For backward elastic scattering of deuterons by ${}^3\mathrm{He},$ cross sections $\sigma ,$ and tensor analyzing power $T_{20}$ are measured at $E_d=140\mathrm{}-270$ MeV. The data are analyzed by the plane wave impluse approximation (PWIA) and by the general formula which includes virtual excitations of other channels, with the assumption of the proton transfer from ${}^3\mathrm{He}$ to the deuteron. Using ${}^3\mathrm{He}$ wave functions calculated by the Faddeev equation, the PWIA describes global features of the experimental data, while the virtual excitation effects are important for quantitative fits to the $T_{20}$ data. Theoretical predictions on $T_{20},$ $K_y^y$ (polarization transfer coefficient), and $C_{\mathrm{yy}}$ (spin correlation coefficient) are provided up to GeV energies.

The dilepton production rate from the quark-gluon plasma is calculated from the imaginary part of the photon self-energy using a quark propagator that contains the gluon condensate. The low mass dilepton rate obtained in this way exhibits interesting structures (peaks and gaps), which might be observable at the relativistic heavy-ion collider and large hadron collider.

Measurements of the cross section, vector and tensor analyzing powers, and linear gamma-ray polarization in the radiative capture reactions $D(p,\gamma {)}^3\mathrm{He}$ and $p(d,\gamma {)}^3\mathrm{He}$ at c.m. energies in the range 0–53 keV allow the determination of the reduced matrix elements (RMEs) relevant for these transitions. From these RMEs the value of the integral which determines the Gerasimov-Drell-Hearn sum rule for ${}^3\mathrm{He}$ is obtained in the threshold region, corresponding to two-body breakup, and compared with the results of an ab initio microscopic three-body model calculation. The theoretical predictions for the value of this integral based on a “nucleons-only” assumption are an order of magnitude smaller than experiment. The discrepancy is reduced to about a factor of 2 when two-body currents are taken into account. This factor of 2 is due to an almost exact cancellation between the dominant $E1\mathrm{}$ RMEs in the theoretical calculation. The excess $E1\mathrm{}$ strength observed experimentally could provide useful insights into the nuclear interaction at low energies.

The reliable extraction of information from the two-proton correlation functions measured in heavy-ion reactions is a long-standing problem. Recently introduced imaging techniques give one the ability to reconstruct source functions from the correlation data in a model independent way. We explore the applicability of two-proton imaging to realistic sources with varying degrees of transverse space-momentum correlations. By fixing the freeze-out spatial distribution, we find that both the proton images and the two-particle correlation functions are very sensitive to these correlations. We show that one can reliably reconstruct the source functions from the two-proton correlation functions, regardless of the degree of the space-momentum correlations.

Pion and photon production cross sections are analyzed in proton-nucleus collisions at energies $20\hspace{0.5em}\mathrm{GeV}\mathrm{}\lesssim \sqrt{s}\lesssim 60$ GeV using a phenomenological description for the proton-proton collision. We separate the proton-proton and nuclear contributions to transverse-momentum broadening and suggest a new mechanism for the nuclear enhancement at high $p_T.$

The $p\overrightarrow{p}\mathrm{pp}{\eta }^{\prime }$ reaction is investigated within a relativistic meson-exchange model of hadronic interactions. We explore the role of nucleonic and mesonic, as well as the $N^{*}$ resonance currents, in producing ${\eta }^{\prime }$ mesons. In order to learn more about the production mechanisms, new measurements in the energy region far from the threshold are required.

Lifetimes of high-spin states in the $N=52\mathrm{}-54\hspace{0.5em}\mathrm{Ru}$ nuclei have been investigated via the ${}^{65}\mathrm{Cu}{(}^{36}\mathrm{S}{,pyn)}^{96,97,98}\mathrm{Ru}\hspace{0.5em}\mathrm{}(y=4,3,2\mathrm{})\mathrm{}$ reactions using the recoil-distance Doppler-shift technique. The data were collected in coincidence mode. Lifetimes have been extracted for both the positive- and the negative-parity states in ${}^{96}\mathrm{Ru}$ and ${}^{98}\mathrm{Ru}$ and for the positive-parity states in ${}^{97}\mathrm{Ru}.$ The levels studied have lifetimes in the range 2–31 ps. The observed reduced transition probabilities $B\left(E2\mathrm{}\right)\mathrm{}$ and $B\left(M1\mathrm{}\right)\mathrm{}$ are compared with the predictions of the shell model. Theoretical implications of these results are discussed.

High-spin states in the ${}^{94,95,96}\mathrm{Tc}(N=51,$ 52, and 53) nuclei have been investigated using the ${}^{65}\mathrm{Cu}{+}^{36}\mathrm{S}$ reaction at a beam energy of 142 MeV. More than 60 new transitions have been identified and placed in their level schemes, which now extend up to spin $J\approx 22ħ$ and excitation energies $E_x\approx 12$ MeV. Spherical shell-model calculations have been performed using different model spaces. A restricted model space, using ${}^{88}\mathrm{Sr}$ as the core and the $\pi {(p}_{1/2}{,g}_{9/2})$ $\nu {(d}_{5/2}{,s}_{1/2})$ valence orbitals, reproduces the experimental excitation energies up to $J\approx 14ħ.$ The higher-angular-momentum states are dominated by the excitation of a $g_{9/2}$ neutron across the $N=50\mathrm{}$ magic core, as indicated by large-basis shell model calculations.

Differential cross sections for the reactions ${}^9\mathrm{Be}{\mathrm{}(p,pn)\mathrm{}}^8\mathrm{Be}$ and ${}^9\mathrm{Be}{\mathrm{}(p,2p)\mathrm{}}^8\mathrm{Li}$ were simultaneously measured at an incident proton energy of 70 MeV. The measured spectra were decomposed into contributions from $1p$ and $1s$ shells. The cross sections were then analyzed in the framework of the DWTA approach. The radius of ${}^8\mathrm{Be}$ was derived.

A hadronic cascade model based on resonances and strings is used to study mass dependence of relativistic nuclear collisions from $p+\mathrm{Be}$ to Au+Au at AGS energies $\left(\sim 10A\mathrm{GeV}\right)$ systematically. Hadron transverse momentum and rapidity distributions obtained with both cascade calculations and Glauber-type calculations are compared with experimental data, leading to a detailed discussion concerning the importance of rescattering among hadrons. We find good agreement with the experimental data without any change of model parameters with the cascade model. It is found that rescattering is of importance both for the explanation of the high transverse momentum tail and for the multiplicity of produced particles.

Proton emission from ${}^{150}\mathrm{Lu}$ was studied using a double-sided silicon strip detector placed at the focal plane of the Holifield Radioactive Ion Beam Facility’s Recoil Mass Spectrometer. The ${}^{150}\mathrm{Lu}$ nuclei were produced in the ${}^{96}\mathrm{Ru}{(}^{58}\mathrm{Ni},p3n)$ reaction at a beam energy of 292 MeV. The half-life of the previously observed proton emitting state at 1.261 MeV was remeasured to be $49\pm 5\mathrm{ms}.$ A new proton emitting state in ${}^{150}\mathrm{Lu}$ was observed with a transition energy of $1.295\pm 0.015\mathrm{MeV}$ and a half-life of ${30}_{-15}^{+95\mathrm{}}\mu \mathrm{s}.$ These values are consistent with an $l=2\mathrm{}$ character for the new proton transition.

We compare measurements of the cross section, analyzing power, induced polarization, and polarization transfer coefficients for $(\overrightarrow{p},p^{\prime })$ reactions leading to unnatural-parity, high-spin states in ${}^{16}\mathrm{O}$ and ${}^{28}\mathrm{Si}$ with distorted wave impulse approximation calculations. We use an effective nucleon-nucleon (NN) interaction obtained from a microscopic treatment of nuclear medium effects. The NN potential is generated from a one-boson-exchange model of the nuclear force that reproduces NN scattering data well. Medium effects are incorporated through a G matrix obtained within a Dirac-Brueckner approach to nuclear matter. While agreement for some observables is good, differences for the polarization transfer coefficients indicate that systematic problems with the relative sizes of the spin-orbit and tensor interaction components exist. The differences are larger for ${}^{28}\mathrm{Si}$ than for ${}^{16}\mathrm{O}.$ A new model that incorporates density-dependent meson mass reductions produces only small effects that do not change the quality of the agreement. Connections to previous calculations are investigated.

The ground state normal deformed band and the recently discovered superdeformed band in ${}^{60}\mathrm{Zn}$ can be well described by treating them as ${}^{56}\mathrm{Ni}+\alpha$ and ${}^{32}\mathrm{S}{+}^{28}\mathrm{Si}$ cluster structures, respectively. In addition, the quadrupole deformation of the superdeformed band is reproduced satisfactorily.

We investigate the generic pairing properties of shell-model many-body Hamiltonians drawn from ensembles of random two-body matrix elements. Many features of pairing that are commonly attributed to the interaction are in fact seen in a large part of the ensemble space. Not only do the spectra show evidence of pairing with favored $J=0\mathrm{}$ ground states and an energy gap, but the relationship between ground-state wave functions of neighboring nuclei shows signatures of pairing as well. Matrix elements of pair creation-annihilation operators between ground states tend to be strongly enhanced. Furthermore, the same or similar pair operators connect several ground states along an isotopic chain. This algebraic structure is reminiscent of the generalized seniority model. Thus pairing may be encoded to a certain extent in the Fock space connectivity of the interacting shell model even without specific features of the interaction required.

High-spin states in ${}^{118}\mathrm{Te}$ have been populated via heavy-ion induced reactions. Excited states were observed up to $I=32\mathrm{}ħ$ and, in addition to irregular level sequences, several bands were identified for the first time. The decoupled negative parity bands based upon $7^{-}$ and $8^{-}$ states are interpreted to arise from the proton $h_{11/2}{g}_{7/2}$ configuration coupled to the $2p-2h$ intruder states in ${}^{116}\mathrm{Sn}.$ These bands show very smooth alignment behavior, in accordance with the proton $h_{11/2}$ bands in neighboring Sb and I nuclei. Above $I=20\mathrm{}$ the yrast positive parity band is built on the proton $h_{11/2}^2$ configuration, also coupled to the proton $2p-2h$ excitation. The strongly coupled band built upon the 2914 keV $6^{+}$ state involves a proton hole on the $g_{9/2}$ orbital. Another strongly coupled band based upon the 5006 keV $I=11\mathrm{}ħ$ state was also observed.

We study fusion reactions of ${}^{16}\mathrm{O}$ with ${}^{154}\mathrm{Sm},$ ${}^{186}\mathrm{W},$ and ${}^{238}\mathrm{U}$ at sub-barrier energies by a coupled-channels framework. We focus especially on the effects of ${\beta }_6$ deformation and low-lying vibrational excitations of the target nucleus. It is shown that the inclusion of ${\beta }_6$ deformation leads to a considerable improvement of the fit to the experimental data for all of these reactions. For the ${}^{154}\mathrm{Sm}$ and ${}^{238}\mathrm{U}$ targets, the octupole vibration significantly affects the fusion barrier distribution and the optimum values of the deformation parameters. The effect of $\beta$ band is negligible in all the three reactions, while the $\gamma$ band causes a non-negligible effect on the barrier distribution at energies above the main fusion barrier. We compare the optimum values of the deformation parameters obtained by fitting the fusion data with those obtained from inelastic scatterings and the ground state mass calculations. We show that the channel coupling of high multipolarity beyond the quadrupole coupling is dominated by the nuclear coupling and hence higher order Coulomb coupling does not much influence the optimum values of ${\beta }_4$ and ${\beta }_6$ parameters. We also discuss the effect of two neutron transfer reactions on the fusion of ${}^{16}\mathrm{O}$ with ${}^{238}\mathrm{U}.$

Experimental data obtained with the $4\pi$ multidetector system INDRA are used to study midvelocity emissions of light charged particles (LCP) and intermediate mass fragments for peripheral and semicentral collisions of Xe and Sn at energies between 25 and 50 MeV/nucleon. The analysis is performed as a function of incident energy and of impact parameter, defined through the total transverse energy of LCP. The onset of midvelocity emissions is found to be close to 25 MeV/nucleon. Evaporative processes are also identified and are found to be sensitive to the impact parameter but show, for a given impact parameter, little dependence on the incident energy. A chemical analysis of the midvelocity component is performed. Compared to the evaporative process, midvelocity matter is found to be more neutron rich. Results are compared with the predictions of a dynamical model (CHIMERA). The general trends are well reproduced but some interesting differences are observed, notably in the amount of relative energy dissipation, showing that midvelocity emissions could be sensitive to the finer details of the interaction.

We present a direct calculation of the cross section for the reaction ${}^3\mathrm{He}{(e,e}^{\prime }p)$ including the radiation tail originating from bremsstrahlung processes. This calculation is compared to measured cross sections. The calculation is carried out from within a Monte Carlo simulation program so that acceptance-averaging effects, along with a subset of possible energy losses, are taken into account. Excellent agreement is obtained between our calculation and measured data, after a correction factor for higher-order bremsstrahlung is devised and applied to the tail. Industry-standard radiative corrections fail for these data, and we use the results of our calculation to dissect the failure. Implications for design and analysis of experiments in the Jefferson-Laboratory energy domain are discussed.

The isoscalar monopole, isovector dipole, and isoscalar quadrupole excitations in ${}^{40}\mathrm{Ca}$ at zero and finite temperature are investigated in the quantal framework of the extended TDHF. Resonance excitations are broadened and shift down in energy due to coupling of collective modes with the $2p-2h$ doorway states, and the strength distributions exhibit fine structure. It is pointed out that a suitable finite range effective force is needed for a realistic description of the self-energies of the collective modes.

Single-particle removal reactions are becoming an important tool for studying radioactive nuclei. The nuclei far from stability may reveal new regions of large deformation. We discuss the influence of the projectile deformation on the stripping cross sections and longitudinal momentum distributions of the core. The Glauber formalism for describing such reactions is developed and compared with the simpler geometric approach and with existing experimental data. The most significant effects are expected for nuclei with valence spherical orbitals strongly mixed by deformation. The shape of the momentum distribution, in turn, can be used for determining the degree of deformation of the projectile.