We investigate asymmetric nuclear matter with two- and three-nucleon interactions based on chiral effective field theory, where three-body forces are fit only to light nuclei. Focusing on neutron-rich matter, we calculate the energy for different proton fractions and include estimates of the theoretical uncertainty. We use our ab initio results to test the quadratic expansion around symmetric matter with the symmetry energy term and confirm its validity for highly asymmetric systems. Our calculations are in remarkable agreement with an empirical parametrization for the energy density. These findings are very useful for astrophysical applications and for developing new equations of state.

The dependence on an applied electric field of the ionization current produced by an energetic electron stopped in liquid helium can be used to determine the spatial distribution of secondary electrons with respect to their geminate partners. An analytic expression relating the current and distribution is derived. The distribution is found to be non-Gaussian with a long tail at larger distances.

Nuclear shell evolution in neutron-rich Na nuclei around $N=20$ was studied by determining reduced transition probabilities, i.e., $B\left(E2\right)$ and $B\left(M1\right)$ values, in order to map the border of the island of inversion. To this end Coulomb-excitation experiments, employing radioactive ${}^{29,30}$Na beams with a final beam energy of 2.85 $\mathrm{M}$$\mathrm{e}\mathrm{V}$/nucleon, were performed at REX-ISOLDE, CERN. De-excitation $\gamma$ rays were detected by the MINIBALL $\gamma$-ray spectrometer in coincidence with scattered particles in a segmented Si detector. Transition probabilities to excited states were deduced. The measured $B\left(E2\right)$ values agree well with shell-model predictions, supporting the idea that in the Na isotopic chain the ground-state wave function contains significant intruder admixture already at $N=18$, with $N=19$ having an almost pure two-particle–two-hole deformed ground-state configuration.

The response to the addition of a $\Lambda$ hyperon is investigated for the deformed states such as superdeformation in ${}_{\Lambda }^{41}$Ca, ${}_{\Lambda }^{46}$Sc, and ${}_{\Lambda }^{48}$Sc. In the present study, we use the antisymmetrized molecular dynamics model. It is pointed out that many kinds of deformed bands appear in ${}^{45}$Sc and ${}^{47}$Sc. Especially, it is found that there exists superdeformed states in ${}^{45}$Sc. By the addition of a $\Lambda$ particle to ${}^{40}$Ca, ${}^{45}$Sc, and ${}^{47}$Sc, it is predicted, for the first time, that the superdeformed states exist in the hypernuclei ${}_{\Lambda }^{41}$Ca and ${}_{\Lambda }^{46}$Sc. The manifestation of the dependence of the $\Lambda$-separation energy on nuclear deformation such as spherical, normal deformation, and superdeformation is shown in the energy spectra of ${}_{\Lambda }^{41}$Ca, ${}_{\Lambda }^{46}$Sc, and ${}_{\Lambda }^{48}$Sc hypernuclei.

Using the well-known quantum hadrodynamics, we study the effects of meson-hyperon coupling constants on the onset of hyperons in dense nuclear matter. We use the SU(3) symmetry group to fix all these coupling constants, constrained to experimental nuclear matter results and astrophysical observations. While the discovery of massive pulsars PSR J1614-2230 and PSR J0348+0432 points towards a very stiff equation of state at very large densities, results from heavy-ion collisions point in the opposite direction for densities below 5 times the nuclear saturation density. We study some well-known parametrizations and see that most of them cannot satisfy both types of constraints. Indeed, although in our model we can simulate a 2.25 $M_{\odot }$ hyperonic neutron star, the heavy-ion collision constraints limit the maximum mass around 2.06 $M_{\odot }$.

We report on the first application of in-flight fast-timing measurements, a method developed in order to directly measure lifetimes in the picosecond to nanosecond range. As a proof of principle of the method, lifetimes of the states belonging to the ground-state band in ${}^{152}\mathrm{Sm}$ are measured up to the 8${}_1^{+}$ state. An excellent agreement with recommended values is found. A slightly improved determination of the spectroscopic quadrupole moment of the 4${}_1^{+}$ state is also reported. In-flight fast-timing measurements open interesting opportunities for future studies of collective properties in radioactive nuclei.

In this paper, the implication of the extreme large $N_c$ limit for nucleon-nucleon cross section is examined. Starting from the $N_c$ scaling of the $S$-matrix elements, a relation between the total inelastic and total cross sections is derived for the regime in which the momenta are much larger than the QCD scale. A conceptual complication arises from the fact that there is a tower of baryons, such as the $\Delta$, with mass splittings from the nucleon which go to zero at large $N_c$. Since these baryons are stable at large $N_c$, the meaning of elasticity must be modified. Processes which only transform nucleons to these baryons are considered elastic; processes in which at least one additional meson is produced are considered inelastic. It is shown that in the extreme large $N_c$ limit, the total inelastic cross section is exactly one eighth of the total cross section. In contrast, in the physical world of $N_c=3$, the total cross section for high-energy nucleon-nucleon scattering is dominated by inelastic processes.

Background: Incomplete fusion has been found to be an important contributor in light heavy-ion ($A\le 20$) induced reactions even at slightly above barrier energies.

Purpose: For better insight into the dynamics of incomplete fusion, the onset and influence of incomplete fusion need to be investigated in terms of projectile energy ($E_{\mathrm{lab}}$) and entrance channel mass-asymmetry (${\mu }_A$). A rich set of experimental data on incomplete fusion may be useful to correlate the probability of incomplete fusion with the various entrance channel parameters and eventually to develop a theoretical model code for the same. Presently, there is no theoretical model available which can explain low-energy incomplete fusion data consistently.

Methods: The excitation functions of complete and incomplete fusion residues populated in the ${}^{13}C$+${}^{169}\mathrm{Tm}$ system have been measured using the recoil-catcher activation technique followed by offline $\gamma$ spectroscopy. The evaporation residues have been identified on the basis of characteristic $\gamma$ lines and confirmed through the decay-curve analysis.

Results: The excitation functions of $xn$ and $pxn$ channels are found to be in good agreement with the statistical model code pace4; this suggests the population of these channels via complete fusion. Some residues are found to have a contribution from their higher charge isobar precursor decay. The precursor contribution has been deduced from the cumulative cross section using the standard successive radioactive decay formulations. The excitation functions of $\alpha$-emitting channels are observed to be significantly enhanced as compared to the statistical model code pace4. This enhancement may be attributed to the contribution from incomplete fusion. The incomplete fusion strength function for ${}^{13}C$+${}^{169}\mathrm{Tm}$ is compared with that obtained in the ${}^{12}C$+${}^{169}\mathrm{Tm}$ system. It has been found that the one-neutron (1$n$) excess projectile ${}^{13}C$ (as compared to ${}^{12}C$) results in a less incomplete fusion contribution due to its relatively large negative alpha-$Q$ value. Recently proposed “alpha-$Q$-value systematics” seems to explain incomplete fusion data.

Experimental measurements of evaporation residue (ER) cross sections for the ${}^{19}F$ + ${}^{194,196,198}\mathrm{Pt}$ reactions forming ${}^{213,215,217}\mathrm{Fr}$ compound nuclei are reported. The cross sections are measured at beam energies in the range of 101–137.3 MeV. The survival probability of the ${}^{213}\mathrm{Fr}$ compound nucleus with neutron number $N=126$ is found to be lower than the survival probabilities of ${}^{215}\mathrm{Fr}$ and ${}^{217}\mathrm{Fr}$ with neutron numbers $N=128$ and 130 respectively. Statistical model analysis of the ER cross sections show that an excitation energy dependent scaling of the finite-range rotating liquid drop model fission barrier is necessary to fit the experimental data. The fitted scaling factors for ${}^{213}\mathrm{Fr}$ are found to be smaller than those of ${}^{215}\mathrm{Fr}$ and ${}^{217}\mathrm{Fr}$ for almost the entire range of excitation energies.

This study uses classical molecular dynamics to simulate infinite nuclear matter and study the effect of isospin asymmetry on bulk properties such as energy per nucleon, pressure, saturation density, compressibility, and symmetry energy. The simulations are performed on systems embedded in periodic boundary conditions with densities and temperatures in the ranges $\rho =0.02$ to $0.2{\mathrm{fm}}^{-3}$ and $T=1$, 2, 3, 4, and 5 MeV, and with isospin content of $x=Z/A=0.3$, 0.4, and 0.5. The results indicate that symmetric and asymmetric matter are self-bound at some temperatures and exhibit phase transitions from a liquid phase to a liquid-gas mixture. The main effect of isospin asymmetry is found to be a reduction of the equilibrium densities, a softening of the compressibility and a disappearance of the liquid-gas phase transition. A procedure leading to the evaluation of the symmetry energy and its variation with the temperature was devised, implemented and compared to mean field theory results.

Correlation functions measured as a function of $\Delta \eta ,\Delta \varphi$ have emerged as a powerful tool to study the dynamics of particle production in nuclear collisions at high energy. They are however subject, like any other observables, to instrumental effects which must be properly accounted for to extract meaningful physics results. We compare the merits of several techniques used towards measurement of these correlation functions in nuclear collisions. We discuss and distinguish the effects of finite acceptance, and detection efficiency that may vary with collision parameters such as the position of the event in the detector and the instantaneous luminosity of the beam. We focus in particular on instrumental effects which break the factorization of the particle pair detection efficiency, and describe a technique to recover the robustness of correlation observables. We finally introduce a multidimensional weight method to correct for efficiencies that vary simultaneously with particle pseudo rapidity, azimuthal angle, transverse momentum, and the collision vertex position. The method can be generalized to account for any number of “event variables” that may break the factorability of the pair efficiency.

We propose a picture of turbulent pattern formation in the relativistic heavy-ion collision, which follows an efficient process to break color strings and dispose energy in the whole phase space. We perform numerical simulations using the SU(2) pure Yang–Mills theory in a nonexpanding box to observe a dynamical phenomenon in the transverse plane akin to the domain growth in time-dependent spin systems.

The radiative decay of $\Lambda \left(1405\right)$ is investigated from the viewpoint of compositeness, which corresponds to the amount of two-body states composing resonances as well as bound states. For a $\overline{K}N(I=0)$ bound state without couplings to other channels, we establish a relation between the radiative decay width and the compositeness. Especially the radiative decay width of the bound state is proportional to the compositeness. Applying the formulation to $\Lambda \left(1405\right)$, we observe that the decay to $\Lambda \gamma$ is dominated by the $K^{-}p$ component inside $\Lambda \left(1405\right)$, because in this decay ${\pi }^{+}{\Sigma }^{-}$ and ${\pi }^{-}{\Sigma }^{+}$ strongly cancel each other and the $\pi \Sigma$ component can contribute to the $\Lambda \gamma$ decay only through the slight isospin breaking. This means that the decay $\Lambda \left(1405\right)\to \Lambda \gamma$ is suitable for the study of the $\overline{K}N$ component in $\Lambda \left(1405\right)$. Fixing the $\Lambda \left(1405\right)$-$\pi \Sigma$ coupling constant from the usual decay of $\Lambda \left(1405\right)\to \pi \Sigma$, we show a relation between the absolute value of the $\overline{K}N$ compositeness for $\Lambda \left(1405\right)$ and the radiative decay width of $\Lambda \left(1405\right)\to \Lambda \gamma$ and ${\Sigma }^0\gamma$, and we find that large decay width to $\Lambda \gamma$ implies large $\overline{K}N$ compositeness for $\Lambda \left(1405\right)$. By using the “experimental” data on the radiative decay widths, which is based on an isobar model fitting of the $K^{-}p$ atom data, we estimate the $\overline{K}N$ compositeness for $\Lambda \left(1405\right)$. We also discuss the pole position dependence of our relation on the $\Lambda \left(1405\right)$ radiative decay width and the effects of the two-pole structure for $\Lambda \left(1405\right)$.

In this Brief Report we use a simple model to describe the dynamical effects of break-up processes in the subbarrier fusion involving weakly bound nuclei. We model two similar cases involving either a neutron or a proton halo nucleus, both schematically coupled to the break-up channels. We find that the decrease of the Coulomb barrier in the proton break-up channel leads, ceteris paribus, to a larger enhancement of the subbarrier fusion probabilities with respect to the neutron halo case.

We perform calculations of the cross sections for charged-current neutrino and antineutrino scattering off ${}^{116}\mathrm{Cd}$ using ten different Skyrme interactions, at energies typical of supernova neutrinos. We use the quasiparticle random-phase approximation in its charged-changing mode (pnQRPA) to construct the required nuclear wave functions for the participant initial and final states. We compare the results of these calculations with the results of calculations based on the Bonn one-boson-exchange potential. The response of ${}^{116}\mathrm{Cd}$ to supernova neutrinos is calculated by folding the obtained cross sections with suitably parametrized Fermi-Dirac distributions of the electron-neutrino and electron-antineutrino energies.

We have developed an approximate way of dealing with explicit energy dependence of nonlocal nucleon optical potentials as used to predict the $(d,p)$ cross sections within the adiabatic theory. Within this approximation, the nonlocal optical potentials have to be evaluated at an energy shifted from half the incident deuteron energy by the $n\text{−}p$ kinetic energy averaged over the range of the $n\text{−}p$ interaction and then treated as an energy-independent nonlocal potential. Thus, the evaluation of the distorting potential in the incident channel is reduced to a problem solved in our previous work [N. K. Timofeyuk and R. C. Johnson, Phys. Rev. Lett. 110, 112501 (2013); Phys. Rev. C 87, 064610 (2013)]. We have demonstrated how our new model works for the case of ${}^{16}$O${(d,p)}^{17}$O, ${}^{36}$Ar(${d,p)}^{37}$Ar, and ${}^{40}$Ca${(d,p)}^{41}$Ca reactions and highlighted the need for a detailed understanding of the energy dependence of nonlocal potentials. We have also suggested a simple way of correcting the $d\text{−}A$ effective potentials for nonlocality when the underlying energy-dependent nonlocal nucleon potentials are unknown but energy-dependent local phenomenological nucleon potentials are available.