The masses of 15 stable nuclides in the rare-earth region have been measured with the Penning-trap mass spectrometer TRIGA-TRAP. This is the first series of absolute mass measurements linking these nuclides to the atomic-mass standard ${}^{12}\mathrm{C}$. Previously, nuclear reaction studies almost exclusively determined the literature values of these masses in the Atomic-Mass Evaluation. The TRIGA-TRAP results show deviations on the order of 3–4 standard deviations from the latest published values of the Atomic-Mass Evaluation 2003 for some cases. However, the binding-energy differences that are important for nuclear structure studies have been confirmed and improved. The new masses are discussed in the context of valence proton-neutron interactions using double differences of binding energies, $\delta V_{\mathit{pn}}(Z,N)$.

The activation cross sections of $(d,p)$, $(d,2n)$, $(d,3n)$, and $(d,2p)$ reactions on ${}^{63,65}\mathrm{Cu}$ were measured in the energy range from 4 to 20 MeV using the stacked-foil technique. Then, following the available elastic-scattering data analysis that provided the optical potential for reaction cross-section calculations, an increased effort was devoted to the breakup mechanism, direct reaction stripping, and pre-equilibrium and compound-nucleus cross-section calculations, corrected for the breakup and stripping decrease of the total reaction cross section. The overall agreement between the measured and calculated deuteron activation cross sections proves the correctness of the nuclear mechanism account, next to the simultaneous analysis of the elastic-scattering and reaction data.

Double polarization elastic $\mathrm{e⃗}$-$\mathrm{p⃗}$ cross sections and asymmetries are considered in collider kinematics. Covariant expressions are derived for the general situation involving crossed beams; these are checked against the well-known results obtained when the proton is at rest. Results are given using modern models for the proton electromagnetic form factors for kinematics of interest in e-p colliders such as the Electron-Ion Collider facility which is in its planning stage. In context, parity-violating elastic $\mathrm{e⃗}$-$p$ scattering is compared and contrasted with these double-polarization (parity-conserving) results.

In this Rapid Communication we update our predictions for the photoproduction of vector mesons in coherent $\mathit{pp}$ and $\mathit{AA}$ collisions at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies using the color dipole approach and the Color Glass Condensate formalism. In particular, we present our predictions for the first run of the LHC at half energy and for the rapidity dependence of the ratio between the $J/\Psi$ and $\rho$ cross sections at RHIC energies.

This paper explores properties of baryons and finite density baryonic matter in an artificial world in which $N_c$, the number of colors, is large and the quarks of all species are degenerate and much larger than ${\Lambda }_{\mathrm{QCD}}$. It has long been known that in large $N_c$ quantum chromodynamics (QCD), baryons composed entirely of heavy quarks are accurately described in the mean-field approximation. However, the detailed properties of baryons in the combined large $N_c$ and heavy-quark limits have not been fully explored. Here some basic properties of baryons are computed using a variational approach. At leading order in both the large $N_c$ and heavy-quark expansions the baryon mass is shown to be $M_{\mathrm{baryon}}\approx N_c{M}_Q(1-0.054\hspace{0.5em}26{\mathrm{\alpha ̃}}_s^2)$, where ${\mathrm{\alpha ̃}}_s\equiv N_c{\alpha }_s$. The baryon form factor is also computed. Baryonic matter, the analog of nuclear matter in this artificial world, should also be well described in the mean-field approximation. In the special case where all baryons have an identical spin-flavor structure, it is shown that in the formal heavy-quark and large $N_c$ limit interactions between baryons are strictly repulsive at low densities. The energy per baryon is computed in this limit and found to be exponentially small. It is shown that when the restriction to baryons with an identical spin-flavor structure is dropped, a phase of baryonic matter exists with a density of $2N_f$ times that for the restricted case but with the same energy (where $N_f$ is the number of degenerate flavors). It is shown that this phase is at least metastable.

We obtain a minimal form of the two-derivative three-nucleon contact Lagrangian, by imposing all constraints deriving from discrete symmetries, Fierz identities, and Poincaré covariance. The resulting interaction, depending on 10 unknown low-energy constants, leads to a three-nucleon potential which we give in a local form in configuration space. We also consider the leading (no-derivative) four-nucleon interaction and show that there exists only one independent operator.

The ${}^{157}\mathrm{Gd}$($n,\gamma$) reaction was measured with the DANCE $\gamma$ calorimeter (consisting of 160 BaF${}_2$ scintillation detectors) at the Los Alamos Neutron Science Center. The multiplicity distributions of the $\gamma$ decay were used to determine the resonance spins up to $E_n=300$ eV. The $\gamma$-ray energy spectra for different multiplicities were measured for the $s$-wave resonances. The shapes of these spectra were compared with simulations based on the use of the DICEBOX statistical model code. Simulations showed that the scissors mode is required not only for the ground-state transitions but also for transitions between excited states.

Several technical aspects concerning the evaluation of the overlap between two mean-field wave functions of the Hartree-Fock-Bogoliubov type are discussed. The limit when several orbitals become fully occupied is derived as well as the formula to reduce the dimensionality of the problem when exactly empty orbitals are present. The formalism is also extended to deal with different bases for each of the wave functions. Several practical results concerning the evaluation of pfaffians, as well as the canonical decomposition of norm overlaps, are also discussed in the Appendices.

Angular distributions for the elastic scattering of ${}^8\mathrm{B}$, ${}^7\mathrm{Be}$, and ${}^6\mathrm{Li}$ on a ${}^{12}\mathrm{C}$ target have been measured at $E_{\mathrm{lab}}=25.8$, 18.8, and 12.3 MeV, respectively. The analyses of these angular distributions have been performed in terms of the optical model using Woods-Saxon and double-folding type potentials. The effect of breakup in the elastic scattering of ${}^8\mathrm{B}+{}^{12}\mathrm{C}$ is investigated by performing coupled-channels calculations with the continuum discretized coupled-channel method and cluster-model folding potentials. Total reaction cross sections were deduced from the elastic-scattering analysis and compared with published data on elastic scattering of other weakly and tightly bound projectiles on ${}^{12}\mathrm{C}$, as a function of energy. With the exception of ${}^4\mathrm{He}$ and ${}^{16}\mathrm{O}$, the data can be described using a universal function for the reduced cross sections.

An effective nucleon-nucleon interaction adapted to cluster-model calculations of collisions is derived from the realistic Argonne potential AV18 with the unitary correlation operator method. The unitary correlation is determined from the $\alpha +\alpha$ elastic phase shifts calculated in a cluster approach by the generator coordinate method coupled with the microscopic $R$-matrix method. With this interaction, the elastic phase shifts for the $\alpha +n$, $\alpha +p$, and $\alpha +{}^3\mathrm{He}$ collisions are calculated within the same model. Without further adjustment, a good agreement with experimental data is obtained with a small model space.

The $S$-wave ${\Sigma }_c\overline{D}$ and ${\Lambda }_c\overline{D}$ states with isospin $I=1/2$ and spin $S=1/2$ are dynamically investigated within the framework of a chiral constituent quark model by solving a resonating group method equation. The results show that the interaction between ${\Sigma }_c$ and $\overline{D}$ is attractive, which consequently results in a ${\Sigma }_c\overline{D}$ bound state with a binding energy of about $5-42$ MeV, unlike the case of the ${\Lambda }_c\overline{D}$ state, which has a repulsive interaction and thus is unbound. The channel-coupling effect of ${\Sigma }_c\overline{D}$ and ${\Lambda }_c\overline{D}$ is found to be negligible owing to the fact that the gap between the ${\Sigma }_c\overline{D}$ and ${\Lambda }_c\overline{D}$ thresholds is relatively large and the ${\Sigma }_c\overline{D}$ and ${\Lambda }_c\overline{D}$ transition interaction is weak.

We analyze the elliptic flow parameter $v_2$ in Pb+Pb collisions at $\sqrt{s_{\mathit{NN}}}$ $=$ 2.76 TeV and in Au+Au collisions at $\sqrt{s_{\mathit{NN}}}=200$ GeV using a hybrid model in which the evolution of the quark gluon plasma is described by ideal hydrodynamics with a state-of-the-art lattice QCD equation of state, and the subsequent hadronic stage by a hadron cascade model. For initial conditions, we employ Monte Carlo versions of the Glauber and the Kharzeev-Levin-Nardi models and compare results with each other. We demonstrate that the differential elliptic flow $v_2(p_T)$ hardly changes when the collision energy increases, whereas the integrated $v_2$ increases due to the enhancement of mean transverse momentum. The amount of increase of both $v_2$ and mean $p_T$ depends significantly on the model of initialization.

High-spin excited states in the neutron-rich nucleus ${}^{115}\mathrm{Rh}$ have been identified for the first time by studying prompt $\gamma$ rays from the spontaneous fission of ${}^{252}\mathrm{Cf}$ with the Gammasphere detector array. A new yrast band and a sideband are built in ${}^{115}\mathrm{Rh}$. This level scheme is proposed to be built on the $7/2^{+}$ ground state. The existence of a large signature splitting and an yrare band in ${}^{115}\mathrm{Rh}$ shows typical features of a triaxially deformed nucleus. The rigid triaxial rotor plus particle model is used to interpret the level structure of ${}^{115}\mathrm{Rh}$. The level energies, the $\gamma$ branching ratios, the large signature splitting in the yrast band, and the inverted signature splitting in the yrare band in ${}^{115}\mathrm{Rh}$ are reproduced very well. Strong $K$ mixing occurs in ${}^{115}\mathrm{Rh}$ at high spin.

The impact of particle-vibration coupling and polarization effects due to deformation and time-odd mean fields on single-particle spectra is studied systematically in doubly magic nuclei from low-mass ${}^{56}\mathrm{Ni}$ up to superheavy ones. Particle-vibration coupling is treated fully self-consistently within the framework of the relativistic particle-vibration coupling model. Polarization effects due to deformation and time-odd mean field induced by odd particle are computed within covariant density functional theory. It has been found that among these contributions the coupling to vibrations makes a major impact on the single-particle structure. The impact of particle-vibration coupling and polarization effects on calculated single-particle spectra, the size of the shell gaps, the spin-orbit splittings and the energy splittings in pseudospin doublets is discussed in detail; these physical observables are compared with experiment. Particle-vibration coupling has to be taken into account when model calculations are compared with experiment since this coupling is responsible for observed fragmentation of experimental levels; experimental spectroscopic factors are reasonably well described in model calculations.

The spectroscopy of ${}^{21}\mathrm{O}$ has been investigated using a radioactive ${}^{20}\mathrm{O}$ beam and the ($d$,$p$) reaction in inverse kinematics. The ground and first excited states have been determined to be $J^{\pi }$$=5/2^{+}$ and $1/2^{+}$, respectively. Two neutron unbound states were observed at excitation energies of 4.77(10) and 6.17(11) MeV. The spectroscopic factor deduced for the lower of these, interpreted as a 3/$2^{+}$ level, reveals a relatively pure ($60\%$) $0d_{3/2}$ single-particle configuration, in good agreement with shell-model calculations that predict ${}^{26}\mathrm{O}$ to be unbound. The large energy difference between the $3/2^{+}$ and $1/2^{+}$ states is indicative of the emergence of the $N=16$ shell gap, which is estimated to be 5.1(11) MeV. For the higher-lying resonance, which has a character consistent with a spin-parity assignment of $3/2^{+}$ or $7/2^{-}$, a 0.71(22) branching ratio to the first $2^{+}$ state in ${}^{20}\mathrm{O}$ has been observed.

Corrections to the ratio of electron capture (EC) rates in hydrogen- and helium-like ions are calculated. We find that the most significant contribution is the electron screening effect. The correction has a simple form $(1-5/16Z){}^3(1-{\delta }_3)$ which ranges from almost $50\%$ in helium to $1\%$ in heavier nuclei. We discuss also EC in helium-like ions accompanied by an emission of the remaining electron into the continuum, a new decay channel, for which we calculate the decay probability. It is a very exotic type of Auger electron emission.

Microscopic energy density functionals have become a standard tool for nuclear structure calculations, providing an accurate global description of nuclear ground states and collective excitations. For spectroscopic applications, this framework has to be extended to account for collective correlations related to restoration of symmetries broken by the static mean field, and for fluctuations of collective variables. In this paper, we compare two approaches to five-dimensional quadrupole dynamics: the collective Hamiltonian for quadrupole vibrations and rotations and the interacting boson model (IBM). The two models are compared in a study of the evolution of nonaxial shapes in Pt isotopes. Starting from the binding energy surfaces of ${}^{192,194,196}\mathrm{Pt}$, calculated with a microscopic energy density functional, we analyze the resulting low-energy collective spectra obtained from the collective Hamiltonian, and the corresponding IBM Hamiltonian. The calculated excitation spectra and transition probabilities for the ground-state bands and the $\gamma$-vibration bands are compared to the corresponding sequences of experimental states.

In the framework of a Skyrme-Hartree-Fock approach combined with Bardeen-Cooper-Schrieffer (BCS) method, the role of the tensor force on the pseudospin energy splitting for tin isotope chain is investigated. The tensor force turns out to obviously affect the pseudospin energy splitting of the spin-unsaturated nuclei. Since the tensor force shifts the single-particle levels, it modifies the single-particle level density and the shell correction energy thereof. The influence of the tensor interaction on shell correction energy is considerable according to our analysis taking a magic nucleus ${}^{132}\mathrm{Sn}$ as well as a superheavy nucleus ${}^{298}114$ as examples. This modification of the shell correction energy due to the tensor component affects the stability of the superheavy nuclei.

Semi-inclusive deep inelastic scattering off the deuteron with production of a slow nucleon in recoil kinematics is studied in the virtual nucleon approximation, in which the final-state interaction (FSI) is calculated within generalized eikonal approximation. The cross section is derived in a factorized approach, with a factor describing the virtual photon interaction with the off-shell nucleon and a distorted spectral function accounting for the final-state interactions. One of the main goals of the study is to understand how much the general features of the diffractive high-energy soft rescattering accounts for the observed features of FSI in deep inelastic scattering (DIS). Comparison with the Jefferson Lab data shows good agreement in the covered range of kinematics. Most importantly, our calculation correctly reproduces the rise of the FSI in the forward direction of the slow nucleon production angle. By fitting our calculation to the data we extracted the $W$ and $Q^2$ dependencies of the total cross section and slope factor of the interaction of DIS products, $X$, off the spectator nucleon. This analysis shows the $\mathit{XN}$-scattering cross section rising with $W$ and decreasing with an increase of $Q^2$. Finally, our analysis points at a largely suppressed off-shell part of the rescattering amplitude.