A new version, v2.0, of the $\mathrm{HIJING}∕B\overline{B}$ Monte Carlo nuclear collision event generator is introduced in order to explore further the possible role of baryon junctions loops in the baryon-meson anomaly $(2<p_T<5\mathrm{GeV}∕c)$ observed in $200A\mathrm{GeV}$ $\mathrm{Au}+\mathrm{Au}$ reactions at RHIC. We show that junction loops with an enhanced intrinsic $k_T\approx 1\mathrm{GeV}∕c$ transverse momentum kick may provide a partial explanation of the anomaly as well as other important baryon stopping observables.

Sum rule of superconvergence type for parity violating amplitudes (p.v. analogue of Gerasimov-Drell-Hearn sum rule) is discussed. Elementary processes initiated by polarized photons in the lowest order of electroweak theory are calculated as examples illustrating the validity of the p.v. sum rules. The parity violating polarized photon-induced processes for the proton target are considered in the frame of effective low energy theories and phenomenological models based on p.v. nucleon-meson effective interactions. Assuming the saturation of p.v. sum rule, bounds on the range of parameters, poorly known from existing experimental data and used in these models, are found. The asymmetries for p.v. ${\pi }^0$ and ${\pi }^{+}$ production are discussed. It is argued that verification of the sum rule in future high intensity polarized photon beam experiments is feasible.

We study the lepton number violating (LNV) process of $({\mu }^{-},e^{+})$ conversion in nuclei mediated by the exchange of light and heavy Majorana neutrinos. Nuclear structure calculations have been carried out for the case of an experimentally interesting nucleus ${}^{48}\mathrm{Ti}$ in the framework of a renormalized proton-neutron quasiparticle random phase approximation. We demonstrate that the imaginary part of the amplitude of a light Majorana neutrino exchange mechanism gives an appreciable contribution to the $({\mu }^{-},e^{+})$ conversion rate. This specific feature is absent in the allied case of $0\nu \beta \beta$ decay. Using the present neutrino oscillations, tritium beta decay, accelerator, and cosmological data, we derived the limits on the effective masses of light ${⟨m⟩}_{\mu e}$ and heavy ${⟨M_N^{-1}⟩}_{\mu e}$ neutrinos. The expected rates of nuclear $({\mu }^{-},e^{+})$ conversion, corresponding to these limits, were found to be so small that even within a distant future the $({\mu }^{-},e^{+})$ conversion experiments will hardly be able to detect the neutrino signal. Therefore, searches for this LNV process can only rely on the presence of certain physics beyond the trivial extension of the standard model by inclusion of massive Majorana neutrinos.

The three-body photodisintegration of ${}^3\mathrm{He}$ has been measured with the CLAS detector at Jefferson Lab, using tagged photons of energies between $0.35$ GeV and $1.55\mathrm{GeV}$. The large acceptance of the spectrometer allowed us for the first time to cover a wide momentum and angular range for the two outgoing protons. Three kinematic regions dominated by either two- or three-body contributions have been distinguished and analyzed. The measured cross sections have been compared with results of a theoretical model, which, in certain kinematic ranges, have been found to be in reasonable agreement with the data.

Additional experimental information concerning the level structure of ${}^{26}\mathrm{Si}$ above the proton threshold is needed to reduce uncertainties in the ${}^{25}\mathrm{Al}(p,\gamma ){}^{26}\mathrm{Si}$ reaction rate and consequently better determine ${}^{26}\mathrm{Al}$ radioisotope production in astrophysical environments. The ${}^{24}\mathrm{Mg}({}^3\mathrm{He},n){}^{26}\mathrm{Si}$ reaction was measured and excitation energies of states in ${}^{26}\mathrm{Si}$ were determined with improved accuracy. Spins were assigned to a number of states by comparing their measured differential cross sections with Hauser-Feshbach cross sections. The $3^{+}$ resonance state of the ${}^{25}\mathrm{Al}(p,\gamma ){}^{26}\mathrm{Si}$ reaction was identified at $5912\left(4\right)\mathrm{keV}$ excitation energy and the ${}^{25}\mathrm{Al}(p,\gamma ){}^{26}\mathrm{Si}$ reaction rate in explosive hydrogen burning environments was calculated.

Nonuniform neutron-rich matter present in both core-collapse supernovae and neutron-star crusts is described in terms of a semiclassical model that reproduces nuclear-matter properties and includes long-range Coulomb interactions. The neutron-neutron correlation function and the corresponding static structure factor are calculated from molecular dynamics simulations involving 40 000 to 100 000 nucleons. The static structure factor describes coherent neutrino scattering which is expected to dominate the neutrino opacity. At low momentum transfers the static structure factor is found to be small because of ion screening. In contrast, at intermediate momentum transfers the static structure factor displays a large peak due to coherent scattering from all the neutrons in a cluster. This peak moves to higher momentum transfers and decreases in amplitude as the density increases. A large static structure factor at zero momentum transfer, indicative of large density fluctuations during a first-order phase transition, may increase the neutrino opacity. However, no evidence of such an increase has been found. Therefore, it is unlikely that the system undergoes a simple first-order phase transition. Further, to compare our results to more conventional approaches, a cluster algorithm is introduced to determine the composition of the clusters in our simulations. Neutrino opacities are then calculated within a single heavy nucleus approximation as is done in most current supernova simulations. It is found that corrections to the single heavy nucleus approximation first appear at a density of the order of ${10}^{13}\mathrm{g}∕{\mathrm{cm}}^3$ and increase rapidly with increasing density. Thus neutrino opacities are overestimated in the single heavy nucleus approximation relative to the complete molecular dynamics simulations.

The low-momentum nucleon-nucleon interaction $V_{\text{low}k}$ is applied to three- and four-nucleon systems. We investigate the ${}^3\mathrm{H}$, ${}^3\mathrm{He}$, and ${}^4\mathrm{He}$ binding energies for a wide range of the momentum cutoffs. By construction, all low-energy two-body observables are cutoff independent, and therefore, any cutoff dependence is due to missing three-body or higher-body forces. We argue that for reasonable cutoffs $V_{\text{low}k}$ is similar to high-order interactions derived from chiral effective field theory. This motivates augmenting $V_{\text{low}k}$ by corresponding three-nucleon forces. The set of low-momentum two- and three-nucleon forces can be used in calculations of nuclear structure and reactions. We find that three-nucleon force contributions are perturbative for small cutoffs.

The gamma-ray decay of the giant dipole resonance (GDR) in the compound nucleus ${}^{216}\mathrm{Rn}$ formed with the reaction ${}^{18}\mathrm{O}{+}^{198}\mathrm{Pt}$ at the bombarding energy of 96 MeV was investigated. High-energy gamma-ray spectra in coincidence with both prompt and delayed low-energy transitions were measured. The obtained GDR width at the average temperature $⟨T⟩\approx 1\mathrm{MeV}$ was found to be larger than that at $T=0\mathrm{MeV}$ and to be approximately constant as a function of spin. The measured width value of 7 MeV is found to be consistent with the predictions based on calculations of the nuclear shape distribution using the newest approach for the treatment of the fission barrier within the liquid drop model. The present study is the first investigation of the giant dipole resonance width from the fusion-evaporation decay channel in this nuclear mass range.

We have studied the dependence of the production cross sections of the isotopes ${}^{282,283}112$ and ${}^{286,287}114$ on the excitation energy of the compound nuclei ${}^{286}112$ and ${}^{290}114$. The maximum cross section values of the $xn$-evaporation channels for the reaction ${}^{238}\mathrm{U}({}^{48}\mathrm{Ca},xn){}^{286-x}112$ were measured to be ${\sigma }_{3n}={2.5}_{-1.1}^{+1.8}\mathrm{pb}$ and ${\sigma }_{4n}={0.6}_{-0.5}^{+1.6}\mathrm{pb}$; for the reaction ${}^{242}\mathrm{Pu}({}^{48}\mathrm{Ca},xn){}^{290-x}114$: ${\sigma }_{2n}\sim 0.5\mathrm{pb}$, ${\sigma }_{3n}={3.6}_{-1.7}^{+3.4}\mathrm{pb}$, and ${\sigma }_{4n}={4.5}_{-1.9}^{+3.6}\mathrm{pb}$. In the reaction ${}^{233}\mathrm{U}({}^{48}\mathrm{Ca},2–4n){}^{277–279}112$ at $E*=34.9\pm 2.2\mathrm{MeV}$ we measured an upper cross section limit of ${\sigma }_{xn}⩽0.6\mathrm{pb}$. The observed shift of the excitation energy associated with the maximum sum evaporation residue cross section ${\sigma }_{\mathrm{ER}}(E*)$ to values significantly higher than that associated with the calculated Coulomb barrier can be caused by the orientation of the deformed target nucleus in the entrance channel of the reaction. An increase of ${\sigma }_{\mathrm{ER}}$ in the reactions of actinide targets with ${}^{48}\mathrm{Ca}$ is consistent with the expected increase of the survivability of the excited compound nucleus upon closer approach to the closed neutron shell $N=184$. In the present work we detected 33 decay chains arising in the decay of the known nuclei ${}^{282}112$, ${}^{283}112$, ${}^{286}114$, ${}^{287}114$, and ${}^{288}114$. In the decay of ${}^{287}114\left(\alpha \right)\to {}^{283}112\left(\alpha \right)\to {}^{279}110\left(\mathrm{SF}\right)$, in two cases out of 22, we observed decay chains of four and five sequential $\alpha$ transitions that end in spontaneous fission of ${}^{271}\mathrm{Sg}(T_{\alpha ∕\mathrm{SF}}={2.4}_{-1.0}^{+4.3}\min )$ and ${}^{267}\mathrm{Rf}(T_{\mathrm{SF}}\sim 2.3\mathrm{h})$, longer decay chains than reported previously. We observed the new nuclide ${}^{292}116(T_{\alpha }={18}_{-6}^{+16}\mathrm{ms},E_{\alpha }=10.66\pm 0.07\mathrm{MeV})$ in the irradiation of the ${}^{248}\mathrm{Cm}$ target at a higher energy than in previous experiments. The observed nuclear decay properties of the nuclides with $Z=104–118$ are compared with theoretical nuclear mass calculations and the systematic trends of spontaneous fission properties. As a whole, they give a consistent pattern of decay of the 18 even-$Z$ neutron-rich nuclides with $Z=104–118$ and $N=163–177$. The experiments were performed with the heavy-ion beam delivered by the U400 cyclotron of the FLNR (JINR, Dubna) employing the Dubna gas-filled recoil separator.

The lattice gas model was extended to incorporate the effect of radial flow. Contrary to popular belief, radial flow has little effect on the clusterization process in intermediate energy heavy-ion collisions except adding an ordered motion to the particles in the fragmentation source. We compared the results from the lattice gas model with and without radial flow to experimental data. We found that charge yields from central collisions are not significantly affected by inclusion of any reasonable radial flow.

We have searched for neutrons from the three-body photon-induced reaction ${}^9\mathrm{Be}+\gamma \to \alpha +\alpha +n$ using bremsstrahlung produced by electrons from a $2\text{‐}\mathrm{MV}$ Van de Graaff on a gold target. The target was located within a block of beryllium surrounded by an array of ${}^3\mathrm{He}$ proportional counters embedded in paraffin. Based on energy and intensity calibrations of the accelerator and detector using the ${}^9\mathrm{Be}+\gamma \to {}^8\mathrm{Be}+n$ reaction, an upper limit of $93\mathrm{nb}$ $\left(4\sigma \right)$ was placed on the cross section for neutron production between the three-body and two-body thresholds. This value is substantially below a previous experimental result using photoexcitation by ${}^{142}\mathrm{Pr}$ gamma rays and also below an earlier theoretical estimate. Bremsstrahlung spectra from the gold target were also measured in a NaI(Tl) detector at electron energies from $1.7\text{to}2.0\mathrm{MeV}$ and angles of 0° to 60° with respect to the beam axis. An analysis of photons above the $1665\text{‐}\mathrm{keV}$ two-body threshold shows that bremsstrahlung due to beta rays between $1665\mathrm{keV}$ and the $2160\text{‐}\mathrm{keV}$ end point of the ${}^{142}\mathrm{Pr}$ beta-ray spectrum could account for the photoneutron yield in the three-body region that had previously been attributed to ${}^{142}\mathrm{Pr}$ gamma rays.

We define a set of model-independent observables which generally characterize the azimuthal dependence of two-particle correlations in nucleus-nucleus collisions. We explain how they can be analyzed, and show to what extent such analyses are model dependent. We discuss specific applications to the anisotropic flow of decaying particles, azimuthally sensitive Hanbury-Brown Twiss interferometry, and correlations between particles at large transverse momentum. A quantitative prediction is made for jet quenching with respect to the reaction plane.

Gamma-ray transitions in have been identified for the first time. The experiment, which utilized the recoil decay tagging technique, was performed at the accelerator laboratory of the University of Jyväskylä, Finland. Prompt gamma rays produced in reactions were detected by the JUROGAM -ray spectrometer. The gamma rays belonging to were selected based on the recoil identification provided by the RITU gas-filled recoil separator and the GREAT focal plane spectrometer. A first excited state at , tentatively of character, is proposed.

A new high-spin superdeformed band has been discovered in ${}_{\mathrm{\hspace{0.17em}\hspace{0.17em}60}}{}^{140}\mathrm{Nd}_{80}$. It was populated in the ${}^{96}\mathrm{Zr}({}^{48}\mathrm{Ca},4n)$ reaction and investigated using the EUROBALL $\gamma$-ray spectrometer array. The band is observed in the approximate spin range of $I=36$ to 66. It is associated with shell gaps around $Z=60$ and at $N=80$ at large deformation. These gaps produce a pronounced minimum in the calculated total Routhian surfaces at a quadrupole deformation of ${ϵ}_2=0.45$. The new band which lies between the high-deformation bands in the $A\approx 130$ region and the superdeformed bands in $A\approx 150$ nuclei provides insight into the development of the deformation between these two regions. Two possible configurations are suggested involving four neutrons of $i_{13∕2}$ origin $\left(\nu 6^4\right)$ and either six protons of $h_{11∕2}∕h_{9∕2}$ origin $\left(\pi 5^6\right)$ or five protons of $h_{11∕2}∕h_{9∕2}$ and one of $i_{13∕2}$ origin $\left(\pi 5^5{6}^1\right)$.

We study in the quasiparticle-phonon model the shell structure and the phonon content of the low-lying excited $0^{+}$ states in ${}^{158}\mathrm{Gd}$. We show that the model accounts for the large abundance of $0^{+}$ states observed in recent experiments and provides a detailed and exhaustive information about the properties of all these states, especially the extent and nature of their collectivity. This is achieved through an explicit investigation of the structure of the model wave functions and, more objectively, the calculation and comparative analysis of $E2$ and $E0$ transition probabilities, and, especially, two-nucleon transfer spectroscopic factors.

Isotopically resolved cross sections and velocity distributions have been measured in charge-pickup reactions of $1A\mathrm{GeV}$ ${}^{208}\mathrm{Pb}$ with proton, deuterium, and titanium targets. The total and partial charge-pickup cross sections in the reactions ${}^{208}\mathrm{Pb}+{}^1\mathrm{H}$ and ${}^{208}\mathrm{Pb}+{}^2\mathrm{H}$ are measured to be the same within the limits of the error bars. A weak increase in the total charge-pickup cross section is seen in the reaction of ${}^{208}\mathrm{Pb}$ with the titanium target. The measured velocity distributions show different contributions—quasielastic scattering and $\Delta$-resonance excitation—to the charge-pickup production. Data on total and partial charge-pickup cross sections from these three reactions are compared with other existing data and also with model calculations based on the coupling of different intranuclear cascade codes and an evaporation code.

The observation of a granular structure in high-energy heavy-ion collisions can be used as a signature for the quark-gluon plasma phase transition, if the phase transition is first order in nature. We propose methods to detect a granular structure by the single-event intensity interferometry. We find that the correlation function from a chaotic source of granular droplets exhibits large fluctuations, with maxima and minima at relative momenta which depend on the relative coordinates of the droplet centers. The presence of this type of maxima and minima of a single-event correlation function at many relative momenta is a signature for a granular structure and a first-order QCD phase transition. We further observe that the Fourier transform of the correlation function of a granular structure exhibits maxima at the relative spatial coordinates of the droplet centers, which can provide another signature of the granular structure.

The beta equilibrated dense matter with kaon condensate is analyzed with respect to extended stability conditions, including charge fluctuations. This kind of the diffusive instability appeared to be common property in the kaon condensation case. Results for three different nuclear models are presented.

The ${}^{12}\mathrm{C}({}^{12}\mathrm{C},{}^8\mathrm{Be}+{}^8\mathrm{Be}){}^8\mathrm{Be}$ reaction has been studied with 18 beam energies from $82\text{to}120\mathrm{MeV}$. The detection of four of the six final-state $\alpha$-particles in an array of eight 16-element strip detectors permitted the full reconstruction of the reaction kinematics. ${}^{16}\mathrm{O}$ excitation energy spectra spanning $19–40\mathrm{MeV}$ were measured, which provided evidence for ${}^{16}\mathrm{O}$ excited states up to $35.1\mathrm{MeV}$. Angular correlation analysis indicates the dominant spins are 6 and $8\hslash$, possibly extending to $10\hslash$ at the highest excitation energies. The resulting energy-spin systematics are compared with the predictions of the $\alpha$ cluster model and cranked Nilsson-Strutinsky calculations.

Neutron-rich ${}^{96,97}\mathrm{Sr}$ and ${}^{98,99}\mathrm{Zr}$ nuclei were populated as fission fragments produced by the ${}^{238}\mathrm{U}(\alpha ,\mathrm{f})$ fusion-fission reaction. The yrast states of these nuclei have been extended up to $\approx 20\hslash$, which is about $6\hslash$ on average beyond the previously known spin, by studying the prompt $\mathrm{\gamma }$ rays in coincidence with the detection of both fission fragments. This extension allows the observation of yrast states with spins beyond $\approx 4^{+}$ in ${}^{96}\mathrm{Sr}$ and ${}^{98}\mathrm{Zr}$ evolving from vibrationlike states to rotationlike states. With an additional neutron, the yrast states with excitation energies above $\approx 600\mathrm{keV}$ in ${}^{97}\mathrm{Sr}$ and ${}^{99}\mathrm{Zr}$ have the characteristics of members of rotationlike bands for both positive- and negative-parity states. However, their underlying single-particle configurations cannot be determined uniquely by the measured intensity ratios of $\mathrm{\Delta }\mathrm{I}=1$ to $\mathrm{\Delta }\mathrm{I}=2$ transitions because of possible configuration mixing. The sharp variations in the yrast structure of these nuclei are discussed in terms of the gradualness of the onset of quadrupole deformation.