We consider the excitation of the nuclear transition ${}^{229g}\mathrm{Th}\mathrm{\text{−}}{}^{229m}\mathrm{Th}$ near 7.6 eV in singly ionized thorium via an electronic bridge process. The process relies on the excitation of the electron shell by two laser photons whose sum frequency is equal to the nuclear transition frequency. This scheme allows us to determine the nuclear transition frequency with high accuracy. Based on calculations of the electronic level structure of ${\mathrm{Th}}^{+}$ which combine the configuration-interaction method and many-body perturbation theory, we estimate that a nuclear excitation rate in the range of $10{\mathrm{s}}^{-1}$ can be obtained using conventional laser sources.

A quark interaction with topologically nontrivial gluonic fields, instantons and sphalerons, violates $\mathcal{P}$ and $\mathcal{C}\mathcal{P}$ symmetry. In the strong magnetic field of a noncentral nuclear collision such interactions lead to the charge separation along the magnetic field, the so-called chiral magnetic effect (CME). Recent results from the STAR collaboration on charge dependent correlations are consistent with theoretical expectations for CME but may have contributions from other effects, which prevents definitive interpretation of the data. Here I propose to use central body-body $U+U$ collisions to disentangle correlations due to CME from possible background correlations due to elliptic flow. Further, more quantitative studies can be performed with collision of isobaric beams.

With the help of a unified nuclear-structure–direct-reaction theory we analyze the reaction ${}^1\mathrm{H}({}^{11}\mathrm{Li},{}^9\mathrm{Li}){}^3\mathrm{H}$. The two halo neutrons are correlated through the bare and the induced (medium polarization) pairing interaction. By considering all dominant reaction channels leading to the population of the $1/2^{-}$ (2.69 MeV) first excited state of ${}^9\mathrm{Li}$, namely, multistep transfer (successive, simultaneous, and nonorthogonality), breakup, and inelastic channels, it is possible to show that the experiment provides direct evidence of phonon mediated pairing.

A study of cooled ${}^{197}\mathrm{Au}$ projectile-fragmentation products has been performed with a storage ring. This has enabled metastable nuclear excitations with energies up to 3 MeV, and half-lives extending to minutes or longer, to be identified in the neutron-rich nuclides ${}^{183,184,186}\mathrm{Hf}$ and ${}^{186,187}\mathrm{Ta}$. The results support the prediction of a strongly favored isomer region near neutron number 116.

We rederive the equations of motion of dissipative relativistic fluid dynamics from kinetic theory. In contrast with the derivation of Israel and Stewart, which considered the second moment of the Boltzmann equation to obtain equations of motion for the dissipative currents, we directly use the latter’s definition. Although the equations of motion obtained via the two approaches are formally identical, the coefficients are different. We show that, for the one-dimensional scaling expansion, our method is in better agreement with the solution obtained from the Boltzmann equation.

By studying the ${}^{109}\mathrm{Xe}\to {}^{105}\mathrm{Te}\to {}^{101}\mathrm{Sn}$ superallowed $\alpha$-decay chain, we observe low-lying states in ${}^{101}\mathrm{Sn}$, the one-neutron system outside doubly magic ${}^{100}\mathrm{Sn}$. We find that the spins of the ground state ($J=7/2$) and first excited state ($J=5/2$) in ${}^{101}\mathrm{Sn}$ are reversed with respect to the traditional level ordering postulated for ${}^{103}\mathrm{Sn}$ and the heavier tin isotopes. Through simple arguments and state-of-the-art shell-model calculations we explain this unexpected switch in terms of a transition from the single-particle regime to the collective mode in which orbital-dependent pairing correlations dominate.

We present a good description of recent experimental data on forward dihadron azimuthal correlations measured in deuteron-gold collisions at the BNL Relativistic Heavy Ion Collider (RHIC), where monojet production has been observed. Our approach is based on the color glass condensate theory for the small-$x$ degrees of freedom of the nuclear wave function, including the use of nonlinear evolution equations with running QCD coupling. Our analysis provides further evidence for the presence of saturation effects in RHIC data.

The radionuclide ${}^{22}\mathrm{Na}$ is a potential astronomical observable that is expected to be produced in classical novae in quantities that depend on the thermonuclear rate of the ${}^{22}\mathrm{Na}(p,\gamma ){}^{23}\mathrm{Mg}$ reaction. We have measured the strengths of low-energy ${}^{22}\mathrm{Na}(p,\gamma ){}^{23}\mathrm{Mg}$ resonances directly and absolutely using a radioactive ${}^{22}\mathrm{Na}$ target. We find the strengths of resonances at $E_p=213$, 288, 454, and 610 keV to be higher than previous measurements by factors of 2.4–3.2, and we exclude important contributions to the rate from proposed resonances at $E_p=198$, 209, and 232 keV. The ${}^{22}\mathrm{Na}$ abundances expected in the ejecta of classical novae are reduced by a factor of $\approx 2$.

Fragment partitions of fragmenting hot nuclei produced in central and semiperipheral collisions have been compared in the excitation energy region 4–10 MeV per nucleon where radial collective expansion takes place. It is shown that, for a given total excitation energy per nucleon, the amount of radial collective energy fixes the mean fragment multiplicity. It is also shown that, at a given total excitation energy per nucleon, the different properties of fragment partitions are completely determined by the reduced fragment multiplicity (i.e., normalized to the source size). Freeze-out volumes seem to play a role in the scalings observed.

We have measured the azimuthal anisotropy of ${\pi }^0$ production for $1<p_T<18\mathrm{GeV}/c$ for $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=200\mathrm{GeV}$. The observed anisotropy shows a gradual decrease for $3\lesssim p_T\lesssim 7–10\mathrm{GeV}/c$, but remains positive beyond $10\mathrm{GeV}/c$. The magnitude of this anisotropy is underpredicted, up to at least $\sim 10\mathrm{GeV}/c$, by current perturbative QCD (PQCD) energy-loss model calculations. An estimate of the increase in anisotropy expected from initial-geometry modification due to gluon saturation effects and fluctuations is insufficient to account for this discrepancy. Calculations that implement a path-length dependence steeper than what is implied by current PQCD energy-loss models show reasonable agreement with the data.

The availability of the double-differential charged-current neutrino cross section, measured by the MiniBooNE Collaboration by using a carbon target, allows for a systematic comparison of nuclear effects in quasielastic electron and neutrino scattering. The results of our study, based on the impulse approximation scheme and a state-of-the-art model of the nuclear spectral functions, suggest that the electron cross section and the flux averaged neutrino cross sections, corresponding to the same target and comparable kinematical conditions, cannot be described within the same theoretical approach using the value of the nucleon axial mass obtained from deuterium measurements. We analyze the assumptions underlying the treatment of electron-scattering data and argue that the description of neutrino data will require a new paradigm, suitable for application to processes in which the lepton kinematics is not fully determined.

We have studied the ${}^{15}\mathrm{C}(d,p){}^{16}\mathrm{C}$ reaction in inverse kinematics using the Helical Orbit Spectrometer at Argonne National Laboratory. Prior studies of electromagnetic-transition rates in ${}^{16}\mathrm{C}$ suggested an exotic decoupling of the valence neutrons from the core in that nucleus. Neutron-adding spectroscopic factors give a different probe of the wave functions of the relevant states in ${}^{16}\mathrm{C}$. Shell-model calculations reproduce both the present transfer data and the previously measured transition rates, suggesting that ${}^{16}\mathrm{C}$ may be described without invoking very exotic phenomena.

We extend density-matrix expansions in nuclei to higher orders in derivatives of densities and test their convergence properties. The expansions allow for converting the interaction energies characteristic to finite- and short-range nuclear effective forces into quasilocal density functionals. We also propose a new type of expansion that has excellent convergence properties when benchmarked against the binding energies obtained for the Gogny interaction.

Because of their long lifetimes, the $\omega$ and $\varphi$ mesons are the ideal candidates for the study of possible modifications of the in-medium meson-nucleon interaction through their absorption inside the nucleus. During the E01-112 experiment at the Thomas Jefferson National Accelerator Facility, the mesons were photoproduced from ${}^2\mathrm{H}$, C, Ti, Fe, and Pb targets. This Letter reports the first measurement of the ratio of nuclear transparencies for the $e^{+}{e}^{-}$ channel. The ratios indicate larger in-medium widths compared with what have been reported in other reaction channels. The absorption of the $\omega$ meson is stronger than that reported by the CBELSA-TAPS experiment and cannot be explained by recent theoretical models.

The structure of ${}^{44}\mathrm{S}$ has been studied by using delayed $\gamma$ and electron spectroscopy. The decay rates of the $0_2^{+}$ isomeric state to the $2_1^{+}$ and $0_1^{+}$ states, measured for the first time, lead to a reduced transition probability $B(E2\mathrm{\text{:}}{2}_1^{+}\to 0_2^{+})=8.4(26)e^2{\mathrm{fm}}^4$ and a monopole strength ${\rho }^2(E0\mathrm{\text{:}}{0}_2^{+}\to 0_1^{+})=8.7(7)\times {10}^{-3}$. Comparisons to shell model calculations point towards prolate-spherical shape coexistence, and a two-level mixing model is used to extract a weak mixing between the two configurations.

We propose that the adiabatic separation of collective and intrinsic motions in many-body systems is related to increased regularity of the intrinsic dynamics. The surmise is verified on the separation of rotations from intrinsic vibrations in the interacting boson model of nuclear structure.

We obtained an unprecedentedly large number of $s$-wave neutron widths through $\mathcal{R}$-matrix analysis of neutron cross-section measurements on enriched Pt samples. Careful analysis of these data rejects the validity of the Porter-Thomas distribution with a statistical significance of at least 99.997%.

The charge exchange spin-dipole (SD) excitations of ${}^{208}\mathrm{Pb}$ are studied by using a fully self-consistent Skyrme Hartree-Fock plus random phase approximation formalism which includes the tensor interaction. It is found, for the first time, that the tensor correlations have a unique, multipole-dependent effect on the SD excitations; that is, they produce a softening of $1^{-}$ states, but a hardening of $0^{-}$ and $2^{-}$ states. This paves the way to a clear assessment of the strength of the tensor terms. We compare our results with a recent measurement, showing that our choice of tensor terms improves the agreement with experiment. The robustness of our results is supported by the analytic form of the tensor matrix elements.

Differential measurements of the elliptic ($v_2$) and hexadecapole ($v_4$) Fourier flow coefficients are reported for charged hadrons as a function of transverse momentum ($p_T$) and collision centrality or number of participant nucleons ($N_{\mathrm{part}}$) for $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=200\mathrm{GeV}$. The $v_{2,4}$ measurements at pseudorapidity $|\eta |\le 0.35$, obtained with four separate reaction-plane detectors positioned in the range $1.0<|\eta |<3.9$, show good agreement, indicating the absence of significant $\Delta \eta$-dependent nonflow correlations. Sizable values for $v_4(p_T)$ are observed with a ratio $v_4(p_T,N_{\mathrm{part}})/v_2^2(p_T,N_{\mathrm{part}})\approx 0.8$ for $50\lesssim N_{\mathrm{part}}\lesssim 200$, which is compatible with the combined effects of a finite viscosity and initial eccentricity fluctuations. For $N_{\mathrm{part}}\gtrsim 200$ this ratio increases up to 1.7 in the most central collisions.

Mass measurements of ${}^{96,97}\mathrm{Kr}$ using the ISOLTRAP Penning-trap spectrometer at CERN-ISOLDE are reported, extending the mass surface beyond $N=60$ for $Z=36$. These new results show behavior in sharp contrast to the heavier neighbors where a sudden and intense deformation is present. We interpret this as the establishment of a nuclear quantum phase transition critical-point boundary. The new masses confirm findings from nuclear mean-square charge-radius measurements up to $N=60$ but are at variance with conclusions from recent gamma-ray spectroscopy.