Isomers have been populated in ${}^{246}\mathrm{Cm}$ and ${}^{252}\mathrm{No}$ with quantum numbers $K^{\pi }=8^{-}$, which decay through $K^{\pi }=2^{-}$ rotational bands built on octupole vibrational states. For $N=150$ isotones with (even) atomic number $Z=94–102$, the $K^{\pi }=8^{-}$ and $2^{-}$ states have remarkably stable energies, indicating neutron excitations. An exception is a singular minimum in the $2^{-}$ energy at $Z=98$, due to the additional role of proton configurations. The nearly constant energies, in isotones spanning an 18% increase in Coulomb energy near the Coulomb limit, provide a test for theory. The two-quasiparticle $K^{\pi }=8^{-}$ energies are described with single-particle energies given by the Woods-Saxon potential and the $K^{\pi }=2^{-}$ vibrational energies by quasiparticle random-phase approximation calculations. Ramifications for self-consistent mean-field theory are discussed.

Using the transient field technique, the magnetic moments of the second excited $2^{+}$ states in ${}^{92,94}\mathrm{Zr}$ have been measured for the first time. The large positive $g$ factors, $g(2_2^{+};{}^{92}\mathrm{Zr})=+0.76(50)$ and $g(2_2^{+};{}^{94}\mathrm{Zr})=+0.88(27)$, which are in contrast to the known negative $g$ factors of the $2_1^{+}$ states, are found to be a consequence of weak proton-neutron coupling combined with the $Z=40$ subshell closure. From their large $M1$ transition strengths to the $2_1^{+}$ states, in earlier works an assignment to the $2_2^{+}$ states as proton-neutron symmetric and mixed-symmetry states has been made, which are now found to be polarized in their proton-neutron content. This fact allows to identify the underlying microscopic main configurations in the wave functions, which form the building blocks of symmetric and mixed-symmetry states in this region as valence nucleons are added and shell structure changes.

Excitation functions for the $1n$ and $2n$ exit channels of the ${}^{208}\mathrm{Pb}({}^{51}\mathrm{V},\mathit{xn}){}^{259\text{−}x}\mathrm{Db}$ reaction were measured. A maximum cross section of the $1n$ exit channel of ${2070}_{-760}^{+1100}$ pb was measured at an excitation energy of 16.0 $\pm$ 1.8 MeV. For the $2n$ exit channel, a maximum cross section of ${1660}_{-370}^{+450}$ pb was measured at 22.0 $\pm$ 1.8 MeV excitation energy. The $1n$ excitation function for the ${}^{209}\mathrm{Bi}({}^{50}\mathrm{Ti},n){}^{258}\mathrm{Db}$ reaction was remeasured, resulting in a cross section of ${5480}_{-1370}^{+1730}$ pb at an excitation energy of 16.0 $\pm$ 1.6 MeV, in agreement with previous values [F. P. Heßberger et al., Eur. Phys. J. A 12, 57 (2001)]. Differences in cross section maxima are discussed in terms of the fusion probability below the barrier.

The in-medium spectral functions of ρ and ω mesons and the broadening of nucleon resonances at finite baryon density are calculated self-consistently by combining a resonance dominance model for the vector meson production with an extended vector meson dominance model. The influence of the in-medium modifications of the vector meson properties on the dilepton spectrum in heavy-ion collisions is investigated. The dilepton spectrum is generated for the $\mathrm{C}+\mathrm{C}$ reaction at 2.0$A$ GeV and compared with recent HADES Collaboration data. The collision dynamics is then described by the Tübingen relativistic quantum molecular dynamics transport model. We find that an iterative calculation of the vector meson spectral functions that takes into account the broadening of the nucleon resonances due to their increased in-medium decay branchings is convergent and provides a reasonable description of the experimental data in the mass region $0.45⩽M⩽0.75$ GeV. On the other side, the theoretical calculations slightly underestimate the region $m_{\pi }⩽M⩽0.4$ GeV. Popular in-medium scenarios such as a schematic collisional broadening and dropping vector mesons masses are discussed as well.

Recently, it has been demonstrated that the chemical composition of jets in heavy ion collisions is significantly altered compared to the jets in the vacuum. This signal can be used to probe the medium formed in nuclear collisions. In this study we investigate the possibility that fast light quarks and gluons can convert to heavy quarks when passing through a quark-gluon plasma. We study the rate of light to heavy jet conversions in a consistent Fokker-Planck framework and investigate their impact on the production of high-$p_T$ charm and bottom quarks at the Relativistic Heavy Ion Collider and the Large Hadron Collider.

Obtaining cross sections for nuclear reactions at intermediate energies based on the Glauber formulation has a long tradition. Only recently the energy regime of a few hundred MeV has become accessible to ab initio Faddeev calculations of three-body scattering. In order to go to higher energies, the Faddeev equation for three-body scattering is formulated and directly solved without employing a partial wave decomposition. In the simplest form the Faddeev equation for interacting scalar particles is a three-dimensional integral equation in five variables, from which the total cross section, the cross sections for elastic scattering and breakup reactions, as well as differential cross sections are obtained. The same observables are calculated based on the Glauber formulation. The first order Glauber calculation and the Glauber rescattering corrections are compared in detail with the corresponding terms of the Faddeev multiple scattering series for projectile energies between 100 MeV and 2 GeV.

The ${}^{44}\mathrm{Ar}$($d,p$)${}^{45}\mathrm{Ar}$ neutron transfer reaction was performed at $10A$ MeV. Measured excitation energies, deduced angular momenta, and spectroscopic factors of the states populated in ${}^{45}\mathrm{Ar}$ are reported. A satisfactory description of these properties is achieved in the shell model framework using a new $\mathit{sdpf}$ interaction. The model analysis is extended to more exotic even-$Z$ nuclei down to ${}_{14}^{41}{\mathrm{Si}}_{27}$ to study how collectivity impacts the low-lying structure of $N=27$ neutron-rich nuclei.

We investigate phase transitions for the Walecka model at very high temperatures. As is well known, depending on the parametrization of this model and for the particular case of a zero chemical potential ($\mu$), a first-order phase transition is possible [J. Theis, G. Graebner, G. Buchwald, J. A. Maruhn, W. Greiner, H. Stocker, and J. Polonyi, Phys. Rev. D 28, 2286 (1983)]. We investigate this model for the case in which $\mu \ne 0$. It turns out that, in this situation, phases with different values of antinucleon-nucleon ratios and net baryon densities may coexist. We present the temperature versus antinucleon-nucleon ratio as well as the temperature versus the net baryon density for the coexistence region. The temperature versus chemical potential phase diagram is also presented.

New measurements of differential and total cross sections for the ${}^{12}\mathrm{C}(p,\gamma ){}^{13}\mathrm{N}$ reaction have been made at beam energies of $E_p=354,390,460,463,565,750$, and 1061 keV. Analysis of the astrophysical $S$ factor $S(E)$ for the ${}^{12}\mathrm{C}(p,\gamma ){}^{13}\mathrm{N}$ reaction at low energies and of the reaction rates has been carried out within the R-matrix approach by using the previously measured nuclear vertex constant (or the respective asymptotic normalization coefficient) for the virtual decay ${}^{13}\mathrm{N}\to p+{}^{12}\mathrm{C}$ to fix the direct capture part of the amplitude in $S(E)$. It is demonstrated that the R-matrix approach, using the measured asymptotic normalization coefficient, can be employed as an ideal tool, minimizing the uncertainties associated with a calculation of the direct capture cross section of the ${}^{12}\mathrm{C}(p,\gamma ){}^{13}\mathrm{N}$ reaction at extremely low energies. New information on the proton and $\gamma$ width for the first excited state of ${}^{13}\mathrm{N}$ is obtained.

The correlation between the nuclear stopping and the scale invariant nucleon sideward flow at energies ranging from those available at the GSI heavy ion synchrotron (SIS) to those at the CERN Super Proton Synchrotron (SPS) is studied within ultrarelativistic quantum molecular dynamics (UrQMD). The universal behavior of the two experimental observables for various colliding systems and scale impact parameters are found to be highly correlated with each other. As there is no phase transition mechanism involved in the UrQMD, the correlation may be broken down by the sudden change of the bulk properties of the nuclear matter, such as the formation of quark-gluon plasma (QGP), which can be employed as a QGP phase transition signal in high-energy heavy ion collisions. Furthermore, we also point out that the appearance of a breakdown of the correlation may be a powerful tool for searching for the critical point on the QCD phase diagram.

We discuss the least-squares and linear-regression methods, which are relevant for a reliable determination of good nuclear-mass-model parameter sets and their errors. In this perspective, we define exact and inaccurate models and point out differences in using the standard error analyses for them. As an illustration, we use simple analytic models for nuclear binding energies and study the validity and errors of models’ parameters and uncertainties of its mass predictions. In particular, we show explicitly the influence of mass-number-dependent weights on uncertainties of liquid-drop global parameters.

We present a Monte Carlo simulation of the perturbative quantum chromodynamics shower developing after a hard process embedded in a heavy-ion collision. The main assumption is that the cascade of branching partons traverses a medium that (consistent with standard radiative energy loss pictures) is characterized by a local transport coefficient $\widehat{q}$ that measures the virtuality per unit length transferred to a parton that propagates in this medium. This increase in parton virtuality alters the development of the shower and in essence leads to extra induced radiation and hence a softening of the momentum distribution in the shower. After hadronization, this leads to the concept of a medium-modified fragmentation function. On the level of observables, this is manifest as the suppression of high-transverse-momentum ($P_T$) hadron spectra. We simulate the soft medium created in heavy-ion collisions by a 3D hydrodynamical evolution and average the medium-modified fragmentation function over this evolution to compare with data on single inclusive hadron suppression and extract the $\widehat{q}$ that characterizes the medium. Finally, we discuss possible uncertainties of the model formulation and argue that the data in a soft momentum show evidence of qualitatively different physics that presumably cannot be described by a medium-modified parton shower.

The production of prompt photons at high energies provides a direct probe of the dynamics of strong interactions. In particular, one expects that it could be used to constrain the behavior of the nuclear gluon distribution in $\mathit{pA}$ and $\mathit{AA}$ collisions. In this brief report, we investigate the influence of nuclear effects in the production of prompt photons and estimate the transverse momentum dependence of the nuclear ratios $R_{\mathit{pA}}=\frac{d\sigma (\mathit{pA})}{\mathit{dy}\hspace{0.5em}{d}^2{p}_T}/A\frac{d\sigma (\mathit{pp})}{\mathit{dy}\hspace{0.5em}{d}^2{p}_T}$ and $R_{\mathit{AA}}=\frac{d\sigma (\mathit{AA})}{\mathit{dy}\hspace{0.5em}{d}^2{p}_T}/A^2\frac{d\sigma (\mathit{pp})}{\mathit{dy}\hspace{0.5em}{d}^2{p}_T}$ at at energies currently available at the BNL Relativistic Heavy Ion Collider and CERN Large Hadron Collider. We demonstrate that the study of these observables can be useful in determining the magnitude of the shadowing and antishadowing effects in the nuclear gluon distribution.

The direct comparison of two different continuum discretization methods toward the solution of a composite particle scattering off a nucleus is presented. The first approach—the continuum-discretized coupled-channel method—is based on the differential equation formalism, while the second one—the wave-packet continuum discretization method—uses the integral equation formulation for the composite-particle scattering problem. As benchmark calculations, we have chosen the deuteron off ${}^{58}\mathrm{Ni}$ target scattering (as a realistic illustrative example) at three different incident energies: high, middle, and low. Clear nonvanishing effects of closed inelastic channels at small and intermediate energies are established. The elastic cross sections found in both approaches are very close to each other for all three considered energies.

We present an analysis of $\Omega ,\Xi ,\Lambda$, and $\varphi$ spectra from $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{\mathit{NN}}}=200$ GeV in terms of distributions of effective constituent quarks at hadronization. Consistency in quark ratios derived from various hadron spectra provides clear evidence for hadron formation dynamics as suggested by quark coalescence or recombination models. We argue that the constituent quark distribution reflects properties of the effective partonic degree of freedom at hadronization. Experimental data indicate that strange quarks have a transverse-momentum distribution flatter than that of up/down quarks consistent with hydrodynamic expansion in partonic phase prior to hadronization. Our extracted parton transverse-momentum distributions at the hadronization provide a unique constraint on the partonic evolution history. After the multiphase transport model is tuned to reproduce the strange and up/down quark distributions, the model can describe the measured spectra of hyperons and $\varphi$ mesons very well where hadrons are formed through dynamical coalescence.

Differential cross sections for $\gamma p\to K^{+}\Lambda (1405)$ and $\gamma p\to K^{+}{\Sigma }^0(1385)$ reactions have been measured in the photon energy range from 1.5 to 2.4 GeV and the angular range of $0.8<\cos (\Theta )<1.0$ for the $K^{+}$ scattering angle in the center-of-mass system. This data is the first measurement of the $\Lambda (1405)$ photoproduction cross section. The line shapes of $\Lambda (1405)$ measured in ${\Sigma }^{+}{\pi }^{-}$ and ${\Sigma }^{-}{\pi }^{+}$ decay modes were different with each other, indicating a strong interference of the isospin 0 and 1 terms of the $\Sigma \pi$ scattering amplitudes. The ratios of $\Lambda (1405)$ production to ${\Sigma }^0(1385)$ production were measured in two photon energy ranges: near the production threshold ($1.5<E_{\gamma }<2.0$ GeV) and far from it ($2.0<E_{\gamma }<2.4$ GeV). The observed ratio decreased in the higher photon energy region, which may suggest different production mechanisms and internal structures for these hyperon resonances.

With the aim at quantitatively investigating the longstanding problem concerning the effect of short-range nucleon-nucleon correlations on scattering processes at high energies, the total neutron-nucleus cross section is calculated within a parameter-free approach which, for the first time, takes into account, simultaneously, central, spin, isospin, spin-isospin, and tensor nucleon-nucleon correlations, and Glauber elastic and Gribov inelastic shadowing corrections. Nuclei ranging from ${}^4\mathrm{He}$ to ${}^{208}\mathrm{Pb}$ and incident neutron momenta in the range 3 GeV/$c$–300 GeV/$c$ are considered; the commonly used approach which approximates the square of the nuclear wave function by a product of one-body densities is carefully analyzed, showing that $\mathit{NN}$ correlations can play a non-negligible role in high energy scattering off nuclei