The inclusive spectra of pre-equilibrium nucleons produced in low-energy antiproton-nucleus collisions are thoroughly investigated within the the Lanzhou quantum molecular dynamics transport approach for the first time. The reaction channels of elastic scattering, annihilation, charge exchange, and inelastic processes in antibaryon-baryon, baryon-baryon, and meson-baryon collisions have been implemented in the model. The unexpected neutron to proton yield ratios are caused from the isospin effects of pion-nucleon collisions and the symmetry energy. It is found that the ${\pi }^{-}$-neutron collisions enhance the neutron emission in the antiproton annihilation in a nucleus. A soft symmetry energy with the stiffness of ${\gamma }_s=0.5$ at subsaturation densities is constrained from the available data of the neutron/proton spectra.

A comparison study of world data for the structure function $F_2$ for iron, as measured by both charged lepton and neutrino scattering experiments, is presented. Consistency of results for both charged lepton and neutrino scattering is observed for the full global data set in the valence regime. Consistency is also observed at low $x$ for the various neutrino data sets, as well as for the charged lepton data sets, independently. However, data from the two probes exhibit differences on the order of 15% in the shadowing-antishadowing transition region where the Bjorken scaling variable $x$ is $<0.15$. This observation is indicative that neutrino probes of nucleon structure might be sensitive to different nuclear effects than charged lepton probes. Details and results of the data comparison are presented here.

The existence of two close-lying nuclear states in ${}^{73}\mathrm{Ga}$ has recently been experimentally determined: a $1/2^{-}$ spin-parity for the ground state was measured in a laser spectroscopy experiment, while a ${\mathrm{J}}^{\pi }=3/2^{-}$ level was observed in transfer reactions. This scenario is supported by Coulomb excitation studies, which set a limit for the energy splitting of 0.8 keV. In this work, we report on the study of the excited structure of ${}^{73}\mathrm{Ga}$ populated in the $\beta$ decay of ${}^{73}\mathrm{Zn}$ produced at ISOLDE, CERN. Using $\beta$-gated, $\gamma$-ray singles, and $\gamma -\gamma$ coincidences, we have searched for energy differences to try to delimit the ground-state energy splitting, providing a more stringent energy difference limit. Three new half-lives of excited states in ${}^{73}\mathrm{Ga}$ have been measured using the fast-timing method with ${\mathrm{LaBr}}_3$(Ce) detectors. From our study, we help clarify the excited structure of ${}^{73}\mathrm{Ga}$ and we extend the existing ${}^{73}\mathrm{Zn}$ decay to ${}^{73}\mathrm{Ga}$ with 8 new energy levels and 35 $\gamma$ transitions. We observe a 195-keV transition consistent with a $\gamma$ ray de-exciting a short-lived state in the $\beta$-decay parent ${}^{73}\mathrm{Zn}$.

The role of relativistic corrections in heavy-ion Coulomb scattering at intermediate energies ($E_{\text{lab}}\gtrsim 50$ MeV/nucleon) is investigated by numerically solving a full set of coupled equations. We compare two methods: (a) one involving an exact account of interaction retardation and (b) a method based on the expansion of effective Lagrangians in powers of the ion velocities, $v/c$. Our study makes it possible to infer the relevance of kinematic corrections, retardation, and magnetic interactions such as the Darwin force. We show that analytical formulas are able to describe all aspects of experimental interest in relativistic effects in heavy-ion Coulomb scattering at intermediate energies without having to solve numerically the coupled equations.

It is not physically obvious why one can calculate with similar accuracy, as compared to the experimental data, the absolute cross section associated with two-nucleon transfer processes between members of pairing rotational bands, making use of simple BCS (constant matrix elements) or of many-body [Nambu-Gorkov (NG), nuclear field theory (NFT)] spectroscopic amplitudes. Restoration of spontaneous symmetry breaking and associated emergent generalized rigidity in gauge space provides the answer and points to a new emergence: A physical sum rule resulting from the intertwining of structure and reaction processes, closely connected with the central role induced pairing interaction plays in structure, together with the fact that successive transfer dominates Cooper pair tunneling.

Higher moments of multiplicity fluctuations of hadrons produced in central nucleus-nucleus collisions are studied within the hadron-resonance gas model in the canonical ensemble. Exact conservation of three charges, baryon number, electric charge, and strangeness is enforced in the large volume limit. Moments up to the fourth order of various particles are calculated at CERN Super Proton Synchrotron, BNL Relativistic Heavy Ion Collider (RHIC), and CERN Large Hadron Collider energies. The asymptotic fluctuations within a simplified model with only one conserved charge in the canonical ensemble are discussed where simple analytical expressions for moments of multiplicity distributions can be obtained. Moments products of net-proton, net-kaon, and net-charge distributions in Au + Au collisions at RHIC energies are calculated. The pseudorapidity coverage dependence of net-charge fluctuation is discussed.

In this work the energetics and strength distributions of isovector spin-dipole and spin-quadrupole transitions from the ground states of the pairs (${}^{76}\mathrm{Ge}, {}^{76}\mathrm{Se}$), (${}^{82}\mathrm{Se}, {}^{82}\mathrm{Kr}$), (${}^{96}\mathrm{Zr}, {}^{96}\mathrm{Mo}$), (${}^{100}\mathrm{Mo}, {}^{100}\mathrm{Ru}$), (${}^{116}\mathrm{Cd}, {}^{116}\mathrm{Sn}$), (${}^{128}\mathrm{Te}, {}^{128}\mathrm{Xe}$), (${}^{130}\mathrm{Te}, {}^{130}\mathrm{Xe}$), and (${}^{136}\mathrm{Xe}, {}^{136}\mathrm{Ba}$), of double-$\beta$-decay initial and final nuclei, to the $J^{\pi }=0^{-},1^{-},2^{-},1^{+},2^{+}$, and $3^{+}$ excited states of the intermediate odd-odd nuclei ${}^{76}\mathrm{As}, {}^{82}\mathrm{Br}, {}^{96}\mathrm{Nb}, {}^{100}\mathrm{Tc}, {}^{116}\mathrm{In}, {}^{128,130}\mathrm{I}$, and ${}^{136}\mathrm{Cs}$ are investigated. The calculations are performed using a proton-neutron quasiparticle random-phase approximation (pnQRPA) theory framework with the Bonn-A two-body interaction in no-core single-particle valence spaces.

We developed a new variational method for tensor-optimized antisymmetrized molecular dynamics (TOAMD) for nuclei. In TOAMD, the correlation functions for the tensor force and the short-range repulsion are introduced and used in the power series form of the wave function, which is different from the Jastrow method. Here, nucleon pairs are correlated in multisteps with different forms, while they are correlated only once including all pairs in the Jastrow correlation method. Each correlation function in every term is independently optimized in the variation of total energy in TOAMD. For $s$-shell nuclei using the nucleon-nucleon interaction, the energies in TOAMD are better than those in the variational Monte Carlo method with the Jastrow correlation function. This means that the power series expansion using the correlation functions in TOAMD describes the nuclei better than the Jastrow correlation method.

The evolution and coexistence of the nuclear shapes as well as the corresponding low-lying collective states and electromagnetic transition rates are investigated along the krypton isotopic chain within the framework of the interacting boson model (IBM). The IBM Hamiltonian is determined through mean-field calculations based on the several parametrizations of the Gogny energy density functional and the relativistic mean-field Lagrangian. The mean-field energy surfaces, as functions of the axial $\beta$ and triaxial $\gamma$ quadrupole deformations, are mapped onto the expectation value of the interacting-boson Hamiltonian that explicitly includes the particle-hole excitations. The resulting boson Hamiltonian is then used to compute low-energy excitation spectra as well as $E2$ and $E0$ transition probabilities for ${}^{70–100}\mathrm{Kr}$. Our results point to a number of examples of prolate-oblate shape transitions and coexistence both on the neutron-deficient and neutron-rich sides. A reasonable agreement with the available experimental data is obtained for the considered nuclear properties.

In two-particle angular correlation measurements, jets give rise to a near-side peak, formed by particles associated to a higher-$p_{\mathrm{T}}$ trigger particle. Measurements of these correlations as a function of pseudorapidity ($\mathrm{\Delta }\eta$) and azimuthal ($\mathrm{\Delta }\phi$) differences are used to extract the centrality and $p_{\mathrm{T}}$ dependence of the shape of the near-side peak in the $p_{\mathrm{T}}$ range $1<p_{\mathrm{T}}<8$ $\mathrm{GeV}/c$ in Pb-Pb and $\mathit{pp}$ collisions at $\sqrt{s_{NN}}$ = 2.76 TeV. A combined fit of the near-side peak and long-range correlations is applied to the data and the peak shape is quantified by the variance of the distributions. While the width of the peak in the $\mathrm{\Delta }\phi$ direction is almost independent of centrality, a significant broadening in the $\mathrm{\Delta }\eta$ direction is found from peripheral to central collisions. This feature is prominent for the low-$p_{\mathrm{T}}$ region and vanishes above $4 \mathrm{GeV}/c$. The widths measured in peripheral collisions are equal to those in $\mathit{pp}$ collisions in the $\mathrm{\Delta }\phi$ direction and above $3 \mathrm{GeV}/c$ in the $\mathrm{\Delta }\eta$ direction. Furthermore, for the 10% most central collisions and $1<p_{\mathrm{T},\mathrm{assoc}}<$ $2 \mathrm{GeV}/c, 1<p_{\mathrm{T},\mathrm{trig}}<$ $3 \mathrm{GeV}/c$, a departure from a Gaussian shape is found: a depletion develops around the center of the peak. The results are compared to A Multi-Phase Transport (AMPT) model simulation as well as other theoretical calculations indicating that the broadening and the development of the depletion are connected to the strength of radial and longitudinal flow.

Jet energy loss and single inclusive jet suppression in high-energy heavy-ion collisions are studied within a pQCD parton model that includes both elastic and radiative interactions between jet shower and medium partons as they propagate through the quark-gluon plasma. The collisional energy loss of jets with a given cone size is found to be relatively small comparing with the radiative energy loss. However, the effect of transverse momentum broadening due to elastic scattering is significant in the calculation of radiative energy loss within the high-twist formalism. The nuclear modification factors for single inclusive jets with different cone sizes are calculated and compared to experimental data as measured by ALICE and ATLAS experiments in Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV. Results on jet suppression in Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV are also presented.

Martini et al. [Phys. Rev. C 94, 015501 (2016)] recently observed that when the produced-lepton's mass plays an important role, the charged-current quasielastic cross section for muon neutrinos can be higher than that for electron neutrinos. Here I argue that this effect appears solely in the theoretical descriptions of nuclear effects in which nucleon knockout requires the energy and momentum transfers to lie in a narrow range of the kinematically allowed values.

To explore the nature of collective modes in weakly bound nuclei, we have investigated deformation effects and surface flow patterns of isovector dipole modes in a shape-coexisting nucleus, ${}^{40}\mathrm{Mg}$. The calculations were done in a fully self-consistent continuum finite-amplitude quasiparticle random phase approximation in a large deformed spatial mesh. An unexpected result of pygmy and giant dipole modes having disproportionate deformation splittings in strength functions was obtained. Furthermore, the transition current densities demonstrate that the long-sought core-halo oscillation in pygmy resonances is collective and compressional, corresponding to the lowest excitation energy and the simplest quantum flow topology. Our calculations show that surface flow patterns become more complicated as excitation energies increase.

Excited states have been studied in ${}^{159}\mathrm{Sm}, {}^{161}\mathrm{Sm}, {}^{162}\mathrm{Sm}$ ($Z=62$), ${}^{163}\mathrm{Eu}$ ($Z=63$), and ${}^{164}\mathrm{Gd}$ ($Z=64$), populated by isomeric decay following ${}^{238}\mathrm{U}$ projectile fission at RIBF, RIKEN. The isomer half-lives range from 50 ns to $2.6\mu \mathrm{s}$. In comparison with other published data, revised interpretations are proposed for ${}^{159}\mathrm{Sm}$ and ${}^{163}\mathrm{Eu}$. The first data for excited states in ${}^{161}\mathrm{Sm}$ are presented, where a 2.6-$\mu \mathrm{s}$ isomer is assigned a three-quasiparticle, $K^{\pi }=17/2^{-}$ structure. The interpretation is supported by multi-quasiparticle Nilsson-BCS calculations, including the blocking of pairing correlations. A consistent set of reduced $E1$ hindrance factors is obtained. Limited evidence is also reported for isomeric decay in ${}^{163}\mathrm{Sm}, {}^{164}\mathrm{Eu}$, and ${}^{165}\mathrm{Eu}$.

I have investigated structures of the ground and excited states of ${}^{16}\mathrm{O}$ with the method of variation after spin-parity projection in the antisymmetrized molecular dynamics model combined with the generator coordinate method of ${}^{12}\mathrm{C}+\alpha$ cluster. The calculation reasonably reproduces the experimental energy spectra; $E2, E3, E4$, and $IS1$ transitions; and $\alpha$-decay properties. The formation of $4\alpha$ clusters has been confirmed from nucleon degrees of freedom in the AMD model without assuming the existence of any clusters. They form “tetrahedral” $4\alpha$- and ${}^{12}\mathrm{C}+\alpha$ cluster structures. The ${}^{12}\mathrm{C}+\alpha$ structure constructs the $K^{\pi }=0^{+}$ band consisting of the $0_2^{+}, 2_1^{+}$, and $4_1^{+}$ states and the $K^{\pi }=0^{-}$ band of the $1_2^{-}, 3_2^{-}$, and $5_1^{-}$ states. The $0_1^{+}, 3_1^{-}$, and $4_2^{+}$ states are assigned to the ground band constructed from the tetrahedral $4\alpha$ structure. The $0_1^{+}$ and $3_1^{-}$ are approximately interpreted as $T_d$ band members with the ideal tetrahedral configuration. The ground-state $4\alpha$ correlation plays an important role in the enhancement of the $E3$ transition strength to the $3_1^{-}$. The $4_2^{+}$ state is not the ideal $T_d$ member but constructed from a distorted tetrahedral $4\alpha$ structure. Moreover, significant state mixing of the tetrahedral $4\alpha$ and ${}^{12}\mathrm{C}+\alpha$ cluster structures occurs between $4_1^{+}$ and $4_2^{+}$ states, indicating that the $T_d$ configuration of $4\alpha$ is rather fragile at $J^{\pi }=4^{+}$.

The properties of nuclear matter are studied using state-of-the-art nucleon-nucleon forces up to fifth order in chiral effective field theory. The equations of state of symmetric nuclear matter and pure neutron matter are calculated in the framework of the Brueckner-Hartree-Fock theory. We discuss in detail the convergence pattern of the chiral expansion and the regulator dependence of the calculated equations of state and provide an estimation of the truncation uncertainty. For all employed values of the regulator, the fifth-order chiral two-nucleon potential is found to generate nuclear saturation properties similar to the available phenomenological high precision potentials. We also extract the symmetry energy of nuclear matter, which is shown to be quite robust with respect to the chiral order and the value of the regulator.

Formation time of heavy quarkonia in a homogeneous magnetic field is analyzed by using a phenomenological ansatz of the vector current correlator. Because the existence of a magnetic field mixes vector quarkonia ($J/\psi , {\psi }^{\prime }$) and their pseudoscalar partners (${\eta }_c, {\eta }_c^{\prime }$), the properties of the quarkonia can be modified through such a spin mixing. This means that the formation time of quarkonia is also changed by the magnetic field. We show the formation time of vector quarkonia is delayed by an idealized constant magnetic field, where the formation time of the excited state becomes longer than that of the ground state. As a more realistic situation in heavy-ion collisions, effects by a time-dependent magnetic field are also discussed, where delayed formation of $J/\psi$ and ${\psi }^{\prime }$ and very early formation of ${\eta }_c$ and ${\eta }_c^{\prime }$ are found.

The effective chiral model is extended by introducing the contributions from the cross-couplings between isovector and isoscalar mesons. These cross-couplings are found to be instrumental in improving the density content of the nuclear symmetry energy. The nuclear symmetry energy as well as its slope and curvature parameters at the saturation density are in harmony with those deduced from a diverse set of experimental data. The equation of state for pure neutron matter at subsaturation densities is also in accordance with the ones obtained from different microscopic models. The maximum mass of a neutron star is consistent with the measurement, and the radius at the canonical mass of the neutron star is within the empirical bounds.

The effect of a three-nucleon ($3N$) interaction is studied for the production of high energy protons in heavy-ion collisions in the incident energy range of 44 to $400A\mathrm{MeV}$. The $3N$ interaction is incorporated into the antisymmetrized molecular dynamics transport model of Ono [A. Ono, Phys. Rev. C 59, 853 (1999)] as a $3N$ collision term, following a diagram of three consecutive binary collisions. For the theoretical ${}^{40}\mathrm{Ar}+{}^{51}\mathrm{V}$ reaction studies, no contribution from the $3N$ collisions is observed for high energy proton production at the incident energy of $44A\mathrm{MeV}$. However when the incident energy increases, the contribution increases gradually. At $200A\mathrm{MeV}$ and above, the contribution is observed as distinctly harder energy slopes in the proton energy spectra. The model is applied to the available Bevalac data for ${}^{40}\mathrm{Ar}+{}^{40}\mathrm{Ca}$ at $42,92$, and $137A\mathrm{MeV}$. The experimental proton energy spectra are reasonably well reproduced at angles $\theta \ge {70}^{\circ }$ for all three incident energies, showing negligible $3N$ contributions at $42A\mathrm{MeV}$ and significant contributions at $137A\mathrm{MeV}$ at the large laboratory angles. Good agreement at these large angles, where the $3N$ collision is a major mechanism to produce such protons, strongly indicates for the first time the importance of the $3N$ interaction in intermediate heavy ion reactions in a full transport calculation. The possible relation between the $3N$ collision term and the short range and the tensor interactions is suggested.

Production cross sections of residual nuclei obtained by knockout and fragmentation reactions of different tin isotopes accelerated at $1A$ GeV have been measured with the fragment separator (FRS) at GSI, Darmstadt. The new measurements are used to investigate the neutron-excess dependence of the neutron- and proton-knockout cross sections. These cross sections are compared to Glauber model calculations coupled to a nuclear de-excitation code in order to investigate the role of the remnant excitations. This bench marking shows an overestimation of the cross sections for the removal of deeply bound nucleons. A phenomenological increase in the excitation energy induced in the remnants produced in these cases allows us to reproduce the measured cross sections.