the fifth response function. All of the methods developed here can be applied to any target nucleus.

Multiple Coulomb excitation of collective nuclear modes is examined in the context of an extremely schematic dynamic model consisting of a harmonic oscillator, taken to represent the relevant collective mode, damped by linear coupling to a “bath” consisting also of harmonic oscillators, and forced by an applied external pulse. The (well-known) exact solution of the model allows for an estimate cross section which takes into account the joint effect of all excitation mechanisms leading to definite excitation energy domains, including the Brink-Axel mechanism, which occurs very naturally in this type of model. The semiclassical estimate of cross sections leading to the two-phonon domain shows enhancement with respect to the corresponding values obtained in the case of no damping. The magnitude of the enhancement decreases as the beam energy increases (or, equivalently, as the impact parameter averaged time width of the external pulse decreases), for model parameters chosen to conform to the appropriate nuclear orders of magnitude.

The relationship between measured transverse energy, total charge recovered in the detector, and size of the emitting system is investigated. Using only very simple assumptions, we are able to reproduce the observed binomial emission probabilities and their dependences on the transverse energy. Our results show that the observed scaling can arise due to a combination of finite-size effects and detector acceptance effects.

We present results from Experiment 864 for antiproton production and antideuteron limits in Au + Pb collisions at 11.5 $\mathrm{GeV}/c$ per nucleon. We have measured invariant multiplicities for antiprotons for rapidities $1.4<y<\mathrm{}2.4\mathrm{}$ at low transverse momentum as a function of collision geometry. When compared with the results from Experiment 878 our measurements suggest a significant contribution to the measured antiproton yield from the decay of strange antibaryons. We have also searched for antideuterons and see no statistically significant signal. Thus, we set upper limits on the production at approximately $3\times {10}^{-7}$ per 10% highest multiplicity Au+Pb interaction.

We calculate the survival probability of $J/\psi$ particles in various colliding systems using a Glauber model. An analysis of recent data has reported a $J/\psi$-nucleon breakup cross section of $6.2\pm 0.7\hspace{0.5em}\mathrm{mb}$ derived from an exponential fit to the ratio of $J/\psi$ to Drell-Yan yields as a function of a simple, linearly averaged mean path length $〈L〉$ through the nuclear medium. Our calculations indicate that, due to the nature of the calculation, this approach yields an apparent breakup cross section which is systematically lower than the actual value.