The newly discovered $\alpha$ decay of ${}^{209}\mathrm{Bi}$ [Marcillac et al., Nature (London) $422,$ 876 (2003)] is investigated in the cluster model of $\alpha$ decay. It is found that the cluster model can reproduce the data of this longest-lived $\alpha$ emitter in all known $\alpha$-decay nuclei. This decay belongs to a special class of $\alpha$ decays occurring in odd-$A$ nuclei with an extra nucleon outside a closed shell. By combining the cluster model of $\alpha$ decay with a microscopic model of preformation $\alpha$ cluster, we can successfully describe the half-lives of odd-$A$ $N=127\mathrm{}$ isotones. The cluster model of the favored $\alpha$ decays is interestingly generalized to the hindered $\alpha$ decays of odd-$A$ nuclei.

Neutron-induced fission cross sections have been extracted for targets of ${}^{240,241,243}\mathrm{Pu},$ ${}^{234,236,237,239}\mathrm{U},$ and ${}^{231,233}\mathrm{Th}$ from $E_n=100\mathrm{}\mathrm{keV}$ to $\approx 2.5\mathrm{MeV}$ using surrogate $\mathrm{}(t,pf)\mathrm{}$ fission-probability data and a detailed statistical model to compensate for the difference between neutron-induced and $\mathrm{}(t,p)\mathrm{}$ reactions. This paper extends the results of previous work on the ${}^{235}\mathrm{U}\mathrm{}(n,f)\mathrm{}$ cross section, which serves as a proof-of-principle study. The $\mathrm{}(n,f)\mathrm{}$ cross sections are compared to earlier estimates based on the same surrogate data, but obtained using a more simplistic approach. The cross sections are also compared to accepted values where direct measurements exist and are consistently accurate to within 20% below $E_n\approx 0.5\mathrm{MeV}$ and 10% at higher energies. The case of the ${}^{237}\mathrm{U}\mathrm{}(n,f)\mathrm{}$ cross section, simulated from surrogate $\mathrm{}(t,pf)\mathrm{}$ data, is investigated in greater detail to reconcile contradictory measurements in the literature.

Employing a previously derived formulation, and extending the treatment from purely transverse modes to wave vectors having a longitudinal component, we discuss the prospects for the occurrence of Weibel-type color-current filamentation in high-energy nuclear collisions. Numerical solutions of the dispersion equation for a number of scenarios relevant to RHIC and LHC suggest that modes with (predominantly transverse) wave numbers of several hundred MeV may become moderately agitated during the early collision stage. The emergence of filamentation helps to speed up the equilibration of the parton plasma and it may lead to nonstatistical azimuthal patterns in the hadron final state.

Using the relativistic quantum molecular dynamics model, transverse momentum distributions and particle ratios are studied for ${}^{197}\mathrm{Au}{+}^{197}\mathrm{Au}$ collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=200\mathrm{}\mathrm{GeV}.$ In particular, we present results on the mean transverse momentum of charged pions, charged kaons, protons, and antiprotons and compare with experimental measurements. We discuss an approach to study early partonic collectivity in high energy nuclear collisions.

Production of resonances is considered in the framework of the single-freeze-out model of ultrarelativistic heavy-ion collisions. The formalism involves the virial expansion, where the probability to form a resonance in a two-body channel is proportional to the derivative of the phase shift with respect to the invariant mass. The thermal model incorporates the longitudinal and the transverse flow, as well as kinematic cuts of the STAR experiment at RHIC. We find that the shape of the ${\pi }^{+}{\pi }^{-}$ spectral line qualitatively reproduces the preliminary experimental data when the position of the $\rho$ peak is lowered. This confirms the need to include the medium effects in the description of the RHIC data. We also analyze the transverse-momentum spectra of $\rho ,$ $K^{*}{\mathrm{}\left(892\right)\mathrm{}}^0,$ and $f_0\mathrm{}\left(980\right),$ and find that the slopes agree with the observed values. Predictions are made for $\eta ,$ ${\eta }^{\prime },$ $\omega ,$ $\phi ,$ $\Lambda \mathrm{}\left(1520\right),$ and $\Sigma \mathrm{}\left(1385\right).$

Within a light-cone QCD formalism based on the Green function technique incorporating color transparency and coherence length effects, we study nuclear shadowing in deep-inelastic scattering at moderately small Bjorken $x_{\mathrm{Bj}}.$ Calculations performed so far were based only on approximations leading to an analytical harmonic oscillatory form of the Green function. We present for the first time an exact numerical solution of the evolution equation for the Green function using a realistic form of the dipole cross section and nuclear density function. We compare numerical results for nuclear shadowing with previous predictions and discuss differences.

The nonstrange baryon spectrum is studied within a three-body model that incorporates relativistic kinematics. We found that the combined effect of relativistic kinematics together with the pion exchange between quarks is able to reverse the order of the first positive- and negative-parity nucleon excited states as observed experimentally. Including the chiral partner of the pion (the $\sigma$ meson) leads to an overall good description of the spectrum.

Improving previous calculations, we compute the $J/\psi \overrightarrow{\pi }\mathrm{charmed}\mathrm{}\mathrm{meson}$ cross section using QCD sum rules. Our sum rules for the $J/\psi \overrightarrow{\pi }\overline{D}{D}^{*},$ $D{D}^{*},$ $D^{*}{D}^{*},$ and $\overline{D}D$ hadronic matrix elements are constructed by using vacuum-pion correlation functions, and we work up to twist-4 in the soft-pion limit. Our results suggest that using meson exchange models is perfectly acceptable, provided that they include form factors and that they respect chiral symmetry. After evaluating a thermal average we get $〈{\sigma }^{\pi J/\psi }v〉\sim 0.3\mathrm{mb}$ at $T=150\mathrm{}\mathrm{MeV}.$

We study the nuclear modification of the scalar QCD susceptibility, calculated as the derivative of the quark condensate with respect to the quark mass. We show that it has two origins. One is the low lying nuclear excitations. At normal nuclear density this part is constrained by the nuclear incompressibility. The other part arises from the individual nucleon response and it is dominated by the pion cloud contribution. Numerically the first contribution dominates. The resulting increase in magnitude of the scalar susceptibility at normal density is such that it becomes close to the pseudoscalar susceptibility, while it is quite different in the vacuum. We interpret it as a consequence of chiral symmetry restoration in nuclei.

The neutron capture cross section of ${}^{139}\mathrm{La}$ has been measured relative to that of ${}^{197}\mathrm{Au}$ by means of the activation method. The sample was irradiated in a quasistellar neutron spectrum for $kT=25\mathrm{}\mathrm{keV}$ generated via the ${}^7\mathrm{Li}{\mathrm{}(p,n)\mathrm{}}^7\mathrm{Be}$ reaction with the proton energy adjusted 30 keV above the threshold. Maxwellian averaged neutron capture cross sections were calculated for energies $kT=5\mathrm{}–100\mathrm{keV}.$ The new value for $kT=30\mathrm{}\mathrm{keV}$ is found to be $31.6\pm 0.8\mathrm{mb},$ 18% lower and considerably less uncertain than the previously recommended value of $38.4\pm 2.7\mathrm{mb}.$ With these results the s- and r-process components could be more accurately determined, making lanthanum a reliable s- and r-process indicator in stellar spectroscopy.

In a recent paper, the giant dipole resonance width was studied as a function of angular momentum in the nucleus ${}^{86}\mathrm{Mo}.$ The width of the resonance was found to be constant over a spin range of $(0\mathrm{}–40)ħ.$ It was concluded that the angular momentum dependence for ${}^{86}\mathrm{Mo}$ differs from that of Sn isotopes. We compared both datasets with a phenomenological formula based on the thermal fluctuation theory. The ${}^{86}\mathrm{Mo}$ data are inconsistent with the formula in contrast to the previously analyzed Sn data, which seems to indicate that the angular momentum dependence of the phenomenological model is not universally applicable.

Experimental data in the Hf-Hg mass region indicate the presence of a prolate-oblate phase transition. The transition in which $\gamma$-soft nuclei exhibit a first-order quantum phase transition in their shape is of the type that was recently proposed on very general grounds using Landau theory. The transition is situated close to the O(6) limit of the interacting boson model which is indeed found empirically in this mass region. Our study also hints at explaining why the quadrupole moments in Pt isotopes deviate from the O(6) value and confirms the recently proposed prolate-oblate phase transition with experimental data.

The spontaneous decay of the $K^{\pi }{=16\mathrm{}}^{+},$ 31-yr ${}^{178}\mathrm{Hf}{}^{m2\mathrm{}}$ isomer has been investigated with a 15-kBq source placed at the center of a 20-element $\gamma$-ray spectrometer. High-multipolarity $M4\mathrm{}$ and $E5\mathrm{}$ transitions, which represent the first definitive observation of direct $\gamma$-ray emission from the isomer, have been identified, together with other low-intensity transitions. Branching ratios for these other transitions have elucidated the spin dependence of the mixing between the two known $K^{\pi }{=8\mathrm{}}^{-}$ bands. The $M4\mathrm{}$ and $E5\mathrm{}$ $\gamma$-ray decays are the first strongly K-forbidden transitions to be identified with such high multipolarities, and demonstrate a consistent extension of K-hindrance systematics, with an inhibition factor of approximately 100 per degree of K forbiddenness. Some unplaced transitions are also reported.

Thermal photon emission rates due to meson-nucleon interactions have been evaluated. An exhaustive set of reactions involving $p\left(\overline{p}\right),$ $n\left(\mathrm{n̄}\right),$ $\rho ,$ $\omega ,$ $a_1,$ $\pi ,$ and $\eta$ is seen to provide a sizable contribution to the emission rate of photons from hot hadronic matter. Contributions from the decays of baryonic resonances are found to be negligibly small.

The Hartree-Fock-Bogoliubov (HFB) equation in a simplified model is solved in coordinate space with the correct asymptotic boundary conditions, in order to study the pair correlation in nuclei close to the neutron drip line. The occupation probability obtained in the HFB approach for lower-l orbits decreases considerably already when the binding energy of the corresponding Hartree-Fock (HF) one-particle level becomes smaller. When the HF one-particle level enters into the continuum, the lower-l orbit soon becomes almost unavailable for the pair correlation of the many-body system. In contrast, the contribution to the pair correlation by high-l orbits which have one-particle resonant levels with narrow width in the HF potential can be estimated in the BCS approximation using the one-particle resonant energies, though the associated wave functions in the HFB approach are bound-state wave functions.

In a previous publication [T. Abbott et al., E802 Collaboration, Phys. Rev. C 63, 064602 (2001); 64, 029901(E) (2001)], measurements of the A dependence and pseudorapidity interval $\left(\delta \eta \right)$ dependence of midrapidity $E_T$ distributions in a half-azimuth $(\Delta \phi =\pi )$ electromagnetic calorimeter were presented for $p+\mathrm{Be},$ $p+\mathrm{Au},$ O+Cu, Si+Au, and Au+Au collisions at the BNL-AGS. The validity of the “nuclear geometry” characterization versus $\delta \eta$ was illustrated by plots of the $E_T\left(\delta \eta \right)$ distribution in each $\delta \eta$ interval in units of the measured $〈E_T\left(\delta \eta \right){〉}_{p+\mathrm{A}\mathrm{u}}$ in the same $\delta \eta$ interval for $p+\mathrm{Au}$ collisions. These plots, with aperture corrected scale in the physically meaningful units of number of average observed $p+\mathrm{Au}$ collisions, were nearly universal as a function of $\delta \eta ,$ confirming that the reaction dynamics for $E_T$ production at midrapidity at AGS energies is governed by the number of projectile participants and can be well characterized by measurements in apertures as small as $\Delta \phi =\pi ,\delta \eta =\mathrm{0.3.}\mathrm{}$ A key ingredient in these analyses is the probability $p_0$ for no signal to be detected in a given aperture $\delta \eta$ for the fundamental $p+\mathrm{Au}$ collision. In fact the measured $〈E_T\left(\delta \eta \right){〉}_{p+\mathrm{A}\mathrm{u}}$ is biased and the true $〈E_T\left(\delta \eta \right){〉}_{p+\mathrm{A}\mathrm{u}}^{\mathrm{true}}$ for the detector aperture is the measured value times $1-p_0.$ The issues and merits of measuring the $E_T\left(\delta \eta \right)$ distribution in units of $〈E_T\left(\delta \eta \right){〉}_{p+\mathrm{A}\mathrm{u}}$ or $〈E_T\left(\delta \eta \right){〉}_{p+\mathrm{A}\mathrm{u}}^{\mathrm{true}}$ in the same $\delta \eta$ interval are presented and discussed. This method has application at RHIC, where p-$p$ data could be used as the reference distribution for two participants. The $E_T$ distributions for $B+A$ collisions, with $E_T\left(\delta \eta \right)$ scale normalized by $〈E_T\left(\delta \eta \right){〉}_{p-p}^{\mathrm{true}}$ in the same aperture for $p-p$ collisions, would then be given directly in the popular unit “per participant-pair” [K. Adcox et al., PHENIX Collaboration, Phys. Rev. Lett. 86, 3500 (2001); I. G. Bearden et al., BRAHMS Collaboration, Phys. Lett. B523, 227 (2001); B. B. Back et al., PHOBOS Collaboration, Phys. Rev. C 65, 031901(R) (2002); C. Adler et al., STAR Collaboration, Phys. Rev. Lett. 89, 202301 (2002)].

The properties of $\eta$-nucleus interaction and their experimental consequences are investigated with $\eta$-nucleus optical potentials obtained by postulating the $N^{*}\mathrm{}\left(1535\right)\mathrm{}$ dominance for $\eta -N$ system. The $N^{*}\mathrm{}\left(1535\right)\mathrm{}$ properties in the nuclear medium are evaluated by two kinds of chiral effective models based on distinct pictures of $N^{*}\mathrm{}\left(1535\right).$ We find that these two models provide qualitatively different optical potentials of the $\eta$ meson, reflecting the in-medium properties of $N^{*}\mathrm{}\left(1535\right)\mathrm{}$ in these models. In order to compare these models in physical observables, we calculate spectra of ${(d,}^3\mathrm{He})$ reactions for the $\eta$ mesic nucleus formation with various kinds of target nuclei. We show that the ${(d,}^3\mathrm{He})$ spectra obtained in these models are significantly different and are expected to be distinguishable in experiments.

Parity and time invariance violating $(\mathcal{P},\mathcal{T}$-odd) nuclear forces produce $\mathcal{P},\mathcal{T}$-odd nuclear moments, for example, the nuclear Schiff moment. In turn, this moment can induce electric dipole moments (EDMs) in atoms. We estimate the contribution to the Schiff moment from the soft collective octupole vibrations existing in many heavy nuclei. Two possible mechanisms are considered, mixing of the ground state of an odd-$A$ nucleus with the octupole phonon state, and $\mathcal{P},\mathcal{T}$-odd admixture to the single-particle wave function of the valence nucleon. We found practically the same contribution to the Schiff moment as that of the static octupole deformation calculated earlier. This confirms a suggestion that the soft octupole vibrations can replace the (controversial) static octupoles in development of the collective Schiff moments. The values of atomic EDM predicted for ${}^{223,225}\mathrm{Ra}$ and ${}^{223}\mathrm{Rn}$ are enhanced by factors ${10}^2–{10}^3$ compared to experimentally studied spherical nuclei ${}^{199}\mathrm{Hg}$ and ${}^{129}\mathrm{Xe}.$

The properties of symmetric nuclear matter are investigated within Green’s functions approach. We have implemented an iterative procedure allowing for a self-consistent evaluation of the single-particle and two-particle propagators. The in-medium scattering equation is solved for a realistic (nonseparable) nucleon-nucleon interaction including both particle-particle and hole-hole propagation. The corresponding two-particle propagator is constructed explicitly from the single-particle spectral functions. Results are obtained for finite temperatures and an extrapolation to $T=0\mathrm{}$ is presented.