The two-step process of transfer followed by breakup is explored by measuring a rather complete set of exclusive data for reaction channels populating states in the ejectile continua of the ${}^7\mathrm{Li}+{}^{93}\mathrm{Nb}$ system at energies close to the Coulomb barrier. The cross sections for $\alpha +\alpha$ events from one proton pickup were found to be smaller than those for $\alpha +d$ events from one neutron stripping and $\alpha +t$ events from direct breakup of ${}^7\mathrm{Li}$. Coupled-channels Born approximation and continuum-discretized coupled-channels calculations describe the data well and support the conclusion that the $\alpha +d$ and $\alpha +\alpha$ events are produced by direct transfer to unbound states of the ejectile.

Multipole strength distributions for isoscalar $L\le 2$ transitions in ${}^{28}\mathrm{Si}$ have been extracted using 386-MeV inelastic $\alpha$ scattering at extremely forward angles, including $0^{\circ }$. Observed strength distributions are in good agreement with microscopic calculations for an oblate-deformed ground state. In particular, a large peak at an excitation energy of 17.7 MeV in the isoscalar giant monopole resonance strength is consistent with the calculations.

We study the details and time dependence of particle production in nuclear collisions at a fixed target beam energy of $E_{\mathrm{lab}}=1.76A$ GeV with the UrQMD transport model. We find that the previously proposed production mechanisms for multistrange hadrons $\varphi$ and $\mathrm{\Xi }$ are possible due to secondary interactions of incoming nuclei of the projectile and target with already created nuclear resonances, while the Fermi momenta of the nuclei play only a minor role. We also show how the centrality dependence of these particle multiplicities can be used to confirm the proposed mechanism, as it strongly depends on the number of participants in the reaction. Furthermore we investigate the time dependence of particle production in collisions of Ca + Ca at this beam energy, in order to understand the origins of the apparent chemical equilibration of the measured particle yields. We find that indeed the light hadron yields appear to be in equilibrium already from the very early stage of the collision, while in fact no local equilibration, through multicollision processes, takes place. The apparent equilibrium is reached only through the decay of the resonances according to available phase space.

We show that the measured yield ratio ${}_{\mathrm{\Lambda }}{}^3\mathrm{H}/{}^3\mathrm{He}({}_{\overline{\mathrm{\Lambda }}}{}^3\overline{\mathrm{H}}/{}^3\overline{\mathrm{He}})$ in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=200$ GeV and in $\mathrm{Pb}+\mathrm{Pb}$ collisions at $\sqrt{s_{NN}}=2.76$ TeV can be understood within a covariant coalescence model if (anti-)$\mathrm{\Lambda }$ particles freeze out earlier than (anti-)nucleons but their relative freeze-out time is closer at $\sqrt{s_{NN}}=2.76$ TeV than at $\sqrt{s_{NN}}=200$ GeV. The earlier (anti-)$\mathrm{\Lambda }$ freeze-out can significantly enhance the yield of (anti)hypernucleus ${}_{\mathrm{\Lambda }}{}^4\mathrm{H}\left({}_{\overline{\mathrm{\Lambda }}}{}^4\overline{\mathrm{H}}\right)$, leading to that ${}_{\overline{\mathrm{\Lambda }}}{}^4\overline{\mathrm{H}}$ has a comparable abundance with ${}^4\overline{\mathrm{He}}$ and thus provides an easily measured antimatter candidate heavier than ${}^4\overline{\mathrm{He}}$. The future measurement on ${}_{\mathrm{\Lambda }}{}^4\mathrm{H}\left({}_{\overline{\mathrm{\Lambda }}}{}^4\overline{\mathrm{H}}\right)$ would be very useful to understand the (anti-)$\mathrm{\Lambda }$ freeze-out dynamics and the production mechanism of (anti)hypernuclei in relativistic heavy-ion collisions.

”Additional” ionization of light atoms and ions during nuclear ${\beta }^{-}$ decay is investigated. A procedure that can be used to determine the corresponding transition probabilities and the velocity/energy spectrum of secondary electrons is developed. Emission of very fast secondary electrons ($\delta$ electrons) from ${\beta }^{-}$-decaying atoms is also briefly discussed.

The $\beta$-decay properties of the very neutron-rich ${}^{84}\mathrm{Ge}$ nucleus were studied at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. Several new $\gamma$-transitions and levels were added to its decay scheme and the order of the two lowest-lying levels in the daughter ${}^{84}\mathrm{As}$ was corrected. For the first time $\gamma$ radiation following $\beta$-delayed neutron emission was observed. The shell-model calculations and apparent $\beta$ transition intensities were used to guide the spin assignment to the ${}^{84}\mathrm{As}$ levels, in particular for the low-energy part of the level scheme. The new spin-parity $\left(2^{-}\right)$ proposed for the ground state of ${}^{84}\mathrm{As}$ is supported also by the systematics of $N=51$ isotones.

The recent update of the strangeness $-2$ ESC08c Nijmegen potential incorporating the NAGARA and KISO events predicts a $\mathrm{\Xi }N$ bound state, $D^{*}$, in the ${}^{3}S_1(I=1)$ channel. We study if the existence of this two-body bound state could give rise to stable three-body systems. For this purpose we solve the bound state problem of three-body systems where the $\mathrm{\Xi }N$ state is merged with $N\text{’s}$, $\mathrm{\Lambda }\text{’s}$, $\mathrm{\Sigma }\text{’s}$, or $\mathrm{\Xi }\text{’s}$, making use of the most recent updates of the two-body ESC08c Nijmegen potentials. We found that there appear stable states in the $\mathrm{\Xi }NN$ and $\mathrm{\Xi }\mathrm{\Xi }N$ systems, the $\mathrm{\Xi }\mathrm{\Lambda }N$ and $\mathrm{\Xi }\mathrm{\Sigma }N$ systems being unbound.

The neutron decay of the resonant states of light neutron-rich nuclei is an important and poorly explored property, useful to extract valuable nuclear structure information. In the present paper the neutron decay of the ${}^{15}\mathrm{C}$ resonances populated via the two-neutron transfer reaction ${}^{13}\mathrm{C}({}^{18}\mathrm{O},{}^{16}\mathrm{O}n)$ at 84-MeV incident energy is reported for the first time using an innovative technique which couples the MAGNEX magnetic spectrometer and the EDEN neutron detector array. Experimental data show that the resonances below the one-neutron emission threshold decay to the ${}^{14}\mathrm{C}$ ground state via one-neutron emission with an almost $100\%$ total branching ratio, whereas the recently observed ${}^{15}\mathrm{C}$ giant pairing vibration at 13.7 MeV mainly decays via two-neutron emission.

Excitations of colliding nuclei during a nuclear reaction considerably affect fusion cross sections at energies around the Coulomb barrier. It has been demonstrated that such channel coupling effects can be represented in terms of a distribution of multiple fusion barriers. I here apply a Bayesian approach to analyze the so-called fusion barrier distributions. This method determines simultaneously the barrier parameters and the number of barriers. I particularly investigate the ${}^{16}\mathrm{O}+{}^{144}\mathrm{Sm}$ and ${}^{16}\mathrm{O}+{}^{154}\mathrm{Sm}$ systems in order to demonstrate the effectiveness of the method. The present analysis indicates that the fusion barrier distribution for the former system is most consistent with three fusion barriers, even though the experimental data show only two distinct peaks.

We study the event-by-event generation of flow vorticity in the BNL Relativistic Heavy Ion Collider $\mathrm{Au}+\mathrm{Au}$ collisions and CERN Large Hadron Collider $\mathrm{Pb}+\mathrm{Pb}$ collisions by using the hijing model. Different definitions of the vorticity field and velocity field are considered. A variety of properties of the vorticity are explored, including the impact parameter dependence, the collision energy dependence, the spatial distribution, the event-by-event fluctuation of the magnitude and azimuthal direction, and the time evolution. In addition, the spatial distribution of the flow helicity is also studied.

To analyze the property of nuclear matter in the ${}^{16}\text{O}+{}^{208}\text{Pb}$ collision system, the internuclear potential of the fusion reaction is calculated by using the Skyrme forces associated with an extensive nuclear matter incompressibility $K$ range in the semiclassical energy-density formalism. Comparison of the experimental fusion cross sections and those obtained by using potentials derived from different forces with various $K$ values shows that the incompressibility of nuclear matter changes during the fusion process at different bombarding energies. The results indicate that, as the energy increases, the nuclear matter becomes more incompressible.

We study the integrated elastic and inelastic scattering cross sections together with their angular distributions of $n+{}^{6,7}\mathrm{Li}$ using $n+$ $\left(\alpha +d\right)$ and $n+$ $\left(\alpha +t\right)$ cluster models, respectively, and the continuum-discretized coupled-channel framework. The microscopic single-folding potential is used for the neutron energies from 1 to 24 MeV. The calculated elastic and inelastic scattering cross sections are in good agreement with experimental and evaluated data for the observed incident energies.

The recently developed semilocal improved chiral nucleon-nucleon interaction is used for the first time to study several electromagnetic and weak processes at energies below the pion production threshold. Cross sections and selected polarization observables for deuteron photodisintegration, nucleon-deuteron radiative capture, three-body ${}^3\mathrm{He}$ photodisintegration, as well as capture rates for decays of the muonic ${}^2\mathrm{H}$ and ${}^3\mathrm{He}$ atoms are calculated. The Lippmann-Schwinger and Faddeev equations in momentum space are solved to obtain nuclear states. The electromagnetic current operator is taken as a single nucleon current supplemented by many-body contributions induced via the Siegert theorem. For muon capture processes the nonrelativistic weak current together with the dominant relativistic corrections is used. Our results compare well with experimental data, demonstrating the same quality as is observed for the semiphenomenological Argonne V18 potential. Compared to the older version of the chiral potential with a nonlocal regularization, a much smaller cut-off dependence is found for the state-of-art chiral local interaction employed in this paper. Finally, estimates of errors due to the truncation of the chiral expansion are given.

Within the framework of a dinuclear system model, the influence of projectile and target neutron number on capture cross section, fusion probability, and survival probability for the reactions ${}^{34,36}\mathrm{S}+{}^{238}\mathrm{U}$ and ${}^{48}\mathrm{Ca}+{}^{239,240,242,244}\mathrm{Pu}$ are investigated. The calculated excitation functions are in good agreement with the experimental data. To synthesize more unknown neutron-deficient isotopes of already-known superheavy elements, the possibility of using lighter calcium isotopes to induce hot fusion reactions is investigated and the maximal evaporation residual cross sections for ${}^{44,46,48}\mathrm{Ca}$-induced hot fusion reactions to produce unknown neutron-deficient superheavy nuclei with $Z=112–116$ are predicted.

New results of the NA61/SHINE Collaboration at the CERN SPS on mean hadron multiplicities in proton-proton (p+p) interactions are analyzed within the transport models and the hadron resonance gas (HRG) statistical model. The chemical freeze-out parameters in p+p interactions and central Pb+Pb (or Au+Au) collisions are found and compared with each other in the range of the center-of-mass energy of the nucleon pair $\sqrt{s_{NN}}=3.2–17.3$ GeV. The canonical ensemble formulation of the HRG model is used to describe mean hadron multiplicities in p+p interactions and the grand canonical ensemble in central Pb+Pb and Au+Au collisions. The chemical freeze-out temperatures in p+p interactions are found to be larger than the corresponding temperatures in central nucleus-nucleus collisions.

We have previously calculated the pion-nucleon ${\mathrm{\Sigma }}_{\pi N}$ term in the chiral mixing approach with $u,d$ flavors only, and found the lower bound ${\mathrm{\Sigma }}_{\pi N}\ge \left(1+\frac{16}{3}{sin}^2\theta \right)\frac{3}{2}\left(m_u^0+m_d^0\right)$, where $m_u^0,m_d^0$ are the current quark masses, and $\theta$ is the mixing angle of the $[(\frac{\mathbf{1}}{\mathbf{2}},\mathbf{0})\oplus (\mathbf{0},\frac{\mathbf{1}}{\mathbf{2}})]$ and the $[(\mathbf{1},\frac{\mathbf{1}}{\mathbf{2}})\oplus (\frac{\mathbf{1}}{\mathbf{2}},\mathbf{1})]$ chiral multiplets. This mixing angle can be calculated as ${sin}^2\theta =\frac{3}{8}\left(g_A^{\left(0\right)}+g_A^{\left(3\right)}\right)$, where $g_A^{\left(0\right)},g_A^{\left(3\right)}$, are the flavor-singlet and the isovector axial couplings. With presently accepted values of current quark masses, this leads to ${\mathrm{\Sigma }}_{\pi N}\ge 58.0\pm 4.5{}_{-6.5}^{+11.4}$ MeV, which is in agreement with the values extracted from experiments, and substantially higher than most previous two-flavor calculations. The causes of this enhancement are: (1) the large, $\left(\frac{16}{3}\simeq 5.3\right)$, purely ${\mathrm{SU}}_L\left(2\right)\times {\mathrm{SU}}_R\left(2\right)$ algebraic factor; (2) the admixture of the $[(\mathbf{1},\frac{\mathbf{1}}{\mathbf{2}})\oplus (\frac{\mathbf{1}}{\mathbf{2}},\mathbf{1})]$ chiral multiplet component in the nucleon, whose presence has been known for some time, but that had not been properly taken into account, yet. We have now extended these calculations of ${\mathrm{\Sigma }}_{\pi N}$ to three light flavors, i.e., to ${\mathrm{SU}}_L\left(3\right)\times {\mathrm{SU}}_R\left(3\right)$ multiplet mixing. Phenomenology of chiral ${\mathrm{SU}}_L\left(3\right)\times {\mathrm{SU}}_R\left(3\right)$ multiplet mixing demands the presence of three chiral ${\mathrm{SU}}_L\left(3\right)\times {\mathrm{SU}}_R\left(3\right)$ multiplets, viz. $\left[\right(\mathbf{6},\mathbf{3})\oplus (\mathbf{3},\mathbf{6}\left)\right],[(\mathbf{3},\overline{\mathbf{3}})\oplus (\overline{\mathbf{3}},\mathbf{3})]$, and $[(\overline{\mathbf{3}},\mathbf{3})\oplus (\mathbf{3},\overline{\mathbf{3}})]$, in order to successfully reproduce the baryons' flavor-octet and flavor-singlet axial current coupling constants, as well as the baryon anomalous magnetic moments. Here we use these previously obtained results, together with known constraints on the explicit chiral symmetry breaking in baryons to calculate the ${\mathrm{\Sigma }}_{\pi N}$ term, but find no change of ${\mathrm{\Sigma }}_{\pi N}$ from the above successful two-flavor result. The physical significance of these results lies in the fact that they show no need for $q^4\overline{q}$ components, and in particular, no need for an $s\overline{s}$ component in the nucleon, in order to explain the large “observed” ${\mathrm{\Sigma }}_{\pi N}$ value. We also predict the kaon-nucleon $\sigma$ term ${\mathrm{\Sigma }}_{KN}$ that is experimentally unknown, but may be calculable in lattice QCD.

Using the iEBE-VISHNU hybrid model with AMPT initial conditions, we study the higher order flow harmonics of identified hadrons in $2.76A$ TeV Pb+Pb collisions. Comparison with the recent ALICE measurements at 20–30% centrality shows that our calculations generally describe the data below 2 GeV, especially for the $v_2, v_3$, and $v_4$ mass orderings among pions, kaons, and protons. We also extended the calculations to other centrality bins, which presents similar mass-ordering patterns for these flow harmonics as the ones observed at 20–30% centrality. In the later part of this article, we explore the development of $v_n$ mass ordering/splitting during the hadronic evolution through comparison runs from the iEBE-VISHNU hybrid model and pure hydrodynamics with different decoupling temperatures.

We discuss the effect of a neutron-proton pair in the $T=0,S=1$ channel in the low-lying states of the ${}^{102}\mathrm{Sb}={}^{100}\mathrm{Sn}+p+n$ nucleus. To this end, we construct a $\mathrm{core}+p+n$ three-body model with a model space based on Skyrme and relativistic mean-field calculations. The latter model is found to be more realistic for the present case due to the pseudospin symmetry. It turns out that the $(L,S,T)=(0,1,0)$ coupling scheme of valence nucleons is strongly hindered in ${}^{102}\mathrm{Sb}$ with the relativistic model because of the near degeneracy of the $g_{7/2}$ and $d_{5/2}$ orbitals in the valence space. The effect of this neutron-proton coupling is clearly seen in the charge-exchange Gamow-Teller-type transitions rather than in the binding energies of $T=0$ and $T=1$ states.

Background: Measurements of $\beta$ decay provide important nuclear structure information that can be used to probe isospin asymmetries and inform nuclear astrophysics studies.

Purpose: To measure the $\beta$-delayed $\gamma$ decay of ${}^{26}\text{P}$ and compare the results with previous experimental results and shell-model calculations.

Method: A ${}^{26}\text{P}$ fast beam produced using nuclear fragmentation was implanted into a planar germanium detector. Its $\beta$-delayed $\gamma$-ray emission was measured with an array of 16 high-purity germanium detectors. Positrons emitted in the decay were detected in coincidence to reduce the background.

Results: The absolute intensities of ${}^{26}\text{P}\beta$-delayed $\gamma$ rays were determined. A total of six new $\beta$-decay branches and 15 new $\gamma$-ray lines have been observed for the first time in ${}^{26}\text{P}\beta$ decay. A complete $\beta$-decay scheme was built for the allowed transitions to bound excited states of ${}^{26}\text{Si}$. $ft$ values and Gamow-Teller strengths were also determined for these transitions and compared with shell-model calculations and the mirror $\beta$ decay of ${}^{26}\text{Na}$, revealing significant mirror asymmetries.

Conclusions: A very good agreement with theoretical predictions based on the USDB shell model is observed. The significant mirror asymmetry observed for the transition to the first excited state $\left(\delta =51\left(10\right)\%\right)$ may be evidence for a proton halo in ${}^{26}\text{P}$.