The three electromagnetic form factors for the transition from a $3/2^{+}{\mathrm{\Sigma }}^{*}$ hyperon to the ground-state $\mathrm{\Lambda }$ hyperon are studied. At low energies, combinations of the transition form factors can be deduced from Dalitz decays of the ${\mathrm{\Sigma }}^{*}$ hyperon to $\mathrm{\Lambda }$ plus an electron-positron pair. It is pointed out how more information can be obtained with the help of the self-analyzing weak decay of the $\mathrm{\Lambda }$. In particular, it is shown that these transition form factors are complex quantities already in this kinematical region. Such measurements are feasible at hyperon factories such as, for instance, the Facility for Antiproton and Ion Research (FAIR). At higher energies, the transition form factors can be measured in electron-positron collisions. The transition form factors are related to decay distributions and differential cross sections. Using dispersion theory, the low-energy electromagnetic form factors for the ${\mathrm{\Sigma }}^{*}$-to-$\mathrm{\Lambda }$ transition are related to the pion vector form factor. The additionally required input, i.e., the two-pion–${\mathrm{\Sigma }}^{*}$–$\mathrm{\Lambda }$ amplitudes, is determined from relativistic next-to-leading-order (NLO) baryon chiral perturbation theory, including the baryons from the octet and the decuplet. A poorly known NLO parameter is fixed to the experimental value of the ${\mathrm{\Sigma }}^{*}\to \mathrm{\Lambda }\gamma$ decay width. Pion rescattering is taken into account by using dispersion theory and solving a Muskhelishvili-Omnès equation. Subtracted and unsubtracted dispersion relations are discussed. However, in view of the fact that the transition form factors are complex quantities, the current data situation does not allow for a full determination of the subtraction constants. To reduce the number of free parameters, unsubtracted dispersion relations are used to make predictions for the transition form factors in the low-energy space- and timelike regions.

We generalize our earlier work on neutron stars, which assumed spherical Wigner-Seitz cells in the inner crust, to admit the possibility of pasta phases, i.e., nonspherical cell shapes. Full fourth-order extended Thomas-Fermi (ETF) calculations using the density functional BSk24 are performed for cylindrical and platelike cells. Unlike in our spherical-cell calculations we do not include shell and pairing corrections, but there are grounds for expecting these corrections for pasta to be significantly smaller. It is therefore meaningful to compare the ETF pasta results with the full spherical-cell results, i.e., with shell and pairing corrections included. However, in view of the many previous studies in which shell and pairing corrections were omitted entirely, it is of interest to compare our pasta results with the ETF part of the corresponding spherical calculations. Making this latter comparison, we find that as the density increases the cell shapes pass through the usual sequence sphere $\to$ cylinder $\to$ plate before the transition to the homogeneous core. The filling fractions found at the phase transitions are in close agreement with expectations based on the liquid-drop model. On the other hand, when we compare with the full spherical-cell results, we find the sequence to be sphere $\to$ cylinder $\to$ sphere $\to$ cylinder $\to$ plate. In neither case do any “inverted,” i.e., bubblelike, configurations appear. The analytic fitting formulas for the equation of state and composition that we derived in our earlier work, with the assumption of spherical cell shapes for the entire density range from the outer crust to the core of a neutron star, are found to remain essentially unchanged for pasta shapes. Here, however, we provide more accurate fitting formulas to all our essential numerical results for each of the three phases, designed especially for the density range where the nonspherical shapes are expected, which enable one to capture not only the general behavior of the fitted functions but also the differences between them in different phases.

The impact of electron-capture (EC) cross sections for neutron-rich nuclei on the dynamics of core collapse during infall and early post-bounce is studied by performing spherically symmetric simulations in general relativity using a multigroup scheme for neutrino transport and full nuclear distributions in extended nuclear statistical equilibrium models. We thereby vary the prescription for EC rates on individual nuclei, the nuclear interaction for the equation of state, the mass model for the nuclear statistical equilibrium distribution, and the progenitor model. In agreement with previous works, we show that the individual EC rates are the most important source of uncertainty in the simulations, while the other inputs only marginally influence the results. A recently proposed analytic formula to extrapolate microscopic results on stable nuclei for EC rates to the high densities and temperatures and the neutron-rich region, with a functional form motivated by nuclear-structure data and parameters fitted from large scale shell-model calculations, is shown to lead to a sizable (16%) reduction of the electron fraction at bounce compared to more primitive prescriptions for the rates, leading to smaller inner core masses and slower shock propagation. We show that the EC process involves $\approx 170$ different nuclear species around ${}^{86}\mathrm{Kr}$, mainly in the $N=50$ shell closure region, and establish a list of the most important nuclei to be studied in order to constrain the global rates.

The adiabatic hyperspherical approach is a natural extension of the well-known three-dimensional polar coordinate method to solving a Schrödinger equation of a few-body system. To evaluate the matrix element of an adiabatic Hamiltonian at a fixed hyper-radius is crucially important in that approach, but due to the difficulty of its calculation real applications have been limited mostly up to four-body systems. To resolve this limitation I introduce a localized hyper-radial function and show that the matrix element needed for $N$-body system can be obtained using correlated Gaussians with arbitrary angular momentum. I demonstrate its feasibility in the systems of $N=3\text{–}6\alpha$ particles. It is pointed out that an extension into correlated Gaussians with double global vectors is desirable for further realistic descriptions of the hyperangular motion.

We show that the quasielastic (QE) response calculated with the superscaling approach (SuSAv2) model, that relies on the scaling phenomenon observed in the analysis of $(e,e^{\prime })$ data and on the relativistic mean-field theory, is very similar to that from a relativistic distorted-wave impulse approximation model when only the real part of the optical potentials is employed. The coincidence between the results from these two completely independent approaches, which satisfactorily agree with the inclusive data, reinforces the reliability of the quasielastic predictions stemming from both models and sets constraints for the QE response. We also study the low-energy and momentum-transfer region of the inclusive response by confronting the results of the relativistic mean-field model with those of the Hartree-Fock continuum random-phase approximation model, which accounts for nuclear long-range correlations. Finally, we present a comparison of our results with the recent Jefferson Laboratory (JLab) $(e,e^{\prime })$ data for argon, titanium, and carbon, finding good agreement with the three data sets.

From the subsubleading chiral three-nucleon forces [intermediate-range contributions, published in Phys. Rev. C 87, 054007 (2013)] a density-dependent $NN$-interaction $V_{\text{med}}$ is derived in isospin-symmetric nuclear matter. Following the division of the pertinent $3N$ diagrams into two-pion-one-pion exchange topology and ring topology, one evaluates for these all self-closings and concatenations of nucleon lines to an in-medium loop. In the case of the $2\pi 1\pi$-exchange topology, 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 require at most one numerical integration. For the more challenging (concatenations of the) ring diagrams proportional to $c_{1,2,3,4}$, one ends up with regularized double-integrals ${\int }_0^{\lambda }drr{\int }_0^{\pi /2}d\psi$ from which the ${\lambda }^2$ divergence has been subtracted and the logarithmic piece $\sim ln(m_{\pi }/\lambda )$ is isolated. The derived semianalytical results are most helpful to implement the subsubleading chiral $3N$ forces into nuclear many-body calculations.

Five new $2^{+}$ levels have been established in the semimagic ${}^{210}\mathrm{Po}$ nucleus from a ${}^{208}\mathrm{Pb}({}^{12}\mathrm{C},{}^{10}\mathrm{Be}$) two-proton transfer experiment, performed at energies close to the Coulomb barrier at JAEA Tokai. A setup combining Ge, ${\mathrm{LaBr}}_3$, and Si telescopes was used to detect both in-beam $\gamma$ rays and ejectile residues. The new $2^{+}$ states have been established by means of the transitions toward the $0^{+}$ ground state which are present in the $\gamma$ spectra produced by properly selecting the excitation energy in ${}^{210}\mathrm{Po}$ after kinematical reconstruction. ${\left(f_{7/2}\right)}^2$, $h_{9/2}\otimes f_{5/2}$, ${\left(i_{13/2}\right)}^2$, $f_{7/2}\otimes p_{3/2}$, and $f_{7/2}\otimes f_{5/2}$ two-proton configurations are assigned to these states. In addition, a new $3^{-}$ level has also been established in this nucleus, very likely originating from the $f_{7/2}\otimes i_{13/2}$ configuration. Shell-model calculations strongly support these assignments.

We analyze here in details the probability to find a given number of particles in a finite volume inside a normal or superfluid finite system. This probability, also known as counting statistics, is obtained using projection operator techniques directly linked to the characteristic function of the probability distribution. The method is illustrated in atomic nuclei. The nature of the particle number fluctuations from small to large volumes compared to the system size is carefully analyzed in three cases: normal systems, superfluid systems, and superfluid systems with total particle number restoration. The transition from Poissonian distribution in the small volume limit to Gaussian fluctuations as the number of particles participating to the fluctuations increases is analyzed both in the interior and at the surface of the system. While the restoration of the total number of particles is not necessary for small volume, we show that it affects the counting statistics as soon as more than a very few particles are involved.

Fission barriers heights and excitation energies of superdeformed isomeric minima are calculated within the microscopic-macroscopic Woods-Saxon model for 75 actinide nuclei for which the experimental data are known. State-of-the-art methods were used: minimization over many deformation parameters for minima and the imaginary water flow on a many-deformation energy grid for saddles, including nonaxial and reflection-asymmetric shapes. We obtain 0.82–0.94 MeV rms deviation between the calculated and experimental barriers and 0.53 MeV rms error in the excitation of superdeformed minima. Experimental vs theory discrepancies seem to be of various natures and not easy to eliminate, especially if one cares about more than one or two observables. As an example, we show that by strengthening pairing in odd systems one can partially improve agreement in barriers, while spoiling it for masses. We also discuss the “thorium anomaly” and suggest its possible relation to a different way in which the Ac and Th barriers are derived from experimental data.

The statistical model of compound-nucleus reactions predicts that the fluctuations of the partial $\gamma$-decay widths for a compound-nucleus resonance are governed by the Porter-Thomas distribution (PTD), and that consequently the distribution of total $\gamma$-decay widths is very narrow. However, a recent experiment [Koehler, Larsen, Guttormsen, Siem, and Guber, Phys. Rev. C 88, 041305(R) (2013)] reported large fluctuations of the total $\gamma$-decay widths in the ${}^{95}\mathrm{Mo}(n,\gamma ){}^{96}\mathrm{Mo}^{*}$ reaction, contrary to this expectation. Furthermore, in recent theoretical works it was argued that sufficiently strong channel couplings can cause deviations of the partial width distributions from PTD. Here, we investigate whether the combined influence of a large number of nonequivalent $\gamma$-decay channels, each of which couples weakly to the compound-nucleus resonances, can modify the statistics of the partial widths. We study this effect in neutron scattering off ${}^{95}\mathrm{Mo}$ within a random-matrix model that includes coupling to the entrance neutron channel and to the large number of $\gamma$ channels. Using realistic coupling parameters obtained from empirical models for the level density and the $\gamma$ strength function, we find that the PTD describes well the distribution of partial widths for all decay channels, in agreement with the statistical-model expectation. Furthermore, we find that the width of the distribution of the total $\gamma$-decay widths is insensitive to wide variations in the parameters of the $\gamma$ strength function, as well as to deviations of the partial-width distributions from the PTD. Our results rule out an explanation of the recent experimental data within a statistical-model description of the compound nucleus.

The capabilities of the new version of the Liège intranuclear cascade model (labeled $\mathrm{INCL}++6$ from now on) are presented in detail. This new version of INCL is able to handle strange particles, such as kaons and the $\mathrm{\Lambda }$ and $\mathrm{\Sigma }$ hyperons, and the associated reactions and also allows extending nucleon-nucleon collisions up to about $15\text{–}20$ GeV incident energy. Compared to the previous version, new observables can be studied, e.g., kaon, hyperon, and hypernuclei production cross sections (with the use of a suitable de-excitation code) as well as aspects of kaon-induced spallation reactions. The main purpose of this paper is to present the specific ingredients of the new INCL version and its new features, notably the newly implemented variance reduction scheme. We also compare, for some illustrative strangeness production cases, theoretical results calculated using this version of INCL with experimental data.

We discuss multiplicity fluctuations of charged particles produced in nuclear collisions measured event by event by the NA49 experiment at European Organization for Nuclear Research Super Proton Synchrotron within the Glauber Monte Carlo approach. We use the concepts of wounded nucleons and wounded quarks in the mechanism of multiparticle production to characterize multiplicity fluctuations expressed by the scaled variance of multiplicity distribution. Although the wounded nucleon model correctly reproduces the centrality dependence of the average multiplicity in $\mathrm{Pb}+\mathrm{Pb}$ collisions, it completely fails in the description of corresponding centrality dependence of scaled variance of multiplicity distribution. Using subnucleonic degrees of freedom, i.e., wounded quarks within the wounded quark model, it is possible to describe quite well the multiplicity distribution of charged particles produced in $\text{proton}+\text{proton}$ interactions. However, the wounded quark model with parameters describing multiplicity distribution of particles produced in $\text{proton}+\text{proton}$ interactions substantially exceeds the average multiplicity of charged particles produced in $\mathrm{Pb}+\mathrm{Pb}$ collisions. To obtain values of average multiplicities close to those experimentally measured in $\mathrm{Pb}+\mathrm{Pb}$ collisions, the concept of shadowed quark sources is implemented. The wounded quark model with implemented shadowing source scenario reproduces the centrality dependence of scaled variance of multiplicity distribution of charged particles produced in $\mathrm{Pb}+\mathrm{Pb}$ collisions in the range from the most central to midperipheral interactions.

We show how exclusive vector meson production off light ions can be used to probe the spatial distribution of small-$x$ gluons in the deuteron and ${}^3\mathrm{He}$ wave functions. In particular, we demonstrate how short-range repulsive nucleon-nucleon interactions affect the predicted coherent $J/\mathrm{\Psi }$ production spectra. Fluctuations of the nucleon substructure are shown to have a significant effect on the incoherent cross section above $\left|t\right|\gtrsim 0.2{\mathrm{GeV}}^2$. By explicitly performing the Jalilian-Marian–Iancu–McLerran–Weigert–Leonidov–Kovner (JIMWLK) evolution, we predict the $x$ dependence of coherent and incoherent cross sections in the electron-ion collider energy range. In addition to the increase of the average size of the nucleus with decreasing $x$, both the growth of the nucleons and subnucleonic hot spots are visible in the cross sections. The decreasing length scale of color charge fluctuations with decreasing $x$ is also present, but may not be observable for $\left|t\right|<1{\mathrm{GeV}}^2$, if subnucleonic spatial fluctuations are present.

Possible $N\mathrm{\Omega }$-like dibaryons $N{\mathrm{\Omega }}_{ccc}$ and $N{\mathrm{\Omega }}_{bbb}$ are investigated within the framework of two quark models: the chiral quark model (ChQM) and quark delocalization color screening model (QDCSM). We find both of these two states are bound in these two models, and the binding energy increases as the quark of the system becomes heavier. In the ChQM, only coupling both color-singlet and hidden-color channels can make the $N{\mathrm{\Omega }}_{ccc}$ and $N{\mathrm{\Omega }}_{bbb}$ systems bound. While in the QDCSM, the attraction between $N$ and ${\mathrm{\Omega }}_{ccc}$ (or ${\mathrm{\Omega }}_{bbb}$) mainly comes from the kinetic energy term due to quark delocalization and color screening. The effect of channel coupling provides more effective attraction to $N{\mathrm{\Omega }}_{ccc}$ and $N{\mathrm{\Omega }}_{bbb}$ systems. Besides, the calculation of the low-energy scattering phase shifts, the scattering length, the effective range, and the binding energy (obtained from the scattering length) also supports the existence of the $N{\mathrm{\Omega }}_{ccc}$ and $N{\mathrm{\Omega }}_{bbb}$ states. All these properties can provide more information for experimental search for the $N\mathrm{\Omega }$-like dibaryons with heavy quarks. And the experimental progress can also check the mechanism of the intermediate-range attraction of the baryon-baryon interaction in quark models.

Four $(\alpha ,\gamma )$ cross-section measurements on stable nuclei in the $A=100$ mass range were performed at the University of Notre Dame Nuclear Science Laboratory. The ${}^{102}\mathrm{Pd}(\alpha ,\gamma ){}^{106}\mathrm{Cd}$ and ${}^{110}\mathrm{Cd}(\alpha ,\gamma ){}^{114}\mathrm{Sn}$ reactions were measured for the first time. The ${}^{90}\mathrm{Zr}(\alpha ,\gamma ){}^{94}\mathrm{Mo}$ and ${}^{108}\mathrm{Cd}(\alpha ,\gamma ){}^{112}\mathrm{Sn}$ results extended the measured range down to energies lower than those of the previous experiments. These reactions were studied as possible branching points in $\gamma$-process reaction networks. The measured cross-section values were compared to the nonsmoker database as well as to calculations performed with talys 1.9. The combination of parameters available in talys that gave the best fit to the data was found and the corresponding reaction rates were obtained. The inverse $(\gamma ,\alpha )$ rates were then obtained and compared to the corresponding $(\gamma ,n)$ rates to investigate the relative strength between the two reaction pathways. It was found that in all four cases the $(\gamma ,\alpha )$ reaction pathway begins to dominate within the 1.5–3.5 GK temperature range.

Electron-capture reactions play important roles in the late evolution of core-collapse supernovae. The electron-capture rates used in astrophysical simulations rely on theoretical calculations which have to be tested against and guided by experimental data. We report on the measurement of the Gamow-Teller strength distribution of the odd-mass nucleus ${}^{93}\mathrm{Nb}$ via the ($t,{}^3\mathrm{He}$ + $\gamma$) charge-exchange reaction at a beam energy of 115 MeV/u. The Gamow-Teller strength distributions were extracted up to an excitation energy in ${}^{93}\mathrm{Zr}$ of 10 MeV. The results were compared with shell-model and quasiparticle random-phase approximation (QRPA) calculations. The theoretical calculations fail to describe the details of the strength distribution, but estimate reasonably well the integrated Gamow-Teller transition strength. Electron-capture rates derived from the measured and theoretical strength distributions match reasonably well, especially at the higher stellar densities of importance for deleptonization during the collapse of the stellar core, since the electron-capture $Q$ value is close to zero and the Fermi energy sufficiently high to ensure that the details of the strength distribution do not have a strong impact on the derived rates. At stellar densities in excess of ${10}^9$ g/${\mathrm{cm}}^3$, the electron-capture rate based on a single-state approximation used in astrophysical simulations is slightly higher than the rates based on the data and the shell-model and QRPA calculations, likely due to the fact that the approximation includes temperature-dependent effects, which increase the rates. However, the difference is much smaller than that observed in recent studies of nuclei with $Z<40$ near $N=50$, suggesting that the single-state approximation does not account for Pauli-blocking effects for nuclei with $Z<40$ that are much stronger than those for ${}^{93}\mathrm{Nb}$ with $Z=41$.

The formation mechanism of hyperfragments with strangeness $s=-1$ and $s=-2$ in collisions of antikaons on nuclei has been investigated within a microscopic transport model. Dynamics of pseudoscalar mesons and hyperons is modeled within the transport model, in which all possible reaction channels for creating hyperons such as the elastic scattering, resonance production and decay, strangeness exchange reaction, and direct strangeness production in meson-baryon and baryon-baryon collisions have been included. A coalescence approach is used for constructing hyperfragments in phase space and the statistical model is modified to describe the decay of hyperfragments. It is found that the ${\mathrm{\Xi }}^{-}$ production is correlated to the $K^{+}$ dynamics. The hyperons $\mathrm{\Lambda }$ and $\mathrm{\Sigma }$ are created within a broad rapidity region. The production cross sections of nucleonic fragments and hyperfragments weakly depends on the incident momentum. The yields of $\mathrm{\Lambda }$ hyperfragments are the sixth order of magnitude of ${\mathrm{\Xi }}^{-}$ hyperfragments. Possible experiments on the hypernuclear physics at the high-intensity heavy-ion accelerator facility (HIAF) in China are discussed.

Complete fusion (CF) cross section measurement for the weakly bound ${}^9\mathrm{Be}$ projectile interacting with the intermediate mass target ${}^{89}\mathrm{Y}$ has been extended to energies greater than the fusion barrier, by implementing off-line characteristic $\gamma$-ray detection techniques. The available experimental data for the ${}^9\mathrm{Be}+{}^{89}\mathrm{Y}$ reaction system were compared with the theoretical predictions, using the platypus code that is based on a classical dynamical model. By introducing the breakup probability that deduced in the literature from the fitting of the experimental data, the model managed to reproduce the CF cross sections of ${}^9\mathrm{Be}$ beam with targets of different atomic mass. Through the study, it is revealed that the extended CF excitation function for the ${}^9\mathrm{Be}+{}^{89}\mathrm{Y}$ system is consistent with the systematical behavior that the prompt-breakup probability at above-barrier energies is roughly independent of the target in the reactions induced by the same weakly bound projectiles.

In a framework of a semianalytic model with longitudinally extended strings of fluctuating endpoints, we demonstrate that the rapidity spectra and two-particle correlations in collisions of Pb-Pb, $p$-Pb, and $p\text{−}p$ at the energies of the Large Hadron Collider can be universally reproduced. In our approach, the strings are pulled by wounded constituents appearing in the Glauber modeling at the partonic level. The obtained rapidity profile for the emission of hadrons from a string yields bounds for the distributions of the endpoint fluctuations. Then, limits for the two-particle correlations in pseudorapidity can be obtained. Our results are favorably compared to recent experimental data from the ATLAS Collaboration.

Correlations between azimuthal anisotropy Fourier harmonics $v_n$ ($n=2,3,4$) are studied using the events from PbPb collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=2.76$ TeV generated by the $\text{HYDJET}++$ and multiphase transport (AMPT) models, and compared to the corresponding experimental results obtained by the ATLAS Collaboration. The Fourier harmonics $v_n$ are measured over a wide centrality range using the two-particle azimuthal correlation method. The slopes of the $v_2\text{−}{v}_3$ correlation from both models are in a good agreement with the ATLAS data. The $\text{HYDJET}++$ model predicts a stronger slope for the $v_2\text{−}{v}_4$ and $v_3\text{−}{v}_4$ correlations than the ones experimentally measured, while the results from the AMPT model are in a rather good agreement with the experimental results. In contrast to the $\text{HYDJET}++$ predictions, the AMPT model predicts a boomeranglike shape in the structure of the correlations as found in the experimental data.