We measured $\gamma$-ray spectra in coincidence with charged particles for the reactions ${}^{40}\mathrm{Ca}+{}^{48}\mathrm{Ca},{}^{46}\mathrm{Ti}$ at beam energy of $25\text{MeV}$∕nucleon. Events corresponding to reaction mechanisms from quasielastic to fusion were observed. In fusion and in inelastic reactions an enhancement in the $\gamma$-ray spectra is present in the energy region around $10\text{MeV}$ for the ${}^{48}\mathrm{Ca}$ target with respect to ${}^{46}\mathrm{Ti}$ data. The analysis of the $\gamma$-ray spectra relative to ${}^{48}\mathrm{Ca}$ and ${}^{46}\mathrm{Ti}$ targets shows the persistence of the GDR up to an excitation energy around $4-5\text{MeV}$∕nucleon for the mass region around 60. This result was obtained by including, in the statistical calculations, corrections due to the open decay channels, the mass dependence of the GDR parameters, and isospin effects.

The recoil corrected continuum shell model is employed to calculate the $148°,p+{}^7\mathrm{Be}$ excitation function and identify the nature of the structures in those cross sections. Asymptotic normalization constants for the ${}^8\mathrm{B}$ ground state are also provided. The ground state is nearly an even mix of channel spins one and two. The $R$-matrix formalism is then used to clarify the use of asymptotic normalization constants.

We discuss the negative Feynman-$x$ regime of the new data for the production of the ${\psi }^{\prime }$ meson in $pA$ collisions at $450\text{GeV}$ at CERN-SPS (of the NA50 Collaboration). We extract from the CERN data $\sigma \left({\psi }^{\prime }N\right)\approx 8$ mb under the assumption that the ${\psi }^{\prime }$ is produced as a result of the space-time evolution of a pointlike $c\overline{c}$ pair which expands with time to the full size of the charmonium state. In the analysis we assume the existence of a relationship between the distribution of color in a hadron and the cross section of its interaction with a nucleon. However, our result is rather sensitive to the pattern of the expansion of the wave packet and significantly larger values of $\sigma \left({\psi }^{\prime }N\right)$ are not ruled out by the data. We show that recent CERN data confirm the suggestion of Gerland et al. [Phys. Rev. Lett. 81, 762 (1998); Nucl. Phys. A663, 1019 (2000)] that color fluctuations of the strengths in charmonium-nucleon interaction are the major source of suppression of the $J∕\psi$ yield as observed at CERN in both $pA$ and $AA$ collisions.

We have measured the ${}^{147}\mathrm{Sm}\left(n,\alpha \right)$ cross section from $3\text{eV}$ to $500\text{keV}$ and performed an $\mathcal{R}$-matrix analysis in the resolved region $\left(E_n<700\text{eV}\right)$ to extract $\alpha$ widths for 104 resonances. We computed strength functions from these resonance parameters and compared them to transmission coefficients calculated using optical model potentials similar to those employed as inputs to statistical model calculations. The statistical model often is used to predict cross sections and astrophysical reaction rates. Comparing resonance parameters rather than cross sections allows more direct tests of potentials used in the model and hence should offer greater insight into possible improvements. In particular, an improved $\alpha +\text{nucleus}$ potential is needed for applications in nuclear astrophysics. In addition to providing a more direct test of the $\alpha +\text{nucleus}$ potential, the $\alpha$-width distributions show indications of nonstatistical effects.

Excited states in ${}^{141}\mathrm{Cs}$ and ${}^{143}\mathrm{Cs}$, populated in spontaneous fission of ${}^{248}\mathrm{Cm}$, were studied by means of prompt-$\gamma$ spectroscopy, using the EUROGAM2 multidetector array. This work reports the first observation of octupole excitations in the ${}^{141}\mathrm{Cs}$ and ${}^{143}\mathrm{Cs}$ nuclei. The new data for ${}^{141,143}\mathrm{Cs}$ do not support theoretical predictions of octupole deformation in the neutron-rich $\text{Cs}$ isotopes and indicates octupole correlations weaker than observed in the corresponding $\text{Ba}$ isotones.

The self-consistent random phase approximation (SCRPA) is applied to the exactly solvable model with fermion-boson coupling proposed by Schütte and Da Providencia. Very encouraging results in comparison with the exact solution of the model for various observables are obtained. The transition from the normal phase to the phase with a spontaneously broken symmetry is carefully investigated. The strong reduction of the variance in SCRPA vs Hartree-Fock is pointed out.

Using the cranked interacting boson model, we estimate critical frequencies for the rotation-induced spherical-to-deformed shape transition in $A\approx 100$ nuclei. The predictions are shown to roughly agree with the backbending frequencies deduced from experimental yrast sequences in these nuclei.

In the ${}^{208}\mathrm{Pb}$-based cold fusion-evaporation reactions the dependence of the yield of heaviest nuclei on the isotopic composition of the projectile nucleus is studied within the dinuclear system model for compound nucleus formation. Projectiles with a larger number of neutrons are not expected to increase always the production cross section of superheavy nuclei. New optimal reactions for the synthesis of superheavy nuclei with $Z=112$ and 114 are suggested.

The $pd\to pd\eta$ reaction has been studied in a kinematically complete experiment at five beam energies 927, 961, 996, 1032, and $1096\text{MeV}$. In contrast to our measurement of the $pd\to {}^3\mathrm{He}\eta$ at the same energies, all the c.m. angular distributions are consistent with isotropy. The energy dependence of the total cross section seems to follow a three-body phase space as modified by a proton-deuteron final-state interaction, and such an extrapolation is consistent with other near-threshold data. The distributions of the $pd$ and $p\eta$ invariant mass at fixed beam energy are both close to those of phase space. However, this is not the case for the $d\eta$ invariant mass, which shows significant structure in the first few MeV above threshold. This behavior is similar to that observed in the energy variation of the $pn\to d\eta$ total cross section and is the sign of a large $\eta$-deuteron scattering length that has been predicted in many theoretical models.

In the generalization of the cranking model from rotation about a principal axis [one dimensional (1D)] to tilted rotation (2D and 3D), the mapping of the lowest total routhian on the yrast band is broken. In tilted rotation the single-particle energy diagrams cannot alone be used to construct the yrast band, because they lack information of the spin component perpendicular to the rotation axis. In fact, in tilted rotation the yrast band for high spin can correspond to high particle-hole excitations in the rotating frame.

We calculate properties of the $A=6$ system using the accurate charge-dependent nucleon-nucleon (NN) potential at fourth order of chiral perturbation theory. By application of the ab initio no-core shell model and a variational calculation in the harmonic-oscillator basis with basis size up to $16\hslash \Omega$ we obtain the ${}^6\mathrm{Li}$ binding energy of $28.5\left(5\right)\text{MeV}$ and a converged excitation spectrum. Also, we calculate properties of ${}^{10}\mathrm{B}$ using the same NN potential in a basis space of up to $8\hslash \Omega$. Our results are consistent with results obtained by standard accurate NN potentials and demonstrate a deficiency of Hamiltonians consisting of only two-body terms. At this order of chiral perturbation theory three-body terms appear. It is expected that inclusion of such terms in the Hamiltonian will improve agreement with experiment.

The ${}^{24}\mathrm{Na}$ nucleus was investigated via $\left(\vec{d},p\right)$ and $\left(n,\gamma \right)$ reactions. Within the range of excitation energy from 0 to $6.3\text{MeV}$ 75 levels were observed. The angular distribution of partial cross sections and vector analyzing powers for 70 levels were determined within the framework of distorted-wave Born approximation. Of 240 $\gamma$ transitions assigned to ${}^{24}\mathrm{Na}$, 234 were placed in the decay scheme. Based on the extensive $\left(n,\gamma \right)$ data the neutron separation energy was deduced to be $6959.44\pm 0.05\text{keV}$. Using spectroscopic information from our $\left(\vec{d},p\right)$ measurement we investigated the role of the direct capture mechanism in the ${}^{23}\mathrm{Na}\left(n,\gamma \right){}^{24}\mathrm{Na}$ reaction.

A method is described to calculate the heavy ion reaction cross section ${\sigma }_R$ when one of the two nuclei is deformed. This method is based on both the double folding model and the optical limit approximation to Glauber theory. Both finite range of the nucleon-nucleon $\left(NN\right)$ interaction and in-medium effects of $NN$ cross section are included. The interacting pair ${}^{12}\mathrm{C}\text{−}{}^{238}\mathrm{U}$ is taken to study orientation, energy, and deformation dependence of ${\sigma }_R$. The finite range force increases the value of ${\sigma }_R$ by about $5\%$. In-medium $NN$ cross section decreases ${\sigma }_R$ by about $1.9\%$ compared to the free $NN$ cross section.

The production cross section for the heaviest nuclei in the ${}^{48}\mathrm{Ca}$ induced hot fusion-evaporation reactions is shown to depend on the isotopic composition of actinide target. It is analyzed within the dinuclear system model for compound nucleus formation. In the actinide-based reactions most neutron-rich targets available for the experiment lead to smaller cross sections. New optimal reactions for the synthesis of superheavy nuclei are suggested.

We study the thermal emission of photons from hot and dense strongly interacting hadronic matter at temperatures close to the expected phase transition to the quark-gluon plasma (QGP). Earlier calculations of photon radiation from ensembles of interacting mesons are reexamined with additional constraints, including new production channels as well as an assessment of hadronic form factor effects. Whereas strangeness-induced photon yields turn out to be moderate, the hitherto not considered $t$-channel exchange of $\omega$ mesons is found to contribute appreciably for photon energies above $\sim 1.5\text{GeV}$. The role of baryonic effects is assessed using existing many-body calculations of lepton pair production. We argue that our combined results constitute a rather realistic emission rate, appropriate for applications in relativistic heavy-ion collisions. Supplemented with recent evaluations of QGP emission, and an estimate for primordial (hard) production, we compute photon spectra at Super Proton Synchrotron (SPS), Relativistic Heavy Ion Collider (RHIC), and Large Hadron Collider (LHC) energies.

The $\beta$-decay half-life of ${}^{62}\mathrm{Ga}$ has been studied with high precision using on-line mass separated samples. The decay of ${}^{62}\mathrm{Ga}$ which is dominated by a $0^{+}$ to $0^{+}$ transition to the ground state of ${}^{62}\mathrm{Zn}$ yields a half-life of $T_{1∕2}=116.19\left(4\right)\text{ms}$. This result is more precise than any previous measurement by about a factor of 4 or more. The present value is in agreement with older literature values, but slightly disagrees with a recent measurement. We determine an error-weighted average value of all experimental half-lives of $116.18\left(4\right)\text{ms}$.

The interacting boson fermion-fermion model is employed in the analysis of the positive-parity doublet bands in ${}^{134}\mathrm{Pr}$. It is shown that stable triaxial deformation gives rise to the experimentally observed crossing between the yrast and yrare bands built on the $\pi h_{11∕2}\otimes \nu h_{11∕2}$ configuration. The collective structure of the yrast band is basically built on the ground-state band of the triaxial core, whereas the collective structure of the yrare band is predominantly based on the $\gamma$ band of the core. The mixing between the two bands increases with angular momentum. A constant energy spacing between the two lowest positive-parity bands is predicted in other odd-odd $N=75$ nuclei with $\gamma$-soft potential energy surfaces.

The in-medium neutron-proton, proton-proton (neutron-neutron) elastic scattering cross sections $\left({\sigma }_{np}^{*},{\sigma }_{pp\left(nn\right)}^{*}\right)$ are studied based on the effective Lagrangian of density dependent relativistic hadron theory in which the $\delta \left[a_0\left(980\right)\right]$ meson is included. Our study shows that at low densities the ${\sigma }_{np}^{*}$ is about three to four times larger than ${\sigma }_{pp\left(nn\right)}^{*}$ and at densities higher than the normal density the isospin effect is almost washed out. Because of coupling to $\delta$ meson the ${\sigma }_{nn}^{*}$ and ${\sigma }_{pp}^{*}$ are different in isospin asymmetric medium following the splitting of the proton and neutron masses. The isospin effect on the density dependence of the in-medium nucleon elastic cross section is dominantly contributed by the isovector $\delta$ and $\rho$ mesons. The temperature effect on the ${\sigma }_{np}^{*}$ and ${\sigma }_{pp\left(nn\right)}^{*}$ is studied. It is shown that the temperature effect is weaker compared with the density effect but it becomes obvious as density increases.

The structure of the excited states of ${}^{10}\mathrm{Be}$ is theoretically explored by means of the microscopic $\alpha +\alpha +n+n$ four-cluster model. The two-body scattering problem of $\left\{{}^9\mathrm{Be}\left(3∕2^{-},1∕2^{+},5∕2^{-}\right)+n\right\}+\left\{{}^6\mathrm{He}\left(0^{+},2^{+}\right)+\alpha \right\}$ is solved by the microscopic $R$-matrix method in order to localize the resonance excited states in ${}^{10}\mathrm{Be}$. The wave functions of ${}^9\mathrm{Be}$ and ${}^6\mathrm{He}$ are given by the microscopic $\alpha +\alpha +n$ and $\alpha +n+n$ three-cluster models, respectively. Our model can reproduce not only the ground $0^{+}$ state but also the second $0^{+}$ state simultaneously. The second $0^{+}$ state has a highly developed $\alpha +\alpha \left({}^6\mathrm{He}+\alpha \right)$ clustering and is dominated by the $2\hslash \omega$ excitation in the shell-model configuration wherein two neutrons occupy the $1s_{1∕2}$ orbit. The ground state has a more compact structure due to the large binding energy but some weak $\alpha +\alpha$ clustering still persists. Our microscopic multicluster model is applied to the resonance excited states lying above the ${}^9\mathrm{Be}+n$ threshold, and the present model gives various resonance excited states. Among these states, the $0_2^{+}$, $2_4^{+}$, and $4_2^{+}$ states could constitute a $K^{\pi }=0_2^{+}$ rotational band which has a large deformation owing to the $\alpha +\alpha$ clustering. In the wave function for the second $0^{+}$ state in ${}^{10}\mathrm{Be}$, as well as for the $1∕2^{+}$ first excited state of ${}^9\mathrm{Be}$, the motion of the valence neutrons around the two $\alpha$ particles appears to be consistent with the $\sigma$ orbit in the molecular orbital model. We find that two or three competing configurations are necessary to reproduce these two anomalous states (the $1∕2^{+}$ and $0_2^{+}$ states), where one configuration produces a spatially extended neutron distribution outside the ${}^8\mathrm{Be}$ core and another has a strong core $(\alpha +\alpha )$ distortion induced by the valence neutron, with the latter being responsible for lowering the energies of these two states.