The strength of the low-energy $K^{-}$-nucleus real potential has recently received renewed attention in view of experimental evidence for the possible existence of strongly bound $K^{-}$ states. Previous fits to kaonic atom data led to either “shallow” or “deep” potentials, where only the former are in agreement with chiral approaches but only the latter can produce strongly bound states. Here we explore the uncertainties of the $K^{-}$-nucleus optical potentials, obtained from fits to kaonic atom data, using the functional derivatives of the best-fit ${\chi }^2$ values with respect to the potential. We find that only the deep type of potential provides information that is applicable to the $K^{-}$ interaction in the nuclear interior.

Fission and binary fragmentation of the excited nuclear systems of $Z=116$ and 124 were investigated using the reactions induced by ${}^{80}\mathrm{Se}$ beams on ${}^{208}\mathrm{Pb}$ and ${}^{232}\mathrm{Th}$ targets at bombarding energies ranging from 470 to 630 MeV. The mass and kinetic energy of the binary reaction products were reconstructed by measuring their velocities by the time-of-flight method and the angles of emission using multiwire proportional chambers. Total neutron multiplicities were measured in coincidence with the fragments, using an array of neutron detectors. The fragment mass-energy correlation was studied for the two systems. The average total kinetic energy (TKE) of fragments for the ${}^{80}\mathrm{Se}+{}^{208}\mathrm{Pb}$ system agrees with earlier measurements and with Viola's systematics in the mass symmetric region for compound nucleus fission, whereas for the ${}^{80}\mathrm{Se}+{}^{232}\mathrm{Th}$ system, the TKE values are significantly lower. This is also consistent with higher values of total neutron multiplicities observed for the case of ${}^{80}\mathrm{Se}+{}^{232}\mathrm{Th}$ at comparable available energies. From an extrapolation of the measured total neutron multiplicities for the mass symmetric region to zero compound nucleus excitation energy, the average number of prompt neutrons expected to be emitted in the spontaneous fission of the superheavy $Z=116$ has been estimated to be ${\nu }_{\mathrm{tot}}^{\mathrm{sf}}=10\pm 2$, which is consistent with the value derived for the same compound nucleus populated in the ${}^{56}\mathrm{Fe}+{}^{232}\mathrm{Th}$ reaction in an earlier work. In the case of the ${}^{80}\mathrm{Se}+{}^{232}\mathrm{Th}$ system, similar analysis was carried out by taking the average TKE from Viola's systematics for estimating the available energy for particle emission corresponding to compound nucleus fission. In this way, by extrapolating the observed neutron multiplicities to zero compound nucleus excitation energy, a value of ${\nu }_{\mathrm{tot}}^{\mathrm{sf}}=15\pm 2$ was obtained for the spontaneous fission of the superheavy $Z=124$ nucleus. The increase in the average number of neutrons emitted in fission as a function of the atomic number of the nucleus in the superheavy mass region was confirmed by comparing the results of the present work with published data.

We investigate the possibility of extracting the symmetry energy from multifragmentation data. The applicability of the grandcanonical formula earlier proposed by Ono et al. [Phys. Rev. C 68, 051601(R) (2003)] in the case of finite excited nuclei is tested within a microcanonical framework. Relatively good results are obtained except for large residual nuclei, especially when large sources are highly excited. Effects of secondary particle emission and the extent in which relevant information may be inferred from experimental observables are finally discussed.

The excitation of soft dipole modes in light nuclei via inelastic electron scattering is investigated. I show that, under the proposed conditions of the forthcoming electron-ion colliders, the scattering cross sections have a direct relation to the scattering by real photons. The advantages of electron scattering over other electromagnetic probes is explored. The response functions for direct breakup are studied with few-body models. The dependence on final-state interactions is discussed. A comparison between direct breakup and collective models is performed. The results of this investigation are important for the planned electron-ion colliders at the GSI and RIKEN facilities.

A systematic study of the relations between fluctuations of the extensive multiparticle variables and integrals of the inclusive multiparticle densities is presented. The generalized factorial moments are introduced and their physical meaning discussed. The effects of the additive conservation laws are analyzed.

We measured angular distributions of differential cross section, beam analyzing power, and recoil polarization for neutral pion electroproduction at $Q^2=1.0\hspace{1em}(\mathrm{GeV}/c){}^2$ in 10 bins of $1.17⩽W⩽1.35$ GeV across the Δ resonance. A total of 16 independent response functions were extracted, of which 12 were observed for the first time. Comparisons with recent model calculations show that response functions governed by real parts of interference products are determined relatively well near the physical mass, $W=M_{\Delta }\approx 1.232$ GeV, but the variation among models is large for response functions governed by imaginary parts, and for both types of response functions, the variation increases rapidly with $W>M_{\Delta }$. We performed a multipole analysis that adjusts suitable subsets of ${\ell }_{\pi }⩽2$ amplitudes with higher partial waves constrained by baseline models. This analysis provides both real and imaginary parts. The fitted multipole amplitudes are nearly model independent—there is very little sensitivity to the choice of baseline model or truncation scheme. By contrast, truncation errors in the traditional Legendre analysis of $N\to \Delta$ quadrupole ratios are not negligible. Parabolic fits to the $W$ dependence around $M_{\Delta }$ for the multiple analysis gives values for $\mathrm{Re}(S_{1+}/M_{1+})=(-6.61\pm 0.18)\%$ and $\mathrm{Re}(E_{1+}/M_{1+})=(-2.87\pm 0.19)\%$ for the $p{\pi }^0$ channel at $W=1.232$ GeV and $Q^2=1.0\hspace{1em}(\mathrm{GeV}/c){}^2$ that are distinctly larger than those from the Legendre analysis of the same data. Similarly, the multipole analysis gives $\mathrm{Re}(S_{0+}/M_{1+})=(+7.1\pm 0.8)\%$ at $W=1.232$ GeV, consistent with recent models, while the traditional Legendre analysis gives the opposite sign because its truncation errors are quite severe.

A reanalysis of data for the ${}^3\mathrm{He}$($d,p$)${}^4\mathrm{He}$ reaction obtained using the Trojan-horse method, together with data from a direct measurement, leads to an electron-screening potential that is not consistent with the adiabatic limit, but it is consistent with a previous value from different data.

The Landau-Pomeranchuk-Migdal effects on photon emission from the quark-gluon plasma have been studied as a function of photon mass, at a fixed temperature of the plasma. The integral equations for the transverse vector function [$\tilde{\mathbf{f}}({\tilde{\mathbf{p}}}_{\perp })$] and the longitudinal function [$\tilde{g}({\tilde{\mathbf{p}}}_{\perp })$] consisting of multiple scattering effects are solved by the self-consistent iterations method and also by the variational method for the variable set $\{p_0,q_0,Q^2\}$. We considered the bremsstrahlung and the off shell annihilation ($\mathbf{aws}$) processes. We define two new dynamical scaling variables, $x_T,x_L$, for bremsstrahlung and $\mathbf{aws}$ processes which are functions of variables $p_0,q_0,Q^2$. We define four new emission functions for massive photon emission represented by $g_T^b,g_T^a,g_L^b,g_L^a$ and we constructed these using the exact numerical solutions of the integral equations. These four emission functions have been parametrized by suitable simple empirical fits. Using the empirical emission functions, we calculated the imaginary part of the photon polarization tensor as a function of photon mass and energy.

In order to predict properties of asymmetric nuclear matter, we construct a relativistic mean field (RMF) model consisting of one-meson exchange (OME) terms and point coupling (PC) terms. In order to determine the density dependent parameters of this model, we use properties of isospin symmetric nuclear matter in combination with the information on nucleon-nucleon scattering data, which are given in the form of the density dependent G-matrix derived from Brueckner calculations based on the Tamagaki potential. We show that the medium- and long-range components of this G-matrix can be described reasonably well by our effective OME interaction. In order to take into account the short-range part of the nucleon-nucleon interaction, which cannot be described well in this manner, a point coupling term is added. Its analytical form is taken from a model based on chiral perturbation theory. It contains only one additional parameter, which does not depend on the density. It is, together with the parameters of the OME potentials adjusted to the equation of state of symmetric nuclear matter. We apply this model for the investigation of asymmetric nuclear matter and find that the results for the symmetry energy as well as for the equation of state of pure neutron matter are in good agreement with either experimental data or with presently adopted theoretical predictions. In order to test the model at higher density, we use its equation of state for an investigation of properties of neutron stars.

The negative parity states of ${}^{11}\mathrm{B}$ and ${}^{11}\mathrm{C}$ were studied based on the calculations of antisymmetrized molecular dynamics (AMD). The calculations reproduced well the experimental strengths of Gamov-Teller (GT), $M1$, and monopole transitions. We especially focused on the $3/2_3^{-}$ and $5/2_2^{-}$ states for which GT transition strengths were recently measured. The weak $M1$ and GT transitions for $3/2_3^{-}$ in ${}^{11}\mathrm{B}$ and ${}^{11}\mathrm{C}$ are described by a well-developed cluster structure of $2\alpha +t$ and $2\alpha {+}^3$He, respectively, while the strong transitions for $5/2_2^{-}$ is characterized by an intrinsic spin excitation with no cluster structure. It was found that the $3/2_3^{-}$ state is a dilute cluster state, and its features are similar to those of ${}^{12}\mathrm{C}(0_2^{+})$ which is considered to be a gas state of $3\alpha$ clusters.

The semiclassical formulation of the Skyrme energy density functional for spin-orbit density part of the interaction potential is compared with the microscopic shell model formulation, at both the ground state and finite temperatures. The semiclassical spin-orbit interaction potential is shown to contain exactly the same shell effects as are there in the microscopic shell model, provided a normalization of all semiclassical results to the spin-saturated case (for one or both nuclei as spin-saturated) is made. On the other hand, the α nucleus structure present in microscopic shell model is found absent in semiclassical approach. The role of temperature is found not to change the behavior of shell or α nucleus structure effects up to about 3 MeV, and increase or decrease the height of the (normalized) barriers in accordance with the shell structure of nuclei. Calculations are made for three two-nucleon transfer reactions forming the α-nucleus $A=4n,N=Z$ compound systems ${}^{56}{\mathrm{Ni}}^{*}$ and ${}^{48}{\mathrm{Cr}}^{*}$ and the non-α-nucleus compound system ${}^{52}{\mathrm{Cr}}^{*}$, and for Skyrme forces SIII and SLy4. The two parameter Fermi density, with its parameters fitted to experiments and made temperature dependent in a model way, is used for the nuclear density in semiclassical calculations, and the same in microscopic shell model is achieved via the Fermi-Dirac occupation of shell model states and particle number conservation.

We developed a $1+1$ dimensional hydrodynamical model for central heavy-ion collisions at ultrarelativistic energies. Deviations from Bjorken's scaling are taken into account by implementing finite-size profiles for the initial energy density. The calculated rapidity distributions of pions, kaons, and antiprotons in central Au+Au collisions at $\sqrt{s_{\mathit{NN}}}=200$ GeV are compared with experimental data of the BRAHMS Collaboration. The sensitivity of the results to the choice of the equation of state, the parameters of the initial state, and the freeze-out conditions were investigated. Experimental constraints on the total energy of produced particles were used to reduce the number of model parameters. The best fits of experimental data were obtained for soft equations of state and Gaussian-like initial profiles of the energy density. It was found that initial energy densities required for fitting the experimental data decrease with the increasing critical temperature of the phase transition.

The cross section of the reaction ${}^{112}\mathrm{Sn}$($\alpha ,\gamma ){}^{116}\mathrm{Te}$ has been measured in the energy range of astrophysical interest for the $p$-process. Highly enriched self-supporting ${}^{112}\mathrm{Sn}$ foils were bombarded with α beams in the effective center of mass energy range from 7.59 to 11.42 MeV at the Notre Dame FN Tandem Van de Graaff accelerator. The characteristic activity of ${}^{116}\mathrm{Te}$ was counted with a pair of large volume Ge clover detectors in close geometry to maximize the detection efficiency. The cross section of the concurrent ($\alpha ,p$) reaction has also been measured. The results are compared with statistical model predictions for different global α-nucleus potentials.

The ability of experimental signatures to resolve the spatiotemporal profile of an expanding quark-gluon plasma is studied. In particular, the single inclusive suppression of high-momentum hadrons versus the centrality of a heavy-ion collision and with respect to the reaction plane in noncentral collisions is critically examined. Calculations are performed in the higher twist formalism for the modification of the fragmentation functions. Radically different nuclear geometries are used. The influence of different initial gluon distributions as well as different temporal evolution scenarios on the single inclusive suppression of high-momentum pions are outlined. It is demonstrated that the modification versus the reaction plane is quite sensitive to the initial spatial density. Such sensitivity remains even in the presence of a strong elliptic flow.

The $H$-dibaryon resonance was sought by a $\Lambda \Lambda$ invariant mass spectrum that was obtained by the ${}^{12}\mathrm{C}$ $(K^{-},K^{+}\Lambda \Lambda X)$ reactions. We observed a bump near the $\Lambda \Lambda$ threshold, as reported by the previous experiment (KEK E224), with better statistics. Data were compared with results of a cascade model calculation including $\Lambda \Lambda$ final state interactions consistent with the newly measured binding energy of ${}_{\Lambda \Lambda }^6\text{He}$. No significant enhancements above levels of the model predictions were observed. The resulting upper limit for the production cross section of the $H$ with a mass range between the $\Lambda \Lambda$ and $\Xi N$ threshold is found to be 2.1 ± 0.6 (stat.) ± 0.1 (syst.) μb/sr at a 90% confidence level.

The possibility of synthesizing a doubly magic superheavy nucleus, ${}^{298}{114}_{184}$, is investigated on the basis of fluctuation-dissipation dynamics. In order to synthesize this nucleus, we must generate more neutron-rich compound nuclei because of the neutron emissions from excited compound nuclei. The compound nucleus ${}^{304}114$ has two advantages to achieving a high survival probability. First, because of low neutron separation energy and rapid cooling, the shell correction energy recovers quickly. Secondly, owing to neutron emissions, the neutron number in the nucleus approaches that of the double closed shell and the nucleus attains a large fission barrier. Because of these two effects, the survival probability of ${}^{304}114$ does not decrease until the excitation energy $E^{*}=50$ MeV. These properties lead to a rather high evaporation residue cross section.

A gauge theory of pions interacting with ρ-mesons at elevated temperatures is used to calculate the pressure in a hot pion gas. No reference is made to the pion's status as a QCD Goldstone boson. The role of the pion is merely that of a carrier of an SU(2) symmetry, gauged to create a vector-meson interaction, the ρ playing the role of the interacting vector particle. The results are in rough agreement with much more elaborate calculations, both of the purely hadronic variety, and those that invoke quark-gluon degrees of freedom. The quark-gluon and purely hadronic calculations seemingly lead to very similar predictions which are in accord with recent data from the BNL Relativistic Heavy Ion Collider (RHIC). The results motivate the question as to whether the two descriptions are dual to each other in the sense of being alternate models, each sufficient to explain the observed data.

We show that a measurement of the reaction energy ($\sqrt{s}$) dependence of relative hadron resonance yields in heavy ion collisions can be used to study the phase structure of the dense strongly interacting matter created in these collisions and investigate the origin of the trends observed in the excitation functions of certain soft hadronic observables. We show that the presence of chemical nonequilibrium in light quark abundance imparts a characteristic signature on the energy dependence of resonance yields that differs considerably from what is expected in the equilibrium picture.

It is extremely important to devise a reliable method to extract spectroscopic factors from transfer cross sections. We analyze the standard DWBA procedure and combine it with the asymptotic normalization coefficient, extracted from an independent data set. We find that the single particle parameters used in the past generate inconsistent asymptotic normalization coefficients. In order to obtain a consistent spectroscopic factor, nonstandard parameters for the single particle overlap functions can be used but, as a consequence, often reduced spectroscopic strengths emerge. Different choices of optical potentials and higher order effects in the reaction model are also studied. Our test cases consist of ${}^{14}\mathrm{C}$($d,p$)${}^{15}\mathrm{C}$(g.s.) at $E_d^{\mathrm{lab}}=14$ MeV, ${}^{16}\mathrm{O}$($d,p$)${}^{17}\mathrm{O}$(g.s.) at $E_d^{\mathrm{lab}}=15$ MeV and ${}^{40}\mathrm{Ca}$($d,p$)${}^{41}\mathrm{Ca}$(g.s.) at $E_d^{\mathrm{lab}}=11$ MeV. We underline the importance of performing experiments specifically designed to extract asymptotic normalization coefficients for these systems.