The ${}^{16}\mathrm{O}{(}^{16}\mathrm{O}{,}^{12}{\mathrm{C}}^{16}\mathrm{O})\alpha$ reaction has been studied at incident energies of 90 and 97 MeV. States in ${}^{28}\mathrm{Si}$ are reconstructed over the excitation energy range 22–45 MeV, and the spins of six states, ranging from $9^{-}$ to ${17}^{-},$ were obtained from angular correlation measurements. A comparison of these breakup states with scattering resonances indicates that some of the breakup states lie below the locus of the ${}^{12}\mathrm{C}{+}^{16}\mathrm{O}$ scattering resonances, and may belong to a highly deformed band with a rotational parameter of $(42\mathrm{}\pm 5)\hspace{0.5em}\mathrm{keV}$ and a bandhead energy of $E_x=(26.3\mathrm{}\pm 0.9)\hspace{0.5em}\mathrm{}\mathrm{MeV}.$

The decay of the mass-separated, very neutron-rich isotope ${}^{93}\mathrm{Br}$ has been studied by γ spectroscopy. A level scheme of its daughter ${}^{93}\mathrm{Kr}$ has been constructed. Level energies, γ-ray branching ratios, and multipolarities suggest spins and parities which are in accord with a smooth systematics of the $N=57\mathrm{}$ isotones for $Z<~40,$ suggesting the $N=56\mathrm{}$ subshell closure still to be effective in Kr isotopes. So far, there is no indication of a progressive onset of deformation in neutron-rich Kr isotopes.

The ${}^{12}\mathrm{C}{+}^{12}\mathrm{C}$ and ${}^8\mathrm{Be}{+}^{16}\mathrm{O}$ decay of ${}^{24}\mathrm{Mg}$ states populated in the ${}^{12}\mathrm{C}{(}^{20}\mathrm{Ne}{,}^{24}{\mathrm{Mg}}^{*})$ reaction has been studied at beam energies of 160 and 110 MeV. Evidence for excited states, which decay by ${}^{12}\mathrm{C}$ and ${}^8\mathrm{Be}$ emission, is observed for the excitation energy range 22 to 33 MeV. Angular correlation analysis shows that the spins of these states lie in the range of 6 to $12ħ.$ These measurements further indicate that the breakup states possess a 4p-4h structure.

Using the Thomas-Fermi nuclear model we have constructed a standard dimensionless function (a simple hyperbola) which can be used to estimate the dependence of the surface tension $\gamma$ on the relative neutron excess $\delta$ for a variety of models, using only the models’ properties calculated for standard (semi-infinite) nuclear matter with $\delta =0.\mathrm{}$ We add some comments clarifying the relation between the Gibbs and the droplet model definitions, ${\gamma }_{\mu }$ and ${\gamma }_e,$ of the surface tension.

We study the utility of a complex Langevin (CL) equation as an alternative for the Monte Carlo (MC) procedure in the evaluation of expectation values occurring in fermionic many-body problems. We find that a CL approach is natural in cases where nonpositive definite probability measures occur, and remains accurate even when the corresponding MC calculation develops a severe “sign problem.” While the convergence of CL averages cannot be guaranteed in principle, we show how convergent results can be obtained in two simple quantum mechanical models, as well as a nontrivial schematic shell model path integral with multiple particles and a noncommuting interaction (the Lipkin model).

Energy distributions of emitted neutrons were measured for $7.2A\mathrm{MeV}$ ${}^{16}\mathrm{O}$ ions incident on a thick ${}^{181}\mathrm{Ta}$ target. Measurements were done at $0°,$ $30°,$ and $60°$ with respect to the projectile direction using the proton recoil scintillation technique. Comparison with calculated results from equilibrium and preequilibrium (PEQ) nuclear reaction models suggests the emission of PEQ neutrons at this projectile energy. This model also implies that PEQ emissions take place only before any scattering between target and projectile nucleons start. The paper discusses the method for selecting the initial exciton configuration with the help of measured data, and the stage at which the PEQ process is completed.

The emission of two coincident energetic $(E>~8\hspace{0.5em}\mathrm{MeV})$ gamma rays has been observed in the 187 MeV ${}^{37}\mathrm{Cl}{+}^{120}\mathrm{Sn}$ reaction by using the cluster detectors of the EUROBALL III array. Those events are attributed to the decay of the double giant dipole resonance built on highly excited states.

Intermediate velocity emissions of light charged particles are studied for the Ar+Ni system at $95A\hspace{0.5em}\mathrm{MeV}.$ Experimental parallel velocity and transverse energy distributions are compared to those of a calculation based on intranuclear cascades followed by percolation and evaporation steps. The trends of the distributions are very similar, confirming the importance of prompt emissions in the experimental data.

The ${}^{\mathrm{nat}}\mathrm{Pb}{(}^3\mathrm{He},t)$ reaction and the subsequent decay of the excited nucleus by proton emission at backward angles were studied at ${E(}^3\mathrm{He})=177\mathrm{}\hspace{0.5em}\mathrm{MeV}$ with the aim to separate the $2ħ\omega$ isovector monopole strength in Bi isotopes from the continuum background. Since the continuum is largely due to quasifree processes associated with forward-peaked high-energy protons, the observed resonance-to-continuum ratio is drastically improved when coincidences between ejectile tritons and protons emitted at backward angles are required. Furthermore, the cross section for the monopole resonances excited via ${(}^3\mathrm{He},t)$ is, unlike the cross sections for higher multipolarity excitations, strongly forward peaked. By comparing coincidence spectra at ${\theta }_t\approx 0°$ and at finite angles, monopole strength was found in the region $-45<Q<\mathrm{}-30\hspace{0.5em}\mathrm{MeV}.$ The measured monopole cross section is compared with distorted-wave Born approximation calculations for spin-flip and non-spin-flip isovector monopole excitations. It is found that 20% of the respective non-energy-weighted sum rules are exhausted in the proton-decay channel.

In this work, the ${\eta }^{\prime }$ meson photoproduction near threshold is studied in the quark model framework. A pseudovector effective Lagrangian is introduced for the ${\eta }^{\prime }\mathrm{NN}$ coupling and the newly published data from the SAPHIR Collaboration provide good constraints to this parameter. Corrections of order ${O(1/m}_q^2)$ for the electromagnetic interaction vertex are taken into account, which produce corrections of order ${O(1/m}_q^3)$ to the transition amplitude for $\gamma \overrightarrow{p}{\eta }^{\prime }p.\mathrm{}$ Some low-lying resonances, $S_{11}\mathrm{}\left(1535\right),$ $P_{13}\mathrm{}\left(1720\right),$ and $P_{13}\mathrm{}\left(1900\right),$ are found to have significant contributions. A bump structure around $E_{\gamma }\approx 2\hspace{0.5em}\mathrm{GeV}$ is found arising from the $n=3\mathrm{}$ terms in the harmonic oscillator basis. The beam polarization asymmetries are predicted and can be tested against the forthcoming data from GRAAL.

The azimuthal pattern of transverse energy flow in nuclear collisions at RHIC and LHC energies is considered. We show that the probability distribution of the event-by-event azimuthal disbalance in transverse energy flow is essentially sensitive to the presence of the semihard minijet component.

It is shown within the strong-coupling BCS approach that, starting from the zero-density limit of superfluid nuclear matter, with increasing density deuterons first shrink before they start expanding.

We reanalyze the dissociation process of the $J/\psi$ by $\pi$ and $\rho$ mesons into $D+\overline{D},$ $D^{*}+\overline{D},$ $D+D^{*},$ and $D^{*}+D^{*}$ within a meson exchange model. In addition to the dissociation mechanisms considered in the literature, we consider anomalous parity interactions, whose couplings are constrained by heavy quark spin symmetry and phenomenology. This opens new dissociation channels and adds new diagrams in the previously considered processes. Compared to the previous results, we find that these new additions have only a minor effect on the $\rho +J/\psi$ total inelastic cross section, but reduce the one for $\pi +J/\psi$ by about 50% near the threshold.

The decay by proton emission of the ${}^{117}\mathrm{La}$ nucleus has been studied via the 310 MeV ${}^{58}\mathrm{Ni}{+}^{64}\mathrm{Zn}$ reaction. The nucleus has two levels that decay to the ground state of ${}^{116}\mathrm{Ba}$ with $E_p=783\mathrm{}\left(6\right)\mathrm{}$ keV ${(T}_{1/2}=22\mathrm{}\left(5\right)\mathrm{}$ ms] and $E_p=933\mathrm{}\left(10\right)\mathrm{}$ keV $[T_{1/2}=10\mathrm{}(5)\mathrm{}$ ms]. Calculations performed for a deformed proton emitter reproduce quite well the experimental results confirming that ${}^{117}\mathrm{La}$ is strongly deformed $({\beta }_2\sim 0.3)$. Spin and parity of the two p-decaying levels have been determined as well: ${3/2}^{+}$ for the ground state and ${9/2}^{+}$ for the $E_x=151\mathrm{}\left(12\right)\mathrm{}$ keV excited state.

We propose a new model to calculate stellar electron capture rates for neutron-rich nuclei. These nuclei are encountered in the core collapse of a massive star. Using the shell model Monte Carlo approach, we first calculate the finite temperature occupation numbers in the parent nucleus. We then use these occupation numbers as a starting point for calculations using the random phase approximation (RPA). Using the RPA approach, we calculate electron capture rates including both allowed and forbidden transitions. Such a hybrid model is particularly useful for nuclei with proton numbers $Z<\mathrm{}40\mathrm{}$ and neutron numbers $N>\mathrm{}40,$ where allowed Gamow-Teller transitions are only possible due to configuration mixing by the residual interaction and by thermal unblocking of $\mathrm{pf}$-shell single-particle states. Using the even germanium isotopes ${}^{68-76}\mathrm{Ge}$ as examples, we demonstrate that the configuration mixing is strong enough to unblock the Gamow-Teller transitions at all temperatures relevant to core-collapse supernovae.

High spin states of ${}^{32}\mathrm{S}$ and ${}^{56}\mathrm{Ni}$ are investigated by means of the cranking Hartree-Fock method with the Gogny interaction without imposing a restriction on the axial reflection symmetry. It is found that a nonaxial octupole deformation of the $Y_{31}$ type becomes important in the yrast states of ${}^{32}\mathrm{S}.$ A similar effect is predicted for the nucleus ${}^{56}\mathrm{Ni}.$

A framework to calculate two-particle matrix elements for fully antisymmetrized three-cluster configurations is presented. The theory is developed for a scattering situation described in terms of the algebraic model. This means that the nuclear many-particle state and its asymptotic behavior are expanded in terms of oscillator states of the intercluster coordinates. The generating function technique is used to optimize the calculation of matrix elements. In order to derive the dynamical equations, a multichannel version of the algebraic model is presented.

The resonance states embedded in the three-cluster continuum of ${}^6\mathrm{He}$ and ${}^6\mathrm{Be}$ are obtained in the algebraic version of the resonating group method. The model accounts for a correct treatment of the Pauli principle. It also provides the correct three-cluster continuum boundary conditions by using a hyperspherical harmonics basis. The model reproduces the observed resonances well and achieves good agreement with other models. A better understanding for the process of formation and decay of the resonance states in six-nucleon systems is obtained.

Producing rare isotopes through statistical multifragmentation is investigated using the Mekjian method for exact solutions of the canonical ensemble. Both the initial fragmentation and the sequential decay are modeled in such a way as to avoid Monte Carlo and thus provide yields for arbitrarily scarce fragments. The importance of sequential decay, exact particle-number conservation and the sensitivities to parameters such as density and temperature are explored. Recent measurements of isotope ratios from the fragmentation of different Sn isotopes are interpreted within this picture.

In the literature, one often finds calculations of ${(e,e}^{\prime }p)$ reactions at GeV energies using the factorization approach. Factorization implies that the differential cross section can be written as the product of an off-shell electron-proton cross section and a distorted missing momentum distribution. While this factorization appears in the nonrelativistic plane wave impulse approximation, it is broken in a more realistic approach. The main source of factorization breaking is final state interactions. In this paper, sources of factorization breaking are identified and their numerical relevance is examined in the reaction ${}^2\mathrm{H}{(e,e}^{\prime }p)$ for various kinematic settings in the GeV regime. The results imply that factorization should not be used for precision calculations, especially as unfactorized calculations are available.