The ${\beta }^{+}$ decay half-lives of 22 neutron-deficient nuclei in the cobalt-to-krypton region have been measured following the fragmentation of a primary ${}^{78}\mathrm{Kr}$ beam at an energy of 73 MeV per nucleon. The half-lives of the $T_z=-1$ nuclei ${}^{62}\mathrm{Ge},$ ${}^{64}\mathrm{As},$ and ${}^{66}\mathrm{Se}$ are determined for the first time with values of (129±35) ms, ${18}_{-7}^{+43\mathrm{}}\mathrm{ms},$ and (33±12) ms, respectively. The impact of these results on the nucleosynthesis and time scale of the astrophysical rapid proton-capture process are discussed.

We have analyzed the NA58 data on $J/\psi$ suppression in Pb+Pb collisions. $J/\psi$ production is assumed to be a two step process, (i) formation of $c\overline{c}$ pair, which is accurately calculable in QCD and (ii) formation of $J/\psi$ meson from the $c\overline{c}$ pair, which can be conveniently parametrized. In a $pA/AA$ collision, a $c\overline{c}$ pair gains relative square momentum as it passes through the nuclear medium and some of the $c\overline{c}$ pairs can gain enough momentum to cross the threshold to become an open charm meson, leading to suppression in $pA/AA$ collisions. A new prescription is proposed for the gain in momentum square, consistent with Krammer process. The model could explain the $E_T$ dependence of $J/\psi$ over Drell-Yan ratio.

A search is reported for deeply bound pionic states of xenon produced in the ${\mathrm{Xe}}_{\mathrm{nat}}{(d,}^3\mathrm{He}){\mathrm{Xe}}_{\pi -\mathrm{bound}}$ reaction at $E_d=500\mathrm{}\mathrm{MeV}.$ In the ${}^3\mathrm{He}$ energy spectrum two peaks are observed corresponding to the production of pionic atoms in the $1s$ state.

A $N\overrightarrow{N}{\mathrm{NN}}^{*}\mathrm{}\left(1440\right)\mathrm{}$ transition potential, based on an effective quark-quark interaction and a constituent quark cluster model for baryons, is derived in the Born-Oppenheimer approach. The potential shows significant differences with respect to those obtained by a direct scaling of the nucleon-nucleon interaction. From its asymptotic behavior we extract the values of $\pi {\mathrm{NN}}^{*}\mathrm{}\left(1440\right)\mathrm{}$ and $\sigma {\mathrm{NN}}^{*}\mathrm{}\left(1440\right)\mathrm{}$ coupling constants in a particular coupling scheme.

A model is developed which allows the investigation and classification of the pairing phase transition in atomic nuclei. The regions of the parameter space are discussed for which a pairing phase transition can be observed. The model parameters include number of particles, attenuation of pairing correlations with increasing seniority, single-particle level spacing, and pairing gap parameter.

The intermediate structures in ${}^{12}\mathrm{C}{+}^{16}\mathrm{O}$ inelastic scattering were investigated at energies around $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=30\mathrm{}\mathrm{MeV}$ in the ${}^{12}\mathrm{C}{(2\mathrm{}}^{+}{)+}^{16}\mathrm{O}(\mathrm{g}.\mathrm{s}.\mathrm{})$ single excitation and the ${}^{12}\mathrm{C}{(2\mathrm{}}^{+}{)+}^{16}\mathrm{O}{(3\mathrm{}}^{-}{,0\mathrm{}}_2^{+})$ mutual excitation channels and at $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=22.6\mathrm{}\mathrm{MeV}$ in the ${}^{12}\mathrm{C}{(2\mathrm{}}^{+}{)+}^{16}\mathrm{O}(\mathrm{g}.\mathrm{s}.\mathrm{})$ single excitation channel. The angular distributions of the magnetic substate cross sections for the $2^{+}$ (4.439 MeV) state of ${}^{12}\mathrm{C}$ were measured by using the γ-ray recoil method in the center-of-mass ejectile-axis frame. It is shown that the structures at $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=29.8\mathrm{}$ and 31.8 MeV in the ${}^{12}\mathrm{C}{(2\mathrm{}}^{+}{)+}^{16}\mathrm{O}(\mathrm{g}.\mathrm{s}.\mathrm{})$ channel are interpreted as resonances of $J^{\pi }{=16\mathrm{}}^{+}$ or ${17}^{-}$ which decay dominantly through the aligned configurations with $L=J-2.$ On the other hand, the structure at $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=22.6\mathrm{}\mathrm{MeV}$ is accounted for by assuming the overlap of two resonances having spins and parities of $J^{\pi }{=12\mathrm{}}^{+}$ and $J^{\pi }{=16\mathrm{}}^{+}.$ In the ${}^{12}\mathrm{C}{(2\mathrm{}}^{+}{)+}^{16}\mathrm{O}{(3\mathrm{}}^{-}{,0\mathrm{}}_2^{+})$ channel, little oscillatory structures are observed in the m-substate angular distributions so that the resonance spins cannot be extracted.

We study the hadron-quark phase transition in the interior of neutron stars (NS’s). We calculate the equation of state (EOS) of hadronic matter using the Brueckner-Bethe-Goldstone formalism with realistic two-body and three-body forces, as well as a relativistic mean field model. For quark matter we employ the MIT bag model constraining the bag constant by using the indications coming from the recent experimental results obtained at the CERN SPS on the formation of a quark-gluon plasma. We find it necessary to introduce a density-dependent bag parameter and the corresponding consistent thermodynamical formalism. We calculate the structure of NS interiors with the EOS comprising both phases, and we find that the NS maximum masses fall in a relatively narrow interval, $1.4M_{\odot }<~M_{\max }<~{1.7M}_{\odot }.$ The precise value of the maximum mass turns out to be only weakly correlated with the value of the energy density at the assumed transition point in nearly symmetric nuclear matter.

High-spin states have been observed in the near-drip-line nucleus ${}^{125}\mathrm{Pr}$ following the reaction ${}^{64}\mathrm{Zn}{(}^{64}\mathrm{Zn},p2n).\mathrm{}$ The detection of charged particles and neutrons evaporated from the compound system, along with the $M/q$ of the recoiling nucleus, have allowed the identification of excited states in ${}^{125}\mathrm{Pr}$ and the unambiguous assignment of five rotational structures to this nucleus. This is the most neutron-deficient Pr isotope in which excited states have been observed. The strongest band is identified as the $h_{11/2}$ single-quasiproton configuration, and is observed to a maximum spin of $I=(67/2\mathrm{}ħ).\mathrm{}$ Another structure is interpreted as the $g_{9/2}$ proton hole state, which is associated with bands of enhanced deformation observed in several nuclei in this mass region. These two bands are compared with analogous bands in the heavier odd-$A$ Pr isotopes and changes in deformation are discussed.

For coherent photoproduction of $\phi$ and $\omega$ mesons from deuteron at forward angles, the isovector $\pi$-exchange amplitude is strongly suppressed. We show a possibility to study the nondiffractive channels associated with the unnatural parity exchange in $\phi$ photoproduction and with the baryon resonance excitations in $\omega$ photoproduction by measuring the spin observables.

We have studied quasicontinuous gamma radiation from reactions of ${}^{48}\mathrm{Ca}$ beams on targets of ${}^{50}\mathrm{Ti},$ ${}^{64}\mathrm{Ni},$ ${}^{96}\mathrm{Zr},$ and ${}^{124}\mathrm{Sn}.$ The bombarding energies were in the range 195–215 MeV, and were chosen so as to bring in a high angular momentum without severe fragmentation of the cross sections for fusion residues. Experiments were performed both with the 8PI spectrometer at the LBNL 88-Inch Cyclotron, and with Gammasphere at the ANL ATLAS accelerator. The results have been analyzed in a variety of ways, with the consistent result that in all but the heaviest target, the nuclear moments of inertia tend to increase with increasing angular momentum up to the highest values observed. This could come from a transition towards a highly deformed Jacobi-like shape, or possibly be due to the appearance of high-$j$ intruder orbitals at the Fermi surface. We will argue that these effects can be equivalent.

The convergence of the effective field theory (EFT) approach of Furnstahl, Serot, and Tang to the nuclear many-body problem is studied by applying it to selected doubly magic nuclei far from stability. An independently developed code, which can incorporate various levels of approximation of the chiral effective Lagrangian, is used to solve the self-consistent relativistic Hartree equations. Results are obtained for ground-state properties such as binding energies, single-particle level structure, and densities of the selected spherical, doubly magic nuclei ${}^{132,100}\mathrm{Sn}$ and ${}^{48,78}\mathrm{Ni}.$ Calculated spectra of neighboring nuclei differing by one particle or one hole show agreement with the most recent experimental data. Predictions for nucleon densities are presented.

It was recently shown that the ground state quantum numbers of even-even nuclei have a high probability to be reproduced by an ensemble of random but rotationally invariant two-body interactions. In the present work we extend these investigations to odd-$A$ and odd-odd nuclei, considering in particular the isospin effects. Studying the realistic shell model as well as the single-$j$ model, we show that random interactions have a tendency to assign the lowest possible total angular momentum and isospin to the ground state. In the $\mathrm{sd}$ shell model this reproduces correctly the isospin but not the spin quantum numbers of actual odd-odd nuclei. An odd-even staggering effect in probability of various ground state quantum numbers is present for even-even and odd-odd nuclei, while it is smeared out for odd-$A$ nuclei. The observed regularities suggest the underlying mechanism of bosonlike pairing of fermionic pairs in $T=0\mathrm{}$ and $T=1\mathrm{}$ states generated by the off-diagonal matrix elements of random interactions. The relation to the models of random spin interactions is briefly discussed.

The microscopic mechanism of identical superdeformed bands in ${}^{192,193,194}\mathrm{Hg}$ is investigated using the particle-number conserving treatment for the cranked shell model with monopole and quadrupole pairing interactions. In combination with the analysis for normally deformed identical bands in the rare-earth nuclei, it is shown that the identical bands observed in normally deformed rare-earth nuclei and superdeformed nuclei in the $A\sim 190$ region result from the competition among shell effect, pairing interaction, blocking effect on pairing, and Coriolis antipairing interaction, where a strict and consistent treatment of blocking effect plays a crucial role.

A new decomposition of the Dirac structure of nucleon self-energies in the Dirac Brueckner-Hartree-Fock (DBHF) approach is adopted to investigate the equation of state for asymmetric nuclear matter. The effective coupling constants of $\sigma ,$ $\omega ,\hspace{0.5em}\delta$, and $\rho$ mesons with a density dependence in the relativistic mean field approach are deduced by reproducing the nucleon self-energy resulting from the DBHF at each density for symmetric and asymmetric nuclear matter. With these couplings the properties of finite nuclei are investigated. The agreement of charge radii and binding energies of finite nuclei with the experimental data are improved simultaneously in comparison with the projection method. It seems that the properties of finite nuclei are sensitive to the scheme used for the DBHF self-energy extraction. We may conclude that the properties of the asymmetric nuclear matter and finite nuclei could be well described by the new decomposition approach of the G matrix.

The momentum distributions of the residual nuclei after one-neutron removal have been measured in coincidence with gamma rays identifying the distributions associated with the excited and ground state levels of these residues. These differential partial cross sections map the momentum content of the removed-nucleon wave functions and their description provides an exacting test of the reaction dynamics. Momentum distribution data when populating the ${}^{14}$C and ${}^{10}$Be ground states show a low-high momentum asymmetry that is incompatible with the hitherto used eikonal descriptions. A fully dynamical coupled discretized continuum channels description of the elastic breakup mechanism is shown to provide an understanding of this new observation which is most pronounced for weakly bound, s-wave, nuclear halo states. This interpretation is clarified further by an analysis of the momentum distributions as a function of the angle of detection of the heavy ground state residues.

We present a new method to account for coherence length effects in a semiclassical transport model. This allows us to describe photoproduction and electroproduction at large nuclei $\mathrm{}(A>\mathrm{}12\mathrm{})\mathrm{}$ and high energies using a realistic coupled channel description of the final state interactions that goes beyond simple Glauber theory. We show that the purely absorptive treatment of the final state interactions can lead to wrong estimates of color transparency and formation time effects in particle production. As an example, we discuss exclusive ${\rho }^0$ photoproduction on Pb at a photon energy of 7 GeV as well as $K^{+}$ production in the photon energy range 1–7 GeV.

In a recent publication we calculated elastic charmonium production in $\mathrm{ep}$ collisions, employing realistic charmonia wave functions and dipole cross sections, and found good agreement with the data in a wide range of s and $Q^2$. Using the ingredients from those calculations we calculate exclusive electroproduction of charmonia off nuclei. Here new effects become important, (i) color filtering of the $c\overline{c}$ pair on its trajectory through nuclear matter, (ii) dependence on the finite lifetime of the $c\overline{c}$ fluctuation (coherence length), and (iii) gluon shadowing in a nucleus compared to the one in a nucleon. Total coherent and incoherent cross sections for C, Cu, and Pb as functions of s and $Q^2$ are presented together with some differential cross sections. The results can be tested with future electron-nucleus colliders or in peripheral collisions of ultrarelativistic heavy ions.

Various measures of charge fluctuations in heavy-ion collisions are discussed. Advantages of the $\Phi$ measure are demonstrated and its relation to other fluctuation measures is established. To get the relation, $\Phi$ is expressed through the moments of multiplicity distribution. We study how the measures act in the case of a “background” model that represents the classical hadron gas in equilibrium. The model assumes statistical particle production constrained by charge conservation. It also takes into account both the effect of incomplete experimental apparatus acceptance and that of tracking inefficiency. The model is shown to approximately agree with the PHENIX and preliminary STAR data on the electric charge fluctuations. Finally, “background-free” measures are discussed.

The neutron capture cross sections of ${}^{110}\mathrm{Cd},$ ${}^{111}\mathrm{Cd},$ ${}^{112}\mathrm{Cd},$ ${}^{113}\mathrm{Cd},$ ${}^{114}\mathrm{Cd},$ and ${}^{116}\mathrm{Cd}$ have been measured in the energy range from 3 to 225 keV at the Karlsruhe 3.75 MV Van de Graaff accelerator. Neutrons were produced via the ${}^7\mathrm{Li}{\mathrm{}(p,n)\mathrm{}}^7\mathrm{Be}$ reaction by bombarding metallic Li targets with a pulsed proton beam. The Karlsruhe $4\pi$ barium fluoride detector was used for registration of capture events. The cross sections were determined relative to the gold standard using highly enriched metallic Cd samples. The respective ratios could be obtained with overall uncertainties between 0.8% and 1.6%, about an order of magnitude more accurate than previous data. Maxwellian averaged neutron capture cross sections were calculated for thermal energies between $kT=8\mathrm{}\hspace{0.5em}\mathrm{keV}$ and 100 keV. Discrepancies of 30% to 40% were found with respect to previous data. The new cross sections provide a reliable definition of the s-abundance pattern of the Cd isotopes, thus improving the corresponding r-process residuals, and, most importantly, the impact of s-only ${}^{110}\mathrm{Cd}$ as a normalization point for the overall distribution of the s abundances.

Based on the recent NA44 and WA98 two- and three-pion interferometry data together with the WA98 pion multiplicity information, we observe that the pions may be mostly emitted from chaotic sources in the peripheral events and coherent pions are mostly generated in the central events. A more refined analysis would be needed, however, to make our observation conclusive by quantifying various effects such as resonance formation of the emerging pions and also experimental uncertainties.