The correlations between event-by-event fluctuations of anisotropic flow harmonic amplitudes have been measured in Pb-Pb collisions at $\sqrt{s_{\mathit{NN}}}=2.76$ TeV with the ALICE detector at the Large Hadron Collider. The results are reported in terms of multiparticle correlation observables dubbed symmetric cumulants. These observables are robust against biases originating from nonflow effects. The centrality dependence of correlations between the higher order harmonics (the quadrangular $v_4$ and pentagonal $v_5$ flow) and the lower order harmonics (the elliptic $v_2$ and triangular $v_3$ flow) is presented. The transverse momentum dependences of correlations between $v_3$ and $v_2$ and between $v_4$ and $v_2$ are also reported. The results are compared to calculations from viscous hydrodynamics and a multiphase transport (AMPT) model calculations. The comparisons to viscous hydrodynamic models demonstrate that the different order harmonic correlations respond differently to the initial conditions and the temperature dependence of the ratio of shear viscosity to entropy density $(\eta /s)$. A small average value of $\eta /s$ is favored independent of the specific choice of initial conditions in the models. The calculations with the AMPT initial conditions yield results closest to the measurements. Correlations among the magnitudes of $v_2, v_3$, and $v_4$ show moderate $p_{\mathrm{T}}$ dependence in midcentral collisions. This might be an indication of possible viscous corrections to the equilibrium distribution at hadronic freeze-out, which might help to understand the possible contribution of bulk viscosity in the hadronic phase of the system. Together with existing measurements of individual flow harmonics, the presented results provide further constraints on the initial conditions and the transport properties of the system produced in heavy-ion collisions.

In collisions of light, stable, weakly bound nuclides, complete fusion (capture of all of the projectile charge) has been found to be suppressed by $\sim 30\%$ at above-barrier energies. This is thought to be related to their low thresholds for breakup into charged clusters. The observation of fusion suppression in the neutron-rich radioactive nucleus ${}^8\mathrm{Li}$ is therefore puzzling: the lowest breakup threshold yields ${}^7\mathrm{Li}+n$ which cannot contribute to fusion suppression because ${}^7\mathrm{Li}$ retains all the projectile charge. In this work, the full characteristics of ${}^8\mathrm{Li}$ breakup in reactions with ${}^{209}\mathrm{Bi}$ are presented, including, for the first time, coincidence measurements of breakup into charged clusters. Correlations of cluster fragments show that most breakup occurs too slowly to significantly suppress fusion. However, a large cross section for unaccompanied $\alpha$ particles was found, suggesting that charge clustering, facilitating partial charge capture, rather than weak binding is the crucial factor in fusion suppression, which may therefore persist in exotic nuclides.

Background: For many years, quasifree scattering reactions in direct kinematics have been extensively used to study the structure of stable nuclei, demonstrating the potential of this approach. The $\mathrm{R}{}^3\mathrm{B}$ collaboration has performed a pilot experiment to study quasifree scattering reactions in inverse kinematics for a stable ${}^{12}\mathrm{C}$ beam. The results from that experiment constitute the first quasifree scattering results in inverse and complete kinematics. This technique has lately been extended to exotic beams to investigate the evolution of shell structure, which has attracted much interest due to changes in shell structure if the number of protons or neutrons is varied.

Purpose: In this work we investigate for the first time the quasifree scattering reactions ($p,pn$) and ($p,2p$) simultaneously for the same projectile in inverse and complete kinematics for radioactive beams with the aim to study the evolution of single-particle properties from $N=14$ to $N=15$.

Method: The structure of the projectiles ${}^{23}\mathrm{O}, {}^{22}\mathrm{O}$, and ${}^{21}\mathrm{N}$ has been studied simultaneously via ($p,pn$) and ($p,2p$) quasifree knockout reactions in complete inverse kinematics, allowing the investigation of proton and neutron structure at the same time. The experimental data were collected at the ${\mathrm{R}}^3\mathrm{B}$-LAND setup at GSI at beam energies of around 400 MeV/u. Two key observables have been studied to shed light on the structure of those nuclei: the inclusive cross sections and the corresponding momentum distributions.

Conclusions: The knockout reactions ($p,pn$) and ($p,2p$) with radioactive beams in inverse kinematics have provided important and complementary information for the study of shell evolution and structure. For the ($p,pn$) channels, indications of a change in the structure of these nuclei moving from $N=14$ to $N=15$ have been observed, i.e., from the $0d_{5/2}$ shell to the $1s_{1/2}$. This supports previous observations of a subshell closure at $N=14$ for neutron-rich oxygen isotopes and its weakening for the nitrogen isotopes.

Precise mass measurements of the neutron-rich ${}^{125–130}\mathrm{In}$ isotopes have been performed with the TITAN Penning trap mass spectrometer. TITAN's electron beam ion trap was used to charge breed the ions to charge state $q=13+$ thus providing the necessary resolving power to measure not only the ground states but also isomeric states at each mass number. In this paper, the properties of the ground states are investigated through a series of mass differentials, highlighting trends in the indium isotopic chain as compared to its proton-magic neighbor, tin ($Z=50$). In addition, the energies of the indium isomers are presented. The ($8^{-}$) level in ${}^{128}\mathrm{In}$ is found to be 78 keV lower than previously thought and the ($21/2^{-}$) isomer in ${}^{127}\mathrm{In}$ is shown to be lower than the literature value by more than 150 keV.

Hydrokinetic theory of thermal fluctuations is applied to a nonconformal relativistic fluid. Solving the hydrokinetic equations for an isotropically expanding background we find that hydrodynamic fluctuations give ultraviolet divergent contributions to the energy-momentum tensor. After shifting the temperature to account for the energy of nonequilibrium modes, the remaining divergences are renormalized into local parameters, e.g., pressure and bulk viscosity. We also confirm that the renormalization of the pressure and bulk viscosity is universal by computing them for a Bjorken expansion. The fluctuation-induced bulk viscosity reflects the nonconformal nature of the equation of state and is modestly enhanced near the QCD deconfinement temperature.

We calculate cross sections and transverse momentum distributions for the incoherent diffractive production of vector mesons $J/\psi$ and $\mathrm{{\rm Y}}$ on heavy nuclei. In distinction to coherent diffraction, the nucleus is allowed to break up, but except for the vector meson no new particles are produced in the reaction. Within the color dipole approach, we derive the multiple scattering expansion of the incoherent diffractive cross section as an expansion over quasielastic scatterings of the color dipole. We also compare our results to the measurement of the ALICE Collaboration for incoherent $J/\psi$ production at $\sqrt{s_{NN}}=2.76\mathrm{TeV}$ and show predictions at $\sqrt{s_{NN}}=5.02\mathrm{TeV}$. We also briefly discuss a possible contribution to $J/\psi$ production in peripheral collisions in the $70–90\%$ centrality class.

Adopting the density dependent relativistic mean-field (RMF) and relativistic Hartree-Fock (RHF) approaches, the properties of the nuclear fourth-order symmetry energy $S_4$ are studied within the covariant density functional (CDF) theory. It is found that the fourth-order symmetry energies are suppressed in RHF at both saturation and supranuclear densities, where the extra contribution from the Fock terms is demonstrated, specifically via the isoscalar meson-nucleon coupling channels. The reservation of $S_4$ and higher-order symmetry energies in the nuclear equation of state then affects essentially the prediction of neutron star properties, which is illustrated in quantities such as the proton fraction, the core-crust transition density, as well as the fraction of crustal moment of inertia. Since the Fock terms enhance the density dependence of the thermodynamical potential, the RHF calculations predict systematically smaller values of density, proton fraction, and pressure at the core-crust transition boundary of neutron stars than density dependent RMF ones. In addition, a linear anticorrelation between the core-crust transition density ${\rho }_t$ and the density slope of symmetry energy $L$ is found which is then utilized to constrain the core-crust transition density as ${\rho }_t\sim [0.069,0.098]{\mathrm{fm}}^{-3}$ with the recent empirical information on $L$. The study clarifies the important role of the fourth-order symmetry energy in determining the properties of nuclear matter at extreme isospin or density conditions.

The cross section of the inclusive process ${\pi }^{+}d\to p\left(\eta p\right)$ is calculated as a function of the $\eta p$ invariant mass when the detected proton is moving in the forward direction. The incident pion has a momentum of $p_{\mathrm{lab}}=898.47$ MeV/$c$ for which the $\eta p$ pair are left at rest in the laboratory system which allows one to study the effect of the $\eta p\to \eta p$ final-state interaction in the region of the $N\left(1535\right)S_{11}$ resonance. The sensitivity of the inclusive cross section to different parametrizations of the $\eta N$ final-state interaction is discussed.

In the present work we perform a systematic shell-model study of Gamow-Teller transition-strength distributions in $sd$ shell nuclei using ab initio effective interactions. The ab initio effective interactions are based on in-medium similarity renormalization-group and coupled-cluster effective interaction approaches. The aim of the present work is to test the predictive power of ab initio effective interactions by using the available experimental data of Gamow-Teller strength distributions in $sd$ shell nuclei. We perform calculations for ${}^{20}\mathrm{Ne}\to {}^{20}\mathrm{F}$, ${}^{23}\mathrm{Na}\to {}^{23}\mathrm{Mg}$, ${}^{23}\mathrm{Na}\to {}^{23}\mathrm{Ne}$, ${}^{24}\mathrm{Mg}\to {}^{24}\mathrm{Na}$, ${}^{24}\mathrm{Mg}\to {}^{24}\mathrm{Al}$, ${}^{25}\mathrm{Mg}\to {}^{25}\mathrm{Al}$, ${}^{26}\mathrm{Mg}\to {}^{26}\mathrm{Na}$, ${}^{26}\mathrm{Mg}\to {}^{26}\mathrm{Al}$, ${}^{26}\mathrm{Si}\to {}^{26}\mathrm{Al}$, ${}^{27}\mathrm{Al}\to {}^{27}\mathrm{Si}$, ${}^{28}\mathrm{Si}\to {}^{28}\mathrm{P}$, ${}^{31}\mathrm{P}\to {}^{31}\mathrm{Si}$, and ${}^{32}\mathrm{S}\to {}^{32}\mathrm{P}$ transitions. For comparison we also show the results obtained by using the phenomenological USDB Hamiltonian. The phenomenological USDB results of the Gamow-Teller (${\mathrm{GT}}_{+}$ and ${\mathrm{GT}}_{-}$) strength distributions show reasonable agreements with the experimental data in comparison with the ab initio interactions. We also calculate the electron-capture reaction rates for ${}^{23}\mathrm{Na}(e^{-},\nu ){}^{23}\mathrm{Ne}$ and ${}^{25}\mathrm{Mg}(e^{-},\nu ){}^{25}\mathrm{Na}$ using ab initio and USDB interactions.

Nuclear resonant excitation and detection of its decay signal for the 26.27-keV level of ${}^{201}\mathrm{Hg}$ is demonstrated with high-brilliance synchrotron radiation (SR) and a fast x-ray detector system. This SR-based photonuclear excitation scheme, known as nuclear resonant scattering (NRS) in the field of materials science, is also useful for investigating nuclear properties, such as the half-lives and radiative widths of excited nuclear levels. To date, because of the limited time response of the x-ray detector, the nuclear levels to which this method could be applied have been limited to the one whose half-lives are longer than $\sim 1$ ns. The faster time response of the NRS measurement makes possible NRS experiments on nuclear levels with much shorter half-lives. We have fabricated an x-ray detector system that has a time resolution of 56 ps and a shorter tail function than that reported previously. With the implemented detector system, the NRS signal of the 26.27-keV state of ${}^{201}\mathrm{Hg}$ could be clearly discriminated from the electronic scattering signal at an elapsed time of 1 ns after the SR pulse. The half-life of the state was determined as 629 $\pm$ 18 ps, which has better precision by a factor of three compared with that reported to date obtained from nuclear decay spectroscopy.

The Wigner isobaric multiplet mass equation (IMME) is the most fundamental prediction in nuclear physics with the concept of isospin. However, it was deduced based on the Wigner-Eckart theorem with the assumption that all charge-violating interactions can be written as tensors of rank two. In the present work, the charge-symmetry breaking (CSB) and charge-independent breaking (CIB) components of the nucleon-nucleon force, which contribute to the effective interaction in nuclear medium, are established in the framework of Brueckner theory with AV18 and AV14 bare interactions. Because such charge-violating components can no longer be expressed as an irreducible tensor due to density dependence, its matrix element cannot be analytically reduced by the Wigner-Eckart theorem. With an alternative approach, we derive a generalized IMME (GIMME) that modifies the coefficients of the original IMME. As the first application of GIMME, we study the long-standing question of the origin of the Nolen-Schiffer anomaly (NSA) found in the Coulomb displacement energy of mirror nuclei. We find that the naturally emerged CSB term in GIMME is largely responsible for explaining the NSA.

High-spin states in ${}^{70}\mathrm{Ge}$ were studied using the ${}^{55}\mathrm{Mn}$(${}^{18}\mathrm{O},p2n$) fusion-evaporation reaction at a beam energy of 50 MeV. Prompt $\gamma \text{−}\gamma$ coincidences were measured using the Florida State University Compton-suppressed Ge array consisting of three Clover detectors and seven single-crystal detectors. An investigation of these coincidences resulted in the addition of 31 new transitions and the rearrangement of four others in the ${}^{70}\mathrm{Ge}$ level scheme, providing a more complete picture of the high-spin decay pattern involving both positive- and negative-parity states with multiple band structures. Spins were assigned based on directional correlation of oriented nuclei ratios, which many times also led to unambiguous parity determinations based on the firm assignments for low-lying states made in previous work. Total Routhian surface calculations, along with the observed trends in the experimental kinematic moment of inertia with rotational frequency, support the multiquasiparticle configurations of the various crossing bands proposed in recent studies. The high-spin excitation spectra predicted by previous shell-model calculations compare favorably with the experimental one determined from this study.

The neutron-rich radium isotopes, ${}^{222-233}\mathrm{Ra}$, were measured with Collinear Resonance Ionization Spectroscopy (CRIS) at the ISOLDE facility, CERN. The hyperfine structure of the $7s^2{}^{1}S_0\to 7s7p{}^{3}P_1$ transition was probed, allowing measurement of the magnetic moments, quadrupole moments, and changes in mean-square charge radii. These results are compared to existing literature values, and the new moments and change in mean-square charge radii of ${}^{231}\mathrm{Ra}$ are presented. Low-resolution laser spectroscopy of the very neutron-rich ${}^{233}\mathrm{Ra}$ has allowed the isotope shift and relative charge radius to be determined for the first time.

The spent fuel of current nuclear reactors contains fissile plutonium isotopes that can be combined with uranium to make mixed oxide (MOX) fuel. In this way the Pu from spent fuel is used in a new reactor cycle, contributing to the long-term sustainability of nuclear energy. However, an extensive use of MOX fuels, in particular in fast reactors, requires more accurate capture and fission cross sections for some Pu isotopes. In the case of ${}^{242}\mathrm{Pu}$ there are sizable discrepancies among the existing capture cross-section measurements included in the evaluations (all from the 1970s) resulting in an uncertainty as high as 35% in the fast energy region. Moreover, postirradiation experiments evaluated with JEFF-3.1 indicate an overestimation of 14% in the capture cross section in the fast neutron energy region. In this context, the Nuclear Energy Agency (NEA) requested an accuracy of 8% in this cross section in the energy region between 500 meV and 500 keV. This paper presents a new time-of-flight capture measurement on ${}^{242}\mathrm{Pu}$ carried out at n_TOF-EAR1 (CERN), focusing on the analysis and statistical properties of the resonance region, below 4 keV. The ${}^{242}\mathrm{Pu}(\mathrm{n},\gamma )$ reaction on a sample containing 95(4) mg enriched to 99.959% was measured with an array of four ${\mathrm{C}}_6{\mathrm{D}}_6$ detectors and applying the total energy detection technique. The high neutron energy resolution of n_TOF-EAR1 and the good statistics accumulated have allowed us to extend the resonance analysis up to 4 keV, obtaining new individual and average resonance parameters from a capture cross section featuring a systematic uncertainty of 5%, fulfilling the request of the NEA.

The origin of bimodal behavior in the residue distribution experimentally measured in heavy ion reactions is reexamined using Boltzmann-Uehling-Uhlenbeck simulations. We suggest that, depending on the incident energy and impact parameter of the reaction, both entrance channel and exit channel effects can be at the origin of the observed behavior. Specifically, fluctuations in the reaction mechanism induced by fluctuations in the collision rate, as well as thermal bimodality directly linked to the nuclear liquid-gas phase transition, are observed in our simulations. Both phenomenologies were previously proposed in the literature but presented as incompatible and contradictory interpretations of the experimental measurements. These results indicate that heavy ion collisions at intermediate energies can be viewed as a powerful tool to study both bifurcations induced by out-of-equilibrium critical phenomena, as well as finite-size precursors of thermal phase transitions.

In a previous publication, we have presented a model for the photoproduction of $J/\psi$ vector mesons off protons, where the proton structure in the impact-parameter plane is described by an energy-dependent hot-spot profile. Here we extend this model to study the photonuclear production of $J/\psi$ vector mesons in coherent and incoherent interactions of heavy nuclei. We study two methods to extend the model to the nuclear case: using the standard Glauber-Gribov formalism and using geometric scaling to obtain the nuclear saturation scale. We find that the incoherent cross section changes sizably with the inclusion of subnucleonic hot spots and that this change is energy dependent. We propose to search for this behavior by measuring the ratio of the incoherent to coherent cross sections at different energies. We compare the results of our model to results from the Relativistic Heavy-Ion Collider (RHIC) and from run 1 at the Large Hadron Collider (LHC), finding satisfactory agreement. We also present predictions for the LHC at the new energies reached in run 2. The predictions include $J/\psi$ production in ultraperipheral collisions, as well as the recently observed photonuclear production in peripheral collisions.

We present a new rearrangement of short-range interactions in the ${}^{1}S_0$ nucleon-nucleon channel within chiral effective field theory. This is intended to address the slow convergence of Weinberg's scheme, which we attribute to its failure to reproduce the amplitude zero (scattering momentum $\simeq 340$ MeV) at leading order. After the power counting scheme is modified to accommodate the zero at leading order, it includes subleading corrections perturbatively in a way that is consistent with renormalization-group invariance. Systematic improvement is shown at next-to-leading order, and we obtain results that fit empirical phase shifts remarkably well all the way up to the pion-production threshold. An approach in which pions have been integrated out is included, which allows us to derive analytic results that also fit phenomenology surprisingly well.

A triaxial rotor Hamiltonian with a rigidly aligned high-$j$ quasiparticle is treated by a time-dependent variational principle, using angular momentum coherent states. The resulting classical energy function has three unique critical points in a space of generalized conjugate coordinates, which can minimize the energy for specific ordering of the inertial parameters and a fixed angular momentum state. Because of the symmetry of the problem, there are only two unique solutions, corresponding to wobbling motion around a principal axis and, respectively, a tilted axis. The wobbling frequencies are obtained after a quantization procedure and then used to calculate $E2$ and $M1$ transition probabilities. The analytical results are employed in the study of the wobbling excitations of ${}^{135}\mathrm{Pr}$ nucleus, which is found to undergo a transition from low angular momentum transverse wobbling around a principal axis toward a tilted-axis wobbling at higher angular momentum.

In this paper, the formalism for the nucleon-pair approximation (NPA) with particle-hole excitations is developed. By using this approach, one is able to perform multiple-major-shell calculations. In this formulation, we use a particle-hole mixed representation, i.e., the particle-hole conjugate transformation is used for operators of the lower major shells, while operators of the upper major shells remain unchanged. We consider collective valence-particle pairs in the upper major shells, collective valence-hole pairs in the lower major shells, and collective pairs consisting of one valence particle in the upper shells and one valence hole in the lower shells to construct our model space. Matrix elements for the shell-model Hamiltonian, both for effective interactions and for phenomenological pairing plus multipole-multipole interactions, are derived in the nucleon-pair basis. As a special case, analytical formulas for doubly magic nuclei with excitations up to two-particle–two-hole are presented. To exemplify this approach, we calculate ${}^{100}\mathrm{Sn}$ considering both proton and neutron up to four-particle–four-hole excitations, where valence particles are in the 50-82 major shell and valence holes in the 28-50 major shell, with the low-momentum nucleon-nucleon interaction derived from the CD-Bonn potential.