We use the coupled cluster expansion $\left[\exp \mathrm{}\right(S)\mathrm{}$ method] to generate the complete ground state correlations due to the $\mathrm{NN}$ interaction. Part of this procedure is the calculation of the two-body $\mathbf{G}$ matrix inside the nucleus in which it is being used. This formalism is being applied to ${}^{16}\mathrm{O}$ in a configuration space of $50ħ\omega .$ The resulting ground state wave function is used to calculate the binding energy and one- and two-body densities for the ground state of ${}^{16}\mathrm{O}.$

The pairing plus quadrupole force model is extended so as to be applicable to $N\approx Z$ nuclei. We obtain an isospin-invariant pairing plus quadrupole-quadrupole plus quadrupole pairing interaction accompanied by a isoscalar proton-neutron force. This interaction includes isoscalar and isovector proton-neutron interactions. It is shown that a J-independent isoscalar proton-neutron force plays an essential role in reproducing the nuclear binding energy and roughly degenerate low-lying states, with $T=1\mathrm{}$ and $T=0\mathrm{}$ being observed in $N=Z$ odd-odd nuclei. Numerical calculations compared with experimental data show that the functional interaction with four force parameters is useful in describing both energy levels and binding energies in $N\approx Z$ nuclei.

An excitation function for the ${}^{12}\mathrm{C}{(}^{20}\mathrm{Ne}{,}^{12}\mathrm{C}\left[0_2^{+}\right]{)}^{20}\mathrm{Ne}$ reaction was measured over the energy range $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=22.5\mathrm{}–31.9$ MeV. An enhancement in the cross section was observed between $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=24.5\mathrm{}$ and 26.5 MeV in both the ${}^{12}\mathrm{C}{(0\mathrm{}}_2^{+}{)+}^{20}\mathrm{Ne}(\mathrm{g}.\mathrm{s}.\mathrm{})$ and ${}^{12}\mathrm{C}{(0\mathrm{}}_2^{+}{)+}^{20}\mathrm{Ne}{(2\mathrm{}}^{+})$ exit channels. Oscillatory angular distributions were observed at $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=25.24,$ 26.56, 28.50, and 30.44 MeV and the range of dominant angular momenta involved at these energies was found to be centered on $14ħ,15\mathrm{}ħ,16\mathrm{}ħ,$ and $17ħ,$ respectively. Excitation functions were also measured for the ${}^{12}\mathrm{C}{(}^{20}\mathrm{Ne}{,}^{12}\mathrm{C}\left[3^{-}\right]{)}^{20}{\mathrm{Ne}}^{*}$ reaction. For the ${}^{12}\mathrm{C}{(}^{20}\mathrm{Ne}{,}^{12}\mathrm{C}\left[0_2^{+}\right]{)}^{20}\mathrm{Ne}$ reaction the data were well described by the results of coupled channel calculations.

$K^{+}$ production far below the free nucleon-nucleon threshold has been investigated in collisions of ${}^{36}\mathrm{Ar}$ on ${}^{12}\mathrm{C},$ ${}^{\mathrm{nat}}\mathrm{Ti},$ and ${}^{181}\mathrm{Ta}$ targets at an incident energy of 92 MeV per nucleon. The cross sections for $K^{+}$ production have been inferred from the observed muon decays of positive kaons. The results are discussed in the framework of a participant-spectator model and are compared to proton induced $K^{+}$ production and to subthreshold pion production experiments.

The yields, recoil properties, and angular distributions of the fragments of the target nucleus were measured for the 29 MeV/nucleon ${}^{208}\mathrm{Pb}{+}^{197}\mathrm{Au}$ reaction using radiochemical techniques. The fragment isobaric yield distribution and mean energies were deduced from these data. The fission cross section is $2.2\pm 0.5\hspace{0.5em}\mathrm{b}$ while the residue formation cross section is 3.9 b. Heavy residues form a part of a large central bump (usually associated with fission) in the fragment mass distribution. Comparing the data from this reaction to other reactions involving massive nuclei at projectile energies from 7 to 45 MeV/nucleon shows the locus of fragment yields $\left[\sigma \mathrm{}\right(Z,A\left)\mathrm{}\right]$ to be roughly independent of the reacting system or projectile energy. The fragment angular distributions evolve from sidewise peaked (for near target, quasielastic residues) to forward peaked as the mass number decreases. The isomer ratios for the residues indicate their formation from the lowest partial wave events while the fission fragments appear to originate in higher l events. Attempts to use the nucleon transport model (or some modification of it) to calculate the residue cross sections were only partially successful. It is suggested the the lack of dynamic multifragmentation mechanisms in these models is the cause of the shortcomings.

Integral cross sections for the scattering of pions by protons into angles greater than $30°$ (lab) have been measured at a wide range of energies spanning the delta resonance using liquid hydrogen targets. Cross sections were measured for ${\pi }^{+}p$ scattering at 40 energies from 39.8 to 283.9 MeV and for ${\pi }^{-}p$ at 15 energies from 80.0 to 283.9 MeV. Comparisons with phase shift predictions from the Karlsruhe group show good agreement on resonance but significant deviations below 100 MeV.

We present zero-degree differential cross sections and transverse spin-transfer coefficients $D_{\mathrm{NN}}\left(0\mathrm{}°\right)$ for the ${}^{17,18}\mathrm{O}(\overrightarrow{p},\overrightarrow{n}{)}^{17,18}\mathrm{F}$ reactions at $E_p=118\mathrm{}\hspace{0.5em}\mathrm{MeV}.$ For the transition to the ${}^{17}\mathrm{F}(\mathrm{g}.\mathrm{s}.\mathrm{})$ to which several multipoles contribute, the measured $D_{\mathrm{NN}}\left(0\mathrm{}°\right)=-0.13\pm 0.05$ is used to separate the Fermi and Gamow-Teller contributions at $0°.$ The empirical Gamow-Teller strengths and the Fermi strengths are employed to estimate the solar neutrino absorption cross section in ${}^{17}\mathrm{O}$ and ${}^{18}\mathrm{O}.$

Radiochemical measurements of the product yields from $(\gamma ,{\pi }^{+})$ and $(\gamma ,{\pi }^{-}xn)$ reactions for $x=0\mathrm{}–9$ were performed on targets of ${}^{27}\mathrm{Al},$ ${}^{37}\mathrm{Cl},$ ${}^{41}\mathrm{K},$ ${}^{51}\mathrm{V},$ ${}^{59}\mathrm{Co},$ ${}^{65}\mathrm{Cu},$ ${}^{75}\mathrm{As},$ ${}^{87}\mathrm{Rb},$ ${}^{88}\mathrm{Sr},$ ${}^{109}\mathrm{Ag},$ ${}^{115}\mathrm{In},$ ${}^{133}\mathrm{Cs},$ ${}^{138}\mathrm{Ba},$ ${}^{139}\mathrm{La},$ and ${}^{181}\mathrm{Ta},$ and of ${}^7\mathrm{Li},$ ${}^{11}\mathrm{B},$ ${}^{14}\mathrm{N},$ ${}^{44}\mathrm{Ca},$ ${}^{51}\mathrm{V},$ ${}^{56}\mathrm{Fe},$ ${}^{59}\mathrm{Co},$ ${}^{63}\mathrm{Cu},$ ${}^{65}\mathrm{Cu},$ ${}^{75}\mathrm{As},$ ${}^{88}\mathrm{Sr},$ ${}^{89}\mathrm{Y},$ ${}^{109}\mathrm{Ag},$ ${}^{115}\mathrm{In},$ ${}^{127}\mathrm{I},$ ${}^{130}\mathrm{Te},$ ${}^{133}\mathrm{Cs},$ ${}^{139}\mathrm{La},$ ${}^{175}\mathrm{Lu},$ ${}^{197}\mathrm{Au},$ and ${}^{209}\mathrm{Bi},$ respectively, over bremsstrahlung end-point energies ${(E}_0)$ of 30–1200 MeV in steps of $E_0=50\mathrm{}\mathrm{MeV}$ or less. Yield variations as a function of the number of the emitted neutrons (x) for each target at $E_0>~400\mathrm{MeV}$ were found to be typical of (3,3) resonance. The reactions for neutron multiplicities as large as $x>~6$ are notable for targets of mass $A_t>~100,$ while only the reactions for smaller x are measurable for the lighter targets. The yields for both $(\gamma ,{\pi }^{-})$ and $(\gamma ,{\pi }^{+})$ are $A_t$-independent for targets heavier than $A_t>30\mathrm{}–40,$ while much smaller yields are reported for targets with $A_t=7\mathrm{}–14.$ The yield ratio $(\gamma ,{\pi }^{-})/(\gamma ,{\pi }^{+})$ becomes as high as 5.5 and such a high value suggests that the neutron density in the surface region of nucleus is higher than that expected from the neutron-to-proton ratio for the entire nucleus. The observed yields for individual $(\gamma ,{\pi }^{-}xn)$ reactions having equal x were also found to be a smoothly varying function of the neutron-to-proton ratio of the target, ${\mathrm{}(N/Z)\mathrm{}}_t,$ not of the target mass, $A_t$ or number of target neutrons, $N_t.$ This implies that the reactions are initiated via competitive photoabsorptions by neutrons and protons in the target nucleus. The smooth variation of the profile changes its characteristics at ${\mathrm{}(N/Z)\mathrm{}}_t=1.30\mathrm{}–1.40,$ corresponding to $A_t=100\mathrm{}–130;$ this implies higher excitation energies due to progressively larger medium effects in nuclei with $A_t>100.\mathrm{}$ The results are compared with theoretical calculations made using the photon-induced intranuclear cascade and evaporation analysis program by Gabriel and Alsmiller.

Fission fragment mass and angular distributions were measured from the ${}^{64}\mathrm{Ni}{+}^{197}\mathrm{Au}$ reaction at 418 MeV and 383 MeV incident energy. A detailed data analysis was performed, using the one-body dissipation theory implemented in the code HICOL. The effect of the window and the wall friction on the experimental observables was investigated. Friction stronger than one body was also considered. The mass and angular distributions were consistent with one-body dissipation. An evaporation code DIFHEAT coupled to HICOL was developed in order to predict reaction time scales required to describe available data on prescission neutron multiplicities. The multiplicity data were again consistent with one-body dissipation. The cross sections for touch, capture and quasifission were also obtained.

Elastic scattering data for different systems, at energies close to the Coulomb barrier, are systematically analyzed with a renormalized M3Y double folding real potential and a Woods-Saxon imaginary one. Then the contribution to the imaginary potential of couplings to the low lying inelastic channels is calculated in the Feshbach formalism and shown to give too weak absorption except for strongly deformed systems, ${}^{35,37}{\mathrm{C}\mathrm{l}+}^{24}\mathrm{Mg}.$ For the others systems the transfer cross sections are known to be large which implies that the coupling to transfer channels should contribute to absorption. To simulate their effect a fitted surface term is added to the Feshbach term. The radial distribution of the reaction cross section shows a strong sensitivity to the absorption but at large distances only.

The tensor analyzing power of the process $d+\overrightarrow{p}d+X,$ for forward deuteron scattering in the momentum interval 3.7 to $9\hspace{0.5em}\mathrm{GeV}/c,$ is studied in the framework of $\omega$ exchange in an algebraic collective model for the electroexcitation of nucleon resonances. We point out a special sensitivity of the tensor analyzing power to the isoscalar longitudinal form factor of the Roper resonance excitation. The main argument is that the $S_{11}\mathrm{}\left(1535\right),D_{13}\mathrm{}\left(1520\right),$ and $S_{11}\mathrm{}\left(1650\right)\mathrm{}$ resonances have only isovector longitudinal form factors. It is the longitudinal form factor of the Roper excitation, which plays an important role in the t dependence of the tensor analyzing power. We discuss possible evidence of swelling of hadrons with increasing excitation energy.

The imaginary and polarization potential for reactions involving exotic nuclei is calculated in terms of one-particle transfer channels. Special attention is devoted to transitions to the continuum since for exotic nuclei the Fermi energy is very close to the continuum threshold.

The methods presently used to calculate fission rates fail to correctly take into account the rotational degrees of freedom of compound nuclei rotating in three dimensions. The statistical model code JOANNE has been modified to correctly calculate the fission rates of classical thermodynamically fluctuating axially symmetric systems rotating in three dimensions. With this new code it is possible to reproduce evaporation residue cross sections, fission cross sections, and prescission neutron multiplicities from O-induced reactions, without the use of large fission delay times or large values of the viscosity of heated nuclear matter.

We present an approach to halo transfer in $\mathrm{}(p,d)\mathrm{}$ and $\mathrm{}(d,p)\mathrm{}$ reactions in which excitation and breakup effects are treated in a simple way. The method assumes that halo excitation energies are small compared with kinetic energies in the channel containing halo nucleus. It is shown that in the zero-range approximation to this approach the transfer amplitude has a formal resemblance to the conventional distorted wave Born approximation amplitude in which the distorted wave in the channel containing the halo nucleus is replaced by an effective distorted wave. Finite-range corrections are included using a generalization of the local-energy approximation. As a first application of the method, numerical calculations have been performed for the ${}^{16}\mathrm{O}{\mathrm{}(d,p)\mathrm{}}^{17}\mathrm{O}{,}^{10}\mathrm{Be}{\mathrm{}(d,p)\mathrm{}}^{11}\mathrm{Be},$ and ${}^{11}\mathrm{Be}{\mathrm{}(p,d)\mathrm{}}^{10}\mathrm{Be}$ reactions. Deuteron breakup was included within the adiabatic approach of Johnson and Soper. It was found that including recoil excitation and breakup of the ${}^{17}\mathrm{O}$ and ${}^{11}\mathrm{Be}$ nuclei increases the calculated cross sections and thus decreases the deduced spectroscopic factors. This effect is expected to increase with incident energy and decrease when the mass of the core of the halo nucleus increases relative to the mass of the halo.

A narrow beam of high energy neutrons or protons can be produced if a target material is bombarded with energetic deuterons. The processes which lead to the formation of stripped particle beams in encounters of high energy deuterons with target nuclei are briefly reviewed. We show that elastic Coulomb dissociation of the deuteron may play a significant role in energetic and forward peaked neutron/proton production on heavy metal targets.

Calculations which improve upon the eikonal model description of the scattering of loosely bound n-cluster composite nuclei at low and medium energies are studied. Each cluster-target eikonal phase shift is replaced by the continuation of the corresponding exact partial wave phase shift to noninteger angular momenta. Comparisons with fully quantum mechanical calculations for two-body projectiles show that this yields an accurate practical alternative to few-body adiabatic model calculations. Calculations are shown to be accurate for projectile energies as low as 10 MeV/nucleon at which the eikonal approximation is no longer reliable.

Influence of sequential decay on nuclear temperature measurements is studied. Particular attention is paid to the contribution of higher-energy resonances and to the role of the primary charge distribution. Results of calculations show that temperatures extracted from the measured double isotope ratios are strongly affected at temperatures beyond 6 MeV. The fluctuations between different isotope thermometers observed in the experiment seem mainly due to structure effects in the secondary decay process.

We present a fast hadronization model for the constituent quark plasma (CQP) produced in relativistic heavy-ion collisions at SPS (Super Proton Synchrotron). The model is based on rate equations and on a confining equation of state inspired by the string phenomenology. We display the time evolution of the relevant physical quantities during the hadronization process and the final hadron multiplicities. The results indicate that the hadronization of CQP is fast.

Using a density matrix approach to describe the process of coalescence, we calculate the coalescence probabilities and invariant momentum spectra for deuterons and antideuterons. We evaluate our expressions with a hydrodynamically motivated parametrization for the source at freeze-out which implements rapid collective expansion of the collision zone formed in heavy ion collisions. We find that the coalescence process is governed by the same lengths of homogeneity which can be extracted from Hanbury Brown–Twiss (HBT) interferometry. They appear in the absolute cluster yield via an effective volume factor as well as in a quantum-mechanical correction factor which accounts for the internal structure of the deuteron cluster. Our analysis provides a new interpretation for the parameters in the popular phenomenological coalescence model and for the effective overlap volume in Hagedorn’s model for cluster production in $\mathrm{pp}$ collisions. Using source parameters extracted from a recent HBT analysis of two-pion correlations, we successfully describe deuteron and antideuteron production data from $\mathrm{Pb}+\mathrm{Pb}$ collisions at the CERN SPS as measured by the NA44 and NA52 Collaborations. We also confirm the recent finding by Polleri et al. that the different measured slopes of nucleon and deuteron transverse mass spectra require a transverse density profile of the source which is closer to a box than to a Gaussian shape.

Anisotropic high energy density domains may be formed at early stages of ultrarelativistic heavy ion collisions, e.g., due to phase transition dynamics or nonequilibrium phenomena like (mini)jets. Here we investigate hadronic observables resulting from an initially created anisotropic high energy density domain. Based on our studies using a transport model we find that the initial anisotropies are reflected in the freeze-out multiplicity distribution of both pions and kaons due to secondary hadronic rescattering. The anisotropy appears to be stronger for particles at high transverse momenta. The overall kaon multiplicity increases with large fluctuations of local energy densities, while no change has been found in the pion multiplicity.