The electromagnetic transition rates for all the high spin levels of the yrast sequence of ${}^{109}\mathrm{Ag}$ have been measured. The observed behavior of the magnetic dipole transition rates as a function of angular momentum establishes that there is a sudden change in rotation axis associated with rotational alignment of two neutrons. The projected shell model calculations give a consistent picture of the observed phenomena in ${}^{109}\mathrm{Ag}$.

The tilted axis cranking formalism is implemented in relativistic mean field (RMF) theory. It is used for a microscopic description of magnetic rotation in the framework of covariant density functional theory. We assume that the rotational axis is in the $\mathit{xz}$ plane and consider systems with the two symmetries $\mathcal{P}$ (space reflection) and ${\mathcal{P}}_y\mathcal{T}$ (a combination of a reflection in the $y$ direction and time reversal). A computer code based on these symmetries is developed, and first applications are discussed for the nucleus ${}^{142}\mathrm{Gd}$: the rotational band based on the configuration $\pi h_{11/2}^2\otimes \nu h_{11/2}^{-2}$ is investigated in a fully microscopic and self-consistent way. The results are compared with available data, such as spectra and electromagnetic transition ratios $B(M1)/B(E2)$. The relation between rotational velocity and angular momentum are discussed in detail together with the shears mechanism characteristic of magnetic rotation.

We study the details of the U(3)–O(4) quantum phase transition in the U(4) vibron model. Both asymptotic analysis in the classical limit and rigorous calculations for finite boson number systems indicate that a second-order phase transition is still there even for the systems with boson number $N$ ranging from tens to hundreds. Two kinds of effective order parameters, including $E1$ transition ratios $B(E1:2_1\to 1_1)/B(E1:1_1\to 0_1)$ and $B(E1:0_2\to 1_1)/B(E1:1_1\to 0_1)$, and the energy ratios $E_{2_1}/E_{0_2}$ and $E_{3_1}/E_{0_2}$ are proposed to identify the second-order phase transition in experiments. We also found that the critical point of phase transition can be approximately described by the E(3) symmetry, which persists even for moderate $N~10$ protected by the scaling behaviors of quantities at the critical point. In addition, a possible empirical example exhibiting roughly the E(3) symmetry is discussed.

A smooth necking region between fission fragments is obtained by rolling a sphere around the symmetry axis of the nuclear shape formed by two intersected spheroids. The potential generated by the necking nucleons is obtained from potential theory, imposing the condition of equipotentiality on the nuclear surface. The final result is a two-Nilsson type potential linked by the necking potential. The proton and neutron level scheme is calculated for ${}^{236}\mathrm{Pu}$ along the ${}^{92}\mathrm{Se}\hspace{0.5em}+\hspace{0.5em}{}^{144}\mathrm{Nd}$ fission channel, and a gap is obtained for a certain neck geometry, leading to a negative proton shell correction energy able to accommodate a shape isomer.

Four isotopes of rutherfordium, ${}^{254-257}\mathrm{Rf}$, were produced by the ${}^{208}\mathrm{Pb}({}^{48}\mathrm{Ti},\hspace{0.5em}\mathit{xn}){}^{256-x}\mathrm{Rf}$ and ${}^{208}\mathrm{Pb}({}^{50}\mathrm{Ti},\hspace{0.5em}\mathit{xn}){}^{258-x}\mathrm{Rf}$ reactions ($x=1,2$) at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. Excitation functions were measured for the $1n$ and $2n$ exit channels. A maximum likelihood technique, which correctly accounts for the changing cross section at all energies subtended by the targets, was used to fit the $1n$ data to allow a more direct comparison between excitation functions obtained under different experimental conditions. The maximum $1n$ cross sections of the ${}^{208}\mathrm{Pb}({}^{48}\mathrm{Ti},\hspace{0.5em}n){}^{255}\mathrm{Rf}$ and ${}^{208}\mathrm{Pb}({}^{50}\mathrm{Ti},\hspace{0.5em}n){}^{257}\mathrm{Rf}$ reactions obtained from fits to the experimental data are $0.38\pm 0.07$ nb and $40\pm 5$ nb, respectively. Excitation functions for the 2$n$ exit channel were also measured, with maximum cross sections of $0.{40}_{-0.17}^{+0.27}$ nb for the ${}^{48}\mathrm{Ti}$ induced reaction, and $15.7\pm 0.2$ nb for the ${}^{50}\mathrm{Ti}$ induced reaction. The impact of the two neutron difference in the projectile on the $1n$ cross section is discussed. The results are compared to the Fusion by Diffusion model developed by Świa˛tecki, Wilczyńska, and Wilczyński.

The problem of forward production of hadrons in heavy-ion collisions at RHIC is revisited with a modification of the theoretical treatment on the one hand and with the use of new data on the other. The basic formalism for hadronization remains the same as before, namely, recombination, but the details of momentum degradation and quark regeneration are improved. Recent data on the $p/\pi$ and $\overline{p}/p$ ratios are used to constrain the value of the degradation parameter. The transverse momentum ($p_T$) spectrum of the average charged particles is well reproduced. A prediction on the $p_T$ dependence of the $\overline{p}/p$ ratio at $\eta =3.2$ is made.

We investigate the dynamics of the critical isoscalar condensate, formed during heavy-ion collisions. Our analysis is based on a simplified model in which the σ's and the pions are the only degrees of freedom. In field description, both in physical and momentum space, we find that the freeze-out profile presents a structure that reveals clear traces of the critical fluctuations in the σ component. In particle representation, using Monte Carlo simulations and factorial moment analysis, we show that signatures of the initial criticality survive at the detected pions. We propose the distribution of suitably defined intermittency indices, incorporating dynamical effects due to σ-pion interaction, as the basic observable for the exploration of critical fluctuations in heavy-ion collision experiments.

We perform numerical simulations of the SU(2) Boltzmann-Vlasov equation including both hard elastic particle collisions and soft interactions mediated by classical Yang-Mills fields. Using this technique we calculate the momentum-space broadening of high-energy jets in real time for both locally isotropic and anisotropic plasmas. In both cases we introduce a separation scale that separates hard and soft interactions and demonstrate that our results for jet broadening are independent of the precise separation scale chosen. For an isotropic plasma this allows us to calculate the jet transport coefficient $\widehat{q}$ including hard and soft nonequilibrium dynamics. For an anisotropic plasma the jet transport coefficient becomes a tensor with ${\widehat{q}}_L\ne {\widehat{q}}_{\perp }$. We find that for weakly coupled anisotropic plasmas the fields develop unstable modes, forming configurations where $B_{\perp }>E_{\perp }$ and $E_z>B_z$, which lead to ${\widehat{q}}_L>{\widehat{q}}_{\perp }$. We study whether the effect is strong enough to explain the experimental observation that high-energy jets traversing the plasma perpendicular to the beam axis experience much stronger broadening in rapidity, $\Delta \eta$, than in azimuth, $\Delta \varphi$.

We study a strong suppression of the relative production rate ($d$-Au)/($p\text{−}p$) for inclusive high-$p_T$ hadrons of different species at large forward rapidities (large Feynman $x_F$). The model predictions calculated in the light-cone dipole approach are in a good agreement with the recent measurements by the BRAHMS and STAR Collaborations at the BNL Relativistic Heavy Ion Collider. We predict a similar suppression at large $p_T$ and large $x_F$ also at lower energies, where no effect of coherence is possible. This allows us to exclude the saturation models or the models based on Color Glass Condensate from interpretation of nuclear effects.

The nuclear $K$-shell electron-capture (EC) and positron (${\beta }^{+}$) decay constants, ${\lambda }_{\mathrm{EC}}$ and ${\lambda }_{{\beta }^{+}}$ of H-like ${}^{140}{\mathrm{Pr}}^{58+}$ and He-like ${}^{140}{\mathrm{Pr}}^{57+}$ ions, measured recently in the experimental storage ring (ESR) at GSI, were calculated using standard weak interaction theory. The calculated ratios $R={\lambda }_{\mathrm{EC}}/{\lambda }_{{\beta }^{+}}$ of the decay constants agree with the experimental values within an accuracy better than 3%.

The ${\nu }_e$-${}^{56}\mathrm{Fe}$ cross section is evaluated in the projected quasiparticle random phase approximation (PQRPA). This model solves the puzzle observed in RPA for nuclei with mass around ${}^{12}\mathrm{C}$, because it is the only RPA model that treats the Pauli Principle correctly. The cross sections as a function of the incident neutrino energy are compared with recent theoretical calculations of similar models. The average cross section weighted with the flux spectrum yields a good agreement with the experimental data. The expected number of events in the detection of supernova neutrinos is calculated for the LVD detector, leading to an upper limit for the electron neutrino energy of particular importance in this experiment.

Using ideas from BCS descriptions of systems of fermions, a covariant extension of the relativistic Fermi gas model is presented as a way to incorporate correlation effects in nuclei. The model is developed for the BCS nuclear ground state and for final states consisting of a single plane-wave nucleon plus a BCS recoiling daughter nucleus. The nuclear spectral function is obtained, and from it the superscaling function for use in treating high-energy quasielastic electroweak processes. Interestingly, this model has the capability of yielding the asymmetric tail seen in the experimental scaling function.

The energy and angular dependence of the double differential cross sections $d^2\sigma /d\Omega \mathit{dE}$ were measured for $p,d,t,$${}^{3,4,6}\mathrm{He}$, ${}^{6,7,8,9}\mathrm{Li}$, ${}^{7,9,10}\mathrm{Be}$, and ${}^{10,11,12}\mathrm{B}$ isotopes produced in reactions of 1.2- and 1.9-GeV protons on a Au target. The beam energy dependence of the data, supplemented by the cross sections from a previous experiment at 2.5 GeV, is very smooth. The shape of the spectra and angular distributions do not change significantly in the beam energy range from 1.2 to 2.5 GeV. However, the absolute value of the cross sections increases for all ejectiles. The intermediate mass fragment spectra and their angular distributions are very well reproduced by a phenomenological model of two emitting, moving sources, with parameters smoothly varying with energy. The double differential cross sections for light charged particles were analyzed in the framework of the microscopic model calculations of intranuclear cascade, including the coalescence of nucleons and a statistical model for evaporation of particles from excited residual nuclei. However, the energy and angular dependencies of the data agree with neither predictions of the microscopic intranuclear cascade calculations for protons nor the coalescence calculations for other light charged particles. A very good description of the data is achieved by the phenomenological inclusion of the emission of light charged particles from a “fireball” (i.e., a fast and hot moving source). It was found that the nonequilibrium processes are very important for the production of light charged particles. They exhaust 40%–80% of the total cross section—depending on the emitted particles. Coalescence and fireball emission yield comparable contributions to the cross sections with the exception of the ${}^3\mathrm{He}$ data where coalescence clearly dominates. For all light charged particles, the ratio of nonequilibrium processes to processes proceeding through a phase of statistical equilibrium does not change significantly between the beam energies of 1.2 and 2.5 GeV.

Event-by-event multiplicity fluctuations in central C$+$C, S$+$S, In$+$In, and Pb$+$Pb as well as $p+p$ collisions at bombarding energies from 10 to 160 AGeV are studied within the hadron string dynamics and ultrarelativistic quantum molecular dynamics microscopic transport approaches. Our investigation is directly related to the future experimental program of the NA61 Collaboration at the SPS for a search of the quantum chromodynamics (QCD) critical point. The dependence on energy and atomic mass number of the scaled variances for negative, positive, and all charged hadrons is presented and compared to the results of the model of independent sources. Furthermore, the nucleus-nucleus results from the transport calculations are compared to inelastic proton-proton collisions for reference. We find a dominant role of the participant number fluctuations in nucleus-nucleus reactions at finite impact parameter $b$. To reduce the influence of the participant numbers fluctuations on the charged particle multiplicity fluctuations only the most central events have to be selected. Accordingly, the samples of the 1% most central nucleus-nucleus collisions with the largest numbers of the projectile participants are studied. The results are compared with those for collisions at zero impact parameter. A strong influence of the centrality selection criteria on the multiplicity fluctuations is pointed out. Our findings are essential for an optimal choice of colliding nuclei and bombarding energies for the experimental search of the QCD critical point.

A $\overline{K}\overline{K}N$ system with $I=1/2$ and $J^P=1/2^{+}$ is investigated with nonrelativistic three-body calculations by using effective $\overline{K}N$ and $\overline{K}\overline{K}$ interactions. The present investigation suggests that a weakly bound state for the $\overline{K}\overline{K}N$ system can be formed below the two-body threshold of $\overline{K}$ and quasibound $\overline{K}N$ with a $40~60$ MeV decay width of $\overline{K}\overline{K}N\to \pi Y\overline{K}$. This corresponds to an excited $\Xi$ baryon with $J^P=1/2^{+}$ located around 1.9 GeV. Studying the wave function of the $\overline{K}\overline{K}N$ system obtained in this formulation, we find that the three-body bound system has a characteristic structure of $\overline{K}N+\overline{K}$ cluster with spatial extent.

The rate of the hydrogen-burning carbon-nitrogen-oxygen (CNO) cycle is controlled by the slowest process, ${}^{14}\mathrm{N}(p,\gamma ){}^{15}\mathrm{O}$, which proceeds by capture to the ground and several excited states in ${}^{15}\mathrm{O}$. Previous extrapolations for the ground state contribution disagreed by a factor 2, corresponding to 15% uncertainty in the total astrophysical $S$ factor. At the Laboratory for Underground Nuclear Astrophysics (LUNA) 400 kV accelerator placed deep underground in the Gran Sasso facility in Italy, a new experiment on ground state capture has been carried out at 317.8, 334.4, and 353.3 keV center-of-mass energy. Systematic corrections have been reduced considerably with respect to previous studies by using a Clover detector and by adopting a relative analysis. The previous discrepancy has been resolved, and ground state capture no longer dominates the uncertainty of the total $S$ factor.

It is well known that the Pauli principle plays a substantial role at low energies because the quasiparticle and phonon operators, used to describe them, are built of fermions and as a consequence they are not ideal bosons. The correct treatment of this problem requires calculation of the exact commutators between the quasiparticle and phonon operators and in this way to take into account the Pauli principle corrections. In addition to the correlations due to the quasiparticle interaction in the ground-state influence the single-particle fragmentation as well. In this article, we generalize the basic equations of the quasiparticle-phonon nuclear model to account for both effects mentioned above. As an illustration of our approach, calculations of the structure of the low-lying states in the odd-mass nuclei ${}^{131-137}\mathrm{Ba}$ have been performed.

The lowest-known excited state in nuclei is the 7.6 eV isomer of ${}^{229}\mathrm{Th}$. This energy is within the range of laser-based investigations that could allow accurate measurements of possible temporal variation of this energy splitting. This in turn could probe temporal variation of the fine-structure constant or other parameters in the nuclear Hamiltonian. We investigate the sensitivity of this transition energy to these quantities. We find that the two states are predicted to have identical deformations and thus the same Coulomb energies within the accuracy of the model (viz., within roughly 30 keV). We therefore find no enhanced sensitivity to variation of the fine-structure constant. In the case of the strong interaction the energy splitting is found to have a complicated dependence on several parameters of the interaction, which makes an accurate prediction of sensitivity to temporal changes of fundamental constants problematical. Neither the strong- nor Coulomb-interaction contributions to the energy splitting of this doublet can be constrained within an accuracy better than a few tens of keV, so that only upper limits can be set on the possible sensitivity to temporal variations of the fundamental constants.

A new mass table calculated by the relativistic mean-field approach with the state-dependent BCS method for the pairing correlation is applied for the first time to study $r$-process nucleosynthesis. The solar $r$-process abundance is well reproduced within a waiting-point approximation approach. Using an exponential fitting procedure to find the required astrophysical conditions, the influence of mass uncertainty is investigated. The $r$-process calculations using the FRDM, ETFSI-Q, and HFB-13 mass tables have been used for that purpose. It is found that the nuclear physical uncertainty can significantly influence the deduced astrophysical conditions for the $r$-process site. In addition, the influence of the shell closure and shape transition have been examined in detail in the $r$-process simulations.

The composition and equation of state of the outer crust of nonaccreting neutron stars is computed by using accurate nuclear mass tables. The main goal of the present study is to understand the impact of the symmetry energy on the structure of the outer crust. First, a simple “toy model” is developed to illustrate the competition between the electronic density and the symmetry energy. Then, realistic mass tables are used to show that models with a stiff symmetry energy—those that generate large neutron skins for heavy nuclei—predict a sequence of nuclei in the stellar environment that is more neutron rich than their softer counterparts. This result may be phrased in the form of a correlation: The larger the neutron skin of ${}^{208}\mathrm{Pb}$, the more exotic the composition of the outer crust.