A direct correlation between experimental values of proton-neutron interaction strengths and experimental measures of the growth of collectivity in nuclei is found. In particular, differences in the $p\mathrm{\text{−}}n$ interaction strengths and differences in growth rates of collectivity in particle-particle (or hole-hole) and particle-hole regions are found to correspond.

We suggest that the “new form of matter” found just above $T_c$ by the Relativistic Heavy Ion Collider is made up of tightly bound quark-antiquark pairs, essentially 32 chirally restored (more precisely, nearly massless) mesons of the quantum numbers of $\pi$, $\sigma$, $\rho$, and $a_1$. Taking the results of lattice gauge simulations (LGS) for the color Coulomb potential from the work of the Bielefeld group and feeding this into a relativistic two-body code, after modifying the heavy-quark lattice results so as to include the velocity-velocity interaction, all ground-state eigenvalues of the 32 mesons go to zero at $T_c$ just as they do from below $T_c$ as predicted by the vector manifestation of hidden local symmetry. This could explain the rapid rise in entropy up to $T_c$ found in LGS calculations. We argue that how the dynamics work can be understood from the behavior of the hard and soft glue.

Excited states in ${}^{138}\mathrm{Ce}$ have been studied via the ${}^{12}\mathrm{C}({}^{138}\mathrm{Ce},{}^{138}\mathrm{Ce}^{*})$ Coulomb excitation reaction at 480 MeV. Relative cross sections have been determined from the $\gamma$-ray yields observed with Gammasphere. The $E2$ and $M1$ strength distributions between the lowest six $2^{+}$ states up to 2.7 MeV enables us to identify the $2_4^{+}$ state in ${}^{138}\mathrm{Ce}$ as the dominant fragment of the one-phonon $2_{1,\mathrm{ms}}^{+}$ mixed-symmetry state. Mixing between this level and a nearby isoscalar state is observed and is more than 4 times larger than in the neighboring isotone ${}^{136}\mathrm{Ba}$. This is direct evidence that the stability of mixed-symmetry states strongly depends on the underlying subshell structure.

The shell structure underlying shape changes in neutron-rich nuclei near $N=28$ has been investigated by a novel application of the transient-field technique to measure the first-excited-state $g$ factors in ${}^{38}\mathrm{S}$ and ${}^{40}\mathrm{S}$ produced as fast radioactive beams. There is a fine balance between proton and neutron contributions to the magnetic moments in both nuclei. The $g$ factor of deformed ${}^{40}\mathrm{S}$ does not resemble that of a conventional collective nucleus because spin contributions are more important than usual.

The ${}^4\mathrm{He}$ total photoabsorption cross section is calculated with the realistic nucleon-nucleon potential Argonne V18 and the three-nucleon force (3NF) Urbana IX. Final state interaction is included rigorously via the Lorentz integral transform method. A rather pronounced giant resonance with peak cross sections of 3.0 (3.2) mb is obtained with (without) the 3NF. Above 50 MeV strong 3NF effects, up to 35%, are present. Good agreement with experiment is found close to threshold. A comparison in the giant resonance region is inconclusive, since data do not show a unique picture.

The experimental information on the observed nearly degenerate bands in the $N=75$ isotones, in particular ${}^{134}\mathrm{Pr}$ and ${}^{136}\mathrm{Pm}$, which are often considered as the best candidates for chiral bands, is critically analyzed. Most properties of the bands, in particular, the recently measured branching ratios and lifetimes, are in clear disagreement with the interpretation of the two bands as chiral bands. For $I=14–18$ in ${}^{134}\mathrm{Pr}$, where the observed energies are almost degenerate, we have obtained a value of 2.0(4) for the ratio of the transition quadrupole moments of the two bands, which implies a considerable difference in the nuclear shape associated with the two bands. The insufficiency of the near-degeneracy criterion to trace nuclear chirality is emphasized.

We propose a new mechanism to explain the unexpected steep falloff of fusion cross sections at energies far below the Coulomb barrier. The saturation properties of nuclear matter are causing a hindrance to large overlap of the reacting nuclei and consequently a sensitive change of the nuclear potential inside the barrier. We report in this Letter a good agreement with the data of coupled-channels calculation for the ${}^{64}\mathrm{Ni}+{}^{64}\mathrm{Ni}$ combination using the double-folding potential with Michigan-3-Yukawa-Reid effective $N-N$ forces supplemented with a repulsive core that reproduces the nuclear incompressibility for total overlap.

We investigate the effects of the nearly fulfilled Efimov conditions on the properties of three-body resonances. Using the hyper-spheric adiabatic expansion method we compute energy distributions of fragments in a three-body decay of a nuclear resonance. As a realistic example we investigate the $1^{-}$ state in the halo nucleus ${}^{11}\mathrm{Li}$ within a three-body ${}^9\mathrm{Li}+n+n$ model. Characteristic features appear as sharp peaks in the energy distributions. Their origin, as in the Efimov effect, is in the large two-body $s$-wave scattering lengths between the pairs of fragments.

The nuclear magnetic moment of the ground state of ${}^{57}\mathrm{Cu}(I^{\pi }=3/2^{-},T_{1/2}=196.3\mathrm{ms})$ has been measured to be $|\mu ({}^{57}\mathrm{Cu})|=(2.00\pm 0.05){\mu }_N$ using the $\beta$-NMR technique. Together with the known magnetic moment of the mirror partner ${}^{57}\mathrm{Ni}$, the spin expectation value was extracted as $⟨\Sigma {\sigma }_z⟩=-0.78\pm 0.13$. This is the heaviest isospin $T=1/2$ mirror pair above the ${}^{40}\mathrm{Ca}$ region for which both ground state magnetic moments have been determined. The discrepancy between the present results and shell-model calculations in the full $fp$ shell giving $\mu ({}^{57}\mathrm{Cu})\sim 2.4{\mu }_N$ and $⟨\Sigma {\sigma }_z⟩\sim 0.5$ implies significant shell breaking at ${}^{56}\mathrm{Ni}$ with the neutron number $N=28$.

The invariant mass spectra of $e^{+}{e}^{-}$ pairs produced in 12 GeV proton-induced nuclear reactions are measured at the KEK Proton Synchrotron. On the low-mass side of the $\omega$ meson peak, a significant enhancement over the known hadronic sources has been observed. The mass spectra, including the excess, are well reproduced by a model that takes into account the density dependence of the vector meson mass modification, as theoretically predicted.

High-spin states in ${}^{58}\mathrm{Ni}$ have been investigated by means of the fusion-evaporation reaction ${}^{28}\mathrm{Si}({}^{32}\mathrm{S},2p){}^{58}\mathrm{Ni}$ at 130 MeV beam energy. Discrete-energy levels are observed in ${}^{58}\mathrm{Ni}$ at record-breaking 42 MeV excitation energy and angular momenta in excess of $30\hslash$. The states form regular rotational bands with unprecedented high rotational frequencies. A comparison with configuration dependent cranked Nilsson-Strutinsky calculations reveals an exceptional two-band crossing scenario, the interaction strength of which is strongly shape dependent.

The ratios of inclusive electron scattering cross sections of ${}^4\mathrm{He}$, ${}^{12}\mathrm{C}$, and ${}^{56}\mathrm{Fe}$ to ${}^3\mathrm{He}$ have been measured at $1<x_B<3$. At $Q^2>1.4{\mathrm{GeV}}^2$, the ratios exhibit two separate plateaus, at $1.5<x_B<2$ and at $x_B>2.25$. This pattern is predicted by models that include 2- and 3-nucleon short-range correlations (SRC). Relative to $A=3$, the per-nucleon probabilities of 3-nucleon SRC are 2.3, 3.1, and 4.4 times larger for $A=4$, 12, and 56. This is the first measurement of 3-nucleon SRC probabilities in nuclei.

Differential production cross sections of $K^{\pm }$ mesons have been measured in $p+\mathrm{C}$ and $p+\mathrm{Au}$ collisions at 1.6, 2.5, and 3.5 GeV proton beam energy. At beam energies close to the production threshold, the $K^{-}$ multiplicity is strongly enhanced with respect to proton-proton collisions. According to microscopic transport calculations, this enhancement is caused by two effects: the strangeness exchange reaction $NY\to K^{-}NN$ and an attractive in-medium $K^{-}N$ potential at saturation density.

Properties of particle-unstable nuclei lying beyond the proton drip line can be ascertained by considering the (usually known) properties of its mirror neutron-rich system. We have used a multichannel algebraic scattering theory to map the known properties of the neutron-${}^{14}\mathrm{C}$ system to those of the proton-${}^{14}\mathrm{O}$ one from which we deduce that the particle-unstable ${}^{15}\mathrm{F}$ will have a spectrum of two low-lying broad resonances of positive parity and, at higher excitation, three narrow negative-parity ones. A key feature is to use coupling to Pauli-hindered states in the target.

The complete exact solution of the $T=1$ neutron-proton pairing Hamiltonian is presented in the context of the SO(5) Richardson-Gaudin model with nondegenerate single-particle levels and including isospin symmetry-breaking terms. The power of the method is illustrated with a numerical calculation for ${}^{64}\mathrm{Ge}$ for a $pf+g_{9/2}$ model space which is out of reach of modern shell-model codes.

A very simple formula is presented that relates the logarithm of the half-life, corrected by the centrifugal barrier, with the Coulomb parameter in proton decay processes. The corresponding experimental data lie on two straight lines which appear as a result of a sudden change in the nuclear shape marking two regions of deformation independently of the angular momentum of the outgoing proton. This feature provides a powerful tool to assign experimentally quantum numbers in proton emitters.

Building on, and extending, the result of a higher-order in-medium chiral perturbation theory combined with renormalization group arguments and a variety of observations of the vector manifestation of Harada-Yamawaki hidden local symmetry theory, we obtain a surprisingly simple description of kaon condensation by fluctuating around the “vector manifestation” fixed point identified to be the chiral restoration point. Our development establishes that strangeness condensation takes place at $\sim 3n_0$ where $n_0$ is nuclear matter density. This result depends only on the renormalization-group (RG) behavior of the vector interactions, other effects involved in fluctuating about the bare vacuum in so many previous calculations being irrelevant in the RG about the fixed point. Our results have major effects on the collapse of neutron stars into black holes.

We performed a coincidence measurement of two nucleons emitted from the nonmesonic weak decay of ${}_{\Lambda }{}^5\mathrm{He}$ formed via the ${}^6\mathrm{Li}({\pi }^{+},K^{+})$ reaction. The energies of the two nucleons and the pair number distributions in the opening angle between them were measured. In both $np$ and $nn$ pairs, we observed a clean back-to-back correlation coming from the two-body weak reactions of $\Lambda p\to np$ and $\Lambda n\to nn$, respectively. The ratio of the nucleon pair numbers was $N_{nn}/N_{np}=0.45\pm 0.11(\mathrm{stat})\pm 0.03(\mathrm{syst})$ in the kinematic region of $\cos {\theta }_{NN}<-0.8$. Since each decay mode was exclusively detected, the measured ratio should be close to the ratio of $\Gamma (\Lambda p\to np)/\Gamma (\Lambda n\to nn)$. The ratio is consistent with recent theoretical calculations based on the heavy meson and/or direct-quark exchange picture.

We present first results for ($3+1$)D simulations of SU(2) Yang-Mills equations for matter expanding into the vacuum after a heavy ion collision. Violations of boost invariance cause a non-Abelian Weibel instability leading soft modes to grow with proper time $\tau$ as $\exp (\Gamma \sqrt{g^2\mu \tau })$, where $g^2\mu$ is a scale arising from the saturation of gluons in the nuclear wave function. The scale for the growth rate $\Gamma$ is set by a plasmon mass, defined as ${\omega }_{\mathrm{pl}}={\kappa }_0\sqrt{g^2\mu /\tau }$, generated dynamically in the collision. We compare the numerical ratio $\Gamma /{\kappa }_0$ to the corresponding value predicted by the hard thermal loop formalism for anisotropic plasmas.

Exited states in ${}^{134}\mathrm{Pr}$ were populated in the fusion-evaporation reaction ${}^{119}\mathrm{Sn}({}^{19}\mathrm{F},4n){}^{134}\mathrm{Pr}$. Recoil distance Doppler-shift and Doppler-shift attenuation measurements using the Euroball spectrometer, in conjunction with the inner Bismuth Germanate ball and the Cologne plunger, were performed at beam energies of 87 MeV and 83 MeV, respectively. Reduced transition probabilities in ${}^{134}\mathrm{Pr}$ are compared to the predictions of the two $\mathrm{\text{quasiparticle}}+\mathrm{\text{triaxial}}$ rotor and interacting boson fermion-fermion models. The experimental results do not support the presence of static chirality in ${}^{134}\mathrm{Pr}$ underlying the importance of shape fluctuations. Only within a dynamical context the presence of intrinsic chirality in ${}^{134}\mathrm{Pr}$ can be supported.