An interpretation of the charge-dependent correlations sensitive to the chiral magnetic effect (CME)—–the separation of the electric charges along the system magnetic field (across the reaction plane)—–is ambiguous due to possible large background (non-CME) effects. The background contribution is proportional to the elliptic flow $v_2$; it is the largest in measurements relative to the participant plane and is smaller in measurements relative to the flow plane determined by spectators, where the CME signal, in contrast, is likely larger. In this paper, I discuss a possible strategy for corresponding experimental measurements and list and evaluate different assumptions related to this approach.

The annihilation of a lepton pair into a proton-antiproton pair, and the time-reverse process allow for a measurement of the timelike proton form factors (FFs). This work aims at studying the corrections due to direct soft interactions between the proton and the antiproton before their annihilation or after their creation. The analysis is carried out in the spacetime formalism used by us in a series of recent works on timelike FFs. In particular the effect of $\overline{p}p$ annihilation into many-meson states is considered. We expect it to determine similar real and imaginary parts for the form factor near the $\overline{p}p$ channel threshold. We also discuss the possibility that the timelike FFs differ by a phase in the hadron pair production and annihilation.

We treat ${}^6\mathrm{Li}$ as an effective three-body $\left(n\text{−}p\text{−}\alpha \right)$ system and compute the $d\text{−}\alpha S$-wave scattering length and three-body separation energy of ${}^6\mathrm{Li}$ for a wide variety of nucleon-nucleon and $\alpha$-nucleon potentials which have the same (or nearly the same) phase shifts. The Coulomb interaction in the $p\text{−}\alpha$ subsystem is omitted. The results of all calculations lie on a one-parameter curve in the plane defined by the $d\text{−}\alpha S$-wave scattering length and the amount by which ${}^6\mathrm{Li}$ is bound with respect to the $n\text{−}p\text{−}\alpha$ threshold. We argue that these aspects of the $n\text{−}p\text{−}\alpha$ system can be understood using few-body universality and that ${}^6\mathrm{Li}$ can thus usefully be thought of as a two-nucleon halo nucleus.

Axial breathing modes are studied within the nuclear energy-density-functional theory to discuss the modification of the nucleon effective mass produced beyond the mean-field approximation. This analysis is performed with the subtracted second random-phase approximation (SSRPA) model applied to two nuclei, ${}^{48}\mathrm{Ca}$ and ${}^{90}\mathrm{Zr}$. Analyzing the centroid energies of axial breathing modes obtained with the mean-field-based random-phase approximation and with the beyond-mean-field SSRPA model, we estimate the modification (enhancement) of the effective mass which is induced beyond the mean field. This is done by employing a relation, obtained with the Landau's Fermi liquid theory, between the excitation frequency of axial modes and $\sqrt{m/m^{*}}$, where $m$ ($m^{*}$) is the bare (effective) mass. Such an enhancement of the effective mass is discussed in connection with the renormalization of single-particle excitation energies generated by the energy-dependent SSRPA self-energy correction. We find that the effective beyond-mean-field compression of the single-particle spectrum produced by the self-energy correction is coherent with the increase of the effective mass estimated from the analysis of axial breathing modes.

Recent high-precision mass measurements and shell-model calculations [M. Brodeur et al., Phys. Rev. Lett. 108, 212501 (2012)] have challenged a longstanding explanation for the requirement of a cubic isobaric multiplet mass equation for the lowest $A=9$ isospin quartet. The conclusions relied upon the choice of the excitation energy for the second $T=3/2$ state in ${}^9\mathrm{B}$, which had two conflicting measurements prior to this work. We remeasured the energy of the state using the ${}^9\mathrm{Be}({}^3\mathrm{He},t)$ reaction and significantly disagree with the most recent measurement. Our result supports the contention that continuum coupling in the most proton-rich member of the quartet is not the predominant reason for the large cubic term required for $A=9$ nuclei.

We derive from the subleading contributions to the chiral three-nucleon force [short-range terms and relativistic corrections, published in Phys. Rev. C 84, 054001 (2011)] a density-dependent two-nucleon interaction $V_{\text{med}}$ in isospin-symmetric nuclear matter. The momentum and $k_f$-dependent potentials associated with the isospin operators (1 and ${\vec{\tau }}_1·{\vec{\tau }}_2$) and five independent spin structures are expressed in terms of loop functions, which are either given in closed analytical form or require at most one numerical integration. Our results for $V_{\text{med}}$ are most helpful to implement subleading chiral $3N$ forces into nuclear many-body calculations.

The temperature dependence of the volume and surface components of the nuclear symmetry energy (NSE) and their ratio is investigated in the framework of the local density approximation. The results of these quantities for finite nuclei are obtained within the coherent density fluctuation model (CDFM). The CDFM weight function is obtained using the temperature-dependent proton and neutron densities calculated through the HFBTHO code, which solves the nuclear Skyrme-Hartree-Fock-Bogoliubov problem by using the cylindrical transformed deformed harmonic-oscillator basis. We present and discuss the values of the volume and surface contributions to the NSE and their ratio obtained for the Ni, Sn, and Pb isotopic chains around double-magic ${}^{78}\mathrm{Ni}, {}^{132}\mathrm{Sn}$, and ${}^{208}\mathrm{Pb}$ nuclei. The results for the $T$ dependence of the considered quantities are compared with estimations made previously for zero temperature showing the behavior of the NSE components and their ratio, as well as with the available experimental data. The sensitivity of the results on various forms of the density dependence of the symmetry energy is studied. We confirm the existence of “kinks” in these quantities as functions of the mass number at $T=0$ MeV for the double closed-shell nuclei ${}^{78}\mathrm{Ni}$ and ${}^{132}\mathrm{Sn}$ and the lack of kinks for the Pb isotopes, as well as the disappearance of these kinks as the temperature increases.

We present results of centroid energies $E_{\mathrm{CEN}}$, of the isoscalar ($T=0$) and isovector ($T=1$) giant resonances of multipolarities $L=0–3$ in ${}^{40,48}\mathrm{Ca}, {}^{68}\mathrm{Ni}, {}^{90}\mathrm{Zr}, {}^{116}\mathrm{Sn}, {}^{144}\mathrm{Sm}$, and ${}^{208}\mathrm{Pb}$, calculated within the fully self-consistent Hartree-Fock-based random phase approximation theory, using 33 different Skyrme-type effective nucleon-nucleon interactions of the standard form commonly adopted in the literature. We compare the results of our theoretical calculations with the available experimental data. We also study the sensitivity of the calculated $E_{\mathrm{CEN}}$ to physical properties of nuclear matter (NM), such as effective mass m*/m, nuclear matter incompressibility coefficient $K_{\mathrm{NM}}$, enhancement coefficient κ of the energy weighted sum rule for the isovector giant dipole resonance and symmetry energy at saturation density, associated with the Skyrme interactions used in the calculations. This is done by determining the Pearson linear correlation coefficient between the calculated $E_{\mathrm{CEN}}$ and a certain NM property. Constraining the values of the NM properties, by comparing the calculated values of $E_{\mathrm{CEN}}$ to the experimental data, we find that interactions associated with the values of $K_{\mathrm{NM}}=210–240\mathrm{MeV}$ and $\kappa =0.25–0.70$ best reproduce the experimental data.

I have computed spectroscopic factors $S$ and single-particle widths ${\mathrm{\Gamma }}_{\mathrm{sp}}$, and hence expected decay widths ${\mathrm{\Gamma }}_{\mathrm{calc}}=S{\mathrm{\Gamma }}_{\mathrm{sp}}$ for decay of the lowest $5/2^{+}$ state of ${}^{15}\mathrm{Be}$ to the ground state and first $2^{+}$ state of ${}^{14}\mathrm{Be}$. Results indicate that decay to the $2^{+}$ state should be appreciable.

The Coulomb shift is analyzed for the mirror cluster systems of ${}^{18}\mathrm{O}=\alpha +{}^{14}\mathrm{C}$ and ${}^{18}\mathrm{Ne}=\alpha +{}^{14}\mathrm{O}$ by applying the orthogonality condition model (OCM). The OCM calculation clearly predicts the suppressed excitation energy of the higher $0^{+}$ states in the proton-rich system of ${}^{18}\mathrm{Ne}$. This results can be interpreted in terms of the extension of the Thomas-Ehrman shift (TES), which is discussed in ${}^{17}\mathrm{O}={}^{16}\mathrm{O}+N$ and ${}^{17}\mathrm{F}={}^{16}\mathrm{O}+P$, to the cluster degrees of freedom. A combination of the cluster TES and the monopole transition is proposed as an experimental probe to identify the cluster structure in mirror systems.

The decreasing proton and charge densities from around 5.0 fm towards the center of ${}^{204,206}\mathrm{Hg}$ are investigated by a covariant density functional theory at the beyond mean-field level. The charge-density difference between ${}^{208}\mathrm{Pb}$ and ${}^{204}\mathrm{Hg}$ is improved significantly and a central depression is still visible in the ground-state density of ${}^{204,206}\mathrm{Hg}$ when the dynamic correlations associated with symmetry restoration and shape mixing are taken into account. For the $0_2^{+}$ and $2_1^{+}$ excited states of ${}^{204,206}\mathrm{Hg}$, their densities remain decreasing from 5.0 fm to around 2.0 fm, but become flat in the interior region. The results show that the bubble structure in ${}^{204,206}\mathrm{Hg}$ within 2.0 fm is mainly attributed to the quantum effect, while that beyond 2.0 fm is formed by the Coulomb repulsion.

The bremsstrahlung of photons emitted during the scattering of ${\pi }^{+}$ mesons off nuclei is studied for the first time. The role of interactions between ${\pi }^{+}$ mesons and nuclei in the formation of the bremsstrahlung emission is analyzed in detail. We discover an essential contribution of photons emitted from nuclear part of the Johnson–Satchler potential to the full spectrum, in contrast with the optical Woods–Saxon potential. We observe an unusual essential influence of the nuclear part of both potentials on the spectrum at high photon energies. This phenomenon opens a new experimental way to study and check non-Coulomb and nuclear interactions between pions and nuclei via measurements of the emitted photons. We provide predictions of the bremsstrahlung spectra for pion scattering off ${}^{44}\mathrm{Ca}$.

We develop a Boltzmann-Uehling-Uhlenbeck (BUU) transport model based on the $\mathrm{Sk}\chi {\mathrm{m}}^{*}$ energy density functional, which is constructed from fitting the nuclear equation of state and nucleon effective masses in asymmetric nuclear matter predicted by the two- and three-body chiral interactions as well as the binding energies of finite nuclei. This new $\chi \mathrm{BUU}$ transport model is then used to study how baryon mean-field potentials affect the kinematics of a scattering or decay process and the equilibrium properties of a hot $N\text{−}\mathrm{\Delta }\text{−}\pi$ system in a box with periodic boundary conditions. We find that the inclusion of mean-field potentials in the energy conservation condition for scattering and decay processes is necessary to maintain the equilibrium numbers of $N,\mathrm{\Delta }$, and $\pi$. Although the baryon mean-field potentials have significant effects on the total $\mathrm{\Delta }$ and $\pi$ numbers, they only slightly affect the ratio of effective negatively to positively charged pions. We also study pion production in central ${}^{197}\mathrm{Au}+{}^{197}\mathrm{Au}$ collisions at the incident energy of $E/A=400$ MeV and compare the results with the experimental data from the Four Pi (FOPI) Collaboration at the Gesellschaft für Schwerionenforschung mbH (GSI) in Germany. We find that our model can well describe the experimental results and the threshold effect due to baryon mean-field potentials does not affect much the charged pion ratio in this model. We further make predictions on pion production for the ongoing experiments of ${}^{132}\mathrm{Sn}+{}^{124}\mathrm{Sn}$ and ${}^{108}\mathrm{Sn}+{}^{112}\mathrm{Sn}$ at the incident energy of $E/A=270$ MeV by the SAMURAI Pion-Reconstruction and Ion-Tracker ($\mathrm{S}\pi \mathrm{RIT}$) Collaboration at the Institute of Physical and Chemical Research (RIKEN) in Japan.

Background: Recently, a systematic exploration of two-neutron transfer induced by the $\left({}^{18}\mathrm{O},{}^{16}\mathrm{O}\right)$ reaction on different targets has been performed. The high-resolution data have been collected at the MAGNEX magnetic spectrometer of the INFN-LNS Laboratory in Catania and analyzed with the coupled reaction channel (CRC) approach. The simultaneous and sequential transfers of the two neutrons have been considered under the same theoretical framework without the need for adjustable factors in the calculations.

Purpose: A detailed analysis of the one-neutron transfer cross sections is important to study the sequential two-neutron transfer. Here, we examine the $\left({}^{18}\mathrm{O},{}^{17}\mathrm{O}\right)$ reaction on ${}^{16}\mathrm{O},{}^{28}\mathrm{Si}$, and ${}^{64}\mathrm{Ni}$ targets. These even-even nuclei allow for investigation of one-neutron transfer in distinct nuclear shell spaces.

Method: The MAGNEX spectrometer was used to measure mass spectra of ejectiles and extract differential cross sections of one-neutron transfer to low-lying states. We adopted the same CRC formalism used in the sequential two-neutron transfer, including relevant channels and using spectroscopic amplitudes obtained from shell-model calculations. We also compare with the one-step distorted-wave Born approximation (DWBA).

Results: For the ${}^{18}\mathrm{O}+{}^{16}\mathrm{O}$ and the ${}^{18}\mathrm{O}+{}^{28}\mathrm{O}$ systems, we used two interactions in the shell model. The experimental angular distributions are reasonably well reproduced by the CRC calculations. In the ${}^{18}\mathrm{O}+{}^{64}\mathrm{Ni}$ system, we considered only one interaction, and the theoretical curve describes the shape and order of magnitude observed in the experimental data.

Conclusions: Comparisons between experimental DWBA and CRC angle-integrated cross sections suggest that excitations before or after the transfer of a neutron are relevant in the ${}^{18}\mathrm{O}+{}^{16}\mathrm{O}$ and ${}^{18}\mathrm{O}+{}^{64}\mathrm{Ni}$ systems.

Using our developed new relativistic viscous hydrodynamics code, we investigate the temperature dependence of shear and bulk viscosities from comparison with the ALICE data: single-particle spectra and collective flows of Pb+Pb $\sqrt{s_{NN}}=2.76$ TeV collisions at the Large Hadron Collider. We find that from the comprehensive analyses of centrality dependence of single-particle spectra and collective flows we can extract detailed information on the quark-gluon plasma bulk property, without the information being smeared by the final state interactions.

Isobaric ${}_{44}{}^{96}\mathrm{Ru}+{}_{44}{}^{96}\mathrm{Ru}$ and ${}_{40}{}^{96}\mathrm{Zr}+{}_{40}{}^{96}\mathrm{Zr}$ collisions were performed at the Relativistic Heavy Ion Collider in 2018. Using the “a multiphase transport” model with nuclear structures calculated by the density functional theory (DFT), we make predictions for the charged hadron multiplicity distributions and elliptic azimuthal anisotropies in these collisions. Emphases are put on the relative differences between the two collision systems that can decisively discriminate DFT nuclear distributions from the commonly used Woods-Saxon densities.

The dilepton emission in heavy-ion reactions at low beam energies is examined within a hadronic transport approach. In this article, the production of electron-positron pairs from a new approach named SMASH (Simulating Many Accelerated Strongly-interacting Hadrons) is introduced. The dilepton emission below the hadronic invariant mass threshold is taken into account for all direct vector meson decays. The calculations are systematically confronted with HADES data in the kinetic-energy range of $1\text{–}3.5A\mathrm{GeV}$ for elementary, proton-nucleus and nucleus-nucleus reactions. The present approach employing a resonance treatment based on vacuum properties is validated by an excellent agreement with experimental data up to system sizes of carbon-carbon collisions. After establishing this well-understood baseline in elementary and small systems, medium effects are investigated with a coarse-graining approach based on the same hadronic evolution. The effect of in-medium modifications to the vector meson spectral functions is important for dilepton invariant mass spectra in ArKCl and larger systems, even though the transport approach with vacuum properties reveals similar features due to the coupling to baryonic resonances and the intrinsically included collisional broadening. This article provides a comprehensive comparison of our calculations with published dielectron results from the HADES collaboration. In addition, the emission of dileptons in gold-gold and pion-beam experiments, for which results are expected, is predicted.

We analyze the newest data from the NA61/SHINE Collaboration which, in addition to previous results on pions and kaons, include mean multiplicities of $p$, $\mathrm{\Lambda }$, and $\varphi$ mesons produced in inelastic proton-proton ($p+p$) interactions at $\sqrt{s_{NN}}=6.3\text{–}17.3\mathrm{GeV}$. The canonical ensemble formulation of the ideal hadron resonance gas (HRG) model is used with exact conservation of net baryon number $B=2$, electric charge $Q=2$, and strangeness $S=0$. The chemical freeze-out parameters in $p+p$ interactions are obtained and compared to those in central nucleus-nucleus collisions. Several features of $p+p$ interactions at the CERN Super Proton Synchrotron within a statistical model are studied: (1) the inclusion of the $\varphi$-meson yields in thermal fits worsens significantly the fit quality; (2) the data show large event-by-event multiplicity fluctuations in inelastic $p+p$ interactions which cannot be explained by a single fireball described by a statistical model; and (3) the fits within the canonical ensemble formulation of HRG do not give any improvement over the fits within the grand canonical ensemble formulation, i.e., there are no indications of the existence of a single statistical system in $p+p$ inelastic interactions in the considered energy range.

In the quantum statistical parton distribution approach proposed more than one decade ago to describe the parton structure, new properties are now understood; in particular the relation between quarks and antiquarks leads to very specific properties. The simultaneous treatment of unpolarized and polarized parton distribution functions (PDFs) allows a determination of thermodynamical potentials (the master parameters of the model) which drive their behavior and consequently the behavior of the structure functions. The existence of a possible relation between the gluon and a $q\overline{q}$ pair leads to define a toy model for the unpolarized and polarized gluons. In view of forthcoming experimental results in the large-$x$ region, specific predictions made by the model are presented.