The Trojan horse nucleus invariance for the binary reaction cross section extracted from the Trojan horse reaction was tested using the quasifree ${}^3\mathrm{He}$(${}^6\mathrm{Li}$,$\alpha \alpha$)H and ${}^3\mathrm{He}$(${}^7\mathrm{Li}$,$\alpha \alpha$)${}^2\mathrm{H}$ reactions. The cross sections for the ${}^6\mathrm{Li}$($d$,$\alpha ){}^4$He and ${}^7\mathrm{Li}$($p$,$\alpha ){}^4$He binary processes were extracted in the framework of the plane wave approximation. They are compared with direct behaviors as well as with cross sections extracted from previous indirect investigations of the same binary reactions using deuteron as the Trojan horse nucleus instead of ${}^3\mathrm{He}$. The very good agreement confirms the applicability of the plane wave approximation which suggests the independence of the binary indirect cross section on the chosen Trojan horse nucleus, at least for the investigated cases.

The semi-inclusive deep-inelastic scattering of electrons off ${}^2\mathrm{H}$ and ${}^3\mathrm{He}$ with detection of slow protons and deuterons, respectively, i.e., the processes ${}^2\mathrm{H}(e,e^{\prime }p)X$ and ${}^3\mathrm{He}(e,e^{\prime }d)X$, are calculated within the spectator mechanism, taking into account the final state interaction of the nucleon debris with the detected protons and deuterons. It is shown that by a proper choice of the kinematics the origin of the EMC effect and the details of the interaction between the hadronizing quark and the nuclear medium can be investigated at a level which cannot be reached by inclusive deep-inelastic scattering. A comparison of the results of our calculations, containing no adjustable parameters, with recently available experimental data on the process ${}^2\mathrm{H}(e,e^{\prime }p)X$ shows a good agreement in the backward hemisphere of the emitted nucleons. Theoretical predictions at energies that will be available at the upgraded Thomas Jefferson National Accelerator Facility are presented, and the possibility to investigate the proposed semi-inclusive processes at electron-ion colliders is briefly discussed.

Monte Carlo simulations are used to compute the centrality dependence of the participant eccentricities (${\varepsilon }_n$) in $\mathrm{Au}+\mathrm{Au}$ collisions for the two primary models currently employed for eccentricity estimates—the Glauber and the factorized Kharzeev-Levin-Nardi (fKLN) models. They suggest specific testable predictions for the magnitude and centrality dependence of the flow coefficients $v_n$, respectively measured relative to the event planes ${\Psi }_n$. They also indicate that the ratios of several of these coefficients may provide an additional constraint for distinguishing between the models. Such a constraint could be important for a more precise determination of the specific viscosity of the matter produced in heavy ion collisions.

The constituent quark number scaling of elliptic flow is studied in a nonequilibrium hadronization and freeze-out model with rapid dynamical transition from ideal, deconfined, and chirally symmetric quark-gluon plasma, to final noninteracting hadrons. In this transition a bag model of constituent quarks is considered, where the quarks gain constituent quark mass while the background bag field breaks up and vanishes. The constituent quarks then recombine into simplified hadron states, while chemical, thermal, and flow equilibrium break down one after the other. In this scenario the resulting temperatures and flow velocities of baryons and mesons are different. Using a simplified few source model of the elliptic flow, we are able to reproduce the constituent quark number scaling, with assumptions on the details of the nonequilibrium processes.

We calculate radiative energy loss of heavy and light quarks in an anisotropic medium (static) in a first-order opacity expansion. Such an anisotropy can result from the initial rapid longitudinal expansion of the matter created in relativistic heavy-ion collisions. Significant dependency of the energy loss on the anisotropy parameter $\xi$ and the direction of propagation of the partons with respect to the anisotropy axis is found. It is shown that the introduction of early-time momentum-space anisotropy can enhance the fractional energy loss in the direction of the anisotropy, whereas it decreases when the parton propagates perpendicular to the direction of the anisotropy.

We compute the bulk viscosity of a gas of pions at temperatures below the QCD crossover temperature, for the physical value of $m_{\pi }$, to lowest order in chiral perturbation theory. Bulk viscosity is controlled by number-changing processes which become exponentially slow at low temperatures when the pions become exponentially dilute, leading to an exponentially large bulk viscosity $\zeta ~(F_0^8/m_{\pi }^5)\exp (2m_{\pi }/T)$, where $F_0\simeq 93\hspace{0.5em}$MeV is the pion decay constant.

We study the formation and stability of the fragments by extending the minimum spanning tree method (MST) for clusterization. In this extension, each fragment is subjected to a binding-energy check calculated using the modified Bethe-Weizsäcker formula. Earlier, a constant binding-energy cut of 4 MeV/nucleon was imposed. Our results for ${}^{197}\mathrm{Au}+{}^{197}\mathrm{Au}$ collisions are compared with ALADiN data and also with the calculations based on the simulated annealing technique. We shall show that the present modified version improves the agreement compared to the MST method.

Pion-induced Drell-Yan processes are proposed as a promising tool with which to measure the flavor dependence of the European Muon Collaboration (EMC) effect, that is, the flavor-dependent modification of quark distributions in the nuclear medium. Existing pionic Drell-Yan data are compared with calculations using a recent model for nuclear quark distributions that incorporates flavor-dependent nuclear effects. While no firm conclusions can yet be drawn, we find that existing Drell-Yan data likely imply a flavor dependence of the EMC effect. We demonstrate that pion-induced Drell-Yan experiments on nuclear targets can access new aspects of the EMC effect not probed in deep inelastic scattering and can therefore provide important new constrains on the nuclear quark distributions. Predictions for possible future pion-induced Drell-Yan experiments are also presented.

Excited states in the very neutron-rich nuclei ${}^{35}\mathrm{Mg}$ and ${}^{33}\mathrm{Na}$ were populated in the fragmentation of a ${}^{38}\mathrm{Si}$ projectile beam on a Be target at 83 MeV/u beam energy. We report on the first observation of $\gamma$-ray transitions in ${}^{35}\mathrm{Mg}$, the odd-$N$ neighbor of ${}^{34}\mathrm{Mg}$ and ${}^{36}\mathrm{Mg}$, which are known to be part of the ‘island of inversion” around $N=20$. The results are discussed in the framework of large-scale shell-model calculations. For the $A=3Z$ nucleus ${}^{33}\mathrm{Na}$, a new $\gamma$-ray transition was observed that is suggested to complete the $\gamma$-ray cascade $7/2^{+}\to 5/2^{+}\to 3/2_{\mathit{gs}}^{+}$ connecting three neutron two-particle–two-hole intruder states that are predicted to form a close-to-ideal $K=3/2$ rotational band in the strong-coupling limit.

We extend our formulation of relativistic three-nucleon Faddeev equations to include both pairwise interactions and a three-nucleon force. Exact Poincaré invariance is realized by adding interactions to the mass Casimir operator (rest Hamiltonian) of the noninteracting system without changing the spin Casimir operator. This is achieved by using interactions defined by rotationally invariant kernels that are functions of internal momentum variables and single-particle spins that undergo identical Wigner rotations. To solve the resulting equations one needs matrix elements of the three-nucleon force with these properties in a momentum-space partial-wave basis. We present two methods to calculate matrix elements of three-nucleon forces with these properties. For a number of examples we show that at higher energies, where effects of relativity and of three-nucleon forces are non-negligible, a consistent treatment of both is required to properly analyze the data.

We have calculated the strength distributions of the dipole response in spherical nuclei, ranging all over the periodic table. The calculations were performed within two microscopic models: the discretized quasiparticle random-phase approximation and the continuum quasiparticle random-phase approximation, which takes into account the coupling of the single-particle continuum in an exact way. Pairing correlations are treated with the BCS model. In the calculations, two density functionals were used, namely, the PC-F1 and the DD-PC1. Both are based on relativistic point-coupling Lagrangians. It is explicitly shown that this model is capable of reproducing the giant- as well as the pygmy-dipole resonance for open-shell nuclei in a high level of quantitative agreement with the available experimental observations.

The $\alpha$-cluster structure of F isotopes has been studied based on antisymmetrized molecular dynamics. By using the constraint on the principal quantum number, various neutron configurations are investigated. It is found that a proton excitation into an $\mathit{sd}$ shell does not necessarily induce $\alpha$ clustering in ${}^{21}\mathrm{F}$ and ${}^{23}\mathrm{F}$. However, once one or two neutrons are excited into the $\mathit{pf}$ shell together with a proton excitation, the core nuclei have $\alpha$ clustering. The calculation is extended toward the neutron drip line. The neutron-rich F isotopes also have $\alpha$ clustering in the excited states and their excitation energy greatly decreases toward the neutron drip line. The relation between the reduction of their excitation energies and the breaking of the neutron magic number $N=20$ is suggested.

We present a model for weak charged-current induced nuclear reactions at energies of interest for current and future neutrino oscillation experiments. This model is a natural extension of the work in Refs. [1,2], where the quasielastic contribution to the inclusive electron and neutrino scattering on nuclei was analyzed. The model is based on a systematic many-body expansion of the gauge boson absorption modes that includes one, two, and even three-body mechanisms, as well as the excitation of $\Delta$ isobars. The whole scheme has no free parameters, besides those previously adjusted to the weak pion production off the nucleon cross sections in the deuteron, since all nuclear effects were set up in previous studies of photon, electron, and pion interactions with nuclei. We have discussed at length the recent charged-current quasielastic MiniBooNE cross section data, and showed that two-nucleon knockout mechanisms are essential to describing these measurements.

In this work we study the yrast states of $\mathit{sd}$-boson systems in the presence of random interactions. It is found that the yrast states with spin-zero ground states among the random ensemble exhibit strong correlations, characterized by anharmonic vibration, $s$-boson or $d$-boson condensation, as well as vibrational and rotational motions. We study these correlations explicitly based on their wave functions and the features of two-body interactions in the random ensemble.

An isospin-self-consistent pn-continuum-QRPA approach is formulated and applied to describe the Gamow-Teller strength distributions for $\beta \beta$-decaying open-shell nuclei. Calculation results obtained for the pairs of nuclei ${}^{76}\mathrm{Ge}$-Se, ${}^{100}\mathrm{Mo}$-Ru, ${}^{116}\mathrm{Cd}$-Sn, and ${}^{130}\mathrm{Te}$-Xe are compared with available experimental data.

The transverse flow and relative midrapidity yield of isotopically identified light charged particles (LCPs) has been examined for the 35 MeV/nucleon ${}^{70}\mathrm{Zn}+{}^{70}\mathrm{Zn}$, ${}^{64}\mathrm{Zn}+{}^{64}\mathrm{Zn}$, and ${}^{64}\mathrm{Ni}+{}^{64}\mathrm{Ni}$ systems. A large enhancement of the midrapidity yield of the LCPs was observed relative to the yield near the projectile rapidity. In particular, this enhancement was increased for the more neutron-rich LCPs demonstrating a preference for the production of neutron-rich fragments in the midrapidity region. Additionally, the transverse flow of the LCPs was extracted, which provides insight into the average movement of the particles in the midrapidity region. Isotopic and isobaric effects were observed in the transverse flow of the fragments. In both cases, the transverse flow was shown to decrease with an increasing neutron content in the fragments. A clear inverse relationship between the transverse flow and the relative midrapidity yield is shown. The increased relative midrapidity emission produces a decreased transverse flow. The stochastic mean-field model was used for comparison to the experimental data. The results showed that the model was able to reproduce the general isotopic and isobaric trends for the midrapidity emission and transverse flow. The sensitivity of these observables to the density dependence of the symmetry energy was explored. The results indicate that the transverse flow and midrapidity emission of the LCPs are sensitive to the denisty dependence of the symmetry energy.

Shear $\eta$ and bulk $\zeta$ viscosities are calculated in a quasiparticle model within a relaxation-time approximation for pure gluon matter. Below $T_c$, the confined sector is described within a quasiparticle glueball model. The constructed equation of state reproduces the first-order phase transition for the glue matter. It is shown that with this equation of state, it is possible to describe the temperature dependence of the shear viscosity to entropy ratio $\eta /s$ and the bulk viscosity to entropy ratio $\zeta /s$ in reasonable agreement with available lattice data, but absolute values of the $\zeta /s$ ratio underestimate the upper limits of this ratio in the lattice measurements typically by an order of magnitude.

The cross section for radiative thermal neutron capture on ${}^3\text{He}$ (${}^3\text{He}+n\to {}^4\text{He}+\gamma$; known as the $\mathit{hen}$ reaction) is calculated based on heavy-baryon chiral perturbation theory. The relevant M1 operators are derived up to next-to-next-to-next-to-leading order (N${}^3\mathrm{L}$O). The initial and final nuclear wave functions are obtained from the rigorous Faddeev-Yakubovski equations for five sets of realistic nuclear interactions. Up to $\mathrm{N}{}^3$LO, the M1 operators contain two low-energy constants, which appear as the coefficients of nonderivative two-nucleon contact terms. After determining these two constants using the experimental values of the magnetic moments of the triton and ${}^3\text{He}$, we carry out a parameter-free calculation of the $\mathit{hen}$ cross section. The results are in good agreement with the data.

The Schrödinger equation incorporating the long-range Coulomb potential takes the form of a Fredholm equation whose kernel is singular on its diagonal when represented by a basis bearing a continuum of states, such as in a Fourier-Bessel transform. Several methods have been devised to tackle this difficulty, from simply removing the infinite range of the Coulomb potential with a screening or cut function to using discretizing schemes which take advantage of the integrable character of Coulomb kernel singularities. However, they have never been tested in the context of Berggren bases, which allow many-body nuclear wave functions to be expanded with halo or resonant properties within a shell-model framework. It is thus the object of this paper to test different discretization schemes of the Coulomb potential kernel in the framework of complex-energy nuclear physics. For that, the Berggren basis expansion of proton states pertaining to the $\mathit{sd}$ shell arising in the $A~20$ region, being typically resonant, will be effected. Apart from standard frameworks involving a cut function or analytical integration of singularities, a new method will be presented which replaces diagonal singularities by finite off-diagonal terms. It will be shown that this methodology surpasses in precision the two former techniques.

We show that the fluctuations in the wounded-nucleon model of the initial stage of relativistic heavy-ion collisions, together with the natural assumption that the forward- (backward-) moving wounded nucleons emit particles preferably in the forward (backward) direction, lead to an event-by-event torqued fireball. The principal axes associated with the transverse shape are rotated in the forward region in the opposite direction than in the backward region. On the average, the standard deviation of the relative torque angle between the forward and backward rapidity regions is $~$${20}^{°}$ for the central and ${10}^{°}$ for the midperipheral collisions. The hydrodynamic expansion of a torqued fireball leads to a torqued collective flow, yielding, in turn, torqued principal axes of the transverse-momentum distributions at different rapidities. We propose experimental measures, based on cumulants involving particles in different rapidity regions, which should allow for a quantitative determination of the effect from the data. To estimate the nonflow contributions from resonance decays we run Monte Carlo simulations with therminator, a thermal heavy-ion generator. If the event-by-event torque effect is found in the data, it will support the assumptions concerning the fluctuations in the early stage of the fireball formation, as well as the hypothesis of the asymmetric rapidity shape of the emission functions of the moving sources in the nucleus-nucleus collisions.