We have studied neutron-rich carbon isotopes in terms of the shell model employing a realistic effective Hamiltonian derived from the chiral ${\mathrm{N}}^3$LOW nucleon-nucleon potential. The single-particle energies and effective two-body interaction have both been determined within the framework of the time-dependent degenerate linked-diagram perturbation theory. The calculated results are in very good agreement with the available experimental data, providing a sound description of this isotopic chain toward the neutron drip line. The correct location of the drip line is reproduced.

The liquid-gas phase transition in hot asymmetric nuclear matter is investigated within the relativistic mean-field model using the density dependence of nuclear symmetry energy constrained from the measured neutron skin thickness of finite nuclei. We find symmetry energy has a significant influence on several features of liquid-gas phase transition: the boundary and area of the liquid-gas coexistence region, the maximal isospin asymmetry, and the critical values of pressure and isospin asymmetry, all of which systematically increase with increasing softness in the density dependence of symmetry energy. The critical temperature below which the liquid-gas mixed phase exists is found higher for a softer symmetry energy.

We study medium modifications of the nucleon-nucleon ($\mathit{NN}$) cross sections and their influence on the nucleon knockout reactions. Using the eikonal approximation, we compare the results obtained with free $\mathit{NN}$ cross sections with those obtained with a purely geometrical treatment of Pauli blocking and with $\mathit{NN}$ obtained with more elaborated Dirac-Bruecker methods. The medium effects are parametrized in terms of the baryon density. We focus on symmetric nuclear matter, although the geometrical Pauli blocking also allows for the treatment of asymmetric nuclear matter. It is shown that medium effects can change the nucleon knockout cross sections and momentum distributions up to $10\%$ in the energy range $E_{\mathrm{lab}}=50$–$300$ MeV/nucleon. The effect is more evident in reactions involving halo nuclei.

With an effective Lagrangian approach, we analyze several $\mathit{NN}\to \mathit{NN}\pi \pi$ channels by including various resonances with mass up to $1.72$ GeV. For the channels with the pion pair of isospin zero, we confirm the dominance of $N^{*}(1440)\to N\sigma$ in the near-threshold region. At higher energies and for channels with the final pion pair of isospin one, we find large contributions from $N^{*}(1440)\to \Delta \pi$, double-$\Delta$, $\Delta (1600)\to N^{*}(1440)\pi$, $\Delta (1600)\to \Delta \pi$, and $\Delta (1620)\to \Delta \pi$. There are also sizable contributions from $\Delta \to \Delta \pi$, $\Delta \to N\pi$, $N\to \Delta \pi$, and nucleon pole at energies close to the threshold. We give a good reproduction to the total cross sections up to beam energies of $2.2$ GeV except for the $\mathit{pp}\to \mathit{pp}{\pi }^0{\pi }^0$ channel at energies around $1.1$ GeV and our results agree with the existing data of differential cross sections of $\mathit{pp}\to \mathit{pp}{\pi }^{+}{\pi }^{-}$, $\mathit{pp}\to \mathit{nn}{\pi }^{+}{\pi }^{+}$, and $\mathit{pp}\to \mathit{pp}{\pi }^0{\pi }^0$ which are measured at CELSIUS and COSY.

To gain a better insight into $\alpha$-decay fine structure, we calculate the relative intensities of $\alpha$ decay to $2{}^{+}$ and $4{}^{+}$ rotational states in the framework of the generalized liquid drop model (GLDM) and improved Royer’s formula. The calculated relative intensities of $\alpha$ decay to $2{}^{+}$ states are in good agreement with the experimental data. For the relative intensities of $\alpha$ decay to $4{}^{+}$ states, a good agreement with experimental data is achieved for Th and U isotopes. The formula we obtain is useful for the analysis of experimental data of $\alpha$-decay fine structure. In addition, some predicted relative intensities which are still not measured are provided for future experiments.

The collective moment of inertia is derived analytically within the cranking model for any rotational frequency of the harmonic-oscillator potential well and at a finite temperature. Semiclassical shell-structure components of the collective moment of inertia are obtained for any potential by using the periodic-orbit theory. We found semiclassically their relation to the free-energy shell corrections through the shell-structure components of the rigid-body moment of inertia of the statistically equilibrium rotation in terms of short periodic orbits. The shell effects in the moment of inertia exponentially disappear with increasing temperature. For the case of the harmonic-oscillator potential, one observes a perfect agreement of the semiclassical and quantum shell-structure components of the free energy and the moment of inertia for several critical bifurcation deformations and several temperatures.

Peripheral collisions with radioactive heavy-ion beams at relativistic energies are discussed as an innovative approach for probing the transient regime experienced by fissile systems evolving toward quasiequilibrium and thereby studying the viscous nature of nuclear matter. A dedicated experiment using the advanced technical installations of GSI, Darmstadt, made it possible to realize ideal conditions for the investigation of relaxation effects in a metastable well. Combined with a highly sensitive experimental signature, it provides a measure of the transient effects with respect to the flux over the fission barrier. Within a two-step reaction process, 45 proton-rich unstable spherical isotopes between At and Th produced by projectile-fragmentation of a stable ${}^{238}\mathrm{U}$ beam have been used as secondary projectiles which impinge on lead target nuclei. The fragmentation of the radioactive projectiles results in nearly spherical compound nuclei that span a wide range in excitation energy and fissility. The decay of these excited systems by fission is studied with a dedicated setup which, together with the inverse kinematics of the reaction, permits the detection of both fission products in coincidence and the determination of their atomic numbers with high resolution. The information on the nuclear charges of the two fragments is used to sort the data according to the initial excitation energy and fissility of the compound nucleus. The width of the fission-fragment nuclear charge distribution is shown to be specifically sensitive to presaddle transient effects and is used to establish a clock for the passage of the saddle point. The comparison of the experimental results with model calculations points to a fission delay ${\tau }_{\mathrm{trans}}$ of $(3.3\pm 0.7)\times {10}^{-21}$ s for initially spherical compound nuclei, independent of excitation energy and fissility. This value suggests a nuclear dissipation strength $\beta$ at small deformation of $(4.5\pm 0.5)\times {10}^{21}$ s${}^{-1}$. The very specific combination of the physics and technical equipment exploited in this work sheds light on previous controversial conclusions, which were drawn without considering the influence of the initial conditions.

Yrast states in the neutron-rich ${}_{14}^{33}$Si${}_{19}$ nucleus have been studied using binary grazing reactions produced by the interaction of a $215$-MeV beam of ${}^{36}\mathrm{S}$ ions with a thin ${}^{208}\mathrm{Pb}$ target. An experimental setup that combines the large-acceptance magnetic spectrometer PRISMA and the high-efficiency $\gamma$-ray detection array CLARA was used in the experiment. Four new $\gamma$-ray photopeaks at energies of $971$, $1724$, $1772$, and $2655$ keV were observed and assigned to the ${}^{33}\mathrm{Si}$ level scheme. The experimental level scheme is compared with the results of $1\hslash \omega$ p-sd-pf large-scale shell-model calculations using the recently developed PSDPFB effective interaction; good agreement is obtained. The structure of the populated states of ${}^{33}\mathrm{Si}$ is discussed within the context of an odd neutron coupled to states of the ${}^{32}\mathrm{Si}$ core.

Evaporation residue cross sections for ${}^{19}\mathrm{F}+{}^{184}\mathrm{W}$ have been measured at beam energies in the range of 90–130 MeV using the Heavy Ion Reaction Analyzer at the Inter University Accelerator Centre. A new approach, based on Monte Carlo calculations, has been adopted for estimating evaporation residue (ER) transmission efficiency. The challenges in the detection of ERs caused by the presence of isomeric states with longer half-lives have been thoroughly discussed. Measured cross sections have been fitted with statistical model calculations treating the fission barrier as an adjustable parameter. Comparison with other neighboring systems with nearly similar entrance-channel mass asymmetry indicates the onset of instability in the compound nucleus ${}_{83}^{203}{\mathrm{Bi}}_{120}$ after crossing of the $Z=82$ shell.

Neutrino emission in the processes of breaking and formation of nucleon Cooper pairs is calculated in the framework of the Larkin-Migdal and Leggett approaches to the description of superfluid Fermi liquids at finite temperatures. We explain peculiarities of both approaches and explicitly demonstrate that they lead to the same expression for the emissivity in pair breaking and formation processes.

We address two questions pertaining to the uniqueness and usefulness of a new observable: (i) Considering the current theoretical knowledge, what novel information does new measurement bring in? (ii) How can new data reduce uncertainties of current theoretical models? We illustrate these points by studying the radius of the neutron distribution of a heavy nucleus, a quantity related to the equation of state for neutron matter that determines properties of nuclei and neutron stars. By systematically varying the parameters of two theoretical models and studying the resulting confidence ellipsoid, we quantify the relationships between the neutron skin and various properties of finite nuclei and infinite nuclear matter. Using the covariance analysis, we identify observables and pseudo-observables that correlate, and do not correlate, with the neutron skin. By adding the information on the neutron radius to the pool of observables determining the energy functional, we show how precise experimental determination of the neutron radius in ${}^{208}\mathrm{Pb}$ would reduce theoretical uncertainties on the neutron matter equation of state.

${}^9\mathrm{Be}$-induced inelastic scattering of ${}^{62,64,66}\mathrm{Fe}$ and ${}^{60,62,64}\mathrm{Cr}$ was performed at intermediate beam energies. Excited states in ${}^{64}\mathrm{Cr}$ were measured for the first time. Energies and population patterns of excited states in these neutron-rich Fe and Cr nuclei are compared and interpreted in the framework of large-scale shell-model calculations in different model spaces. Evidence for increased collectivity and for distinct structural changes between the neighboring Fe and Cr isotopic chains near $N=40$ is presented.

A triaxial rotor model with independent inertia and electric quadrupole tensors is applied to nuclei that have certain $E2$ matrix elements equal to zero. It is shown that such vanishing $E2$ matrix elements are explained by the model as a destructive interference effect. The example of ${}^{196}\mathrm{Pt}$ is considered.

High spin states of ${}^{107}\mathrm{In}$ have been investigated using the reaction ${}^{94}\mathrm{Mo}$(${}^{16}\mathrm{O}$,$p2n$)${}^{107}\mathrm{In}$ at a beam energy of $70$ MeV. A total of $62$ new $\gamma$ transitions have been placed in the level scheme and several $\Delta I=1$ sequences and one $\Delta I=2$ sequence have been found. Lifetime measurements using the Doppler-shift attenuation method (DSAM) have been carried out for band states of $\Delta I=1$ and $\Delta I=2$. A decreasing trend of $B(M1)$ strengths with increasing spin deduced for the $\Delta I=1$ band indicates the presence of a shears mechanism. The experimental data for this band are compared with the tilted axis cranking (TAC) calculations. The $\Delta I=2$ band has been found to be a deformed band with ${\beta }_2~0.2$.

Nuclear magnetic resonance (NMR/ON) measurements with $\beta$- and $\gamma$-ray detection have been performed on oriented ${}^{104}\mathrm{Ag}$${}^{\mathit{g},\mathit{m}}$ nuclei with the NICOLE ${}^3\mathrm{He}$-${}^4\mathrm{He}$ dilution refrigerator setup at ISOLDE/CERN. For ${}^{104}\mathrm{Ag}$${}^{\mathit{g}}$ ($I^{\pi }=5^{+}$) the $\gamma$-NMR/ON resonance signal was found at $\nu =266.70(5)$ MHz. Combining this result with the known magnetic moment for this isotope, the magnetic hyperfine field of Ag impurities in an Fe host at low temperature ($<1$ K) is found to be $|{\mathcal{B}}_{\mathrm{hf}}(\mathrm{Ag}\mathit{Fe})|=44.709(35)$ T. A detailed analysis of other relevant data available in the literature yields three more values for this hyperfine field. Averaging all four values yields a new and precise value for the hyperfine field of Ag in Fe; that is, $|{\mathcal{B}}_{\mathrm{hf}}(\mathrm{Ag}\mathit{Fe})|=44.692(30)$ T. For ${}^{104}\mathrm{Ag}$${}^{\mathit{m}}$ ($I^{\pi }=2^{+}$), the anisotropy of the $\beta$ particles provided the NMR/ON resonance signal at $\nu =627.7(4)$ MHz. Using the new value for the hyperfine field of Ag in Fe, this frequency corresponds to the magnetic moment $\mu ({}^{104m}\mathrm{Ag})=+3.691(3)$ ${\mu }_{\mathrm{N}}$, which is significantly more precise than previous results. The magnetic moments of the even-A ${}^{102-110}\mathrm{Ag}$ isotopes are discussed in view of the competition between the $(\pi g_{9/2}){}_{7/2^{+}}^{-3}(\nu d_{5/2}\nu g_{7/2}){}_{5/2^{+}}$ and the $(\pi g_{9/2}){}_{9/2^{+}}^{-3}(\nu d_{5/2}\nu g_{7/2}){}_{5/2^{+}}$ configurations. The magnetic moments of the ground and isomeric states of ${}^{104}\mathrm{Ag}$ can be explained by an almost complete mixing of these two configurations.

Parity ($\mathcal{P}$)-odd domains, corresponding to nontrivial topological solutions of the QCD vacuum, might be created during relativistic heavy-ion collisions. These domains are predicted to lead to charge separation of quarks along the orbital momentum of the system created in noncentral collisions. To study this effect, we investigate a three-particle mixed-harmonics azimuthal correlator which is a $\mathcal{P}$-even observable, but directly sensitive to the charge-separation effect. We report measurements of this observable using the STAR detector in $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ collisions at $\sqrt{s_{\mathit{NN}}}=200$ and 62 GeV. The results are presented as a function of collision centrality, particle separation in rapidity, and particle transverse momentum. A signal consistent with several of the theoretical expectations is detected in all four data sets. We compare our results to the predictions of existing event generators and discuss in detail possible contributions from other effects that are not related to $\mathcal{P}$ violation.

Quick chemical equilibration times of hadrons (specifically, $p\mathrm{p̄}$, $K\mathrm{K̄}$, $\Lambda \mathrm{\Lambda ̄}$, and $\Omega \mathrm{\Omega ̄}$ pairs) within a hadron gas are explained dynamically using Hagedorn states, which drive particles into equilibrium close to the critical temperature. Within this scheme, we use master equations and derive various analytical estimates for the chemical equilibration times. We compare our model to recent lattice results and find that for both $T_c=176$ MeV and $T_c=196$ MeV, the hadrons can reach chemical equilibrium almost immediately, well before the chemical freeze-out temperatures found in thermal fits for a hadron gas without Hagedorn states. Furthermore, the ratios $p/\pi$, $K/\pi$, $\Lambda /\pi$, and $\Omega /\pi$ match experimental values well in our dynamical scenario.

We compute $v_4/(v_2){}^2$ in ideal and viscous hydrodynamics. We investigate its sensitivity to details of the hydrodynamic model and compare the results to experimental data from the BNL Relativistic Heavy Ion Collider (RHIC). Whereas $v_2$ has a significant sensitivity only to initial eccentricity and viscosity while being insensitive to freeze-out temperature, we find that $v_4/(v_2){}^2$ is quite insensitive to initial eccentricity. On the other hand, it can still be sensitive to shear viscosity in addition to freeze-out temperature, although viscous effects do not universally increase $v_4/(v_2){}^2$ as originally predicted. Consistent with data, we find no dependence on particle species. We also make a prediction for $v_4/(v_2){}^2$ in heavy ion collisions at the CERN Large Hadron Collider (LHC).

We estimate the production cross sections of hypernuclei in projectile-like fragments (PLFs) in heavy ion collisions. The discussed scenario for the formation cross section of a $\Lambda$ hypernucleus is (a) $\Lambda$ particles are produced in the participant region but have a considerable rapidity spread and (b) $\Lambda$ with rapidity close to that of the PLF and total momentum (in the rest system of the PLF) up to Fermi motion can then be trapped and produce hypernuclei. Process (a) is considered here within the heavy ion jet interaction generator (HIJING/B$\overline{\mathrm{B}}$) model, and process (b) in the canonical thermodynamic model (CTM). We estimate the production cross sections for a hypernucleus ${}_{\Lambda }^{A_F}Z$ where $Z=1$, $2$, $3$, and $4$ for C $+$ C at total nucleon-nucleon center of mass (c.m.) energy $\sqrt{s_{\mathit{NN}}}=3.7$ GeV, and for Ne $+$ Ne and Ar $+$ Ar collisions at $\sqrt{s_{\mathit{NN}}}=5.0$ GeV. By taking into account explicitly the impact parameter dependence of the colliding systems, it is found that the cross section is different from that predicted by the coalescence model, and large discrepancy is obtained for ${}_{\Lambda }^6$He and ${}_{\Lambda }^9$Be hypernuclei.

Differential cross sections of neutral pions emitted in ${}^{181}\mathrm{Ta}+{}^{197}\mathrm{Au}$ collisions at a beam energy of $39.5A$ MeV have been measured with the two-arm photon spectrometer (TAPS). The kinetic energy and transverse momentum spectra of neutral pions cannot be properly described in the framework of the thermal model, nor when the reabsorption of pions is accounted for in a phenomenological model. However, high energy and high momentum tails of the pion spectra can be well fitted through thermal distributions with unexpectedly soft temperature parameters below 10 MeV.