Three- and four-pion Bose-Einstein correlations are presented in $pp,p$-Pb, and Pb-Pb collisions at the LHC. We compare our measured four-pion correlations to the expectation derived from two- and three-pion measurements. Such a comparison provides a method to search for coherent pion emission. We also present mixed-charge correlations in order to demonstrate the effectiveness of several analysis procedures such as Coulomb corrections. Same-charge four-pion correlations in $pp$ and $p$-Pb appear consistent with the expectations from three-pion measurements. However, the presence of non-negligible background correlations in both systems prevent a conclusive statement. In Pb-Pb collisions, we observe a significant suppression of three- and four-pion Bose-Einstein correlations compared to expectations from two-pion measurements. There appears to be no centrality dependence of the suppression within the 0%–50% centrality interval. The origin of the suppression is not clear. However, by postulating either coherent pion emission or large multibody Coulomb effects, the suppression may be explained.

We show that the correlations generated in the ground state of $N=Z$ nuclei by the isovector and isoscalar pairing forces can be treated with high precision as a condensate of alpha-like quartets. To treat these correlations, the quartet condensation model (QCM) is extended to the treatment of spherically symmetric isovector $(T=1,J=0)$ and isoscalar $(T=0,J=1)$ pairing forces. Within the QCM, we discuss the competition between $T=1$ and $T=0$ pairing correlations in the case of a two-level model and for $N=Z$ nuclei with nucleons moving in the open shells above ${}^{16}\mathrm{O},{}^{40}\mathrm{Ca}$, and ${}^{100}\mathrm{Sn}$. We show that, in $N=Z$ systems, isovector and isoscalar proton-neutron pairing correlations always coexist.

Partial $\gamma$-ray production cross sections and the total radiative thermal-neutron capture cross section for the ${}^{185}\mathrm{Re}(n,\gamma ){}^{186}\mathrm{Re}$ reaction were measured using the Prompt Gamma Activation Analysis facility at the Budapest Research Reactor with an enriched ${}^{185}\mathrm{Re}$ target. The ${}^{186}\mathrm{Re}$ cross sections were standardized using well-known ${}^{35}\mathrm{Cl}(n,\gamma ){}^{36}\mathrm{Cl}$ cross sections from irradiation of a stoichiometric ${}^{\text{nat}}{\text{ReCl}}_3$ target. The resulting cross sections for transitions feeding the ${}^{186}\mathrm{Re}$ ground state from low-lying levels below a cutoff energy of $E_c=746\text{keV}$ were combined with a modeled probability of ground-state feeding from levels above $E_c$ to arrive at a total cross section of ${\sigma }_0=111\left(6\right)\text{b}$ for radiative thermal-neutron capture on ${}^{185}\mathrm{Re}$. A comparison of modeled discrete-level populations with measured transition intensities led to proposed revisions for seven tentative spin-parity assignments in the adopted level scheme for ${}^{186}\mathrm{Re}$. Additionally, 102 primary $\gamma$ rays were measured, including 50 previously unknown. A neutron-separation energy of $S_n=6179.59\left(5\right)\text{keV}$ was determined from a global least-squares fit of the measured $\gamma$-ray energies to the known ${}^{186}\mathrm{Re}$ decay scheme. The total capture cross section and separation energy results are comparable to earlier measurements of these values.

Background: Reaction theory plays a major role in the interpretation of experimental data and one needs to identify and include accurately all the relevant dynamical effects in order to extract reliable structure information. The knockout of a nucleon (neutron/proton) from a high energy exotic nucleus projectile colliding with a proton target allows to get insight on the structure of its valence and inner shells.

Purpose: We aim to clarify the role of the distortion on the calculated observables for nucleon knockout, in particular, the dependence of the calculated observables on the binding energy ${\epsilon }_b$ and angular momentum $L$ of the knockout particle, and on the mass of the projectile core, $A_c$. We consider mainly the knockout of a neutron that may be either in the valence or in the inner shell of the projectile nucleus.

Method: Exact three-body Faddeev/Alt-Grassberger-Sandhas (Faddeev/AGS) calculations are performed for the nucleon knockout from stable and exotic nuclei in the collision of 420 MeV/u projectile beams with a proton target. Results are compared with plane-wave impulse approximation (PWIA) calculations.

Results: The Faddeev/AGS formalism accurately predicts: (i) a systematic nearly logarithmic dependence of the distortion parameter on the separation energy; (ii) roughly linear dependence of the ratio of the full to the PWIA cross section on the asymmetry parameter; (iii) a distinct behavior between the calculated transverse core momentum distribution from the PWIA and full Faddeev/AGS exact approach which indicates that distortion effects do not modify fully exclusive observables through a common renormalization factor.

Conclusions: To extract structure information on deeper shells one needs to include distortion effects accurately. A systematic analysis enables to estimate the total cross section for knockout of a nucleon from a given shell of nuclei at/away the stability line of the nuclear landscape. The comparison with experimental results may provide understanding on the used interaction and structure model.

Following a similar approach suggested recently to derive breakup probabilities [Phys. Rev. C 92, 054620 (2015)], we present a simple method to derive transfer probabilities by measuring only elastic or quasi-elastic scattering for the system under investigation with the positive transfer $Q$ values and a similar system with closed transfer channels. Our estimations and transfer data for the two-neutron stripping in the ${}^{18}\mathrm{O}+{}^{206}\mathrm{Pb}$ reaction are in a reasonable agreement.

We study the hydrodynamic response to jet quenching in expanding quark-gluon plasma (QGP) and its signal in the resulting particle distribution. The ideal hydrodynamic simulations of the $\gamma$-jet events in heavy-ion collisions are performed in a full (3 + 1)-dimensional setup. The jet-induced Mach cone and the radial expansion of the background mutually push and distort each other. As a result, the particle emission is suppressed in the direction in which the radial flow is pushed back by the Mach cone when the jet path is an off-central one. This is the direct signal of hydrodynamic response to the jet and, moreover, includes information about the jet path in the expanding QGP fluid.

Effects of differences between neutron and proton distributions on $\alpha$ decay are investigated for odd-mass nuclei within the generalized density-dependent cluster model. The neutron skin thickness is employed to gauge the differences and it is considered in numerically computing the double-folding $\alpha$-nucleus potentials. In terms of the characteristic of odd-mass $\alpha$ emitters, special attention is paid to the $\alpha$ decays from ground or isomeric states which end in the ground states of daughter nuclei and furthermore belong to favored $\alpha$ decays. The calculations with the neutron skin thickness yield shorter half-lives, suggesting a smaller preformation factor. This is quite consistent with the conclusions for even-even $\alpha$ emitters. Moreover, $\alpha$-decay calculations are extended for odd-mass isomers and superheavy nuclei. The calculated $\alpha$-decay half-lives are found to be in good agreement with the experimental data.

Background: Accurate knowledge of fission fragment yields is an essential ingredient of numerous applications ranging from the formation of elements in the $r$ process to fuel cycle optimization for nuclear energy. The need for a predictive theory applicable where no data are available, together with the variety of potential applications, is an incentive to develop a fully microscopic approach to fission dynamics.

Purpose: In this work, we calculate the pre-neutron emission charge and mass distributions of the fission fragments formed in the neutron-induced fission of ${}^{239}\mathrm{Pu}$ using a microscopic method based on nuclear density functional theory (DFT).

Methods: Our theoretical framework is the nuclear energy density functional (EDF) method, where large-amplitude collective motion is treated adiabatically by using the time-dependent generator coordinate method (TDGCM) under the Gaussian overlap approximation (GOA). In practice, the TDGCM is implemented in two steps. First, a series of constrained EDF calculations map the configuration and potential-energy landscape of the fissioning system for a small set of collective variables (in this work, the axial quadrupole and octupole moments of the nucleus). Then, nuclear dynamics is modeled by propagating a collective wave packet on the potential-energy surface. Fission fragment distributions are extracted from the flux of the collective wave packet through the scission line.

Results: We find that the main characteristics of the fission charge and mass distributions can be well reproduced by existing energy functionals even in two-dimensional collective spaces. Theory and experiment agree typically within two mass units for the position of the asymmetric peak. As expected, calculations are sensitive to the structure of the initial state and the prescription for the collective inertia. We emphasize that results are also sensitive to the continuity of the collective landscape near scission.

Conclusions: Our analysis confirms that the adiabatic approximation provides an effective scheme to compute fission fragment yields. It also suggests that, at least in the framework of nuclear DFT, three-dimensional collective spaces may be a prerequisite to reach 10% accuracy in predicting pre-neutron emission fission fragment yields.

Two scenarios for cluster production have long been discussed in the literature: (i) direct emission of the clusters from a (grand-canonical) thermal source or (ii) subsequent formation of the clusters by coalescence of single nucleons. While both approaches have been successfully applied in the past it has not yet been clarified which of the two mechanisms dominates the cluster production. We propose to use recently developed event-by-event techniques to study particle multiplicity fluctuations on nuclear clusters and employ this analysis to the deuteron number fluctuations to disentangle the two production mechanisms. We argue that for a grand-canonical cluster formation, the cluster fluctuations will follow Poisson distribution, while for the coalescence scenario, the fluctuations will strongly deviate from the Poisson expectation. We estimate the effect to be 10% for the variance and up to a factor of 5 for the kurtosis of the deuteron number multiplicity distribution. Our prediction can be tested in the beam energy scan program at the BNL Relativistic Heavy Ion Collider as well as experiments at the GSI Facility for Antiproton and Ion Research and the Nuclotron-based Ion Collider Facility.

We present a method to compute the number of particles occupying spherical single-particle (SSP) levels within the energy density functional (EDF) framework. These SSP levels are defined for each nucleus by performing self-consistent mean-field calculations. The nuclear many-body states, in which the occupation numbers are evaluated, are obtained with a symmetry conserving configuration mixing (SCCM) method based on the Gogny EDF. The method allows a closer comparison between EDF and shell model with configuration mixing in large valence spaces (SM-CI) results, and can serve as a guidance to define physically sound valence spaces for SM-CI calculations. As a first application of the method, we analyze the onset of deformation in neutron-rich $N=40$ isotones and the role of the SSP levels around this harmonic oscillator magic number, with particular emphasis in the structure of ${}^{64}\mathrm{Cr}$.

Medium and high-spin states in ${}^{133}\mathrm{Ce}$ were investigated using the ${}^{116}\mathrm{Cd}$(${}^{22}\mathrm{Ne}, 5n$) reaction and the Gammasphere array. The level scheme was extended up to an excitation energy of $\sim 22.8$ MeV and spin 93/2 $\hslash$. Eleven bands of quadrupole transitions and two new dipole bands are identified. The connections to low-lying states of the previously known, high-spin triaxial bands were firmly established, thus fixing the excitation energy and, in many cases, the spin parity of the levels. Based on comparisons with cranked Nilsson-Strutinsky calculations and tilted axis cranking covariant density functional theory, it is shown that all observed bands are characterized by pronounced triaxiality. Competing multiquasiparticle configurations are found to contribute to a rich variety of collective phenomena in this nucleus.

Using the Double Chooz detector, designed to measure the neutrino mixing angle ${\theta }_{13}$, the products of ${\mu }^{-}$ capture on ${}^{12}\mathrm{C},{}^{13}\mathrm{C},{}^{14}\mathrm{N}$, and ${}^{16}\mathrm{O}$ have been measured. Over a period of 489.5 days, $2.3\times {10}^6$ stopping cosmic ${\mu }^{-}$ have been collected, of which $1.8\times {10}^5$ captured on carbon, nitrogen, or oxygen nuclei in the inner detector scintillator or acrylic vessels. The resulting isotopes were tagged using prompt neutron emission (when applicable), the subsequent $\beta$ decays, and, in some cases, $\beta$-delayed neutrons. The most precise measurement of the rate of ${}^{12}\mathrm{C}({\mu }^{-},\nu ){}^{12}\mathrm{B}$ to date is reported: $6.{57}_{-0.21}^{+0.11}\times {10}^3{\mathrm{s}}^{-1}$, or $(17.{35}_{-0.59}^{+0.35})\%$ of nuclear captures. By tagging excited states emitting $\gamma \mathrm{s}$, the ground state transition rate to ${}^{12}\mathrm{B}$ has been determined to be $5.{68}_{-0.23}^{+0.14}\times {10}^3{\mathrm{s}}^{-1}$. The heretofore unobserved reactions ${}^{12}\mathrm{C}({\mu }^{-},\nu \alpha ){}^8\mathrm{Li},{}^{13}\mathrm{C}({\mu }^{-},\nu n\alpha ){}^8\mathrm{Li}$, and ${}^{13}\mathrm{C}({\mu }^{-},\nu n){}^{12}\mathrm{B}$ are measured. Further, a population of $\beta n$ decays following stopping muons is identified with $5.5\sigma$ significance. Statistics limit our ability to identify these decays definitively. Assuming negligible production of ${}^8\mathrm{He}$, the reaction ${}^{13}\mathrm{C}({\mu }^{-},\nu \alpha ){}^9\mathrm{Li}$ is found to be present at the $2.7\sigma$ level. Limits are set on a variety of other processes.

With the semiclassical Landau-Vlasov transport model we studied the stopping observable $R_E$, the energy-based isotropy ratio, for the ${}^{129}\mathrm{Xe}+{}^{120}\mathrm{Sn}$ reaction at beam energies spanning $12A$ to $100A$ MeV. We investigated the impacts of the nonlocality of the nuclear mean field, of the in-medium modified nucleon-nucleon ($NN$) cross section, and of the reaction centrality. A fixed set of model parameters yields $R_E$ values that favorably compare with the experimental ones, but only for energies below the Fermi energy $E_F$. Above $E_F$ agreement is readily possible, but by a smooth evolution with energy of the parameter that controls the in-medium modification of $NN$ cross section. By comparing the simulation correction factor $\mathcal{F}$ applied to the free $NN$ cross section with the one deduced from experimental data [Phys. Rev. C 90, 064602 (2014)], we infer that the zero-range mean field almost entirely reproduces it. Also, in accordance with what has been deduced from experimental data, around $E_F$ a strong reduction of the free $NN$ cross section is found. In order to test the impact of sampling central collisions by multiplicity, an event generator (hipse) was used. We obtain that high multiplicity events are spread over a broad impact parameter range, but it turns out that this has a small effect on the observable $R_E$ and, thus, on $\mathcal{F}$ as well.

We investigate the role of the breakup channel in the elastic and breakup cross sections, in collisions of proton-halo nuclei. For this purpose, we perform continuum discretized couple channel (CDCC) calculations for the ${}^8\mathrm{B}+{}^{208}\mathrm{Pb}$ system and evaluate polarization potentials. One-channel calculations including the polarization potential are shown to reproduce very well the elastic cross sections obtained by CDCC calculations. We also study the individual contributions of the Coulomb and the nuclear couplings to the cross sections. To complement our study, we compare the effects of the breakup channel in proton-halo and neutron-halo nuclei, performing calculations treating ${}^8\mathrm{B}$ as a ${}^7\mathrm{B}+n$ core-nucleon system, with an artificially low breakup threshold. When only the nuclear breakup is considered, this approach can reasonably describe the elastic scattering.

Comprehensive spectroscopy of the $N=29$ nucleus ${}^{47}\mathrm{Ar}$ is presented, based on two complementary direct reaction mechanisms: one-neutron pickup onto ${}^{46}\mathrm{Ar}$ projectiles and one-proton removal from the $1^{-}$ ground state of ${}^{48}\mathrm{K}$. The results are compared with shell-model calculations that use the state-of-the-art SDPF-U and SDPF-MU effective interactions. Also, from the ${}^9\mathrm{Be}({}^{46}\mathrm{Cl},{}^{45}\mathrm{S}+\gamma )X$ one-proton-removal reaction, we report the first $\gamma$-ray transitions observed from ${}^{45}\mathrm{S}$. By using comparisons with shell-model calculations, and from the observed intensities and energy sums, we propose a first tentative level scheme for ${}^{45}\mathrm{S}$.

The production cross sections of neutron-deficient isotopes ${}^{108–110}\mathrm{Xe}$ and ${}^{112–114}\mathrm{Ba}$ in the complete fusion reactions ${}^{58,56}\mathrm{Ni}+{}^{54}\mathrm{Fe}$ and ${}^{58,56}\mathrm{Ni}+{}^{58}\mathrm{Ni}$ with stable and radioactive beams are studied with the dinuclear system model. The calculated results are compared with the available experimental data. The optimal beam energies and corresponding maximum production cross sections of new isotopes ${}^{108}\mathrm{Xe}$ and ${}^{112}\mathrm{Ba}$ are predicted.

We calculate the elastic form factors and the generalized parton distributions (GPDs) for four low-lying bound states of a demonstration fermion-antifermion system, strong-coupling positronium ($e\overline{e}$), using basis light-front quantization (BLFQ). By using this approach, we also calculate the impact-parameter-dependent GPDs $q(x,{\vec{b}}_{\perp })$ to visualize the fermion density in the transverse plane (${\vec{b}}_{\perp }$). We compare selected results with corresponding quantities in the nonrelativistic limit to reveal relativistic effects. Our results establish the foundation within BLFQ for investigating the form factors and the GPDs for hadronic systems.

When scale symmetry is implemented into hidden local symmetry in low-energy strong interactions to arrive at a scale-invariant hidden local symmetric (HLS) theory, the scalar $f_0\left(500\right)$ may be interpreted as pseudo-Nambu-Goldstone (pNG) boson, i.e., dilaton, of spontaneously broken scale invariance, joining the pseudoscalar pNG bosons $\pi$ and the matter fields $V=(\rho ,\omega )$ as relevant degrees of freedom. Implementing the skyrmion–half-skyrmion transition predicted at large $N_c$ in QCD at a density roughly twice the nuclear matter density found in the crystal simulation of dense skyrmion matter, we determine the intrinsically density-dependent “bare parameters” of the scale-invariant HLS Lagrangian matched to QCD at a matching scale ${\mathrm{\Lambda }}_M$. The resulting effective Lagrangian, with the parameters scaling with the density of the system, is applied to nuclear matter and dense baryonic matter relevant to massive compact stars by means of the double-decimation renormalization-group $V_{\mathrm{low}k}$ formalism. We satisfactorily postdict the properties of normal nuclear matter and more significantly predict the equation of state of dense compact-star matter that quantitatively accounts for the presently available data coming from both the terrestrial and space laboratories. We interpret the resulting structure of compact-star matter as revealing how the combination of hidden-scale symmetry and hidden local symmetry manifests itself in compressed baryonic matter.

We study the nucleation of a quark-gluon plasma (QGP) phase in a hadron gas at low temperatures and high baryon densities. This kind of process will presumably happen very often in nuclear collisions at the GSI Facility for Antiproton and Ion Research (FAIR) and the Nuclotron-based Ion Collider Facility (NICA). When the appropriate energy densities (or baryon densities) and temperatures are reached the conversion of one phase into another is not instantaneous. It is a complex process, which involves the nucleation of bubbles of the new phase. One important element of this transition process is the rate of growth of a QGP bubble. In order to estimate it we solve the Relativistic Rayleigh–Plesset equation which governs the dynamics of a relativistic spherical bubble in a strongly interacting medium. The baryon rich hadron gas is represented by the nonlinear Walecka model and the QGP is described by the MIT bag model and also by a mean field model of QCD.

A partial screening of nucleon electric dipole moments (EDMs) in nuclear systems, which is related to the Schiff mechanism known for neutral atomic systems, is discussed. It is shown that the direct contribution from the neutron EDM to the deuteron EDM is partially screened by about 1% in a zero-range approximation calculation.