We consider the single-inclusive minijet cross section in $\mathrm{pA}$ at forward rapidity within the color glass condensate model of high energy collisions. We show that the nucleus appears black to the incident quarks except for very large impact parameters. A markedly flatter $p_t$ distribution as compared to QCD in the dilute perturbative limit is predicted for transverse momenta about the saturation scale, which could be as large as $Q_s^2\simeq 10{\mathrm{GeV}}^2$ for a gold nucleus boosted to rapidity $\sim 10$ (as at the BNL-RHIC).

Five prompt proton decay lines have been identified between deformed states in ${}^{59}\mathrm{Cu}$ and three spherical states in ${}^{58}\mathrm{Ni}$ by means of high-resolution in-beam particle- $\gamma \gamma$ coincidence spectroscopy. The GAMMASPHERE array coupled to dedicated ancillary detectors including four $\Delta E-E$ silicon strip detectors was used to study high-spin states in ${}^{59}\mathrm{Cu}$. The multiple discrete proton lines are found to probe the wave functions of states in the decay-out regime of well- and superdeformed states.

We report on the first measurement of mutual Coulomb dissociation in heavy-ion collisions. We employ forward calorimeters to measure neutron multiplicity at beam rapidity. The cross section for simultaneous electromagnetic breakup of Au nuclei at a nucleon-nucleon center of mass energy $\sqrt{s_{\mathrm{NN}}}=130\mathrm{}\mathrm{GeV}$ is ${\sigma }_{\mathrm{MCD}}=3.67\mathrm{}\pm 0.26$ barns, which is comparable to the geometrical cross section. The ratio of the electromagnetic to the total cross section is in good agreement with calculations, as is the neutron multiplicity distribution.

Relativistic heavy ions are copious sources of virtual photons. The large photon flux gives rise to a substantial photonuclear interaction probability at impact parameters where no hadronic interactions can occur. Multiple photonuclear interactions in a single collision are possible. In this Letter, we use mutual Coulomb excitation of both nuclei as a tag for moderate-impact-parameter collisions. We calculate the cross section for coherent vector-meson production accompanied by mutual excitation and show that the median impact parameter is much smaller than for untagged production. The vector-meson rapidity and transverse-momentum distribution are very different from untagged exclusive vector-meson production.

Isospin mixing of the recently discovered doublet of $4^{+}$ states with isospin quantum numbers $T=0\mathrm{}$ and $T=1\mathrm{}$ in ${}^{54}\mathrm{Co}$ is analyzed. It is shown that the measured $E2/M1\mathrm{}$ multipole mixing ratios can be used to estimate the isospin mixing of these states. Combining the new experimental data with results of a shell model calculation, the amount of isospin mixing is found to be $\approx 0.2\%$.

The two-neutron removal cross section ( ${\sigma }_{-2n}$) and the longitudinal momentum distribution of ${}^{15}\mathrm{B}$ fragments from the breakup of ${}^{17}\mathrm{B}$ on ${}^9\mathrm{Be}$ were measured at $70A\mathrm{MeV}$. The distribution in the projectile rest frame is characterized by a FWHM of $80\pm 10\mathrm{MeV}/c$ for ${}^{15}\mathrm{B}$. The ${\sigma }_{-2\mathrm{n}}$ is found to be $0.22\pm 0.05\mathrm{b}$. A Glauber–type analysis of the data provides clear evidence of a two-neutron halo structure in ${}^{17}\mathrm{B}$.

More than half a century after the fundamental, spherical shell structure in nuclei had been established, theoretical predictions indicated that the shell gaps comparable or even stronger than those at spherical shapes may exist. Group-theoretical analysis supported by realistic mean-field calculations indicate that the corresponding nuclei are characterized by the $T_d^D$ (“double-tetrahedral”) symmetry group. Strong shell-gap structure is enhanced by the existence of the four-dimensional irreducible representations of $T_d^D$; it can be seen as a geometrical effect that does not depend on a particular realization of the mean field. Possibilities of discovering the $T_d^D$ symmetry in experiment are discussed.

We show that homogeneous superconductors with broken spin/isospin symmetry lower their energy via a transition to a novel superconducting state where the Fermi surfaces are deformed to a quasiellipsoidal form at zero total momentum of Cooper pairs. In this state, the gain in the condensation energy of the pairs dominates over the loss in the kinetic energy caused by the lowest order (quadrupole) deformation of Fermi surfaces from the spherically symmetric form. The phase transition from the spherically symmetric state to the superconducting state with broken rotational symmetry is first order.

The most precise value of $V_{\mathrm{ud}}$, which is obtained from superallowed nuclear $\beta$ decay, leads to a violation of Cabibbo-Kobayashi-Maskawa unitarity by $2.2\sigma$. Experiments are underway on two continents to test and improve this result through decay studies of odd-odd $N=Z$ nuclei with $A\ge 62$. We show, in a series of illustrative shell-model calculations, that numerous weak Gamow-Teller branches are expected to compete with the superallowed branch in each of these nuclei. Though the total Gamow-Teller strength is significant, many of the individual branches will be unobservably weak. Thus, new techniques must be developed if reliable $\mathrm{ft}$ values are to be obtained with $0.1\%$ precision for the superallowed branches.

Recent data from RHIC for high- $p_T$ hadrons raised again the long-standing problem of quantitatively understanding the Cronin effect, i.e., nuclear enhancement of high- $p_T$ hadrons. All existing models for the Cronin effect rely on a fit to the data to be explained. We develop a phenomenological description based on the light-cone QCD-dipole approach which allows one to explain data without fitting to them and to provide predictions for $\mathrm{pA}$ collisions at RHIC and LHC. We point out that the underlying mechanism drastically changes with energy, from incoherent production of high- $p_T$ hadrons on different nucleons at low energies, to an entirely coherent process at very high energies.

Identified ${\pi }^{+/-}$, $K^{+/-}$, $p$, and $\overline{p}$ transverse momentum spectra at midrapidity in $\sqrt{s_{\mathrm{NN}}}=130\mathrm{GeV}\mathrm{Au}+\mathrm{Au}$ collisions were measured by the PHENIX experiment at RHIC as a function of collision centrality. Average transverse momenta increase with the number of participating nucleons in a similar way for all particle species. Within errors, all midrapidity particle yields per participant are found to be increasing with the number of participating nucleons. There is an indication that $K^{+/-}$, $p$, and $\overline{p}$ yields per participant increase faster than the ${\pi }^{+/-}$ yields. In central collisions at high transverse momenta $(p_T\gtrsim 2\mathrm{GeV}/c)$, $\overline{p}$ and $p$ yields are comparable to the ${\pi }^{+/-}$ yields.

We propose a model for calculating $J/\psi$ suppression in high-energy hadron-nucleus and nucleus-nucleus collisions. We factorized the process into a production of the $c\overline{c}$ pairs convoluted with a transition probability into the observed $J/\psi$ mesons. As the produced $c\overline{c}$ pairs exit the nuclear matter, multiple scattering increases the square of the relative momentum between the $c$ and $\overline{c}$ such that some pairs are transmuted into open charm states. With only one parameter, the energy gained by the produced $c\overline{c}$ pair per unit length in the nuclear medium, our model can fit all observed $J/\psi$ suppression data in hadron-nucleus and nucleus-nucleus collisions.

We have analyzed the latest NA50 data on $J/\psi$ suppression in $\mathrm{Pb}+\mathrm{Pb}$ collisions. $J/\psi$ production is assumed to be a two-step process: (i) formation of a $c\overline{c}$ pair, which is accurately calculable in QCD, and (ii) formation of a $J/\psi$ meson from the $c\overline{c}$ pair, which can be conveniently parametrized. The parameters of the model were fixed from experimental data on the total $J/\psi$ cross section as a function of effective nuclear length. The model gives an excellent description of NA50 data on the $E_T$ dependence of the $J/\psi$–to–Drell-Yan ratio. It was applied to the $E_T$ dependence of $J/\psi$ at RHIC energies, and predicts a much larger suppression of $J/\psi$, in agreement with other model calculations.

Lifetimes of states in ${}^{150}\mathrm{Nd}$ were measured using the recoil distance method following Coulomb excitation of ${}^{150}\mathrm{Nd}$ by a 132 MeV ${}^{32}\mathrm{S}$ beam. The experiment was performed at the Yale Tandem accelerator, employing the SPEEDY gamma-ray detector array and the New Yale Plunger Device. Reduced transition probabilities in ${}^{150}\mathrm{Nd}$ are compared to the predictions of the critical point symmetry X(5) of the phase/shape transition that occurs for the $N=90\mathrm{}$ rare earth isotones. Very good agreement was observed between the parameter-free (apart from scale) X(5) predictions and the low-spin level scheme of ${}^{150}\mathrm{Nd}$, revealing this as the best case thus far for the realization of the X(5) symmetry.

The $B({E2;0\mathrm{}}^{+}\to 2^{+})$ values for the first $2^{+}$ excited states of neutron-rich ${}^{132,134,136}\mathrm{Te}$ have been measured using Coulomb excitation of radioactive ion beams. The $B\left(E2\mathrm{}\right)$ values obtained for ${}^{132,134}\mathrm{Te}$ are in excellent agreement with expectations based on the systematics of heavy stable Te isotopes, while that for ${}^{136}\mathrm{Te}$ is unexpectedly small. These results are discussed in terms of proton-neutron configuration mixing and shell-model calculations using realistic effective interactions.

Deuteron breakup has been studied in a ${}^2\mathrm{H}\left({e,e}^{\prime }p\right)$ coincidence experiment at low momentum transfer and for energies close to threshold. The longitudinal-plus-transverse ( $L+T$) and longitudinal-transverse ( $\mathrm{LT}$) interference cross sections are deduced. Nonrelativistic calculations based on the Bonn potential and including leading order relativistic contributions, meson exchange currents, and isobar configurations describe the ( $L+T$) data well. Surprisingly, large deviations of $30\%$ to $45\%$ are observed for the $\mathrm{LT}$ contribution.

We present charged-particle multiplicities as a function of pseudorapidity and collision centrality for the ${}^{197}\mathrm{Au}{+}^{197}\mathrm{Au}$ reaction at $\sqrt{s_{\mathrm{NN}}}=200\mathrm{}\mathrm{GeV}$. For the $5\%$ most central events we obtain ${\mathrm{dN}}_{\mathrm{ch}}/d\eta {|}_{\eta =0\mathrm{}}=625\mathrm{}\pm 55$ and $N_{\mathrm{ch}}{|}_{-4.7\mathrm{}\le \eta \le 4.7}=4630\mathrm{}\pm 370$, i.e., $14\%$ and $21\%$ increases, respectively, relative to $\sqrt{s_{\mathrm{NN}}}=130\mathrm{}\mathrm{GeV}$ collisions. Charged-particle production per pair of participant nucleons is found to increase from peripheral to central collisions around midrapidity. These results constrain current models of particle production at the highest RHIC energy.

We point out that, in analogy with spin waves in antiferromagnets, all parameters describing the real-time propagation of soft pions at temperatures below the QCD chiral phase transition can be expressed in terms of static correlators. This allows, in principle, the determination of the soft pion dispersion relation on the lattice. Using scaling and universality arguments, we determine the critical behavior of the parameters of pion propagation. We predict that, when the critical temperature is approached from below, the pole mass of the pion drops despite the growth of the pion screening mass. This fact is attributed to the decrease of the pion velocity near the phase transition.

If a quark-gluon plasma is formed in relativistic heavy-ion collisions, there may or may not be a mixed phase of quarks, gluons, and hadronic clusters when the critical temperature is reached in the expansion of the fireball. If there is a temperature gradient in the fireball, the hadronic clusters, embedded in the heat bath of quarks and gluons, would be subjected to a thermophoretic force. It is shown that, even for small temperature gradients and short lifetimes of the mixed phase, thermophoresis would lead to a flow essentially stronger than the observed one. The absence of this strong flow provides support for a rapid or sudden hadronization mechanism without a mixed phase.

The $\overline{\Omega }/\Omega$ ratio originating from string decays is predicted to be larger than unity in proton-proton interactions at SPS energies ( $E_{\mathrm{lab}}=160\mathrm{}\mathrm{GeV}$). The antiomega dominance increases with decreasing beam energy. This surprising behavior is caused by the combinatorics of quark-antiquark production in small and low-mass strings. Since this behavior is not found in a statistical description of hadron production in proton-proton collisions, it may serve as a key observable to probe the hadronization mechanism in such collisions.