The five dimensional collective Hamiltonian (5DCH) implemented with Gogny force has been employed in systematic calculations of electric monopole $\left(E0\right)$ transitions in even-even nuclei with masses $30<A<310$. Significant improvements in the comparison between experimental data and calculations are achieved using (i) stronger collective masses than those inferred from the Inglis-Beliaev approximation and (ii) the $E0$ transition operator as defined by Church and Weneser [E. L. Church and J. Weneser, Phys. Rev. 103, 1035 (1956)]. Main emphasis has been placed on the square of the $E0$ transition strength, ${\rho }^2(E0;0_2^{+}\to 0_1^{+})$, for transitions between the first $0^{+}$ excited state and ground state levels. The dimensionless parameter $X(E0/E2)$ has also been considered in 5DCH calculations covering the rare earth and actinide regions where sparse data are available. Finally, the quasiparticle random-phase approximation (QRPA) implemented with Gogny force has been considered as a complementary model for the interpretation of ${\rho }^2(E0;0_i^{+}\to 0_1^{+})$, $i\ne 2$, data available for ${}^{166}\mathrm{Er}$ and ${}^{238}\mathrm{U}$. The 5DCH model provides a reasonable description of collective $E0$ transitions, but fails otherwise. Specific shell effects are not considered in the present modeling. Global improvements in ${\rho }^2\left(E0\right)$ and $X(E0/E2)$ predictions would be achieved by implementing the energy density functional with quasiparticle components.

Photoneutron emission cross sections were measured for ${}^{13}\mathrm{C}$ below $2n$ threshold using quasimonochromatic $\gamma$-ray beams produced in laser Compton scattering at the NewSUBARU synchrotron radiation facility. The data show fine structures in the low-energy tail of the giant-dipole resonance; the integrated strength of the fine structure below 18 MeV is intermediate among the past measurements with bremsstrahlung and the positron annihilation $\gamma$ rays. We compare the photoneutron emission data with the talys statistical model calculation implemented with the simple modified Lorentzian model of $E1$ and $M1$ strengths. We also compare the total photoabsorption cross sections for ${}^{13}\mathrm{C}$ with shell model and antisymmetrized molecular dynamics calculations as well as the statistical model calculation. We further investigate the consistency between the present photoneutron emission and the reverse ${}^{12}\mathrm{C}(n,\gamma$) cross sections through their corresponding astrophysical rate.

We performed a systematic study on the formation of vorticity rings as the process for jet thermalization in the medium created in high-energy nuclear collisions. In this work, we expanded our previous analysis to a more realistic framework by considering noncentral events and fluctuations in the initial condition. We simulate the formation and evolution of the flow vortex structure in a relativistic viscous hydrodynamic model and study the sensitivity of the proposed “ring observable” $\left({\mathcal{R}}_{\mathrm{\Lambda }}^t\right)$ that can be measured experimentally through the polarization of $\mathrm{\Lambda }$ hyperons. We show that this observable is robust with respect to fluctuating initial conditions to capture the jet-induced vortex flow signal and further study its dependence on different model parameters, such as the jet's velocity, position, the fluid's shear viscosity, and the collision centrality. The proposed observable is associated with the formation of vorticity in a quark-gluon plasma, showing that the measurement of particle polarization can be a powerful tool to probe different properties of jet-medium interactions and to understand better the polarization induced by the transverse and longitudinal expansions of the medium.

Four magnetic dipole bands in ${}^{202}\mathrm{Bi}$ and ${}^{203}\mathrm{Bi}$ are investigated by the systematic comparison with similar bands in Pb isotopes and the tilted axis cranking covariant density functional theory (TAC-CDFT) calculations. The spin and configuration are assigned by the comparison with magnetic rotational bands in Pb isotopes. The corresponding configurations are suggested to be $\pi h_{9/2}{i}_{13/2}{s}_{1/2}^{-1}\otimes \nu i_{13/2}^{-1}$, $\pi h_{9/2}{i}_{13/2}{s}_{1/2}^{-1}\otimes \nu i_{13/2}^{-2}{\left(fp\right)}^{-1}$, and $\pi h_{9/2}{i}_{13/2}{s}_{1/2}^{-1}\otimes \nu i_{13/2}^{-1}{\left(fp\right)}^{-1}$ for the four magnetic dipole bands. The calculated energy spectra and the relation between spin and rotational frequency with TAC-CDFT are in good agreement with available experimental data, further supporting the spin and configuration assignments. The deformation parameters, transition probabilities, and the angular momenta contributions of protons and neutrons are also studied. These calculated quantities, together with the experimental data and the similarity with Pb isotopes, confirm the shear mechanism of these four magnetic dipole bands in ${}^{202}\mathrm{Bi}$ and ${}^{203}\mathrm{Bi}$.

Quantum resonances, i.e., metastable states with a finite lifetime, play an important role in nuclear physics and other domains. Describing this phenomenon theoretically is generally a challenging task. In this work, we combine two established techniques to address this challenge. Complex scaling makes it possible to calculate resonances with bound-state-like methods. Finite-volume simulations exploit the fact that the infinite-volume properties of quantum systems are encoded in how discrete energy levels change as one varies the size of the volume. We apply complex scaling to systems in finite periodic boxes and derive the volume dependence of states in this scenario, demonstrating with explicit examples how one can use these relations to infer infinite-volume resonance energies and lifetimes.

Within the nuclear shell model, we derive the exact expression for the isospin-symmetry breaking correction to the nuclear matrix element of Fermi $\beta$ decays. Based on a perturbation expansion in small quantities, such as the deviation of the overlap integral between proton and neutron radial wave functions from unity and of the transition density from its isospin-symmetry value, we demonstrate that ${\delta }_C$ can be obtained as a sum of six terms. These terms comprise two leading order (LO) terms, two next-to-leading order (NLO) terms, one next-to-next-to-leading order (NNLO) term, and one next-to-next-to-next-to-leading order (NNNLO) term. While the first two terms have been considered in a series of shell-model calculations [J. C. Hardy and I. S. Towner, Phys. Rev. C 102, 045501 (2020), and references therein], the remaining four terms have been neglected. A numerical calculation has been carried out for 24 superallowed $0^{+}\to 0^{+}$ transitions (18 isotriplets and six isoquintets) and three non-$0^{+}\to 0^{+}$ transitions, across the $p$ to $pf$ shells. For most $0^{+}\to 0^{+}$ transitions, the higher-order contribution is of the order ${10}^{-3}\%$ or smaller, well below the typical theoretical errors quantified within the shell model with Woods-Saxon radial wave functions given in the reference cited above. However, for specific cases such as ${}^{70}\mathrm{Br}$ and ${}^{74}\mathrm{Rb}$, where weakly bound effect dominates, it increases considerably, becoming comparable to or even exceeding the errors in the isospin mixing component of the LO terms. In the cases of ${}^{20}\mathrm{Mg}$ and ${}^{48}\mathrm{Fe}$, as well as in non-$0^{+}\to 0^{+}$ transitions, the higher-order contribution becomes more substantial. Notably, it reaches as large as $-4.460\%$ in ${}^{31}\mathrm{Cl}$ and $-2.027\%$ in ${}^{32}\mathrm{Cl}$, due to the concurrent effect of the weakly bound and strong isospin mixing in their daughter nuclei. In contrast, for ${}^{26}\mathrm{P}$, the NLO terms, despite their substantial magnitude, effectively cancel each other out due to their opposite signs.

In stellar environments nuclei appear at finite temperatures, becoming extremely hot in core-collapse supernovae and neutron-star mergers. However, due to theoretical and computational complexity, most model calculations of nuclear properties are performed at zero temperature, while those existing at finite temperatures are limited only to selected regions of the nuclide chart. In this study we perform the global calculation of nuclear properties for even-even $8\le Z\le 104$ nuclei at temperatures in range $0\le T\le 2$ MeV. Calculations are based on the finite-temperature relativistic Hartree-Bogoliubov model supplemented by the Bonche-Levit-Vautherin vapor subtraction procedure. We find that near the neutron-drip line the continuum states have significant contribution already at moderate temperature $T\approx 1$ MeV, thus emphasizing the necessity of the vapor subtraction procedure. Results include neutron emission lifetimes, quadrupole deformations, neutron-skin thickness, proton and neutron pairing gaps, entropy and excitation energy. Up to the temperature $T\approx 1$ MeV, the nuclear landscape is influenced only moderately by the finite-temperature effects, mainly by reducing the pairing correlations. As the temperature increases further, the effects on nuclear structures become pronounced, reducing both the deformations and the shell effects.

The fragment mass and total kinetic energy distributions were measured in fission of ${}^{204}\mathrm{Pb}$, populated in the ${}^7\mathrm{Li}+{}^{197}\mathrm{Au}$ reaction at excitation energies down to 15.3 MeV above the fission barrier. Fits considering admixture of symmetric and asymmetric fission indicate the presence of substantial asymmetric fission at all measured energies. The measured mass distributions are in good agreement with the model predictions. The observed excitation energy dependence of asymmetric fission fractions for the present system is compared with those for near$-$by nuclei and predictions of theoretical models to understand the damping of shell correction at large deformation.

A self-consistent description of angular correlations in neutron-induced reactions is required for quantitative analysis of parity violating (PV) and time-reversal invariance violating (TRIV) effects in neutron-nucleus scattering. The 1.33 eV $p$-wave compound resonance in ${}^{117}\mathrm{Sn}$ is one of the few $p$-wave resonances where enough measurements have been performed to allow a nontrivial test of the internal consistency of the theory. We present the results of a global analysis of the several different asymmetries and angular distribution measurements in ($n,\gamma$) reactions on the 1.33 eV $p$-wave resonance in ${}^{117}\mathrm{Sn}$ conducted over the last few decades. We show that the compound resonance mixing theory can give an internally consistent description of all observations made in this system to date within the experimental measurement errors. We also confirm the conclusions of previous analyses that a subthreshold resonance in ${}^{117}\mathrm{Sn}$ dominates correlations related to $s\text{−}p$ mixing and discuss the implications of these results for future searches for TRIV in this system.

We have revisited the spin dynamics in intermediate-energy heavy-ion collisions based on the improved spin- and isospin-dependent Boltzmann-Uehling-Uhlenbeck (SIBUU) transport model, particularly with the constraint of rigorous angular momentum conservation incorporated. We have studied the spin polarization of free nucleons and $\mathrm{tritons}/{}^3\mathrm{He}$ as well as the spin alignment of deuterons, and predicted the flow splittings for their different spin states. We have also demonstrated that the spin-dependent potential may enhance dissipations and thus have a non-negligible effect on the spin-averaged transverse flow at low collision energies. When rigorous angular momentum conservation in each spin-dependent nucleon-nucleon collision is incorporated, it affects the overall dynamics, the flow, and also the spin polarization, while the effects of the spin-orbit potential on the spin-related observables are still appreciable. The well-developed SIBUU model could be further extended to include hyperons or vector mesons, or used as a hadronic afterburner for spin-related studies in relativistic heavy-ion collisions, with more inelastic channels incorporated in the future.

We combine the ab initio symmetry-adapted no-core shell model (SA-NCSM) with the single-particle Green's function approach to construct optical potentials rooted in first principles. Specifically, we show that total cross sections and phase shifts for neutron elastic scattering from a ${}^4\mathrm{He}$ target with projectile energies between 0.5 and 10 MeV closely reproduce the experiment. In addition, we discuss an important new development that resolves a long-standing issue with spurious center-of-mass motion in the Green's function formalism for many-body approaches. The new development opens a path for first-principle predictions of cross sections for elastic scattering of single-nucleon projectiles, nucleon capture, and deuteron breakup reactions, feasible for a broad range of open-shell spherical and deformed nuclei in the SA-NCSM approach.

We calculate the balance function for charm in relativistic heavy-ion collisions. The distribution of pairs of charm-anticharm quarks produced in hard processes in the early stages of the nucleus-nucleus collision evolves in the dense fireball formed in the collision. The evolution of the dense matter is described using a relativistic viscous hydrodynamic model and the quark diffusion with a Langevin equation. The evolution of the charm quark balance function from the formation of the charm-anticharm pair up to the freeze-out traces the partial thermalization of the heavy quarks in the dense matter. For the balance function in azimuthal angle we reproduce the collimation effect due to the transverse flow. The evolution in rapidity shows the thermalization of the longitudinal velocity of the quark in the fluid. We provide estimates for the one- and two-dimensional balance functions for $D^0\text{−}\overline{D^0}$ mesons produced in ultrarelativistic $\mathrm{Pb}+\mathrm{Pb}$ collisions at $\sqrt{s_{NN}}=5.02$ TeV. The shape of the charm balance function in relative rapidity is sensitive to the rescattering of heavy quarks in the early stages of the collision, while the shape of the balance function in azimuthal angle is sensitive to the rescattering in the latter stages.

The extreme temperature and density conditions that arise in ultrarelativistic collisions of heavy nuclei enable the formation of the most fundamental fluid in the universe, the deconfined phase of quantum chromodynamics known as quark-gluon plasma. Despite the extensive experimental evidence gathered over the last decade for the production of quark-gluon plasma in colliding systems such as Au-Au and Pb-Pb, the formation of quark-gluon plasma in the collision of smaller systems such as $p$-Pb remains an open question. In this study, we describe the evolution of matter formed in $p$-Pb collisions at 5.02 TeV using a state-of-the-art hybrid model based on viscous relativistic hydrodynamics. We study the thermodynamic properties of the medium and the final state observables. Our results are compared with experimental data and first-principles lattice quantum chromodynamics calculations. The results support the formation of a collective phase of strongly interacting matter in high-multiplicity $p$-Pb collisions.

A comprehensive study of the proton capture reaction is performed. The three major reaction mechanisms, namely, compound-nucleus capture (CNC), pre-equilibrium capture (PEC), and direct capture (DIC), are simultaneously considered on the basis of the Hauser-Feshbach model, the exciton model, and potential model, respectively. The same nuclear ingredients are consistently used in the three models, and especially the same nucleon-nucleus optical model potential (OMP) ensures that the three components are calculated on the same footing and represents partial fluxes of the same total reaction cross section. For about 2700 nuclei with 8 $\le Z\le$ 100 lying between the proton drip line and the valley of $\beta$ stability, the proton capture cross sections and astrophysical reaction rates corresponding to the CNC, PEC, DIC, and total (CNC + PEC + DIC) contributions are computed. The specific nuclear structure ingredients involved in the calculation, namely the nuclear mass, electromagnetic multipole moments, $\gamma$-ray strength function, excited-level scheme, spectroscopic factor, and proton-nucleus OMP, are determined from experimental data whenever available and, if not, from global nuclear models. For the reactions involving the targets with mass number $A\ge 48$, fair agreements between the calculated proton total capture cross sections and the experimental data are found. For the lightest nuclei ($A<28$), however, it is found that only the predicted DIC cross sections reproduce the experimental results well, and the total CNC + PEC + DIC contributions tend to overestimate the experimental cross sections. Furthermore, the systematic analysis for the nuclei beyond ${}^{40}\mathrm{Ca}$ shows that the relative contribution of the proton DIC reaction rate to the total reaction rate increases with increasing temperatures. In particular, the proton DIC reaction rates are comparable to the CNC + PEC reaction rates in the temperature range of the astrophysical $p$ process (2–3 GK) for some open-shell nuclei in the mass region of $70\le A\le 160$ around the valley of $\beta$ stability. Such a high DIC contribution stems from the large number of direct transitions to final excited states. In order to better understand the DIC contribution, further experiment and theoretical analyses need to be performed. The impact of the proton DIC reaction rates on the $rp$- and $p$-process nucleosynthesis remains to be investigated.

The α-decay chains of the isotopes ${}^{293,294,295}\mathrm{Og}$ are studied in the present paper. The modified generalized liquid drop model (MGLDM) is used to study the α-decay half-lives. The results are then compared with other theoretical formalisms. The decay chains of these isotopes are predicted by comparing the α half-lives with the corresponding spontaneous fission half-lives. The study predicted a 5α chain from the isotope ${}^{293}\mathrm{Og}$, a 3α chain from ${}^{294}\mathrm{Og}$, and a 2α chain from ${}^{295}\mathrm{Og}$. The agreement between theoretical and experimental results emphasizes the applicability of the MGLDM in a superheavy region. Since the predicted half-lives are within the experimental limit, these isotopes can be detected in laboratories via α decay.

Finite temperature results in various effects on the properties of nuclear structure and excitations of relevance for nuclear processes in hot stellar environments. Here, we introduce the self-consistent finite temperature relativistic quasiparticle random phase approximation (FT-RQRPA) based on relativistic energy density functional with point coupling interaction for describing the temperature effects in electric dipole ($E1$) transitions. We perform a study of $E1$ excitations in the temperature range $T=0\text{–}2$ MeV for the selected closed- and open-shell nuclei ranging from ${}^{40}\mathrm{Ca}$ to ${}^{60}\mathrm{Ca}$ and ${}^{100}\mathrm{Sn}$ to ${}^{140}\mathrm{Sn}$ by including both thermal and pairing effects. The isovector giant dipole resonance strength is slightly modified for the considered range of temperature, while new low-energy peaks emerge for $E<12$ MeV with non-negligible strength in neutron-rich nuclei at high temperatures. The analysis of relevant two-quasiparticle configurations discloses how new excitation channels open due to thermal unblocking of states at finite temperature. The study also examines the isospin and temperature dependence of electric dipole polarizability (${\alpha }_D$), resulting in systematic increase in the values of ${\alpha }_D$ with increasing temperature, with a more pronounced effect observed in neutron-rich nuclei. The FT-RQRPA introduced in this work will open perspectives for microscopic calculation of $\gamma$-ray strength functions at finite temperatures relevant for nuclear reaction studies.

The complete and incomplete fusion cross sections for the ${}^7\mathrm{Li}+{}^{205}\mathrm{Tl}$ reaction were measured at near barrier energies by the online characteristic $\gamma$-ray detection technique. The complete fusion (CF) cross sections at energies above the Coulomb barrier were found to be suppressed by $\sim 26\%$ compared to the coupled channel calculations. Reduced fusion cross sections for the present system at energies normalized to the Coulomb barrier were also found to be systematically lower than those with strongly bound projectiles forming a similar compound nucleus. The suppression observed in CF cross sections is found to be commensurate with the measured total incomplete fusion (ICF) cross sections. In the ICF cross sections, $t$-capture is found to be dominant than $\alpha$-capture at all the measured energies. The systematic study of available CF, ICF, and total fusion data with the ${}^7\mathrm{Li}$ projectile is performed.

The present work focuses on oxygen-oxygen (O-O) collisions, which are planned at the CERN Large Hadron Collider. Oxygen, being a doubly magic number nucleus, has some very unique features. This study attempts to probe the exotic state of QCD matter in O-O collisions. Additionally, the role of different nuclear density profiles in governing the final-state dynamics in ultrarelativistic nuclear collisions is also explored. Using a multiphase transport model, we obtain the nuclear modification factor $\left(R_{\text{AA}}\right)$ for all charged hadrons and identified particles for O-O collisions at $\sqrt{s_{\mathrm{NN}}}$ = 7 TeV. Furthermore, we investigate the behavior of $R_{\text{AA}}$ as a function of transverse momentum $\left({\mathit{p}}_{\mathrm{T}}\right)$ for three centralities (most central, mid-central, and peripheral) considering both $\alpha$-cluster and Woods-Saxon nuclear density profiles. We also extend this work to study the rapidity dependence of $R_{\text{AA}}$ for all charged hadrons. To better understand our findings of O-O collisions, the results are confronted with the available data of $R_{\text{AA}}$ for Pb-Pb collisions. The present study sheds light on particle production mechanisms, emphasizing factors influencing particle yield from precollision to postcollision stages in the context of O-O collisions.

Excited states in ${}^{193}\mathrm{Os}$ were populated using a ${}^{192}\mathrm{Os}(n_{\text{th.}},\gamma ){}^{193}\mathrm{Os}$ thermal neutron capture reaction, with neutrons provided by the high-flux reactor of the Institut Laue-Langevin in Grenoble, France. Lifetimes of low-spin excited states were measured using the generalized centroid difference method. A total of eight mean lifetimes of low-lying excited states were determined for the first time, and limits for the lifetimes of three further excited states were established. Additionally, $\gamma \text{−}\gamma$ angular correlations were analyzed to assign spins to previously known excited states up to 1 MeV, and extract multipole mixing ratios for several transitions. The new spectroscopic information is compared to calculations in the framework of the interacting boson-fermion model, based on the nuclear density functional theory, to investigate the prolate-to-oblate shape phase transition, predicted to occur in the neutron rich $A\approx 190$ region.