The continuum shell model is an old but recently revived method that traverses the boundary between nuclear many-body structure and nuclear reactions. The method is based on the non-Hermitian energy-dependent effective Hamiltonian. The formalism, interpretation of solutions, and practical implementation of calculations are discussed in detail. The results of the traditional shell model are fully reproduced for bound states; resonance parameters and cross-section calculations are presented for decaying states. Particular attention is given to one- and two-nucleon reaction channels, including sequential and direct two-body decay modes. New calculations of reaction cross sections and comparisons with experimental data for helium and oxygen isotope chains are presented.

The incomplete fusion mechanism following breakup of ${}^{6,7}\mathrm{Li}$ and ${}^9\mathrm{Be}$ projectiles incident on targets of ${}^{209}\mathrm{Bi}$ and ${}^{208}\mathrm{Pb}$ is investigated through isomer ratio measurements for the ${}^{212}\mathrm{At}$ and ${}^{211}\mathrm{Po}$ products. The phenomenological analysis presented in this paper indicates that incomplete fusion brings relatively more angular momentum into the system than equivalent reactions with a direct beam of the fused fragment. This is attributed to the trajectories of breakup fragments. Calculations with a 3D classical trajectory model support this. Isomer ratio measurements for incomplete fusion reactions can provide a test of new theoretical models of breakup and fusion.

We propose net charge fluctuation as a measure of local charge correlation length. It is demonstrated that, in terms of a schematic multiperipheral model, net charge fluctuation satisfies the same Quigg-Thomas relation as satisfied by charge transfer fluctuation. Net charge fluctuations measured in finite rapidity windows depend on both the local charge correlation length and the size of the observation window. When the observation window is larger than the local charge correlation length, the net charge fluctuation only depends on the local charge correlation length, while forward-backward charge fluctuations always have strong dependence on the observation window size. Net charge fluctuations and forward-backward charge fluctuations measured in the present heavy ion experiments show characteristic features similar to those from multiperipheral models. But the data cannot all be understood within this simple model.

We present a relativistic and cross-section factorized framework for computing nuclear transparencies extracted from $A(\gamma ,\pi N)$ reactions at intermediate energies. The proposed quantum mechanical model adopts a relativistic extension to the multiple-scattering Glauber approximation to account for the final state interactions of the ejected nucleon and pion. The theoretical predictions are compared against the experimental ${}^4\mathrm{He}$$(\gamma ,p{\pi }^{-})$ data from the Thomas Jefferson National Accelerator Facility. For those data, our results show no conclusive evidence of the onset of mechanisms related to color transparency.

We perform microscopic calculations of the inelastic cross sections for the double and triple excitation of giant resonances induced by heavy-ion probes within a semiclassical coupled-channels formalism. The channels are defined as eigenstates of a bosonic quartic Hamiltonian constructed in terms of collective random-phase approximation phonons. Therefore, they are superpositions of several multiphonon states, also with different numbers of phonons, and the spectrum is anharmonic. The inclusion of ($n+1$) phonon configurations affects the states whose main component is a $n$-phonon one and leads to an appreacible lowering of their energies. We check the effects of such further anharmonicities on the previously published results for the cross section for the double excitation of giant resonances (GR). We find that the only effect is a shift of the peaks toward lower energies, the double GR cross section being unmodified by the explicity inclusion of the three-phonon channels in the dynamical calculations. The latter provide an important contribution to the cross section in the triple GR energy region, which, however, is still smaller than the experimental available data. The inclusion of four-phonon configurations in the structure calculations does not modify the results.

Event-by-event fluctuations of the net baryon number and electric charge in nucleus-nucleus collisions are studied in Pb+Pb at SPS energies within the Hadron-String Dynamics (HSD) transport model. We reveal an important role of the fluctuations in the number of target nucleon participants. They strongly influence all measured fluctuations even in the samples of events with rather rigid centrality trigger. This fact can be used to check different scenarios of nucleus-nucleus collisions by measuring the multiplicity fluctuations as a function of collision centrality in fixed kinematical regions of the projectile and target hemispheres. The HSD results for the event-by-event fluctuations of electric charge in central collisions at $20A,30A,40A,80A$, and $158A$ GeV are in a good agreement with the NA49 experimental data and considerably larger than expected in a quark-gluon plasma. This demonstrates that the distortions of the initial fluctuations by the hadronization phase and, in particular, by the final resonance decays dominate the observable fluctuations.

A recently developed nonperturbative chiral approach to dynamically generate the $3/2^{-}$ baryon resonances has been extended to investigate the radiative decays ${\Lambda }^{*}(1520)\to \gamma \Lambda (1116)$ and ${\Lambda }^{*}(1520)\to \gamma {\Sigma }^0(1193)$. We show that the ${\Lambda }^{*}(1520)$ decay into $\gamma \Lambda$ is an ideal test for the need of extra components of the resonance beyond those provided by the chiral approach since the largest meson-baryon components give no contribution to this decay. The case is different for $\gamma \Sigma$ decay, where the theory agrees with experiment, though the large uncertainties of these data call for more precise measurements. Some estimates of the weight of the needed genuine resonance component are made.

The conversion of a neutron star to a strange star is studied. Such a transition may be viewed as a two-step process in which the hadronic matter first gets converted to two-flavor quark matter, which, in turn, converts to strange quark matter in the second step of the process. Relativistic hydrodynamical equations are employed to obtain the velocity of propagation of the first conversion front. The second transition front, arising from the conversion of two-flavor to three-flavor quark matter, is studied by using an appropriate weak interaction rate. The propagation velocity of the first conversion front initially shoots up near the core of the star to eventually saturate to some ultrarelativistic value. The first conversion takes about a millisecond, during which the second conversion front is likely to be generated. The second process takes about a hundred seconds to convert the whole quark star into a strange star.

We investigate a linear-chain configuration of three α clusters with a neutron in ${}^{13}\mathrm{C}$. To characterize this configuration, an operator $\mathcal{P}$ is introduced, which is the sum of parity inversion operators for each proton. The states with positive expectation values for this operator are found to form a rotational band structure, and the moment of inertia agrees well with the experimentally suggested value. Allowing a small bending angle stabilizes the linear-chain configuration of three α clusters with a valence neutron, which is a hyper-deformed state.

We calculate the contribution of the nucleon-nucleon tensor interaction to single-particle energies with finite-range $G$-matrix potentials and with zero-range Skyrme potentials. The Skx Skyrme parameters including the zero-range tensor terms with strengths calibrated to the finite-range results are refitted to nuclear properties. The fit allows the zero-range proton-neutron tensor interaction as calibrated to the finite-range potential results which gives the observed change in the single-particle gap $\epsilon (h_{11/2}$)-$\epsilon (g_{7/2}$) going from ${}^{114}\mathrm{Sn}$ to ${}^{132}\mathrm{Sn}$. However, the experimental $\ell$ dependence of the spin-orbit splittings in ${}^{132}\mathrm{Sn}$ and ${}^{208}\mathrm{Pb}$ is not well described when the tensor is added, owing to a change in the radial dependence of the total spin-orbit potential. The gap shift and a good fit to the $\ell$ dependence can be recovered when the like-particle tensor interaction is opposite in sign to that required for the $G$ matrix.

The level structure of the $N=38$ isotone ${}^{64}\mathrm{Fe}$ was studied with the ${}^{64}\mathrm{Ni}$ + ${}^{238}\mathrm{U}$ reaction at 430 MeV. Several new levels were identified and compared to shell model calculations. Results show no evidence for deformation in the ground state, but a possible contribution from intruder orbitals at higher energy and spin.

Capture-fission cross sections were measured for the near symmetric reaction between the massive nuclei ${}^{124}\mathrm{Sn}$ and ${}^{96}\mathrm{Zr}$ for center of mass energies from 195 to 265 MeV. Coincident fission fragments were detected and separated from elastic and deep inelastic scattering products by angle/energy/mass conditions. The measured capture cross sections agree quite well with calculations using the dinuclear system (DNS) model. The DNS model also predicts the fusion cross section for this reaction with a fusion barrier height of 208.0 MeV. The deduced extra push energy, corresponding to this barrier height, differs from that deduced from evaporation residue measurements.

$({\pi }^{-},K^{+})$ hyperon production inclusive spectra with $p_{\pi }=1.2$ GeV/$c$ measured at KEK on ${}^{12}\mathrm{C}$ and ${}^{28}\mathrm{Si}$ are analyzed by the semiclassical distorted-wave model. Single-particle (s.p.) wave functions of the target nucleus are treated using Wigner transformation. This method is able to account for the energy and angular dependences of the elementary process in nuclear medium without introducing the factorization approximation frequently employed. Calculations of the $({\pi }^{+},K^{+})\Lambda$ formation process, for which there is no free parameter because the Λ s.p. potential is known, demonstrate that the present model is useful to describe inclusive spectra. It is shown that to account for the experimental data of the ${\Sigma }^{-}$ formation spectra a repulsive Σ-nucleus potential is necessary whose magnitude is not so strong as around 100 MeV previously suggested.

An event generator is constructed on the basis of a model of multiple scattering of partons so that the trajectory of a parton traversing a dense and expanding medium can be tracked. The parameters in the code are adjusted to fit the $\Delta \varphi$ azimuthal distribution on the far side when the trigger momentum is in the nonperturbative region, $p_T^{\mathrm{trigger}}<4\mathrm{GeV}/c$. The dip-bump structure for $1<p_T^{\mathrm{assoc}}<2.5\mathrm{GeV}/c$ is reproduced by averaging over the exit tracks of deflected jets. An essential characteristic of the model, called Markovian Parton Scattering (MPS) model, is that the scattering angle is randomly selected in the forward cone at every step of a trajectory that is divided into many discrete steps in a semiclassical approximation of the nonperturbative scattering process. Energy loss to the medium is converted to thermal partons, which hadronize by recombination to give rise to the pedestal under the bumps. When extended to high trigger momentum with $p_T^{\mathrm{trigger}}>8\mathrm{GeV}/c$, the model reproduces the single-peak structure observed by STAR without the need to invoke any new dynamical mechanisms.

We present a method based on three-particle azimuthal correlation cumulants for studying jet interactions with the medium produced in heavy ion collisions (at RHIC) where jets cannot be reconstructed on an event-by-event basis with conventional jet-finding algorithms. The method is specifically designed to distinguish a range of jet interaction mechanisms such as Mach cone emission, gluon Cerenkov emission, jet scattering, and jet broadening. We describe how anisotropic flow contributions of second order (e.g., $v_2^2)$ are suppressed in three-particle azimuthal correlation cumulants, and discuss specific model representations of dijets, away-side scattering, and Mach cone emission.

The electromagnetic decay processes of excited hyperon states are a very sensitive probe of the structure of hyperons. We will argue that the recent measurements of electromagnetic decay rates indicate that the wave functions of the hyperon ground states should contain sizable components of excited quark states (configuration mixing). Flavor-$\mathit{SU}(3)$ is a broken symmetry and it appears that the hyperon wave functions should preferably be written in a $\mathit{uds}$-basis, where only the light $u$ and $d$-quarks are symmetrized, and not in the usual $\mathit{SU}(6)$-basis.

We present an evaluation of the box diagram for elastic $\mathit{ep}$ scattering with the proton in the intermediate state. Using analytic properties of the proton form factors we express the amplitude via a twofold integral that involves the form factors in the spacelike region only. Therefore experimentally measured form factors can be used in the calculations directly. The numerical calculation is done with the form factors extracted by Rosenbluth separation, as well as polarization transfer method. The dependence of the results on the form factor choice is small for $Q^2\lesssim 6{\mathrm{GeV}}^2$ but becomes sizable at higher $Q^2$.

Parity-odd asymmetries in the electromagnetic decays of compound nuclei can sometimes be amplified above values expected from simple dimensional estimates by the complexity of compound nuclear states. Using a statistical approach, we estimate the root-mean-square of the distribution of expected parity-odd correlations ${\overrightarrow{s}}_n·{\overrightarrow{k}}_{\gamma }$, where ${\overrightarrow{s}}_n$ is the neutron spin and ${\overrightarrow{k}}_{\gamma }$ is the momentum of the γ, in the integrated γ spectrum from the capture of cold polarized neutrons on Al, Cu, and In. We present measurements of the asymmetries in these and other nuclei. Based on our calculations, large enhancements of asymmetries were not predicted for the studied nuclei and the statistical estimates are consistent with our measured upper bounds on the asymmetries.

The occurrence of oblate and prolate shapes is investigated theoretically for odd-odd neutron-rich nuclei with $A\approx 190$. Using the cranked Woods-Saxon-Strutinsky method, including configuration constraints, it is found that collective oblate rotation coexists with high-$K$ prolate rotation, for tantalum and rhenium isotopes with $N=115$ and 117.