The density profile of a hot nuclear system produced in intermediate-energy heavy ion collisions is studied in a microcanonical formulation with a momentum and density dependent finite range interaction. The caloric curve and density evolution with excitation are calculated for a number of systems for the equilibrium mononuclear configuration; they compare favorably with the recent experimental data. The studied density fluctuations are seen to build up rapidly beyond an excitation energy of $~8$ MeV/u indicating the instability of the system toward nuclear disassembly. Explicit introduction of deformation in the expansion path of the heated nucleus, however, shows that the system might fragment even earlier. We also explore the effects of the nuclear equation of state and of the mass and isospin asymmetry on the nuclear equilibrium configuration and the relevant experimental observables.

A number of theoretical and lattice results lead us to believe that quark-gluon plasma not too far from $T_c$ contains not only electrically charged quasiparticles—quarks and gluons—but magnetically charged ones—monopoles and dyons—as well. Although binary systems such as charge-monopole and charge-dyon were considered in detail before in both classical and quantum settings, this is the first study of coexisting electric and magnetic particles in a many-body context. We perform a molecular dynamics study of strongly coupled plasmas with ∼1000 particles and differing fractions of magnetic charge. Correlation functions and Kubo formulas lead to transport properties such as the diffusion constant, the shear viscosity, and electric conductivity: We compare the first two with empirical data from RHIC experiments as well as with results from anti-de-Sitter space/conformal field theory correspondence. We also study a number of collective excitations in these systems.

The observed limiting fragmentation of charged particle distributions in heavy ion collisions is difficult to explain as it does not apply to the proton spectrum itself. On the other hand, string percolation provides a mechanism to regenerate fast particles, eventually compensating the rapidity shift (energy loss) of the nucleons. However a delicate energy-momentum compensation is required, and in our framework we see no reason for limiting fragmentation to be exact. A prediction, based on percolation arguments, is given for the charged particle density in the full rapidity interval at LHC energy ($\sqrt{s}=5500$ GeV).

We have calculated the ground-state energy of the doubly-magic nucleus ${}^{40}\mathrm{Ca}$ within the framework of the Goldstone expansion using the CD-Bonn nucleon-nucleon potential. The short-range repulsion of this potential has been renormalized by integrating out its high-momentum components so as to derive a low-momentum potential $V_{\mathrm{low}-k}$ defined up to a cutoff momentum Λ. A simple criterion has been employed to establish a connection between this cutoff momentum and the size of the two-nucleon model space in the harmonic oscillator basis. This model-space truncation approach provides a reliable way to renormalize the free nucleon-nucleon potential preserving its many-body physics. The role of the $3p\text{−}3h$ and $4p\text{−}4h$ excitations in the description of the ground state of ${}^{40}\mathrm{Ca}$ is discussed.

I show that the disintegration of weakly-bound nuclei and the ionization of weakly-bound atomic electrons due to their interaction with leptons from β decay is a negligible effect.

The lowest seniority-zero eigenstates of an exactly solvable multilevel pairing Hamiltonian for a finite Fermi system are examined at different pairing regimes. After briefly reviewing the form of the eigenstates in the Richardson formalism, we discuss a different representation of these states in terms of the collective pairs resulting from the diagonalization of the Hamiltonian in a space of two degenerate time-reversed fermions. We perform a two-fold analysis by working both in the fermionic space of these collective pairs and in a space of corresponding elementary bosons. On the fermionic side, we monitor the variations which occur, with increasing the pairing strength, in the structure of both these collective pairs and the lowest eigenstates. On the bosonic side, after reviewing a fermion-boson mapping procedure, we construct exact images of the fermion eigenstates and study their wave function. The analysis allows a close examination of the phenomenon of pair condensation in a finite Fermi system and gives new insights into the evolution of the lowest (seniority-zero) excited states of a pairing Hamiltonian from the unperturbed regime up to a strongly interacting one.

Evaporation residue and fission cross sections of radioactive ${}^{132}\mathrm{Sn}$ on ${}^{64}\mathrm{Ni}$ were measured near the Coulomb barrier. A large subbarrier fusion enhancement was observed. Coupled-channel calculations, including inelastic excitation of the projectile and target, and neutron transfer are in good agreement with the measured fusion excitation function. When the change in nuclear size and shift in barrier height are accounted for, there is no extra fusion enhancement in ${}^{132}\mathrm{Sn}$+${}^{64}\mathrm{Ni}$ with respect to stable Sn+${}^{64}\mathrm{Ni}$. A systematic comparison of evaporation residue cross sections for the fusion of even ${}^{112-124}\mathrm{Sn}$ and ${}^{132}\mathrm{Sn}$ with ${}^{64}\mathrm{Ni}$ is presented.

We study dense nuclear matter and the chiral phase transition in a SU(2) parity doublet model at zero temperature. The model is defined by adding the chiral partner of the nucleon, the $N^{\prime }$, to the linear sigma model, treating the mass of the $N^{\prime }$ as an unknown free parameter. The parity doublet model gives a reasonable description of the properties of cold nuclear matter, and avoids unphysical behavior present in the standard SU(2) linear sigma model. If the $N^{\prime }$ is identified as the $N^{\prime }(1535)$, the parity doublet model shows a first order phase transition to a chirally restored phase at large densities, $\rho \approx 10{\rho }_0$, defining the transition by the degeneracy of the masses of the nucleon and the $N^{\prime }$. If the mass of the $N^{\prime }$ is chosen to be 1.2 GeV, then the critical density of the chiral phase transition is lowered to three times normal nuclear matter density, and for physical values of the pion mass, the first order transition turns into a smooth crossover.

We propose a new model that combines the rigor of full-fledged loop calculations in field theory with the simplicity of the $K$-matrix formalism for channel-coupling effects. We show, for one example, the equivalence of this new model, the renormalized Im-$K$-matrix (RIK) model, with a more standard approach in which nonperturbative loop corrections are calculated. In the RIK model an analytic continuation of the $K$-matrix formalism is combined with a renormalization procedure to arrive at a scattering amplitude that obeys low-energy theorems and is also an analytic function in the complex momentum plane.

Shape coexistence in the light krypton isotopes was studied in two low-energy Coulomb excitation experiments using radioactive ${}^{74}\mathrm{Kr}$ and ${}^{76}\mathrm{Kr}$ beams from the SPIRAL facility at GANIL. The ground-state bands in both isotopes were populated up to the $8^{+}$ state via multi-step Coulomb excitation, and several non-yrast states were observed. Large sets of matrix elements were extracted for both nuclei from the observed γ-ray yields. Diagonal matrix elements were determined by utilizing the reorientation effect. In both isotopes the spectroscopic quadrupole moments for the ground-state bands and the bands based on excited $0_2^{+}$ states are found to have opposite signs. The experimental data are interpreted within a phenomenological two-band mixing model and model-independent quadrupole invariants are deduced for the relevant $0^{+}$ states using the complete sets of matrix elements and the formalism of quadrupole sum rules. Configuration mixing calculations based on triaxial Hartree-Fock-Bogolyubov calculations with the Gogny D1S effective interaction have been performed and are compared both with the experimental results and with recent calculations using the Skyrme SLy6 effective interaction and the full generator-coordinate method restricted to axial shapes.

An extension of the single-freeze-out model with thermal and geometric parameters dependent on the spatial rapidity, ${\alpha }_{\parallel }$, is used to describe the rapidity and transverse-momentum spectra of pions, kaons, protons, and antiprotons measured at the Relativistic Heavy Ion Collider at $\sqrt{s_{\mathit{NN}}}=200\mathrm{GeV}$ by the BRAHMS Collaboration. $\mathrm{THERMINATOR}$ is used to perform the necessary simulation, which includes all resonance decays. The result of the fit to the rapidity spectra in the range of the BRAHMS data is the expected growth of the baryon and strange chemical potentials with the magnitude of ${\alpha }_{\parallel }$, whereas the freeze-out temperature is kept fixed. The value of the baryon chemical potential at ${\alpha }_{\parallel }~3$, which is the relevant region for particles detected at the BRAHMS forward rapidity $y~3$, is about $200\mathrm{GeV}$, i.e., lies in the range of the values obtained for the highest SPS energy. The chosen geometry of the fireball has a decreasing transverse size as the magnitude of ${\alpha }_{\parallel }$ is increased, which also corresponds to decreasing transverse flow. This feature is verified by reproducing the transverse momentum spectra of pions and kaons at various rapidities. The strange chemical potential obtained from the fit to the $K^{+}/K^{-}$ ratio is such that the local strangeness density in the fireball is compatible with zero. The resulting rapidity spectra of net protons are described qualitatively in the model. As a result of the study, the knowledge of the “topography” of the fireball is achieved, making other calculations possible. As an example, we give predictions for the rapidity spectra of hyperons.

We present STAR measurements of the azimuthal anisotropy parameter $v_2$ for pions, kaons, protons, $\Lambda ,\overline{\Lambda },\Xi +\overline{\Xi }$, and $\Omega +\overline{\Omega }$, along with $v_4$ for pions, kaons, protons, and $\Lambda +\overline{\Lambda }$ at midrapidity for Au+Au collisions at $\sqrt{s_{\mathit{NN}}}=62.4$ and 200 GeV. The $v_2(p_T)$ values for all hadron species at 62.4 GeV are similar to those observed in 130 and 200 GeV collisions. For observed kinematic ranges, $v_2$ values at 62.4, 130, and 200 GeV are as little as 10–15% larger than those in Pb+Pb collisions at $\sqrt{s_{\mathit{NN}}}=17.3$ GeV. At intermediate transverse momentum ($p_T$ from 1.5–5 GeV/$c$), the 62.4 GeV $v_2(p_T)$ and $v_4(p_T)$ values are consistent with the quark-number scaling first observed at 200 GeV. A four-particle cumulant analysis is used to assess the nonflow contributions to pions and protons and some indications are found for a smaller nonflow contribution to protons than pions. Baryon $v_2$ is larger than antibaryon $v_2$ at 62.4 and 200 GeV, perhaps indicating either that the initial spatial net-baryon distribution is anisotropic, that the mechanism leading to transport of baryon number from beam- to midrapidity enhances $v_2$ or that antibaryon and baryon annihilation is larger in the in-plane direction.

An experiment has been performed to detect the $\alpha$ emission mode in ${}^{178}\mathrm{Hf}{}^{m2}$ isomer decay and a partial half-life of $(2.5\pm 0.5)\times {10}^{10}$y was measured. It was concluded that $\alpha$ decay is strongly retarded by the centrifugal barrier arising due to the high spin of this isomeric state. Additional analysis shows, however, that the $K$-hindrance in this $\alpha$ decay is relatively weak, despite the strong manifestation of spin-hindrance.

A new transition is reported in the beta-delayed neutron decay of ${}^{18}\mathrm{N}$. The observed neutron energy is 3.78±0.05 MeV with a branching ratio of 0.05±0.03%, which corresponds to an excitation energy of 12.05±0.05 MeV in the daughter nucleus ${}^{18}\mathrm{O}$. The log $\mathit{ft}$ value of this transition is 5.24±0.3, which, together with the previously reported electron scattering data, determines the $J^{\pi }$ value of this level to be $1^{-}$. The experimental data are compared to the shell model calculations in different model spaces.

We present the theoretical study of fragmentation at low excitation energies within dynamical microscopic theory namely, simulated annealing clusterization algorithm (SACA) and quantum molecular dynamics (QMD) model. For low excitation energy reactions, we choose the balance energies for a large number of reactions throughout the periodic table. We see that SACA gives multiplicities in terms of power law. For light fragments, it is close to 1/3, whereas, for heavier fragments it is nearly mass independent suggesting their origin in terms of participant-spectator picture.

We show that $E0$ emission in $\alpha +$ ${}^{12}\mathrm{C}$ fusion at astrophysically interesting energies is negligible compared to $E1$ and $E2$ emission.

In this Comment we point out several problems concerning kinematical singularities which are encountered in the calculation of the dilepton rates by Ruppert and Renk [Phys. Rev. C 71, 064903 (2005)]. We also comment on the method introduced by van Hees and Knoll [Nucl. Phys. A683, 369 (2000)] and further used by Ruppert and Renk [Phys. Rev. C 71, 064903 (2005)], Renk and Ruppert (arXiv:hep-ph/0603110, arXiv:hep-ph/0605130), and Riek and Knoll [Nucl. Phys. A740, 287 (2004)].

The PHENIX experiment at RHIC has measured the invariant cross section for ω-meson production at midrapidity in the transverse momentum range $2.5<p_T<9.25$ GeV/$c$ in $p+p$ and $d$+Au collisions at $\sqrt{s_{\mathit{NN}}}=200$ GeV. Measurements in two decay channels ($\omega \to {\pi }^0{\pi }^{+}{\pi }^{-}$ and $\omega \to {\pi }^0\gamma$) yield consistent results, and the reconstructed ω mass agrees with the accepted value within the $p_T$ range of the measurements. The $\omega /{\pi }^0$ ratio is found to be $0.85\pm 0.{05}^{\mathrm{stat}}\pm 0.{09}^{\mathrm{sys}}$ in $p+p$ and $0.94\pm 0.{08}^{\mathrm{stat}}\pm 0.{12}^{\mathrm{sys}}$ in $d$+Au collisions, independent of $p_T$. The nuclear modification factor $R_{d\mathrm{A}}^{\omega }$ is $1.03\pm 0.{12}^{\mathrm{stat}}\pm 0.{21}^{\mathrm{sys}}$ and $0.83\pm 0.{21}^{\mathrm{stat}}\pm 0.{17}^{\mathrm{sys}}$ in minimum bias and central (0–20%) $d$+Au collisions, respectively.

We report angular distribution measurements of the differential cross section $\sigma (\theta )$ and the analyzing powers ${\mathit{iT}}_{11}(\theta ),T_{20}(\theta )$, and $T_{22}(\theta )$ for deuteron-deuteron elastic scattering at 231.8 MeV. These data are compared to calculations based on the lowest order terms in the Born series expansion of the Alt-Grassberger-Sandhas equation for four nucleons interacting through the CD Bonn potential.