A new method for calculating the Coulomb breakup of unstable neutron-rich isotopes at high energies is presented. The calculations employ the eikonal approximation and use a new Coulomb dynamical polarization potential, calculated by solving the Schrödinger equation for the entire motion of the exotic projectile as a two-body cluster structure using the adiabatic approximation and incorporating excitations to the continuum. Calculations for some exotic isotopes are compared with Coulomb dissociation cross section data and found to be in good agreement.

We derive the spin Boltzmann equations for spin-1/2 fermions in a nonrelativistic model with four-fermion contact interaction which conserves spin degrees of freedom. A great advantage of the model is that the spin matrix elements in collision terms can be completely worked out and be put into such a compact form that one can clearly see how spins are coupled in particle scatterings. A semiclassical expansion in the Planck constant has been made and the on-shell part of the spin Boltzmann equation up to the next-to-leading order is derived. At the leading order the equilibrium spin distribution can be obtained from the vanishing of the collision term for the spin density. The spin chemical potential emerges as a natural consequence of spin conservation. The off-shell part of the spin Boltzmann equation is also discussed. The work can be extended to more sophisticated interaction such as nuclear force in order to apply to spin polarization phenomena in heavy-ion collisions at low energies.

Renormalization of proton-proton fusion is studied in the framework of chiral effective field theory. Strict perturbative treatment of subleading corrections is applied in the analysis. Possible enhancement of two-nucleon contact axial current operators is the focus of the study. We find evidence that supports a previous proposal in the literature to promote one of the contact axial current operators.

The chiral magnetic effect (CME) is a macroscopic transport phenomenon induced by a quantum anomaly in the presence of chiral imbalance and an external magnetic field. Relativistic heavy ion collisions provide the unique opportunity to look for CME in a non-Abelian plasma, where the chiral imbalance is created by topological transitions similar to those occurring in the early universe. The isobar run at Relativistic Heavy Ion Collider was proposed as a way to separate the possible CME signal driven by magnetic field from the background. The first blind analysis results from this important experiment were recently released by the STAR Collaboration. Under the pre-defined assumption of identical background in RuRu and ZrZr, the results are inconsistent with the presence of CME, as well as with all existing theoretical models (whether including CME or not). However the observed difference of backgrounds must be taken into account before any physical conclusion is drawn. In this paper, we show that once the observed difference in hadron multiplicity and collective flow are quantitatively taken into account, the STAR results could be consistent with a finite CME signal contribution of about $(6.8\pm 2.6)\%$.

Tracking the evolution of nuclear properties away from stability serves as a valuable test for nuclear models. In the present work, the $(p,n)$ charge-exchange reaction was used to test the extraction of ${\beta }^{-}$ Gamow-Teller transition strengths, $B\left(\mathrm{GT}\right)$, from proton-rich unstable isotopes, and the resulting $B\left(\mathrm{GT}\right)$ values were compared to shell-model and ab initio calculations. The ${}^{11}\mathrm{C}(p,n){}^{11}\mathrm{N}$ reaction was measured in inverse kinematics at 95 MeV/u at the National Superconducting Cyclotron Laboratory. The $B\left(\mathrm{GT}\right)$ values to the ${\frac{1}{2}}^{-}$ state at 0.73 MeV and the ${\frac{3}{2}}^{-}$ state at 2.86 MeV in ${}^{11}\mathrm{N}$ were determined to be $0.18{\left(1\right)}^{\mathrm{stat}}{\left(3\right)}^{\mathrm{sys}}$ and $0.18{\left(1\right)}^{\mathrm{stat}}{\left(4\right)}^{\mathrm{sys}}$, respectively. These results are consistent with shell-model calculations using the wbp interaction after introducing a phenomenological quenching factor and with ab initio variational Monte Carlo calculations using the $NV2+3I{a}^{*}$ $NN$ and $3N$ interactions without any scaling. Additionally, this result is consistent with the $B\left(\mathrm{GT}\right)$ values extracted from mirror ${}^{11}\mathrm{B}(n,p)$ and ${}^{11}\mathrm{B}(t,{}^3\mathrm{He})$ reactions. This experiment demonstrates the feasibility of using the $(p,n)$ probe in inverse kinematics to extract $B\left(\mathrm{GT}\right)$ from proton-rich nuclei, although improved background suppression will be important in future experiments.

A model is developed to calculate the total kinetic energy (TKE) distribution of fission fragments in the framework of the time-dependent generator coordinate method, extended to include dissipation effects in the description of induced fission dynamics. Starting from an expression for the dissipative term in the generator coordinate method Hamiltonian that determines the time evolution of a statistical collective wave function, derived in the first part of this work, the integrated flux of the probability current through the scission hypersurface can be computed at different temperatures. The kinetic energy at scission for a specific pair of fragments at a given temperature is determined by the energy balance formula. By folding the kinetic energies of the fragments with the flux of the probability current, the TKE distribution is calculated. The method is illustrated with a calculation of the TKE distribution for induced fission of ${}^{228}\mathrm{Th}$, in the three-dimensional space of collective coordinates: axially symmetric quadrupole and octupole deformations, and nuclear temperature.

We present the measured spin correlation coefficient $C_{y,y}$ for $p\text{−}{}^3\mathrm{He}$ elastic scattering at 100 MeV at the angles ${\theta }_{\mathrm{c}.\mathrm{m}.}=46.9^{\circ }$–$149.2^{\circ }$ in the center-of-mass system. The $C_{y,y}$ data and the existing cross section data are compared with rigorous four-nucleon scattering calculations based on realistic nucleon-nucleon potentials. Large differences are seen in the regime around the cross section minimum for both observables. The $\mathrm{\Delta }$-isobar effects estimated by the $NN+N\mathrm{\Delta }$ coupled-channels approach are small for the cross section. Meanwhile, in $C_{y,y}$, the $\mathrm{\Delta }$-isobar effects improve the agreement with the data. The analysis of the $p\text{−}{}^3\mathrm{He}$ elastic scattering amplitudes implies the necessity of three-nucleon forces ($3N\text{Fs}$) that enhance the vector components in the amplitudes. The obtained results indicate that the spin correlation coefficient $C_{y,y}$ expands the knowledge of the nuclear interactions with the $\mathrm{\Delta }$ isobar or those including $3N\text{Fs}$ that are masked in nucleon-deuteron elastic scattering.

We present a calculation of the radiative capture cross section of the $np\to d\gamma$ reaction in the low-energy range, where the $M1$ reaction channel dominates. Employing the LENPIC nucleon-nucleon interaction up to the fifth order (N4LO) that is regularized by the semilocal coordinate space regulators, we obtain the initial and final state wave functions, and evaluate the phase shifts of the scattering state and deuteron properties. We derive the transition operator from the chiral effective field theory up to the next-to-next-to leading order (N2LO), where we also regularize the transition operator using regulators consistent with those of the interactions. We compute the capture cross sections, and the results show a converging pattern with the chiral-order expansion of the nucleon-nucleon interaction, where the regulator dependence of the results is weak when higher-order nucleon-nucleon interactions are employed. We quantify the uncertainties of the cross-section results due to the chiral-order truncation. The chirally complete and consistent cross-section results are calculated up to N2LO and they compare well with the experiments and other theoretical predictions.

The modeling of background sources in large volume detection systems requires accurate nuclear cross sections for a variety of reactions. Among the most important are $(\alpha ,n)$ on light nuclei, where $\alpha$ particles, up to $\approx 9$ MeV, are produced from the decay of actinides present in trace amounts in detection and structural material. In order to model the neutron energy spectra and production of other secondary particles, the partial cross sections are needed. Yet very little experimental data exists for these partial cross sections because past measurements, hampered by the experimental challenges of neutron detection, have focused mostly on total reaction cross section measurements. Here the partial cross section of the ${}^{13}\mathrm{C}(\alpha ,n_1){}^{16}\mathrm{O}$ reaction is reported for the first time. The measurements were made near the reaction threshold using a high energy resolution helium spectrometer. The measurements show a rapidly increasing cross section, which quickly becomes a significant fraction of the total reaction cross section. Measurements are compared with previous theory estimates and differences of more than an order of magnitude are found. A comparison is made with new total cross section measurements and the current level of consistency is demonstrated.

We introduce a new Bose-Fermi framework for studying spectral properties and quantum phase transitions (QPTs) in odd-mass nuclei, in the presence of configuration mixing. A detailed analysis of odd-mass Nb isotopes discloses the effects of an abrupt crossing of states in normal and intruder configurations (Type II QPT), accompanied by a gradual evolution from spherical- to deformed-core shapes within the intruder configuration (Type I QPT). The pronounced presence of both types of QPTs demonstrates, for the first time, the occurrence of intertwined QPTs in odd-mass nuclei.

Quark number susceptibilities as computed in lattice QCD are commonly believed to provide insights into the microscopic structure of QCD matter, in particular its degrees of freedom. We generalize a previously constructed partonic $T$-matrix approach to finite chemical potential to calculate various susceptibilities, in particular for configurations containing a heavy charm quark. At vanishing chemical potential and moderate temperatures, this approach predicts large collisional widths of partons generated by dynamically formed hadronic resonance states which lead to transport parameters characteristic for a strongly coupled system. The quark chemical potential dependence is implemented into the propagators and the in-medium color potential, where two newly introduced parameters for the thermal and screening masses are fixed through a fit to the baryon number susceptibility, ${\chi }_2^B$. With this setup, we calculate heavy-light susceptibilities without further tuning; the results qualitatively agree with the lattice-QCD (lQCD) data for both ${\chi }_{11}^{uc}$ and ${\chi }_{22}^{uc}$. This implies that the lQCD results are compatible with a significant content of broad $D$-meson and charm-light diquark bound states in a moderately hot quark-gluon plasma.

The astrophysical $S$ factor for the radiative proton capture process on the ${}^{15}\mathrm{N}$ nucleus, i.e., ${}^{15}\mathrm{N}(p,\gamma ){}^{16}\mathrm{O}$, at stellar energies are studied within the framework of the cluster effective field theory. The thermonuclear ${}^{15}\mathrm{N}(p,\gamma ){}^{16}\mathrm{O}$ reaction links the type-I to type-II cycles of the carbon-nitrogen-oxygen cycle and affects the abundances of elements in the universe. For investigating this reaction in the effective field theory formalism, we first construct an effective Lagrangian that is appropriate for this reaction at low energies. Since the intermediate excited states of the ${}^{16}\mathrm{O}$ nucleus have a crucial role in this reaction, we include these resonances in the formalism. The corresponding radiative capture amplitudes and cross section are calculated, which lead to the astrophysical $S$ factor. The low-energy constants introduced in the effective Lagrangian are determined by fitting the theoretical results to the observed $S$ factors in the range of $130\mathrm{keV}<E_p<2500\mathrm{keV}$ using three different experimental data sets. Considering the recent data sets, we obtain $S\left(0\right)=29.8–34.1\mathrm{keV}\mathrm{b}$, which is in a good agreement with the estimates from $R$-matrix approaches in the literature. The values of $S$ at the Gamow energy are found to be larger than $S\left(0\right)$ values by about 10%.

The excitation function of proton elastic scattering from ${}^{10}\mathrm{Be}$ at keV energy is calculated using the method of self-consistent Skyrme Hartree-Fock in the continuum. The calculation successfully reproduces the narrow near-threshold proton-emitting resonance ($E_x=11.4$ MeV, $\mathrm{\Gamma }=6$ keV, and quantum number $J^{\pi }=1/2^{+}$) in ${}^{11}\mathrm{B}$ relevant to the $\beta$-delayed proton emission of ${}^{11}\mathrm{Be}$. This supports the recent experimental result of Ayyad et al. at the ReA3 reaccelerator facility of the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. The resonance is interpreted as the $s_{1/2}$ single-proton resonance state in the Skyrme Hartree-Fock mean-field theory.

To solve the Dirac equation with the finite-difference method, one has to face the spurious-state problem due to the fermion doubling problem when using the conventional central difference formula to calculate the first-order derivative on equal interval lattices. This problem is resolved by replacing the central difference formula with the asymmetric difference formula, i.e., the backward or forward difference formula. To guarantee the hermiticity of the Hamiltonian matrix, the backward and forward difference formula should be used alternatively according to the parity of the wave function. This provides a simple and efficient numerical prescription to solve various relativistic problems in the microscopic world.

Chiral anomaly implies the existence of nondissipative transport phenomena, such as the chiral magnetic effect. At second order in the derivative expansion, novel quantum transport phenomena emerge. In this paper, we focus on the anomalous transport driven by a combination of shear, vorticity, and magnetic field. We find that the corresponding transport phenomena—shear-induced chiral magnetic and chiral vortical effects—induce characteristic charge correlations among the hadrons produced in heavy ion collisions. We propose the charge asymmetry of triangular flow as a signature of the anomalous transport, and estimate the strength of the signal, as well as the background, using hydrodynamical model simulations. We find that the signal-to-background ratio for the proposed observable is favorable for experimental detection.

We present the reduced basis method as a tool for developing emulators for equations with tunable parameters within the context of the nuclear many-body problem. The method uses a basis expansion informed by a set of solutions for a few values of the model parameters and then projects the equations over a well-chosen low-dimensional subspace. We connect some of the results in the eigenvector continuation literature to the formalism of reduced basis methods and show how these methods can be applied to a broad set of problems. As we illustrate, the possible success of the formalism on such problems can be diagnosed beforehand by a principal component analysis. We apply the reduced basis method to the one-dimensional Gross-Pitaevskii equation with a harmonic trapping potential and to nuclear density functional theory for ${}^{48}\mathrm{Ca}$, achieving speed-ups of more than $\times 150$ and $\times 250$, respectively, when compared to traditional solvers. The outstanding performance of the approach, together with its straightforward implementation, show promise for its application to the emulation of computationally demanding calculations, including uncertainty quantification.

The nuclear charge radii and density distributions for ${}^{46–62}\mathrm{Cr}$ have been calculated in the frameworks of both relativistic and nonrelativistic self-consistent mean-field models. The relativistic Hartree-Bogoliubov model with density-dependent meson-exchange functional DD-ME2 and the nonrelativistic Hartree-Fock-Bogoliubov model with the Gogny D1S interaction, hereafter referred to as DIRHB and HFB, respectively, are used to compute ground-state properties of even ${}^{46–62}\mathrm{Cr}$ isotopes. Both calculations for the root-mean-squared charge radii reveal the characteristic kink at the $N$ = 28 shell closure in accordance with the corresponding experimental radii. The point proton and neutron density distributions calculated from both DIRHB and HFB are used to obtain the optical potentials for $p$-Cr at an incident proton energy of 65 MeV. The elastic scattering differential and total reaction cross sections, computed from the semimicroscopic proton optical potentials, have been derived by folding each of the target matter densities with the Jeukenne-Lejeune-Mahaux-Bruyeŕes (JLMB) energy- and density-dependent internucleon interaction. The calculated elastic scattering differential cross sections for stable even isotopes, ${}^{50,52,54}\mathrm{Cr}$, using the respective DIRHB and HFB densities in the folding model reproduce the corresponding cross-section data well. The correlation between root-mean-squared charge radii and nuclear reaction observables obtained from the DIRHB and HFB calculations have been used in the folding model approach to predict the reaction cross sections for $p\text{−}{}^{46–62}\mathrm{Cr}$ at an incident proton energy of 65 MeV.

We present results of hydrodynamic modeling of Au-Au collisions from $\sqrt{s_{NN}}=7.7$ to 200 GeV. Our simulations have three novel components. First, we use a Linear EXtrapolation of Ultratrelativistic nucleon-nucleon Scattering to nucleus-nucleus collisions (LEXUS) inspired Monte Carlo initial-state model. Second, we use a crossover equation of state at finite baryon densities without a critical point. Finally, we use departure functions derived from the quasiparticle theory of transport coefficients for hadronic matter at nonzero baryon densities.