The lifetime of the $J^{\pi }=2_1^{+}$ state in ${}^{10}$C was measured using the Doppler shift attenuation method following the inverse kinematics $p{{(}^{10}\text{B},n)}^{10}$C reaction at 95 MeV. The $2_1^{+}$ state, at 3354 keV, has $\tau =219\pm {\left(7\right)}_{\text{stat}}\pm {\left(10\right)}_{\text{sys}}$ fs, corresponding to a $B\left(E2\right)\downarrow$ of 8.8(3) $e^2$ fm${}^4$. This measurement, combined with that recently determined for ${}^{10}$Be [9.2(3) $e^2$ fm${}^4$], provides a unique challenge to ab initio calculations, testing the structure of these states, including the isospin symmetry of the wave functions. Quantum Monte Carlo calculations using realistic two- and three-nucleon Hamiltonians that reproduce the ${}^{10}$Be $B\left(E2\right)$ value generally predict a larger ${}^{10}$C $B\left(E2\right)$ probability but with considerable sensitivity to the admixture of different spatial symmetry components in the wave functions and to the three-nucleon potential used.

Recent studies of the interaction of vector mesons with nuclei make possible and opportune the study of the interaction of the $J/\psi$ with nuclei and the investigation of the origin of the $J/\psi$ suppression in its propagation thorough a nuclear medium. We observe that the transition of $J/\psi N$ to $VN$ with $V$ being a light vector, $\rho ,\omega ,\phi$, together with the inelastic channels, $J/\psi N\to \overline{D}{\Lambda }_c$ and $J/\psi N\to \overline{D}{\Sigma }_c$, leads to a particular shape of the inelastic cross section. Analogously, we consider the mechanisms where the exchanged $D$ collides with a nucleon and gives $\pi {\Lambda }_c$ or $\pi {\Sigma }_c$. The cross section has a peak around $\sqrt{s}=4415$ MeV, where the $J/\psi N$ couples to a resonance predicted recently. We study the transparency ratio for electron-induced $J/\psi$ production in nuclei at about 10 GeV and find that 30–35$\%$ of the $J/\psi$ produced in heavy nuclei are absorbed inside the nucleus. This ratio is in line with depletions of $J/\psi$ through matter observed in other reactions.

The half-life of the ground state of ${}^{94}$Nb has been remeasured by a combination of multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) for the determination of the isotope ratio ${}^{94}$Nb/${}^{93}$Nb and γ-ray spectrometry for the determination of ${}^{94}$Nb activity. The resulting value, (2.04 ± 0.04) × 10${}^4$ yr, is in agreement with the latest literature value of (2.03 ± 0.16) × 10${}^4$ yr [R. P. Schuman and P. Goris, J. Inorg. Nucl. Chem. 12, 1 (1959)] within uncertainty limits, but has a much reduced uncertainty.

We present an unquenched quark model calculation of the mass shifts of $1S$, $2S$, and $1P$ bottomonium states due to the coupling to the meson-meson continuum. In our approach, the effects of the $q\overline{q}$ pairs are taken explicitly into account through a microscopic, QCD-inspired, quark-antiquark pair creation mechanism.

Total Routhian surface calculations have been performed to investigate rapidly rotating transfermium nuclei, the heaviest nuclei accessible by detailed spectroscopy experiments. The observed fast alignment in ${}^{252}$No and slow alignment in ${}^{254}$No are well reproduced by the calculations incorporating high-order deformations. The different rotational behaviors of ${}^{252}$No and ${}^{254}$No can be understood for the first time in terms of ${\beta }_6$ deformation that decreases the energies of the $\nu j_{15/2}$ intruder orbitals below the $N=152$ gap. Our investigations reveal the importance of high-order deformation in describing not only the multiquasiparticle states but also the rotational spectra, both providing probes of the single-particle structure concerning the expected doubly magic superheavy nuclei.

A recent paper [Phys. Rev. C 83, 057304 (2011)] used knockout from ${}^{12}$Be to populate two states near 3.9 MeV in ${}^{11}$Be and observed their neutron decay—but treated the two as a single state. The authors used a branching ratio for the upper state from an experiment that also did not separate the two states. Thus, their energy for ${}^{11}$Be(3.96 MeV) and the spectroscopic factor connecting it to ${}^{12}$Be(gs) are questionable.

In the preceding Comment, Fortune argues that, in our original paper [Peters et al., Phys. Rev. C 83, 057304 (2011)], we did not or could not separate the two neutron-unbound states in ${}^{11}\mathrm{Be}$ near 4 MeV. However, including the suggested contribution of the 3.887-MeV state decaying via 18 keV to the $2^{+}$ state in ${}^{10}\mathrm{Be}$ does not fit the data; neither do any other attempts incorporating any contribution of this decay channel. The best fit was achieved with a single resonance of decay energy 80(2) keV.

The high-spin rotational bands in ${}^{168}$Hf and the triaxial bands in Lu nuclei are analyzed using the configuration-constrained cranked Nilsson-Strutinsky (CNS) model. Special attention is given to the up-sloping extruder orbitals. The relative alignment between the bands which appear to correspond to triaxial shape is also considered, including the yrast ultrahigh-spin band in ${}^{158}$Er. This comparison suggests that the latter band is formed from rotation around the intermediate axis. In addition, the standard approximations of the CNS approach are investigated, indicating that the errors which are introduced by the neglect of off-shell matrix elements and the cutoff at nine oscillator shells (${\mathcal{N}}_{\max }=8$) are essentially negligible compared to other uncertainties. On the other hand, the full inclusion of the hexadecapole degree of freedom is more significant; for example it leads to a decrease of the total energy of $\sim 500$ keV in the triaxial superdeformed (TSD) region of ${}^{168}$Hf.

The probability of incomplete fusion in ${}^{13}$C+${}^{159}$Tb interactions has been measured in the energy range $\approx$4–7 MeV/nucleon. The variation of the incomplete fusion fraction has been studied in terms of projectile energy and type. Present results are compared with the existing ${}^{12}$C+${}^{159}$Tb data, where a strong projectile structure effect on the incomplete fusion fraction has been observed. It has been found that the probability of incomplete fusion is higher in the case of ${}^{12}$C than for a one-neutron rich ${}^{13}$C projectile. For better insight into the projectile structure effect, a systematic study is presented on the incomplete fusion measured in ${}^{12,13}$C,${}^{16}$O+${}^{159}$Tb and ${}^{12,13}$C,${}^{16}$O+${}^{181}$Ta systems by Singh et al. [Phys. Rev.C 80, 014601 (2009)] and by Babu et al. [J. Phys. G 29, 1011 (2003)]. The present analysis indicates a strong dependence of incomplete fusion probability on the $\alpha$-$Q$ value of the projectile at these low energies.

Anisotropic flow, which arises from correlations to common collision geometry, is sensitive to hydrodynamic expansion of the medium created in heavy-ion collisions and has been extensively studied. Anisotropic flow is quantified by the Fourier series in particle azimuthal angle relative to the reaction plane. It is measured using azimuthal correlations of final-state particles and therefore is contaminated by correlations unrelated to the reaction plane (nonflow). Currently anisotropic flow and nonflow cannot be experimentally separated in a model-independent manner. Using pythia simulations of $p+p$ collisions we show that nonflow approximately factorizes in transverse momentum. This fact may be used to disentangle flow and nonflow in heavy-ion data by performing a two-component factorization fit to Fourier coefficients of two-particle cumulants.

Simulated results from a (2+1)-D relativistic viscous hydrodynamic model have been compared to the experimental data on the centrality dependence of invariant yield, elliptic flow ($v_2$), and hexadecapole flow ($v_4$) as a function of transverse momentum ($p_T$) of charged hadrons in Au-Au collisions at $\sqrt{s_{NN}}=200$ GeV. Results from two types of initial transverse energy density profile, one based on the Glauber model and other based on the color glass condensate (CGC) model, are presented. We observe no difference in the simulated results on the invariant yield of charged hadrons for the calculations with different initial conditions. The comparison to the experimental data on invariant yield of charged hadrons supports a shear-viscosity to entropy-density ratio ($\eta /s$) between 0 and 0.12 for the 0$\%$–10$\%$ to 40$\%$–50$\%$ collision centralities. The simulated $v_2\left(p_T\right)$ is found to be higher for a fluid with CGC based initial condition compared to Glauber based initial condition for a given collision centrality. Consequently the Glauber based calculations when compared to the experimental data require a lower value of $\eta /s$ relative to CGC based calculations. In addition, a centrality dependence of the estimated $\eta /s$ is observed from the $v_2\left(p_T\right)$ study. The $v_4\left(p_T\right)$ for the collision centralities 0$\%$–10$\%$ to 40$\%$–50$\%$ supports a $\eta /s$ value between 0 and 0.08 for a CGC based initial condition. Simulated results using the Glauber based initial condition for the ideal fluid evolution underestimate the $v_4\left(p_T\right)$ for collision centralities 0$\%$–10$\%$ to 30$\%$–40$\%$.

The details of the analysis of the near-threshold bump structure in the forward differential cross section of the $\phi$-meson photoproduction to determine whether it is a signature of a resonance, together with more extensive results, are presented. The analysis is carried out in an effective Lagrangian approach which includes Pomeron and $(\pi ,\eta )$ exchanges in the $t$ channel and contributions from the $s$- and $u$-channel excitations of a postulated nucleon resonance. In addition to the differential cross sections, we use the nine spin-density matrix elements as recently measured, instead of the $\phi$-meson decay angular distributions which depend only on six spin-density matrix elements as was done before, to constrain the resonance parameters. We conclude that indeed the nonmonotonic behavior, along with the other experimental data as reported by LEPS, can only be explained with an assumption of the excitation of a resonance of spin 3/2, as previously reported. However, both parities of $(\pm )$ can account for the data equally well with almost identical mass of $2.08\pm 0.04$ GeV and width of $0.501\pm 0.117$ and $0.570\pm 0.159$ for $3/2^{+}$ and $3/2^{-}$, respectively. The ratio of the helicity amplitudes $A_{1/2}/A_{3/2}$ calculated from the resulting coupling constants differs in sign from that of the known $D_{13}\left(2080\right)$. More experimental data on single and double polarization observables are needed to resolve the parity. We further find that with an assumption of large values of the OZI-evading parameters $x_{\mathrm{OZI}}=12$ for $J^P=3/2^{-}$ and $x_{\mathrm{OZI}}=9$ for $J^P=3/2^{+}$, the discrepancy between the recent experimental data on $\omega$-meson photoproduction and the theoretical model can be considerably reduced. We argue that the large value of $x_{\mathrm{OZI}}$ indicates that the postulated resonance contains a non-negligible amount of strangeness content.

Background: The neutron skin of a heavy nucleus as well as many neutron-star properties are highly sensitive to the poorly constrained density dependence of the symmetry energy.

Purpose: To provide for the first time meaningful theoretical errors and to assess the degree of correlation between the neutron-skin thickness of ${}^{208}$Pb and several neutron-star properties.

Methods: A proper covariance analysis based on the predictions of an accurately calibrated relativistic functional “FSUGold” is used to quantify theoretical errors and correlation coefficients.

Results: We find correlation coefficients of nearly 1 (or $-1$) between the neutron-skin thickness of ${}^{208}$Pb and a host of observables of relevance to the structure, dynamics, and composition of neutron stars.

Conclusions: We suggest that a follow-up Lead Radius Experiment (PREX) measurement, ideally with a $0.5\%$ accuracy, could significantly constrain the equation of state of neutron-star matter.

The symmetry energy contribution to the nuclear equation of state impacts various phenomena in nuclear astrophysics, nuclear structure, and nuclear reactions. Its determination is a key objective of contemporary nuclear physics, with consequences for the understanding of dense matter within neutron stars. We examine the results of laboratory experiments that have provided initial constraints on the nuclear symmetry energy and on its density dependence at and somewhat below normal nuclear matter density. Even though some of these constraints have been derived from properties of nuclei while others have been derived from the nuclear response to electroweak and hadronic probes, within experimental uncertainties-they are consistent with each other. We also examine the most frequently used theoretical models that predict the symmetry energy and its slope parameter. By comparing existing constraints on the symmetry pressure to theories, we demonstrate how contributions of three-body forces, which are essential ingredients in neutron matter models, can be determined.

Reaction cross sections of ${}^{169}\text{Tm}{(\alpha ,\gamma )}^{173}\text{Lu}$ and ${}^{169}\text{Tm}{(\alpha ,n)}^{172}\text{Lu}$ have been measured in the energy range $12.6\le E_{\alpha }\le 17.5$ MeV and $11.5\le E_{\alpha }\le 17.5$ MeV, respectively, using the recently introduced method of combining activation with x-ray counting. Improved shielding made it possible to measure the ($\alpha ,\gamma$) to lower energy than previously possible. The combination of ($\alpha$,$\gamma$) and ($\alpha ,n$) data made it possible to study the energy dependence of the $\alpha$ width. While absolute value and energy dependence are perfectly reproduced by theory at the energies above 14 MeV, the observed change in energy dependence at energies below 14 MeV requires a modification of the predicted $\alpha$ width. Using an effective, energy-dependent, local optical $\alpha +\text{nucleus}$ potential it is possible to reproduce the data but the astrophysical rate is still not well constrained at $\gamma$-process temperatures. The additional uncertainty stemming from a possible modification of the compound formation cross section is discussed. Including the remaining uncertainties, the recommended range of astrophysical reaction rate values at 2 GK is higher than the previously used values by factors of $2-37$.

The ${}^{12}$C($\alpha ,\gamma$)${}^{16}$O reaction is one of the most important in nuclear astrophysics since it determines the ratio of ${}^{12}$C to ${}^{16}$O during stellar helium burning. Experimental data, however, are still subject to large uncertainties due to the almost vanishing cross section at stellar energies. So far, most measurements have been performed with germanium detectors. To compensate for their low efficiency, the highest beam currents had to be used, resulting in target degradation and beam-induced backgrounds. Instead, the present measurement was performed with high-efficiency detectors and low beam currents, using the Karlsruhe 4$\pi$ BaF${}_2$ detector and the pulsed 3.7-MV Van de Graaff accelerator at Karlsruhe Institute of Technology. The ${}^{12}$C($\alpha ,\gamma$)${}^{16}$O cross sections have been measured at center-of-mass energies $E$ between 1002 and 1510 keV, and the $E1$ and $E2$ components were derived with an accuracy comparable to the previous best data obtained with HPGe detectors.

We propose a generalized wave function based on the flexible original THSR (Tohsaki, Horiuchi, Schuck, Röpke) wave function [A. Tohsaki et al., Phys. Rev. Lett. 87, 192501 (2001)], which is applicable to studies of general cluster structures in nuclei. The ground-state band in ${}^{20}$Ne is investigated by using this generalized wave function and the energies obtained agree well with the experimental values. Moreover, it is found that the single generalized THSR wave functions almost completely coincide with the exact solutions of the $\alpha {+}^{16}$O resonating group method for the ground-state band in ${}^{20}\mathrm{Ne}$. For the ground state, for instance, the squared overlap between them is 99.3%. This indicates that the THSR model can also be extended to study more compact cluster states in nuclei such as, e.g., the ground-state band in ${}^{20}$Ne.

The low-lying excited states of ${}^{10}$Be and ${}^{12}$Be are investigated within a no-core Monte Carlo shell-model (MCSM) framework employing a realistic potential obtained via the unitary correlation operator method. The excitation energies of the $2_1^{+}$ and $2_2^{+}$ states and the $B(E2;2_{1,2}^{+}\to 0_{g.s.}^{+})$ value for ${}^{10}$Be in the MCSM with a standard treatment of spurious center-of-mass motion show good agreement with experimental data. Some properties of low-lying states of ${}^{10}$Be are studied in terms of quadrupole moments, $E2$ transitions, and single-particle occupation numbers. The $E2$ transition probability of ${}^{10}$C, the mirror nucleus of ${}^{10}$Be, is also presented with a good agreement to experiment. The triaxial deformation of ${}^{10}$Be and ${}^{10}$C is discussed in terms of the $B\left(E2\right)$ values. The removal of the spurious center-of-mass motion affects various states differently: for instance, it has a negligible effect on the $2_1^{+}$ and $2_2^{+}$ levels of ${}^{10}$Be, while it leads to a significant and favorable shift for the $1_1^{-}$ level. It is suggested that the description of ${}^{12}$Be needs a larger model space as well as some other higher excited states of ${}^{10}$Be, as an indicator that these are dominated by intruder configurations.

The evolution of the one-quadrupole phonon mixed-symmetry state is important for understanding the role of the quadrupole proton-neutron interaction in the valence shell. To study the evolution of the $2_{1,\mathrm{ms}}^{+}$ mixed-symmetry state in the $N=78$ isotones above $Z=50$, a Coulomb excitation measurement was performed to identify the $2_{1,\mathrm{ms}}^{+}$ state in ${}^{136}$Ce by measuring absolute transition strengths. The $2_{1,\mathrm{ms}}^{+}$ state was found to be predominantly concentrated in the $2_4^{+}$ state of this nucleus. The simple picture of shell stabilization given to account for the fragmentation of the strength observed in ${}^{138}$Ce does not seem to apply to ${}^{136}$Ce.