Low-lying short-lived isomeric states have been investigated in ${}^{84}\mathrm{Y}$ by the ${}^{84}\mathrm{Sr}$($p,n$) reaction at $E_p=13.5$ MeV. The g factors were measured by applying the time-differential perturbed angular distribution method in an external magnetic field. The properties determined for the new isomers are $E_x=112.4$ keV, $I^{\pi }=(4^{+}),T_{1/2}=79(2)$ ns, $g=+0.578(7);E_x=210.4$ keV, $I^{\pi }=(4^{-}),T_{1/2}=292(10)$ ns, $g=+0.234(6)$. On the basis of the measured g factor, the $\pi 1g_{9/2}\otimes \nu 1g_{9/2}$ configuration has been assigned to the $4^{+}$ isomeric state. The low-lying states in ${}^{84}\mathrm{Y}$ were discussed within the two-quasiparticles plus rotor model. The $4^{-}$ isomeric state has been interpreted by the pure $\pi [301]3/2\otimes \nu [422]5/2$ configuration, which reproduces the experimental g factor at a prolate quadrupole deformation of ${\varepsilon }_2\approx 0.16$.

The β decay of ${}^{31}\mathrm{Mg}$ has been investigated at GANIL. The ions were implanted in a silicon detector array surrounded by germanium γ detectors. β particles and subsequent γ rays have been observed. The ${}^{31}\mathrm{Mg}$ half-life has been measured ($T_{1/2}=237\pm 25$ ms) in good agreement with previously reported values. The decay scheme of ${}^{31}\mathrm{Mg}$ has been enriched with two new low-spin levels and seven new γ transitions in ${}^{31}\mathrm{Al}$. Most importantly, very weak feeding to the ${}^{31}\mathrm{Al}$ ground and lowest excited states has been established. These results are compared to new shell-model calculations in the $\mathit{sd}\text{−}\mathit{fp}$ valence space, using an interaction that was modified in order to reproduce the recently established low-energy level scheme of ${}^{31}\mathrm{Mg}$. A good agreement for all observables is found, supporting the idea that ${}^{31}\mathrm{Al}$ is outside and ${}^{31}\mathrm{Mg}$ is inside the so-called “island of inversion.”

γ rays from neutron-rich Ti nuclei in the vicinity of $N=32$ have been studied at Gammasphere using deep-inelastic reactions induced by ${}^{48}\mathrm{Ca}$ beams on thick ${}^{208}\mathrm{Pb}$ and ${}^{238}\mathrm{U}$ targets. The ${}^{53}\mathrm{Ti}$ yrast cascade was identified for the first time, and the location in energy of states with spin up to I = 21/2 was determined. The excitations of ${}^{53}\mathrm{Ti}$ provide new tests of effective interactions for full-pf-shell calculations. Comparisons between theory and experiment for the highest spin states in ${}^{53}\mathrm{Ti}$ favor the recently proposed GXPF1A interaction, which accounts for the appearance of a neutron subshell closure at $N=32$ in Ti isotopes as well as for the lack of a similar subshell closure at $N=34$, as predicted by earlier calculations with another interaction.

The ${}^{123}\mathrm{Sb}$$(\overrightarrow{p},\alpha )$${}^{120}\mathrm{Sn}$ reaction has been studied in a high resolution measurement at incident energy of 24 MeV using a polarized proton source and a Q3D spectrometer. The differential cross sections and asymmetries for transitions to levels of ${}^{120}\mathrm{Sn}$ homologous to the lowest energy states of ${}^{119}\mathrm{In}$ have been measured and interpreted in terms of the experimental differential cross sections and asymmetries of the parent ${}^{119}\mathrm{In}$ states, on the basis of the weak-coupling model. Several (17) states of the ${}^{120}\mathrm{Sn}$ residual nucleus, not previously reported in the literature, have been detected and spins and parities have been proposed for seven of them, while parities have been proposed for five other previously known levels. In order to analyze the transitions populating the homologous levels, for both differential cross sections and asymmetries, microscopic DWBA calculations have been performed using spectroscopic amplitudes obtained from a shell-model study.

In equilibrium statistical mechanics, the density of microstates representing the statistical weight associated with a partition of an isolated system into subsystems (fragments) is the convolution of the state densities of the component subsystems. The Laplace transform approximation provides a simple representation of this density. Despite the fact that no external heat bath can be said to exist (the canonical ensemble is not appropriate) the approximation leads to partition probabilities that involve a product of factors (one for each fragment) expressed in terms of a characteristic inverse temperature. We apply the method to nuclear multifragmentation with particular emphasis on a transition that occurs when the major part of the available energy appears as kinetic (as opposed to internal excitation) energy of fragments. Finally, we discuss the shortcomings and advantages of expressing the weights of partitions with fixed total mass (charge) and multiplicity in a simple multinomial form.

We investigate the equations of state for pure neutron matter and for nonstrange and strange hadronic matter in β equilibrium, including $\Lambda ,\Sigma$, and Ξ hyperons. The masses and radii of these kinds of stars are obtained. For a pure neutron star, the maximum mass is about $1.8M_{\mathrm{sun}}$, while for a strange (nonstrange) hadronic star in β equilibrium, the maximum mass is around $1.45M_{\mathrm{sun}}\hspace{1em}(1.7M_{\mathrm{sun}})$. The typical radii of pure neutron stars and strange hadronic stars are about 11.5–13.0 km and 11.5–12.5 km, respectively.

Proton radioactivity from ${}^{105}\mathrm{Sb}$ has been reinvestigated at the GSI on-line mass separator. The nucleus was produced in the reaction ${}^{50}\mathrm{Cr}$(${}^{58}\mathrm{Ni}$,$1p2n$), and collected with a tape transport system. A double-sided Si strip detector was used for proton spectroscopy. The direct proton decay of ${}^{105}\mathrm{Sb}$ reported in an earlier experiment at Berkeley was not observed. The present data imply an upper limit $~{10}^{-3}$ for the ground-state proton decay branching ratio for proton energies higher than 430 keV.

In an effort to understand the magical status of $N=32$ and $N=34$ at the very neutron rich edge, experiments have been carried out in the titanium isotopes up to $A=56$. The measured staggering of the $B(E2)$'s is not reproduced by the shell model calculations using the best effective interactions. We argue that this may be related to the choice of the isovector effective charge and to the value of the $N=34$ neutron gap.

We evaluate the accuracy of traditional estimators often used to extract $N\to \Delta$ quadrupole ratios from cross-section angular distributions for pion electroproduction. We find that neither $M_{1+}$ dominance nor $\ell \le 1$ truncation is sufficiently accurate for this purpose. Truncation errors are especially large for $R_{\mathrm{EM}}$, for which it is also essential to perform Rosenbluth separation. The accuracy of similar truncated Legendre analyses for $E_{0+},S_{0+}$, and especially $M_{1-}$ is even worse.

A short-range nonlocal nucleon-nucleon potential, which previously provided a better description for the three-nucleon bound states ${}^3\mathrm{H}$ and ${}^3\mathrm{He}$ then the local-potential models, is tested in $p\text{−}d$ scattering calculations at energies below the three-body breakup threshold. This potential again provides an equivalent or better description of the experimental data than the local Argonne+3N force model.

We have performed for the first time the simultaneous measurement of the two-body and three-body photodisintegration cross sections of ${}^4\mathrm{He}$ in the energy range from 21.8 to 29.8 MeV using monoenergetic pulsed photons and a 4π time projection chamber containing ${}^4\mathrm{He}$ gas as an active target in an event-by-event mode. The photon beam was produced via the Compton backscattering of laser photons with high-energy electrons. The ${}^4\mathrm{He}$($\gamma ,p$)${}^3\mathrm{H}$ and ${}^4\mathrm{He}$($\gamma ,n$)${}^3\mathrm{He}$ cross sections were found to increase monotonically with energy up to 29.8 MeV, in contrast to the result of a recent theoretical calculation based on the Lorentz integral transform method that predicted a pronounced peak at around 26–27 MeV. The energy dependence of the obtained ${}^4\mathrm{He}$($\gamma ,n$)${}^3\mathrm{He}$ cross section up to 26.5 MeV is marginally consistent with a Faddeev-type calculation predicting a flat pattern of the excitation function. The cross section ratio of ${}^4\mathrm{He}$($\gamma ,p$)${}^3\mathrm{H}$ to ${}^4\mathrm{He}$($\gamma ,n$)${}^3\mathrm{He}$ is found to be consistent with the expected value for charge symmetry of the strong interaction within the experimental uncertainty in the measured energy range. The present results for the total and two-body cross sections of the photodisintegration of ${}^4\mathrm{He}$ are compared to previous experimental data and recent theoretical calculations.

A systematic study of global properties of superheavy nuclei in the framework of macroscopic-microscopic method is performed. Equilibrium deformations, masses, quadrupole moments, radii, shell energies, fission barriers and half-lives are calculated using the following macroscopic models: Myers-Swiatecki liquid drop, droplet, Yukawa-plus-exponential, and Lublin-Strasbourg drop. Shell and pairing energies are calculated in Woods-Saxon potential with a universal set of parameters. The analysis covers a wide range of even-even superheavy nuclei from $Z=100$ to 122. Magic and semimagic numbers occurring in this region are indicated and their influence on the observables is discussed. The strongest shell effects appear at proton number $Z=114$ and at neutron number $N=184$. Deformed shell closures are found at $N=152$ and 162. Spontaneous fission half-lives are calculated in a dynamical approach where the full minimization of the action integral in a three-dimensional deformation space of β deformations is performed. The fission half-lives obtained this way are two orders of magnitude smaller than the ones resulting from static calculations. The agreement of theoretical results and experimental data is satisfying.

We study the reaction $\pi +N\to 2\pi +N$ within the framework of heavy-baryon chiral perturbation theory of chiral order three. The reaction cross section from threshold up to pion laboratory kinetic energies of 400 MeV is found to be in reasonable agreement with experimental data. A host of differential cross sections and angular correlations are also calculated and are found to be in semiquantitative agreement with the data. We find that contributions from amplitudes of chiral order three are large and play an essential role in reproducing the experimental data. Unitarity corrections arising from the imaginary parts of the loop-level Feynman diagrams are the only parameter-free predictions of the present calculations. It is found that the unitarity effects in some reaction channels are sizable. Finally, we evaluate polarization observables (asymmetries) for the transverse polarization of the proton target and find that the asymmetries are generally small ($\le 0.4$) for the reaction under consideration.

The photon and ${}^3\mathrm{He}$ analyzing powers as well as spin correlation coefficients in the semiexclusive three-body photodisintegration of ${}^3\mathrm{He}$ are investigated for incoming photon laboratory energies $E_{\gamma }=12,40$, and 120 MeV. The nuclear states are obtained by solving three-body Faddeev equations with the AV18 nucleon-nucleon potential alone or supplemented with the UrbanaIX three-nucleon force. Explicit π- and ρ-meson exchange currents are taken into account, but we also compare to other models of the electromagnetic current. In some kinematical conditions we have found strong effects of the three-nucleon force for the ${}^3\mathrm{He}$ analyzing power and spin correlation coefficients, as well strong sensitivities to the choice of the currents. This set of predictions should be a useful guidance for the planning of measurements. In addition, we compare our results for two-body ${}^3\mathrm{He}$ breakup induced by polarized photons with a few existing data.

The nuclear magnetic moment of ${}^9\mathrm{Li}$ and the quadrupole moments of ${}^8\mathrm{Li}$ and ${}^9\mathrm{Li}$ have been measured by use of the β-asymmetry detection of nuclear magnetic resonance on optically polarized beams at ISOLDE/CERN. The radioactive beams were implanted in Si for g-factor measurements and in Zn, ${\text{LiNbO}}_3$, and ${\text{LiTaO}}_3$ crystals for quadrupole moment measurements. The electric-field gradient $V_{\mathit{zz}}=4.26(4)\times {10}^{15}$ V/${\text{cm}}^2$ is deduced for Li in Zn. Using a recently adopted reference value, $Q($${}^7\mathrm{Li}$$)=-40.0(3)$ mb, we reevaluated all earlier reported nuclear quadrupole moments of ${}^8\mathrm{Li}$ and ${}^9\mathrm{Li}$. Based on all available previous and present data, the adopted quadrupole moments for these isotopes are $Q($${}^8\mathrm{Li}$$)=+31.4(2)$ mb and $Q($${}^9\mathrm{Li}$$)=-30.6(2)$ mb. The magnetic moment of ${}^9\mathrm{Li}$ is deduced as $\mu ($${}^9\mathrm{Li}$$)=3.43678(6){\mu }_N$. The values are compared with predictions from shell-model and cluster-model calculations.

We calculate the spectra of high-energy photons emitted in relativistic Au + Au collisions for various centralities and compare to data recently collected at the Relativistic Heavy Ion Collider by the PHENIX Collaboration. Our results for photons from primary hard scatterings and photons from interactions of jets with the medium are consistent with the measurements of neutral pion and direct photon production in $p+p$ collisions and give a good description of direct photon spectra measured in Au + Au collisions. The contribution of photons from jet-to-photon conversion in the medium can be as large as the photon yield from hard scatterings in the momentum range $p_T\approx 2–6$ GeV/c. We show that this novel mechanism is not ruled out by any existing data.

The properties of the excited states of ${}^{76}\mathrm{Kr}$, populated in the decay of ${}^{76}\mathrm{Rb}$ produced at ISOLDE isotopic separator, have been investigated by using K-conversion electron, γ-ray, and γ-γ coincidence measurements. The lifetimes of several levels have been measured by means of the advanced time-delayed $\beta \gamma \gamma (t)$ method. The identification of 19 new levels and 55 transitions and the information deduced on spin and/or parity of the observed states from K-conversion coefficients, log ft values and decay properties have led to an improved knowledge of the level scheme. In particular, six $1^{-}$ states have been definitely identified and $J^{\pi }=2^{-}$ has been assigned to the 2227 keV level, on which a band proposed to have negative-parity and even-spin had been previously observed. The strengths of the E0 and E2 transitions deexciting the $0_2^{+}$ and $0_3^{+}$ states (the latter is here identified with the state at 1598 keV) have been measured. The experimental data concerning the $0_2^{+}$ state have been analyzed in a simple two states mixing model and in the framework of the proton-neutron interacting boson model.

We point out the similarity of thermodynamic conditions reached in nuclear multifragmentation and in supernova explosions. We show that a statistical approach previously applied for nuclear multifragmentation reactions can also be used to describe the electroneutral stellar matter. Then properties of hot unstable nuclei extracted from the analysis of multifragmentation data can be used to determine a realistic nuclear composition of hot supernova matter.

Results of charge form factors calculations for several unstable neutron-rich isotopes of light, medium, and heavy nuclei (He, Li, Ni, Kr, Sn) are presented and compared to those of stable isotopes in the same isotopic chain. For the lighter isotopes (He and Li) the proton and neutron densities are obtained within a microscopic large-scale shell-model, while for heavier ones Ni, Kr, and Sn the densities are calculated in deformed self-consistent mean-field Skyrme HF+BCS method. We also compare proton densities to matter densities together with their rms radii and diffuseness parameter values. Whenever possible comparison of form factors, densities and rms radii with available experimental data is also performed. Calculations of form factors are carried out both in plane wave Born approximation (PWBA) and in distorted wave Born approximation (DWBA). These form factors are suggested as predictions for the future experiments on the electron-radioactive beam colliders where the effect of the neutron halo or skin on the proton distributions in exotic nuclei is planned to be studied and thereby the various theoretical models of exotic nuclei will be tested.