In this work the semiclassical model of pure Coulomb excitation was applied to the breakup of ${}^{15,17,19}\mathrm{C}$. The ground state wave functions were calculated in the particle-rotor model including core excitation. The importance of interference terms in the dipole strength arising after including core degrees of freedom is analyzed for each isotope. It is shown that Coulomb interference effects are important for the case of ${}^{17}\mathrm{C}$.

Results are presented on event-by-event fluctuations in transverse momentum of charged particles, produced at forward rapidities in $\mathrm{p}+\mathrm{p}$, $\mathrm{C}+\mathrm{C}$, $\mathrm{Si}+\mathrm{Si}$, and $\mathrm{Pb}+\mathrm{Pb}$ collisions at $158A\mathrm{GeV}$. Three different characteristics are discussed: the average transverse momentum of the event, the ${\Phi }_{p_T}$ fluctuation measure, and two-particle transverse momentum correlations. In the kinematic region explored, the dynamical fluctuations are found to be small. However, a significant system size dependence of ${\Phi }_{p_T}$ is observed, with the largest value measured in peripheral $\mathrm{Pb}+\mathrm{Pb}$ interactions. The data are compared with predictions of several models.

A detailed analysis of the coupled relativistic kinetic equations for two domains separated by a hypersurface having both space- and time-like parts is presented. Integrating the derived set of transport equations, we obtain the correct system of the hydro+cascade equations to model the relativistic nuclear collision process. Remarkably, the conservation laws on the boundary between domains conserve separately both the incoming and outgoing components of energy, momentum and baryonic charge. Thus, the relativistic kinetic theory generates twice the number of conservation laws compared to traditional hydrodynamics. Our analysis shows that these boundary conditions between domains, the three flux discontinuity, can be satisfied only by a special superposition of two cutoff distribution functions for the “out” domain. All these results are applied to the case of the phase transition between quark gluon plasma and hadronic matter. The possible consequences for an improved $\text{hydro}+\text{cascade}$ description of the relativistic nuclear collisions are discussed. The unique properties of the three flux discontinuity and their effect on the space-time evolution of the transverse expansion are also analyzed. The possible modifications of both transversal radii from pion correlations generated by a correct hydro+cascade approach are discussed.

Meson spin splittings are examined within an effective Coulomb gauge QCD Hamiltonian incorporating chiral symmetry and a transverse hyperfine interaction necessary for heavy quarks. For light and heavy quarkonium systems the pseudoscalar-vector meson spectrum is generated by approximate Bardeen-Cooper-Schrieffer, random-phase approximation diagonalizations. This relativistic formulation includes both $S$ and $D$ waves for the vector mesons which generates a set of coupled integral equations. A smooth transition from the heavy to the light quark regime is found with chiral symmetry dominating the $\pi \text{−}\rho$ mass difference. A reasonable description of the observed meson spin splittings and chiral quantities, such as the quark condensate and the $\pi$ mass, is obtained. Similar comparisons with Tamm-Dancoff diagonalizations, which violate chiral symmetry, are deficient for light pseudoscalar mesons, indicating the need to simultaneously include both chiral symmetry and a hyperfine interaction. The ${\eta }_b$ mass is predicted to be around $9400\mathrm{MeV}$, consistent with other theoretical expectations and above the unconfirmed $9300\mathrm{MeV}$ candidate. Finally, for comparison with lattice results, the $J$ reliability parameter is also evaluated.

We obtain the electromagnetic form factors of the $\gamma N\Delta$ transition by analyzing recent pion-electroproduction data using a fully relativistic dynamical model. Special care is taken to satisfy Ward-Takahashi identities for the Born term in the presence of form factors, thereby allowing the use of realistic electromagnetic form factors of the nucleon and pion. We parametrize the $Q^2$ dependence of the bare $\gamma N\Delta$ form factors by a three-parameter form which is consistent with the asymptotic behavior inferred from QCD. The parameters of the bare $\gamma N\Delta$ form factors are the only free parameters of the model and are fitted to the differential cross-section and multipole-analysis data up to $Q^2=4{\left(\mathrm{GeV}∕c\right)}^2$ in the $\Delta \left(1232\right)$-resonance region. This analysis emphasizes the significance of the pion-cloud effects in the extraction of the resonance parameters.

The nucleus ${}^{46}\mathrm{Ti}$ has been studied with the reaction ${}^{24}\mathrm{Mg}({}^{28}\mathrm{Si},\alpha 2p){}^{46}\mathrm{Ti}$, at the bombarding energy of $115\mathrm{MeV}$. Thin target foils backed either with Au or Pb layers were used in order to perform DSAM lifetime measurements. The yrast ${13}^{-}$, ${14}^{-}$, and ${15}^{-}$ levels were found to depopulate towards a sideband with enhanced stretched M1 transitions. The deduced B(E2) and B(M1) rates for the bands with $K=0^{+}$ and $3^{-}$ agree in general with the values predicted by the Large Scale Shell Model. As a complementary information, the lifetimes of the yrast $4^{+}$ states in ${}^{48}\mathrm{Cr}$ and ${}^{50}\mathrm{Cr}$ have been measured in the reactions ${}^{24}\mathrm{Mg}({}^{28}\mathrm{Si},2p2n){}^{48}\mathrm{Cr}$ and ${}^{26}\mathrm{Mg}({}^{28}\mathrm{Si},2p2n){}^{50}\mathrm{Cr}$ and found to agree with Shell Model predictions.

Calculation for the excitation function of $0.136\text{‐}\mathrm{MeV}$ $\left(2^{+}\right)$ isomeric state in ${}^{92}\mathrm{Nb}$ has been carried out using Hauser-Feshbach and pre-equilibrium nuclear reaction models in $10–20\mathrm{MeV}$ energy range. A satisfactory agreement between the calculation and measurements requires the suppression of contribution from the negative-parity doublet consisting of the $0.226\text{‐}\mathrm{MeV}$ $\left(2^{-}\right)$ and $0.390\text{‐}\mathrm{MeV}$ $\left(3^{-}\right)$ states in ${}^{92}\mathrm{Nb}$. This can be explained on the basis of highly retarded gamma transitions of higher energy states to the negative-parity doublet on account of its different shell model configuration compared to the shell model configuration of positive-parity states.

The nucleus ${}^{52}\mathrm{Fe}$ with $(N=Z=26)$ has been investigated using intermediate-energy Coulomb excitation in inverse kinematics. A reduced transition probability of $B(E2;0_1^{+}\to 2_1^{+})=817\left(102\right)e^2{\mathrm{fm}}^4$ to the first excited $2^{+}$ state at 849.0(5) keV was deduced. The increase in excitation strength $B(E2\uparrow )$ with respect to the even-mass neighbor ${}^{54}\mathrm{Fe}\mathbf{(}B(E2\uparrow )=620\left(50\right)e^2{\mathrm{fm}}^4\mathbf{)}$ agrees with shell-model expectations as the magic number $N=28$ is approached. This measurement completes the systematics of reduced transition strengths to the first excited $2^{+}$ state for the even-even $N=Z$ nuclei up to mass $A=56$.

The emission time sequence of neutrons, protons, and deuterons is deduced from velocity-gated two-particle correlation functions in $E∕A=61\mathrm{MeV}$ ${}^{36}\mathrm{Ar}+{}^{112,124}\mathrm{Sn}$ reactions. A dependence of the emission sequence on the isospin of the emitting source is observed.

The $\beta$ decays of the two ${}^{82}\mathrm{As}$ isomers have been investigated by $\beta$- and $\gamma$-ray spectroscopy to elucidate details in the population of levels in ${}^{82}\mathrm{Se}$, and to determine the ground state energy of ${}^{82}\mathrm{As}$. The relative positions of the $\beta$-decaying states have been determined for the first time. The spin of the ground state, previously assumed to be $1^{+}$, is proposed to be $2^{-}$, in agreement with systematics. The new data confirm many previously known features of the ${}^{82}\mathrm{Se}$ level scheme, but has also led to significant corrections. During the course of this work, the first information on absolute $\gamma$-ray intensities in the decay of ${}^{82}\mathrm{Ge}$ was obtained.

Fluctuations of charged particle number are studied in the canonical ensemble. In the infinite volume limit the fluctuations in the canonical ensemble are different from the fluctuations in the grand canonical one. Thus, the well-known equivalence of both ensembles for the average quantities does not extend for the fluctuations. In view of the possible relevance of the results for the analysis of fluctuations in nuclear collisions at high energies, a role of the limited kinematical acceptance is studied.

The influence of gluon and Goldstone boson induced tensor interactions on the dibaryon masses and $D$-wave decay widths has been studied in the quark delocalization, color screening model. The effective $S\text{‐}D$ wave transition interactions induced by gluon and Goldstone boson exchanges decrease rapidly with increasing strangeness of the channel. The tensor contribution of $K$ and $\eta$ mesons is negligible in this model. There is no six-quark state in the light flavor world studied so far that can become bound by means of these tensor interactions besides the deuteron. The partial $D$-wave decay widths of the $I{J}^p=(1∕2)2^{+}N\Omega$ state to spin 0 and 1 $\Lambda \Xi$ final states are 12.0 and 21.9 keV, respectively. This is a very narrow dibaryon resonance that might be detectable in those production reactions with rich high strangeness particles through the reconstruction of the vertex mass of the decay product $\Lambda \Xi$ by existing detectors at RHIC and COMPASS at CERN or at JHF in Japan and FAIR in Germany in the future.

We investigate the space-time evolution of ultrarelativistic $\mathrm{Au}\text{−}\mathrm{Au}$ collisions at full relativistic heavy-ion collider energy using a schematic model of the expansion. Assuming a thermally equilibrated system, we can adjust the essential scale parameters of this model such that the measured transverse momentum spectra and Hanbury-Brown Twiss correlation parameters are well described. We find that the experimental data strongly constrain the dynamics of the evolution of the emission source although hadronic observables for the most part reflect the final breakup of the system.

Two high-accuracy measurements of cross sections and analyzing powers for the proton-proton bremsstrahlung reaction have been performed at $190\mathrm{MeV}$ beam energy. These measurements provide not only the most accurate exclusive cross-section and analyzing-power data to date, but also a wide phase-space coverage. Thus, an accurate test of nucleon-nucleon interaction models is made feasible. The experimental setup and the analysis procedure are discussed in detail. Microscopic calculations and calculations based on the soft-photon theorem show deficiencies in explaining the bulk of the data.

Comprehensive high precision complete and incomplete fusion cross sections have been measured for the ${}^6\mathrm{Li}+{}^{209}\mathrm{Bi}$, ${}^7\mathrm{Li}+{}^{209}\mathrm{Bi}$, and ${}^9\mathrm{Be}+{}^{208}\mathrm{Pb}$ reactions, at energies near and below the Coulomb barrier. The experimental details and the analyses procedures for the characteristic $\alpha$-decay and fission measurements are described. Three different methods are used to conclusively show the large suppression of complete fusion at energies around and above the average barrier, which is associated with the projectile nuclei having a low energy threshold against breakup. First, theoretical predictions of fusion cross sections above the average barrier are compared with the data, and second the area under the measured barrier distribution is compared with expectations. The sensitivity of the suppression factors to variables which can affect the calculated cross sections is thoroughly investigated. The third method, essentially model independent, compares the complete fusion cross sections for the ${}^7\mathrm{Li}+{}^{209}\mathrm{Bi}$ and ${}^9\mathrm{Be}+{}^{208}\mathrm{Pb}$ reactions with those for the fusion of nuclei with a high threshold against breakup, which produce the same compound nucleus. All methods give consistent results, showing that the complete fusion cross sections at energies around and above the barrier are suppressed by $\sim 30\%$ compared with reactions of nuclei having a high energy threshold against breakup. The cross sections for incomplete fusion are found to be similar to the missing complete fusion cross sections. The experimental controversies regarding the effect of breakup on fusion is discussed, and the importance of unambiguously separating complete fusion from incomplete fusion is emphasized. This distinction is also important to achieve theoretically for realistic modelling of fusion of nuclei which break up readily.

Proton and neutron densities have been obtained for the even–even isotopes of $\mathrm{Sn}$ from ${}^{100}\mathrm{Sn}$ to ${}^{176}\mathrm{Sn}$ using a Hartree-Fock-Bogoliubov model with a Skyrme interaction. The matter densities so defined have been used with realistic nucleon–nucleon interactions in a folding model to specify optical potentials for the elastic scattering of protons with energies in the range $40–200\mathrm{MeV}$. Those potentials have been used to make predictions of the differential cross sections and spin observables for proton scattering. As the target mass increases, the emergence of the neutron skin in the $\mathrm{Sn}$ isotopes is revealed by marked effects in the differential cross section. Comparisons with available data show how similar scattering data for the neutron-rich isotopes may provide constraints for the model structures.

Measurements of the neutron removal and cluster breakup cross sections for the neutron-rich nuclei ${}^{14}\mathrm{Be}$ and ${}^{14}\mathrm{B}$ have been performed at 34.4 and $40.8\mathrm{MeV}∕\mathrm{nucleon}$, respectively. Enhancement of the first chance cluster breakup cross section for ${}^{14}\mathrm{Be}$ compared to that of ${}^{14}\mathrm{B}$ provides evidence for a well-developed $\mathrm{He}$ cluster structure of the ground state of ${}^{14}\mathrm{Be}$. Measurements of both the cross sections and decay-particle velocities suggest that multistep processes play an important role in the excitation and decay of both ${}^{14}\mathrm{B}$ and ${}^{14}\mathrm{Be}$.

The spectral density of the $D$ meson in the nuclear environment is studied within a self-consistent coupled-channel approach assuming a separable potential for the bare meson-baryon interaction. The $DN$ interaction, described through a $G$ matrix, generates dynamically the ${\Lambda }_c\left(2593\right)$ resonance. This resonance is the charm counterpart of the $\Lambda \left(1405\right)$ resonance generated from the $s$-wave $\overline{K}N$ interaction in the $I=0$ channel. The medium modification of the $D$-meson spectral density due to the Pauli blocking of intermediate states as well as due to the dressing of the $D$ mesons, nucleons, and pions is investigated. We observe that the inclusion of coupled-channel effects and the self-consistent dressing of the $D$ meson results in an overall reduction of the in-medium $D$-meson changes compared to previous work which neglected those effects.

Phase transitions in hot and dense matter, and the in-medium behavior of pseudoscalar mesons (${\pi }^{\pm }$, ${\pi }^0$, $K^{\pm }$, $K^0$, ${\overline{K}}^0$, $\eta$, and ${\eta }^{\prime }$), are investigated, in the framework of the three flavor Nambu-Jona-Lasinio model, including the ’t Hooft interaction, which breaks the $U_A\left(1\right)$ symmetry. Three different scenarios are considered: zero density and finite temperature, zero temperature and finite density in quark matter with different degrees of strangeness, and finite temperature and density. At $T=0$, the role of strange valence quarks in the medium is discussed, in connection with the phase transition and the mesonic behavior. It is found that the appearance of strange quarks, above certain densities, leads to meaningful changes in different observables, especially in matter with $\beta$ equilibrium. The behavior of mesons in the $T\text{‐}\rho$ plane is analyzed in connection with possible signatures of restoration of symmetries.

We use Landau’s theory of a normal Fermi liquid to derive expressions for the static response of a system with a general tensor interaction that conserves the total spin and the total angular momentum of the quasiparticle-quasihole pair. The magnetic susceptibility is calculated in detail, with the inclusion of the center of mass tensor and cross vector terms in addition to the exchange tensor one. We also introduce a new parametrization of the tensor Landau parameters which significantly reduces the importance of high angular harmonic contributions. For nuclear matter and neutron matter we find that the two most important effects of the tensor interaction are to give a contribution from multipair states and to renormalize the magnetic moments. Response to a weak probe may be calculated using similar methods, replacing the magnetic moments with the matrix elements of the weak charges.