We investigate the low-energy elastic $\overline{D}N$ interaction using a quark model that confines color and realizes dynamical chiral symmetry breaking. The model is defined by a microscopic Hamiltonian inspired in the QCD Hamiltonian in Coulomb gauge. Constituent quark masses are obtained by solving a gap equation, and baryon and meson bound-state wave functions are obtained using a variational method. We derive a low-energy meson-nucleon potential from a quark-interchange mechanism whose ingredients are the quark-quark and quark-antiquark interactions and baryon and meson wave functions, all derived from the same microscopic Hamiltonian. The model is supplemented with ($\sigma$, $\rho$, $\omega$, $a_0$) single-meson exchanges to describe the long-range part of the interaction. Cross sections and phase shifts are obtained by iterating the quark-interchange plus meson-exchange potentials in a Lippmann-Schwinger equation. Once coupling constants of long-range scalar $\sigma$ and $a_0$ meson exchanges are adjusted to describe experimental phase shifts of the $K^{+}N$ and $K^{0}N$ reactions, predictions for cross sections and $s$-wave phase shifts for the ${\overline{D}}^{0}N$ and $D^{-}N$ reactions are obtained without introducing new parameters.

The cross sections of the ${}^{89}$Y($p,\gamma$)${}^{90}$Zr and the ${}^{121,123}$Sb($p,\gamma$)${}^{122,124}$Te reactions were determined from $\gamma$-angular distribution measurements at beam energies from 1.6 to 3.4 MeV. In addition, angle-integrated cross sections were also measured at $E_p=2$, 3, 4, and 4.8 MeV for the ${}^{89}$Y($p,\gamma$)${}^{90}$Zr reaction using the 4$\pi$ $\gamma$-summing method. Astrophysical $S$ factors and reaction rates were deduced from the measured cross sections. Statistical model calculations were performed using the nuclear-reaction code talys. The results from the comparison between theory and experiment are discussed in detail.

We present a new technique to calculate the cross section for diffractive vector meson production and deeply virtual Compton scattering (DVCS) in electron-ion collisions based on the dipole model. The measurement of these processes can provide valuable information on nonlinear QCD phenomena, such as gluon saturation, and is the the only known way to gain insight into the spatial distribution of gluons in nuclei. We present predictions of differential cross-section distribution $d\sigma /d{Q}^2$ and $d\sigma /dt$ for $J/\psi$ and $\varphi$ meson production for diffractive processes of heavy nuclei, and demonstrate the feasibility of extracting the gluon source distribution of heavy nuclei, $F\left(b\right)$, from coherent diffraction. We briefly introduce a new event generator based on our method that can be used for studying exclusive diffractive processes at a future electron-ion collider.

The Trojan horse nucleus invariance for the binary $d(d,p)t$ reaction was tested by means of an experiment using the quasifree ${}^2$H(${}^6$Li,$pt$)${}^4$He and ${}^2$H(${}^3$He,$pt$)H reactions after ${}^6$Li and ${}^3$He breakup, respectively. The astrophysical $S\left(E\right)$ factor for the $d(d,p)t$ binary process was extracted from the present data in the framework of the plane wave approximation applied to the two different breakup schemes. The obtained results are compared with direct data as well as with previous indirect investigations. The very good agreement confirms the applicability of the plane wave approximation and suggests the independence of the binary indirect cross section on the chosen Trojan horse nucleus also for the present case.

The excited states of ${}_{\Lambda }^{25}$Mg with the $\Lambda$ hyperon in $p$ orbit are studied within the framework of the antisymmetrized molecular dynamics for hypernuclei. We obtained five rotational bands in ${}_{\Lambda }^{25}$Mg in which the $\Lambda$ hyperon in $p$ orbit is coupled to the ground and $K^{\pi }=2^{+}$ bands of ${}^{24}$Mg. We predict that the corresponding bands of ${}_{\Lambda }^{25}$Mg energetically split due to the triaxial deformation of the core nucleus ${}^{24}$Mg and the spatial anisotropy of the $p$ orbits of $\Lambda$.

We studied $0^{+}$ states in ${}^{198}$Hg after the ${}^{200}$Hg${(p,t)}^{198}$Hg transfer reaction up to 3 MeV excitation energy. The experiment was performed using the high-resolution Q3D magnetic spectrograph at the Maier-Leibnitz Laboratory Tandem accelerator in Munich. In total, only four $0^{+}$ states were observed in ${}^{198}$Hg, significantly fewer than in other experiments of the $(p,t)$ transfer campaign. We discuss the low-energy $0^{+}$ state density as a function of the valence nucleon number $N_{\mathrm{val}}$ and test if the $0^{+}$ density can be used as a signature for the prolate-oblate shape-phase transition in the Hf-Hg region.

We present a method to extrapolate nuclear binding energies from known values for neighboring nuclei. We select four specific mass relations constructed to eliminate smooth variation of the binding energy as function nucleon numbers. The fast odd-even variations are avoided by comparing nuclei with same parity. The mass relations are first tested and shown to either be rather accurately obeyed or revealing signatures of quickly varying structures. Extrapolations are initially made for a nucleus by applying each of these relations. Very reliable estimates are then produced either by an average or by choosing the extrapolation where the smoothest structures enter. Corresponding mass relations for $Q_{\alpha }$ values are used to study the general structure of superheavy elements. A minor neutron shell at $N=152$ is seen, but no sign of other shell structures are apparent in the superheavy region. Accuracies are typically substantially better than $0.5$ MeV.

Nucleon scattering from ${}^{6,7}$Li is analyzed systematically over a wide range of incident energies up to 150 MeV with the continuum discretized coupled channels method (CDCC) capable of treating the breakup of ${}^{6,7}$Li. The continuum states of ${}^{6,7}$Li are discretized with the pseudostate method. Diagonal and coupling potentials in the CDCC equation are obtained by folding the complex Jeukenne-Lejeune-Mahaux effective nucleon-nucleon interaction with transition densities between corresponding bound and discretized continuum states of ${}^{6,7}$Li. The normalization factors of the complex effective interaction are determined so as to reproduce experimental data on neutron total and proton reaction cross sections for ${}^{6,7}$Li. CDCC calculations with the normalization factors reproduce experimental differential cross sections for nucleon elastic and inelastic scattering from ${}^{6,7}$Li well.

We suggest that the combined effect of screening, gluon-induced dissociation, collisional damping, and reduced feed-down explains most of the sequential suppression of $\Upsilon \left(nS\right)$ states that has been observed in PbPb relative to $pp$ collisions at $\sqrt{s_{NN}}=2.76$ TeV. The suppression is thus a clear, albeit indirect, indication of the presence of a quark-gluon plasma. The $\Upsilon \left(1S\right)$ ground state suppression is essentially due to reduced feed-down, collisional damping, and gluon-induced dissociation, whereas screening prevails for the suppression of the excited states.

The electromagnetic radiation by quark-gluon plasma in a strong magnetic field is calculated. The contributing processes are synchrotron radiation and one-photon annihilation. It is shown that in relativistic heavy-ion collisions at the BNL Relativistic Heavy Ion Collider (RHIC) and CERN Large Hadron Collider (LHC) synchrotron radiation dominates over the annihilation. Moreover, it constitutes a significant part of all photons produced by the plasma at low transverse momenta; its magnitude depends on the plasma temperature and the magnetic field strength. Electromagnetic radiation in a magnetic field is probably the missing piece that resolves a discrepancy between the theoretical models and the experimental data. It is argued that electromagnetic radiation increases with the magnetic field strength and plasma temperature.

Spectrum of low-lying five-quark configurations with strangeness quantum number $S=-3$ and negative parity is studied in three kinds of constituent quark models, namely the one-gluon exchange, Goldstone boson exchange, and instanton-induced hyperfine interaction models, respectively. Our numerical results show that the lowest energy states in all three employed models lie at $\sim 1800$ MeV, about 200 MeV lower than predictions of various quenched three-quark models. In addition, it is very interesting that the state with the lowest energy in the one-gluon exchange model is with spin $3/2$, but $1/2$ in the other two models.

To explain several properties of finite nuclei, infinite matter, and neutron stars in a unified way within the relativistic mean field models, it is important to extend them either with higher order couplings or with density-dependent couplings. These extensions are known to have strong impact in the high-density regime. Here we explore their role on the equation of state at densities lower than the saturation density of finite nuclei which govern the phase transitions associated with pasta structures in the crust of neutron stars.

The reformulated dynamical cluster-decay model (DCM) is applied to study the decay of odd-A and non-$\alpha$ structured ${}^{59}{\text{Cu}}^{*}$ formed in the ${}^{35}\text{Cl}+{}^{24}\text{Mg}$ reaction at $E_{\text{lab}}=275$ MeV. Here, the temperature ($T$)–dependent binding energies due to Krappe are used. The roles of Wigner and pairing energies in the fragmentation potential are explicitly shown in this work. For the temperature $T=4.1898$ MeV corresponding to $E_{\text{lab}}=275$ MeV, the contribution of pairing vanishes and the resulting structure of the fragmentation potential due to Wigner term is shown. In addition to this, we have studied the role of factor $\alpha$ appearing in the inertia part of the equation of motion dictating the mass-transfer process. It is shown that this factor has significant effect in the structure of preformation probability values and hence in turn we see significant changes in the cross sections. We compare the cross sections of the measured charge distributions of the fission fragments for two limiting values of the parameter $\alpha$ with the experimental data. In order to fit the total cross-section values, a linear relation is obtained between the free parameter of the model $▵R$ and the factor $\alpha$ appearing in the hydrodynamical mass.

The design of generation IV nuclear reactors and the studies of new fuel cycles require knowledge of the cross sections of various nuclear reactions. Our research is focused on ($n,xn\gamma$) reactions occurring in these new reactors. The aim is to measure unknown cross sections and to reduce the uncertainty on present data for reactions and isotopes of interest for transmutation or advanced reactors. The present work studies the ${}^{235}$U($n,n^{\prime }\gamma$) and ${}^{235}$U($n,2n\gamma$) reactions in the fast neutron energy domain (up to 20 MeV). The experiments were performed with the Geel electron linear accelerator GELINA, which delivers a pulsed white neutron beam. The time characteristics enable measuring neutron energies with the time-of-flight (TOF) technique. The neutron induced reactions [in this case inelastic scattering and ($n,2n$) reactions] are identified by on-line prompt $\gamma$ spectroscopy with an experimental setup including four high-purity germanium (HPGe) detectors. A fission ionization chamber is used to monitor the incident neutron flux. The experimental setup and analysis methods are presented and the model calculations performed with the TALYS-1.2 code are discussed.

The leading-order contribution to the shear and bulk viscosities, $\eta$ and $\zeta$, of a gluon plasma in perturbative QCD includes the $gg\leftrightarrow gg$ (22) process, $gg\leftrightarrow ggg$ (23) process, and multiple scattering processes known as the Landau-Pomeranchuk-Migdal (LPM) effect. Complete leading-order computations for $\eta$ and $\zeta$ were obtained by Arnold, Moore, and Yaffe (AMY) and Arnold, Dogan, and Moore (ADM), respectively, with the inelastic processes computed by an effective $g\leftrightarrow gg$ gluon splitting. We study how complementary calculations with 22 and 23 processes and a simple treatment to model the LPM effect compare with the results of AMY and ADM. We find that our results agree with theirs within errors. By studying the contribution of the 23 process to $\eta$, we find that the minimum angle $\theta$ among the final-state gluons in the fluid local rest frame has a distribution that is peaked at $\theta \sim \sqrt{{\alpha }_s}$, analogous to the near-collinear splitting asserted by AMY and ADM. However, the average of $\theta$ is much bigger than its peak value, as its distribution is skewed with a long tail. The same $\theta$ behavior is also seen if the 23 matrix element is taken to the soft-gluon bremsstrahlung limit in the center-of-mass (CM) frame. This suggests that the soft-gluon bremsstrahlung in the CM frame still has some near-collinear behavior in the fluid local rest frame. We also generalize our result to a general $\text{SU}\left(N_c\right)$ pure gauge theory and summarize the current viscosity computations in QCD.

We present the first ab initio coupled-cluster calculations of medium-mass nuclei with explicit chiral three-nucleon (3$N$) interactions. Using a spherical formulation of coupled cluster with singles and doubles excitations including explicit 3$N$ contributions, we study ground states of ${}^{16,24}\text{O}$, ${}^{40,48}\text{Ca,}$ and ${}^{56}\text{Ni}$. We employ chiral nucleon-nucleon ($\mathit{\text{NN}}$) plus 3$N$ interactions softened through a similarity renormalization group (SRG) transformation at the three-body level. We investigate the impact of all truncations and quantify the resulting uncertainties—this includes the contributions from triple excitations, the truncation of the set of three-body matrix elements, and the omission of SRG-induced four-body interactions. Furthermore, we assess the quality of a normal-ordering approximation of the 3$N$ interaction beyond light nuclei. Our study points towards the predictive power of chiral Hamiltonians in the medium-mass regime.

The overlap of the excited states in quasiparticle random-phase approximation (QRPA) is calculated to simulate the overlap of the intermediate nuclear states of the double-$\beta$ decay. Our basic idea is to use the like-particle QRPA with the aid of the closure approximation and calculate the overlap as rigorously as possible by making use of the explicit equation of the QRPA ground state. The formulation is shown in detail, and the mathematical properties of the overlap matrix are investigated. Two test calculations are performed for relatively light nuclei with the Skyrme and volume $\delta$-pairing energy functionals. The validity of the truncations used in the calculation is examined and confirmed.

A density dependent relativistic mean-field model is determined to reproduce the components of the nucleon self-energy at low densities. This model is used to investigate spinodal instabilities in isospin asymmetric nuclear matter at finite temperatures. The inhomogeneous density distributions in the spinodal region are investigated through calculations in a cubic box with periodic boundary conditions. Compared to results obtained in phenomenological calculations the spinodal region is large, i.e., the spinodal region at zero temperature can reach densities above 0.12 fm${}^{-3}$. The predicted spinodal region is strongly concentrated around isospin symmetric nuclear matter and the critical temperature is considerably lower than in the previous microscopic based investigation within a non-relativistic Brueckner-Hartree-Fock approach.

We propose the use of partial dynamical symmetry (PDS) as a selection criterion for higher-order terms in situations when a prescribed symmetry is obeyed by some states and is strongly broken in others. The procedure is demonstrated in a first systematic classification of many-body interactions with SU(3) PDS that can improve the description of deformed nuclei. As an example, the triaxial features of the nucleus ${}^{156}$Gd are analyzed.

Vector analyzing powers for proton elastic scattering from ${}^8$He at 71 MeV/nucleon have been measured using a solid polarized proton target operated in a low magnetic field of 0.1 T. The spin-orbit potential obtained from a phenomenological optical model analysis is found to be significantly shallower and more diffuse than the global systematics of stable nuclei, which is an indication that the spin-orbit potential is modified for scattering involving neutron-rich nuclei. A close similarity between the matter radius and the root-mean-square radius of the spin-orbit potential is also identified.