We compare different models for hadronic and quark phases of cold baryon-rich matter in an attempt to find a deconfinement phase transition between them. For the hadronic phase we consider Walecka-type mean-field models, which describe well the nuclear saturation properties. We also use the variational chain model, which takes into account correlation effects. For the quark phase we consider the MIT bag model, the Nambu–Jona-Lasinio, and the massive quasiparticle models. By comparing pressure as a function of baryon chemical potential we find that crossings of hadronic and quark branches are possible only in some exceptional cases while for most realistic parameter sets these branches do not cross at all. Moreover, the chiral phase transition, often discussed within the framework of QCD motivated models, lies in the region where the quark phases are unstable with respect to the hadronic phase. We discuss possible physical consequences of these findings.

We show that for the S-state ${\pi }^0$ production in processes $\gamma +\overrightarrow{d}d+{\pi }^0$ and $e^{-}+\overrightarrow{d}{e}^{-}+d+{\pi }^0$ the calculations of rescattering effects due to the transition $\gamma +\overrightarrow{d}p+p+{\pi }^{-}$ (or $n+n+{\pi }^{+})\to d+{\pi }^0$ have to take carefully into account the Pauli principle. The large values for these effects predicted in the past may result from the fact that the spin structure of the corresponding matrix element and the necessary antisymmetrization induced by the presence of identical protons (or neutrons) in the intermediate state was not taken into account accurately. One of the important consequences of these considerations is that ${\pi }^0$ photo- and electroproduction on the deuteron near threshold can bring direct information about elementary neutron amplitudes.

For the forward going ejectile, the $\Delta$ excitation and the coherent pion emission in the charge exchange reaction have been described by the real pion induced reaction. Using a pseudovector pion coupling to nucleon and the eikonally distorted waves for projectile and ejectile, the double differential cross section for the ejectile energy/momentum distribution is written in terms of the cross section for pion scattering on the nucleus. This cross section has been approximated by the corresponding measured cross section for the real pion. Calculated spectral shapes for various reactions agree very well with the measured distributions.

The yrast decay sequence of ${}^{36}\mathrm{S},$ populated in deep-inelastic processes produced by the interaction of 234 MeV ${}^{37}\mathrm{Cl}$ ions with a ${}^{160}\mathrm{Gd}$ target, has been studied using the highly sensitive EUROBALL IV $\gamma$-ray detector array. A candidate for the $6^{+}$ state has been located at an excitation energy of 6690 keV. The level structure of ${}^{36}\mathrm{S}$ is compared with the results of $\mathrm{sdfp}$ shell-model calculations.

The stability of the equation of state predicted by Skyrme-type interactions is examined. We consider simultaneously symmetric nuclear matter and pure neutron matter. The stability is defined by the inequalities that the Landau parameters must satisfy simultaneously. A systematic study is carried out to define interaction parameter domains where the inequalities are fulfilled. It is found that there is always a critical density ${\rho }_{\mathrm{cr}}$ beyond which the system becomes unstable. The results indicate in which parameter regions one can find effective forces to describe correctly finite nuclei and give at the same time a stable equation of state up to densities of 3–4 times the saturation density of symmetric nuclear matter.

The study of the coupling of various collective excitations is of great interest in nuclear structure physics. The crucial question is to what extent the fundamental building blocks of collective excitations can be combined. A particularly interesting problem is the coupling of the lowest quadrupole and octupole modes in nuclei. We report on first evidence for the complete quadrupole-octupole coupled quintuplet of negative parity ${(2\mathrm{}}_1^{+}\otimes 3_1^{-}{)}^{{(J}^{-})}$ with $J=1,$ 2, 3, 4, 5 in ${}^{108}\mathrm{Cd},$ the fourth full multiplet ever proposed. Excited states of ${}^{108}\mathrm{Cd}$ were populated in $\beta$ decay and with a nonselective $(\alpha ,n)$ fusion-evaporation reaction. The analysis of $\gamma \gamma$ angular correlations served to assign spin values to excited states and to determine multipole mixing ratios of transitions. This powerful combination of experiments and methods resulted in a huge amount of new data allowing us to present a detailed discussion of the quadrupole-octupole coupled multiplet in ${}^{108}\mathrm{Cd}$ based on excitation energies, branching ratios, and multipole mixing ratios and also present a comparison with the well studied neighbor ${}^{112}\mathrm{Cd}.$ The energy splitting within the multiplet is calculated in the vibrational limit of the sdf interacting boson model using a simple Hamiltonian, which results in an analytical single-parameter description for the energies.

Double differential hydrogen isotope production cross sections have been extracted in 62.7 MeV neutron induced reactions on a lead target. The angular distribution was measured at eight angles from $20°$ to $160°$ allowing the extraction of angle-differential, energy differential, and total production cross sections. A first set of comparisons with several theoretical calculations is also presented.

The excitation functions for the reactions ${}^{79}\mathrm{Br}(\alpha {,2n)}^{81}\mathrm{Rb},$ ${}^{81}\mathrm{Br}(\alpha {,4n)}^{81}\mathrm{Rb},$ ${}^{203}\mathrm{Tl}(\alpha {,n)}^{206}\mathrm{Bi},$ ${}^{203}\mathrm{Tl}(\alpha {,2n)}^{205}\mathrm{Bi},$ ${}^{203}\mathrm{Tl}(\alpha {,3n)}^{204}\mathrm{Bi},$ ${}^{203}\mathrm{Tl}(\alpha {,4n)}^{203}\mathrm{Bi},$ ${}^{205}\mathrm{Tl}(\alpha {,3n)}^{206}\mathrm{Bi},$ and ${}^{205}\mathrm{Tl}(\alpha {,4n)}^{205}\mathrm{Bi}$ have been measured using the stacked-foil activation technique and γ-ray spectroscopy. Since bromine as well as thallium have two odd-mass stable isotopes with different abundance, ${}^{79}\mathrm{Br}$ (50.7%), ${}^{81}\mathrm{Br}$ (49.3%), ${}^{203}\mathrm{Tl}$ (29.5%), and ${}^{205}\mathrm{Tl}$ (70.5%), their activation in some cases gives the same residual nucleus through different reaction channels, but very different Q values. Contributions of such reactions have been separated using theoretical calculations. The experimental results have also been compared with the theoretical calculations based on geometry-dependent hybrid model, considering equilibrium as well as the preequilibrium reaction mechanism. The ALICE-91 code has been used. The high-energy parts of these excitation functions are dominated by a preequilibrium reaction mechanism. A value of initial exciton number $n_0=4\mathrm{}$ $\mathrm{}(2p+2n+0h)\mathrm{}$ has been found to give the best agreement between experimental and theoretical excitation functions.

Antisymmetrized molecular dynamics with quantum branching is generalized so as to allow finite time duration of the unrestricted coherent mean field propagation, which is followed by the decoherence into wave packets. In this new model, the wave packet shrinking by the mean field propagation is respected as well as the diffusion, so that it predicts a one-body dynamics similar to that in mean field models. The shrinking effect is expected to change the diffusion property of nucleons in nuclear matter and the global one-body dynamics. The central ${}^{129}\mathrm{Xe}+\mathrm{Sn}$ collisions at 50 MeV/nucleon are calculated by the models with and without shrinking, and it is shown that the inclusion of the wave packet shrinking has a large effect on the multifragmentation in a big expanding system with a moderate expansion velocity.

We calculate dilepton production rates from a fireball adapted to the kinematical conditions realized in ultrarelativistic heavy-ion collisions over a broad range of beam energies. The freeze-out state of the fireball is fixed by hadronic observables. We use this information combined with the initial geometry of the collision region to follow the space-time evolution of the fireball. Assuming entropy conservation, its bulk thermodynamic properties can then be uniquely obtained once the equation of state (EOS) is specified. The high-temperature quark-gluon plasma (QGP) phase is modeled by a nonperturbative quasiparticle model that incorporates a phenomenological confinement description, adapted to lattice QCD results. For the hadronic phase, we interpolate the EOS into the region where a resonance gas approach seems applicable, keeping track of a possible overpopulation of the pion phase space. In this way, the fireball evolution is specified without reference to dilepton data, thus eliminating it as an adjustable parameter in the rate calculations. Dilepton emission in the QGP phase is then calculated within the quasiparticle model. In the hadronic phase, both temperature and finite baryon density effects on the photon spectral function are incorporated. Existing dilepton data from CERES at 158 and $40\hspace{0.5em}A\mathrm{GeV}$ Pb-Au collisions are well described, and a prediction for the PHENIX setup at RHIC for $\sqrt{s}=200A\mathrm{GeV}$ is given.

The lack of knowledge of the ${}^{45}\mathrm{V}(p,\gamma )$ reaction rate has been shown to contribute a large uncertainty to the production of ${}^{44}\mathrm{Ti}$ in core-collapse supernovae. By considering likely contributions from resonances associated with ${}^{46}\mathrm{Cr}$ states that are the isobaric analog of states in ${}^{46}\mathrm{Ti},$ we have determined that the currently accepted value of the ${}^{45}\mathrm{V}(p,\gamma )$ reaction rate is unlikely to be inaccurate by more than an order of magnitude. These conclusions are confirmed by the shell model calculations with the FPD6 effective interaction.

The interaction potential for a deformed-spherical pair is calculated, and the error in using the truncated multipole expansion is evaluated for different numbers of terms of the expansion considered. It was found for the internal region of the nuclear part that three terms are sufficient, but for the surface and tail region up to five terms are necessary, while for the Coulomb potential three terms were found to be sufficient.

We investigated the $\beta$ decay of the neutron drip line nucleus ${}^{14}\mathrm{Be}$ by means of double and triple coincidence measurements of $\beta$ rays, delayed neutrons, and $\gamma$ rays. The decay sequences were established and new values of the half-life and branching ratios were obtained. The decay scheme obtained is characterized by a single dominant branch leading to a $1^{+}$ state in ${}^{14}\mathrm{B}$ with a branching ratio of $(91\mathrm{}\pm 9)\%,$ which subsequently emits a delayed neutron with an energy of $288\pm 8\hspace{0.5em}\mathrm{keV}.$ The excitation energy and width of the $1^{+}$ state were determined to be $1.28\pm 0.02\hspace{0.5em}\mathrm{MeV}$ and $49\pm 2\hspace{0.5em}\mathrm{keV},$ respectively. The excitation energy and width of this level as well as the $\log \mathrm{ft}$ value were treated in terms of a simple shell model and found to be strongly related to the $N=8\mathrm{}$ shell gap quenching ${\mathrm{in}}^{13,14}\mathrm{B}$ and ${}^{12}\mathrm{Be}.$

We present a general method for taking into account correlations due to momentum conservation in the analysis of anisotropic flow, either by using the two-particle correlation method or the standard flow-vector method. In the latter, the correlation between the particle and the flow vector is either corrected through a redefinition (shift) of the flow vector, or subtracted explicitly from the observed flow coefficient. In addition, momentum conservation contributes to the reaction plane resolution. Momentum conservation mostly affects the first harmonic in azimuthal distributions, i.e., directed flow. It also modifies higher harmonics, for instance, elliptic flow, when it is measured with respect to a first harmonic event plane such as the one determined with the standard transverse momentum method. Our method is illustrated by application to NA49 data on pion directed flow.

The relation between the axial vector current of current quark and that of constituent quark has been studied within the framework of the global color symmetry model. Gluon dressing of the axial vector vertex and the quark self-energy function are described by the inhomogeneous Bethe-Salpeter equation in the ladder approximation and the Schwinger-Dyson equation in the rainbow approximation, respectively.

The excitation of the 485-keV state of the neutron-rich “island of inversion” nucleus ${}^{33}\mathrm{Mg}$ was measured in intermediate-energy Coulomb excitation. The result of the present experiment suggests that the 485-keV state is a rotational excitation built on the ground state, not a state with different intrinsic structure as proposed previously. If the 485-keV state is indeed a rotational excitation, then the deformation of ${}^{33}\mathrm{Mg}$ is similar to that of other nuclei in the island of inversion.

What range of momentum components in the deuteron wave function are available $e-d$ elastic scattering data sensitive to? This question is addressed within the context of a model calculation of the deuteron form factors, based on realistic interactions and currents. It is shown that the data on the $A\left(q\right),$ $B\left(q\right),$ and $T_{20}\mathrm{}\left(q\right)\mathrm{}$ observables at $q<~6\hspace{0.5em}{\mathrm{fm}}^{-1}$ essentially probe momentum components up to $\simeq {4m}_{\pi }.$

We present a mean field study of the quadrupole-octupole degree of freedom in collective nuclei within the framework of the $\mathrm{spdf}$-boson model. For realistic choices of the Hamiltonian parameters, the ground state of the system is shown to remain axially symmetric, which considerably simplifies the mean field treatment. The critical point for the onset of octupole deformation in quadrupole deformed systems is identified in the parameter space and importance of the parity projection in this process is emphasized. A systematic survey of excitation energies and electric transitions for one-phonon states is given, which will provide useful guidance for detailed studies of negative parity states within the $\mathrm{spdf}$-boson model.

We present a fully relativistic Hartree-Bogoliubov theory for the description of the ground-state properties of spherical nuclei. The relativistic one-meson exchange interaction in the pp channel is approximated by point couplings, and the NL3 parameter set is used for the effective mean-field Lagrangian. Binding energies, two-neutron separation energies are compared with experimental data and other relativistic calculations performed by using the Gogny force DSA1 in the pp channel. We discuss in detail the relativistic structure of the pairing field in realistic cases. We find that the mixing of large and small components in the Dirac-Hartee-Bogoliubov equations can be neglected to a good approximation.

High-spin states in neutron-rich nuclei ${}^{103,105}\mathrm{Mo},$${}^{103}\mathrm{Nb}$ have been studied using the ${}^{238}\mathrm{U}(\alpha ,f)$ fusion-fission reaction. The deexcitation $\gamma$ rays were detected by Gammasphere in coincidence with the detection of both fission fragments by the Rochester $4\pi$ heavy-ion detector array, CHICO. The measured fission kinematics were used to deduce the masses and velocity vectors for both fission fragments. This allowed Doppler-shift corrections to be applied to the observed $\gamma$ rays on an event-by-event basis and the origin of $\gamma$ rays from either fission fragment to be established. With such advantages, the yrast sequences for these nuclei have been extended to the band crossing region. This band crossing is ascribed to the alignment of a pair of $h_{11/2}$ neutrons, which is supported by the observed blocking effect for the $\nu h_{11/2}$ band in ${}^{105}\mathrm{Mo}$ while there is no evidence for blocking in the alignment measured for either the $\nu d_{5/2}$ band in ${}^{103}\mathrm{Mo}$ or the $\pi g_{9/2}$ band in ${}^{103}\mathrm{Nb}.$ The observed upbend, rather than the sharp backbend seen in the Ru-Pd region, indicates a strong interaction between the ground-state and the aligned $h_{11/2}$ bands.