The evolution of the giant dipole resonance (GDR) properties in nuclei of mass $A=120$ to 132 has been investigated in an excitation energy range between 150 and 270 MeV through the study of complete and nearly complete fusion reactions using ${}^{116}\mathrm{Sn}$ beams at $17A$ and $23A$ MeV from the cyclotron of the Laboratorio Nazionale del Sud impinging on ${}^{12}\mathrm{C}$ and ${}^{24}\mathrm{Mg}$ targets. $\gamma$ rays and light charged particles were detected using the multi-element detector array MEDEA in coincidence with evaporation residues detected by using mass and charge identification spectrometry with telescope (MACISTE). Light-charged-particle energy spectra were analyzed within the framework of a multiple-source-emission scenario by using a fitting procedure to determine the amount of pre-equilibrium emission and deduce the excitation energies reached in the compound nuclei. A detailed analysis of the $\gamma$-ray spectra and their comparison with statistical model calculations is presented. Evidence of a quenching of the GDR gamma yield was found at 270 MeV excitation energy. The quenching effect becomes progressively more important with increasing excitation energy, as observed when the comparison is extended to data from the reaction ${}^{36}\mathrm{Ar}+{}^{96}\mathrm{Mo}$ at $37A$ MeV where hot nuclei were populated up to 430 MeV excitation energy. A coherent scenario emerges indicating the existence of a limiting excitation energy for the collective motion of about $E^{*}/A=2.1$ MeV for systems of mass $A=105$ to 111 while a slightly lower value was observed for nuclei of mass $A\sim 132$. The existence of a possible link between GDR disappearance and the liquid-gas phase transition is discussed.

It is shown that the anomalous sharp increasing of the strength of the near-side ridge structures observed in Au-Au collisions at $\sqrt{s}=62$ and $\sqrt{s}=200$ GeV and the onset of the ridge structure in $p\text{Pb}$ and in $pp$ collisions can be naturally explained in the framework of string percolation. In all the cases the near-side strength reflects the collision area covered by the strings stretched between the colliding objects and therefore it is related to the shape of their profile functions. The dependence of the pseudorapidity and azimuthal widths on multiplicity and energy is qualitatively explained.

We obtain leading- and next-to-leading-order predictions of chiral perturbation theory for several prominent moments of nucleon structure functions. These parameter-free results turn out to be in overall agreement with the available empirical information on nearly all of the considered moments, in the region of low momentum transfer $\left(Q^2<0.3{\mathrm{GeV}}^2\right)$. Especially surprising is the situation for the spin polarizability ${\delta }_{LT}$, which thus far was not reproducible in chiral perturbation theory for proton and neutron simultaneously. This problem, known as the “${\delta }_{LT}$ puzzle,” is not seen in the present calculation.

The interactions of heavy quarks with the partonic environment at finite temperature $T$ and finite quark chemical potential ${\mu }_q$ are investigated in terms of transport coefficients within the dynamical quasiparticle model (DQPM) designed to reproduce the lattice-QCD (lQCD) results (including the partonic equation of state) in thermodynamic equilibrium. These results are confronted with those of nuclear many-body calculations close to the critical temperature $T_c$. The hadronic and partonic spatial diffusion coefficients join smoothly and show a pronounced minimum around $T_c$ at ${\mu }_q=0$ as well as at finite ${\mu }_q$. Close to and above $T_c$ its absolute value matches the lQCD calculations for ${\mu }_q=0$. The smooth transition of the heavy-quark transport coefficients from the hadronic to the partonic medium corresponds to a crossover in line with lattice calculations, and differs substantially from perturbative-QCD calculations which show a large discontinuity at $T_c$. This indicates that in the vicinity of $T_c$ dynamically dressed massive partons should be the effective degrees of freedom in the quark-gluon plasma.

Reduced transition strengths of the deexciting transitions from the first two excited states in ${}^{33}\mathrm{Ar}$ were measured in a relativistic Coulomb excitation experiment at the GSI Helmholtz center. The radioactive ion beam was produced by fragmentation of a primary ${}^{36}\mathrm{Ar}$ beam on a ${}^9\mathrm{Be}$ target followed by the selection of the reaction product of interest via the GSI Fragment Separator. The ${}^{33}\mathrm{Ar}$ beam hit a secondary ${}^{197}\mathrm{Au}$ target with an energy of approximately 145 MeV/nucleon. An array of high-purity germanium cluster detectors and large-volume ${\mathrm{BaF}}_2$ scintillator detectors were employed for $\gamma$-ray spectroscopy at the secondary target position. The Lund-York-Cologne Calorimeter was used to track the outgoing ions and to identify the nuclear reaction channels. For the two lowest energy excited states of ${}^{33}\mathrm{Ar}$ the reduced transition strengths have been determined. With these first results the $T_z=-3/2$ nucleus ${}^{33}\mathrm{Ar}$ is now, together with ${}^{21}\mathrm{Na} \left(T_z=-1/2\right)$, the only neutron-deficient odd-$A sd$ shell nucleus in which experimental transition strengths are available. The experimental values are compared to results of shell-model calculations which describe simultaneously mirror-energy differences and transition-strength values of mirror pairs in the $sd$ shell in a consistent way.

A systemical analysis of the initial fluctuation effect on the collective flows for $\text{Au}+\text{Au}$ at $1A$ GeV is presented in the framework of isospin-dependent quantum molecular dynamics model (IQMD), and a special focus on the initial fluctuation effect on the squeeze out is emphasized. The flows calculated by the participant plane reconstructed by the initial geometry in coordinate space are compared with those calculated by both the ideal reaction-plane and event-plane methods. It is found that initial fluctuation weakens the squeeze-out effect, and some discrepancies between the flows extracted by these different plane methods appear, which indicate that the flows are affected by the evolution of dynamics. In addition, we find that the squeeze-out flow is also proportional to initial eccentricity. Our calculations also qualitatively give a trend for the excitation function of the elliptic flow similar to that of the FOPI Collaboration experimental data. Finally, we address the nucleon number scaling of the flows for light particles. Even though the initial fluctuation significantly decreases the ratio $v_4/v_2^2$ and $v_3/(v_1{v}_2)$, all fragments to mass number 4 keep the same curve and show independence from transverse momentum.

The purpose of this paper is twofold. First, we present the extension of the Liège intranuclear-cascade model to reactions induced by light ions. We describe here the ideas upon which we built our treatment of nucleus-nucleus reactions and we compare the model predictions against a vast set of heterogeneous experimental data. In spite of the discussed limitations of the intranuclear-cascade scheme, we find that our model yields valid predictions for a number of observables and positions itself as one of the most attractive alternatives available to geant4 users for the simulation of light-ion-induced reactions. Second, we describe the c++ version of the code, which is physicswise equivalent to the legacy version, is available in geant4, and will serve as the basis for all future development of the model.

Measurements of multiparticle azimuthal correlations (cumulants) for charged particles in $p$-Pb at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV and Pb-Pb at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV collisions are presented. They help address the question of whether there is evidence for global, flowlike, azimuthal correlations in the $p$-Pb system. Comparisons are made to measurements from the larger Pb-Pb system, where such evidence is established. In particular, the second harmonic two-particle cumulants are found to decrease with multiplicity, characteristic of a dominance of few-particle correlations in $p$-Pb collisions. However, when a $\left|\Delta \eta \right|$ gap is placed to suppress such correlations, the two-particle cumulants begin to rise at high multiplicity, indicating the presence of global azimuthal correlations. The Pb-Pb values are higher than the $p$-Pb values at similar multiplicities. In both systems, the second harmonic four-particle cumulants exhibit a transition from positive to negative values when the multiplicity increases. The negative values allow for a measurement of $v_2\left\{4\right\}$ to be made, which is found to be higher in Pb-Pb collisions at similar multiplicities. The second harmonic six-particle cumulants are also found to be higher in Pb-Pb collisions. In Pb-Pb collisions, we generally find $v_2\left\{4\right\}\simeq v_2\left\{6\right\}\ne 0$ which is indicative of a Bessel-Gaussian function for the $v_2$ distribution. For very high-multiplicity Pb-Pb collisions, we observe that the four- and six-particle cumulants become consistent with 0. Finally, third harmonic two-particle cumulants in $p$-Pb and Pb-Pb are measured. These are found to be similar for overlapping multiplicities, when a $\left|\Delta \eta \right|>1.4$ gap is placed.

We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized ${}^3\mathrm{He}$ target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of $0.1<x_{bj}<0.4$ for $K^{+}$ and $K^{-}$ production. While the Collins and Sivers moments for $K^{+}$ are consistent with zero within the experimental uncertainties, both moments for $K^{-}$ favor negative values. The Sivers moments are compared to the theoretical prediction from a phenomenological fit to the world data. While the $K^{+}$ Sivers moments are consistent with the prediction, the $K^{-}$ results differ from the prediction at the 2-sigma level.

Background: In recent years properties of light rare isotopes have been measured with high accuracy. At the same time, the theoretical description of light nuclei has made enormous progress, and properties of, e.g., the helium isotopes can now be calculated ab initio. These advances make those rare isotopes an ideal testing ground for effective field theories (EFTs) built on cluster degrees of freedom.

Purpose: Systems with widely separated intrinsic scales are well suited to an EFT treatment. The Borromean halo nucleus ${}^6\mathrm{He}$ exhibits such a separation of scales. In this work an EFT in which the degrees of freedom are the valence neutrons ($n$) and an inert ${}^4\mathrm{He}$-core ($\alpha$) is employed. The properties of ${}^6\mathrm{He}$ can then be calculated using the momentum-space Faddeev equations for the $\alpha nn$ bound state to obtain information on ${}^6\mathrm{He}$ at leading order (LO) within the EFT.

Results: The $nn$ virtual state and the ${}^2{P}_{3/2}$ resonance in ${}^5\mathrm{He}$ give the two-body amplitudes which are input to our LO three-body Halo EFT calculation. We find that without a genuine three-body interaction the two-neutron separation energy $S_{2n}$ of ${}^6\mathrm{He}$ is strongly cutoff dependent. We introduce a $nn\alpha$ “three-body” operator which renormalizes the system, adjusting its coefficient to reproduce the $S_{2n}$ of ${}^6\mathrm{He}$. The Faddeev components are then cutoff independent for cutoffs of the order of, and above, the breakdown scale of the Halo EFT.

Conclusions: As in the case of a three-body system where only resonant $s$-wave interactions are present, one three-body input is required for the renormalization of the EFT equations that describe ${}^6\mathrm{He}$ at LO. However, in contrast to the $s$-wave-only case, the running of the LO $nn\alpha$ counterterm does not exhibit discrete scale invariance, due to the presence of the $p$-wave $n\alpha$ interaction.

Low-spin single quasineutron levels in ${}^{153}\mathrm{Gd}$ and ${}^{157}\mathrm{Gd}$ have been studied following the ${}^{154}\mathrm{Gd}$($p,d-\gamma$)${}^{153}\mathrm{Gd}$ and ${}^{158}\mathrm{Gd}$($p,d-\gamma$)${}^{157}\mathrm{Gd}$ reactions. A combined Si telescope and high-purity germanium array was utilized, allowing $d\text{−}\gamma$ and $d\text{−}\gamma \text{−}\gamma$ coincidence measurements. Almost all of the established low-excitation-energy, low-spin structures were confirmed in both ${}^{153}\mathrm{Gd}$ and ${}^{157}\mathrm{Gd}$. Several new levels and numerous new $\gamma$ rays are observed in both nuclei, particularly for $E_x\ge 1$ MeV. Residual effects of a neutron subshell closure at $N=64$ are observed in the form of a large excitation energy gap in the single quasineutron level schemes.

The role of the pairing interaction in multi-quasiparticle isomeric states was examined by calculating $\alpha$-decay half-lives with the superfluid tunneling model. We found that this model reproduces the experimental $\alpha$-decay half-lives with an accuracy typical of current $\alpha$-decay models. In spite of the simplicity of the model, we are able to demonstrate how the reduction of pairing in multi-quasiparticle isomers has a remarkable effect on $\alpha$-decay half-lives. Taking this effect into account may be important for spin and parity assignments of $\alpha$-decaying multi-quasiparticle isomers.

The recent high-precision measurements of $\alpha$-particle-induced-reaction data below the Coulomb barrier ($B$) make possible the understanding of limits and possible improvement of a previous optical model potential (OMP) for $\alpha$ particles on nuclei within the mass number range $45\le A\le 209$ [M. Avrigeanu et al., Phys. Rev. C 82, 014606 (2010)]. An updated version of this potential is given in the present work concerning mainly an increased surface imaginary-potential depth well below $B$ for $A>130$. Moreover, underestimation of reaction cross sections for well-deformed nuclei is removed by using $\sim 7\%$ larger radius for the surface imaginary part of this spherical OMP. Improved input parameters based on recent independent data, particularly $\gamma$-ray strength functions, but no empirical rescaling factor of the $\gamma$ and/or neutron widths have been involved within statistical model calculation of the corresponding $(\alpha ,x)$ reaction cross sections.

A multi-Pomeron exchange potential (MPP) is proposed as a model for the universal many-body repulsion in baryonic systems on the basis of the extended soft core (ESC) baryon-baryon interaction. The strength of the MPP is determined by analyzing the nucleus-nucleus scattering with the $G$-matrix folding model. The interaction in $\Lambda N$ channels is shown to reproduce well the experimental $\Lambda$ binding energies. The equation of state (EoS) in neutron matter with hyperon mixing is obtained including the MPP contribution, and mass-radius relations of neutron stars are derived. It is shown that the maximum mass can be larger than the observed one, $2M_{\odot }$, even in the case of including hyperon mixing on the basis of model parameters determined by terrestrial experiments.

For the first time a direct determination of the atomic mass difference of ${}^{187}\mathrm{Re}$ and ${}^{187}\mathrm{Os}$ has been performed with the Penning-trap mass spectrometer SHIPTRAP applying the novel phase-imaging ion-cyclotron-resonance technique. The obtained value of $2492\left({30}_{\mathrm{stat}}\right)\left({15}_{\mathrm{sys}}\right)$ eV is in excellent agreement with the $Q$ values determined indirectly with microcalorimetry and thus resolves a long-standing discrepancy with older proportional counter measurements. This is essential for the determination of the neutrino mass from the ${\beta }^{-}$ decay of ${}^{187}\mathrm{Re}$ as planned in future microcalorimetric measurements. In addition, an accurate mass difference of ${}^{187}\mathrm{Re}$ and ${}^{187}\mathrm{Os}$ is also important for the assessment of ${}^{187}\mathrm{Re}$ for cosmochronology.

We have performed microscopic distorted-wave Born approximation calculations of differential cross sections for the two reactions ${}^{136}\mathrm{Sn}\left(p,t\right){}^{134}\mathrm{Sn}$ and ${}^{134}\mathrm{Sn}\left(t,p\right){}^{136}\mathrm{Sn}$, which are within reach of near-future experiments with radioactive ion beams. We have described the initial and final nuclear states in terms of the shell model, employing a realistic low-momentum two-body effective interaction derived from the CD-Bonn nucleon-nucleon potential that has already proved quite successful in describing the available low-energy spectrum of ${}^{134}\mathrm{Sn}$. We discuss the main features of the predicted cross sections for the population of the low-lying yrast states in the two nuclei considered.

The Dalitz plot distribution of the $\eta \to {\pi }^{+}{\pi }^{-}{\pi }^0$ decay is determined by using a data sample of $1.2\times {10}^7$ $\eta$ mesons from the $pd\to {}^3\mathrm{He}\eta$ reaction at 1 GeV collected by the WASA detector at COSY.

A new $\gamma$-decay branch has been found from the well-known 661.659(3)-keV $J^{\pi }=11/2^{-}$, $T_{1/2}=2.552\left(1\right)$ min isomer in ${}^{137}\mathrm{Ba}$ which is populated in the $\beta$ decay of ${}^{137}\mathrm{Cs}$. The new 377.9(3)-keV $\gamma$ ray connects the isomer to the low-lying 283.5 keV, $J^{\pi }=1/2^{-}$ state. It is of near-pure $E5$ character. The decay has a $\gamma$ branching ratio (${\mathrm{Br}}_{\gamma }={\Gamma }_{\gamma }/{\Gamma }_{\mathrm{tot}}$) of $1.12\left(9\right)\times {10}^{-7}$. The new decay has a $B\left(E5\right)$ of 0.71(6) W.u. [$B\left(E5\right)\downarrow =6.5\left(6\right)\times {10}^5{e}^2{\mathrm{fm}}^{10}$], a value consistent with other “single-particle” $E5$ decays in the region. The new decay branch is of topical interest, as it competes with the much-sought “two-photon” second-order electromagnetic decay from this state.

We have precisely measured reaction cross sections (${\sigma }_R$) for ${}^8\mathrm{Li}$ using ${}^9\mathrm{Be}$, ${}^{12}\mathrm{C}$, ${}^{27}\mathrm{Al}$, and proton targets at intermediate energies by the transmission method. From the energy dependence of the ${\sigma }_R$ including the high energy data, the density distribution of ${}^8\mathrm{Li}$ was deduced through a modified Glauber model. It is shown that ${}^8\mathrm{Li}$ has a shorter tail structure in the density as compared with that of ${}^8\mathrm{B}$ and the matter radius of ${}^8\mathrm{Li}$ is similar to those of the other nonhalo Li isotopes. The result is consistent with the previous experiments that there is a tendency for ${}^8\mathrm{Li}$ to be a skin nucleus.

The effects of the phonon-phonon coupling on the $\beta$-decay rates of neutron-rich nuclei are studied in a microscopic model based on Skyrme-type interactions. The approach uses a finite-rank separable approximation (FRSA) of the Skyrme-type particle-hole (p-h) residual interaction. Very large two-quasiparticle spaces can thus be treated. A redistribution of the Gamow–Teller (G-T) strength is found due to the tensor correlations and the 2p-2h fragmentation of G-T states. As a result, the ${\beta }^{-}$-decay half-lives are decreased significantly. By using the Skyrme interaction SGII together with a volume-type pairing interaction, we illustrate this reduction effect by comparing with available experimental data for Ni isotopes and neutron-rich $N=50$ isotones. We give predictions for ${}^{76}\mathrm{Fe}$ and ${}^{80}\mathrm{Ni}$ in comparison with the case of the doubly magic nucleus ${}^{78}\mathrm{Ni}$ which is an important waiting point in the $r$ process.