The existence of two decaying isomers in ${}^{184}\mathrm{Au}$ was confirmed through direct observation of the variation of decay rates with time. The ordering of the low- and high-spin isomers was verified by the decay studies. The isomers are identified as a low-spin (probably $2^{+}$) state at an energy of 69 keV with a half-life of $48\pm 1\sec$ and a high-spin (probably $5^{+}$) ground state with a half-life of $21\pm 1\sec .$

The tensor analyzing power $T_{20}({\theta }_{\mathrm{lab}}=90\mathrm{}°)$ has been measured to high precision for the reaction ${}^1$H$(d\to ,\gamma {)}^3$He at $E_d=80\mathrm{}-0$ keV. Direct capture calculations of $T_{20}\left(90\mathrm{}°\right)$ have been performed using asymptotic forms for the bound state ${}^3$He wave function while varying the asymptotic $D$- to $S$-state ratio $\eta$. A best-fit value for $\eta$ was extracted and found to be $-0.0399\pm {0.0091}_{-0.0019}^{+0.0012\mathrm{}}$. The model dependence of this result is discussed.

The leading-logarithm approximation for the Sudakov form factor is examined in a theory containing massive fermion and massive neutral vector meson fields. In the on-shell case, where there is only one mass scale (the meson mass), the Sudakov form factor in this model agrees with the result in QED. In the off-shell case, however, with two different mass scales (the meson mass and the off-shell mass of the fermion), the Sudakov form factor differs from the QED result.

In search of a possible truncation scheme for shell model calculations, the yrast generalized seniority states are compared with the corresponding shell model states for the case of the Sn isotopes ${}^{104-112}$Sn. For most of the cases the energies agree within a few hundred keV. For the $0^{+}$${(2\mathrm{}}^{+})$ states the overlaps decrease from 97% (93%) in ${}^{104}$Sn to 91% (78%) in ${}^{112}$Sn when the coefficients of the pairs in the $S$ and $D$ boson operators are allowed to vary with the number of particles. For constant pairing coefficients throughout the entire isotope range, the overlaps are considerably smaller. It is concluded, with the realistic effective interaction applied here, that a truncation scheme based on seniority zero and two states is inadequate when the number of valence particles gets large and that configurations of higher seniority should be included.

It is shown that $K$-equilibration fission can explain the decrease of mass resolved fission fragment anisotropy at larger mass asymmetries. Two competing mechanisms contribute to the anisotropy. The effective moment of inertia and $K_0^2$ decreases with the increase of mass asymmetry and contribute to the increase of anisotropy. On the other hand, for larger asymmetries, the barriers are higher and lifetimes are longer. Such systems are more $K$ equilibrated and will have smaller anisotropy.

We have evaluated the charge exchange contribution to ${\pi }^{+}$ emission in the weak decay of ${}_{\Lambda }^4$He. The calculated decay rate is about twice as large as the older estimates but it still cannot account for the value of the ${\pi }^{+}/{\pi }^{-}$ branching ratio determined experimentally.

Recently, deeply bound pionic states were found experimentally in ${(d,}^3\mathrm{He})$ reactions on ${}^{208}\mathrm{Pb}.$ The observed spectrum showed an excellent agreement with the distorted-wave impulse approximation calculation and the dominant peak was attributed to the pionic $2p$ state contribution. We studied theoretically ${}^{206}\mathrm{Pb}{(d,}^3\mathrm{He})$ reactions within the same model, and found that it is very likely to observe the pionic $1s$ state as an isolated peak in the ${}^{206}\mathrm{Pb}{(d,}^3\mathrm{He})$ reaction with feasible energy resolution and statistics.

An effective interaction based upon two nucleon $g$ matrices has been used in a fully microscopic calculation of the nonlocal proton-${}^{12}$C optical potential at 135 MeV. Excellent predictions of the differential cross section from elastic scattering result. The same effective interaction, combined with one body density matrix elements specified by a large basis shell model for ${}^{12}$C ${(}^{12}$N), and with the relative motion wave functions from the nonlocal optical potentials define the distorted wave approximation that is employed to analyze cross sections from inelastic proton scattering. With that approximation, inelastic scattering cross sections from various states in ${}^{12}$C and from the charge exchange reactions leading to the low excitation states of ${}^{12}$N have been evaluated. Our results indicate a problem with the structure model when 3$ħ\omega$ components are considered.

It is shown that the representation transformations of multiquark wave functions between different coupling schemes are just the Racah coefficients of the permutation group. The transformation coefficients between the flavor-spin (FS) and the color-spin (CS) schemes are obtained. As an example, the expansion of the physical bases in terms of symmetry bases in the CS scheme are given for the interesting cases $YIJ=201,210,000.\mathrm{}$

Significant differences in the relationships between fragment, neutron, and charged particle multiplicities were found between ${}^{112}$Sn+${}^{112}$Sn and ${}^{124}$Sn+${}^{124}$Sn collisions at 40 MeV/$A$. In this paper we explore the possibility to explain this phenomenon in the framework of percolation models, and find that the results are only reproducible in part.

$\beta$ decay rates for the Gamow-Teller transition between odd-proton and odd-neutron nuclei and between odd-odd and even-even nuclei in the mass-60 region have been calculated in the interacting boson model. Comparison shows a qualitative agreement between the calculated and experimental $\log \mathrm{ft}$ values.

The W80 Collaboration [Phys. Rev. C 50, 1048 (1994)] has presented an analysis of normalized factorial moments (NFM) of multiplicity distributions in central ${}^{32}$S+S and ${}^{32}$S+Au collisions at 200 GeV/nucleon. They claim to observe no intermittency signal, as characterized by a variation of the NFM with rapidity interval, beyond that produced by folding the FRITIOF event generator with a detailed model of their detector. In this Comment, it is pointed out that the difference in magnitude between the measured NFM and the detector simulation, which was not considered by WA80, also contains important information which can be used to extract the true NFM. In particular, $F_2$ is extracted and compared to other experiments.

Excited states in ${}^{110}$Sb have been identified for the first time in a series of $\gamma$-spectroscopy experiments using both thin and backed targets, including neutron-fold and recoil-mass measurements to provide unambiguous channel identification. The three decoupled intruder bands observed in ${}^{110}$Sb are based upon configurations involving 2p-2h excitations across the $Z=50\mathrm{}$ shell gap and show the features of smooth band termination. The yrast intruder band, which has been connected to the low-spin levels, is tentatively identified up to its predicted termination at $I^{\pi }{=45\mathrm{}}^{+}$. Excellent agreement with configuration-dependent cranked Nilsson-Strutinsky calculations is obtained for the high-spin states near termination.

Charge and transverse energy distributions for intermediate mass fragments have been extracted for central ${}^{84}\mathrm{Kr}{+}^{197}\mathrm{Au}$ collisions at $E/A=35\mathrm{}-400$ MeV. The slopes of the measured fragment charge distributions decrease monotonically with incident energy, consistent with the expectations for highly charged systems, but not with recent critical exponent analyses. Statistical model calculations, which reproduce the experimental trends, suggest that post-breakup fragment secondary decays alter significantly the observed charge distributions. Radial expansion velocities extracted from these calculations follow the systematics of Au+Au collisions.

Gamma rays from the decay of states in the proton unstable nucleus ${}^{147}$Tm were observed for the first time following the ${}^{92}$Mo${(}^{58}$Ni,p2n)${}^{147}$Tm reaction at 260 MeV. Prompt $\gamma$ rays were detected with an array of Compton-suppressed Ge detectors, placed in front of the fragment mass analyzer at the ATLAS accelerator, and were assigned to individual reaction channels on an event-by-event basis using the recoil-decay tagging method. Gamma-ray transitions were associated with both the proton decay of the $\pi$$h_{11/2}$ ground state and the $\pi$$d_{3/2}$ isomeric state in ${}^{147}$Tm, even though the cross sections for populating these states were only $\approx$ 16 $\mu$b and 2 $\mu$b, respectively. The level scheme which was constructed for ${}^{147}$Tm is discussed and compared with the level structures for lighter $N$=78 isotones.

The $\alpha$-decay properties of ${}^{190}$Po were investigated through the use of a fragment mass analyzer in conjunction with a double-sided Si strip detector. The isotope was produced via the ${}^{96}\mathrm{Mo}{(}^{96}\mathrm{Mo},2n)$ reaction, and its $\alpha$-decay energy and $T_{1/2}$ were measured as 7529(10) keV and ${2.4}_{-0.3}^{+0.4\mathrm{}}$ ms, respectively. The resulting reduced width is nearly identical to that of the ${}^{192,194}\mathrm{Po}$ isotopes. This is believed to result from significant mixing between the ground state $\pi \mathrm{}\left(2p\right)\mathrm{}$ and the low-lying $0^{+}\pi \mathrm{}(4p-2h)\mathrm{}$ intruder state in the Po parent. The result provides further evidence for shape coexistence in the light Po isotopes. In addition, ${}^{191}\mathrm{Po}$ was unambiguously identified, and the ${}^{186}\mathrm{Pb}$ $\alpha$-decay branch was determined experimentally for the first time.

The yields of neutron-rich fission fragments from the interaction of 20 MeV/nucleon ${}^{238}$U with ${}^{208}$Pb have been measured. The production mechanism of these fragments is consistent with sequential fission following a quasielastic or deep inelastic collision. Substantial yields of very n-rich fragments are observed. The importance of these data for generation of n-rich radioactive beams by fission of intermediate-energy projectiles is discussed.

High-precision lifetime measurements have been performed in superdeformed (SD) bands of ${}^{192,194}$Hg with the Doppler-shift attenuation method. Intrinsic quadrupole moments $Q_0$ were extracted for three SD bands in ${}^{194}$Hg and for the yrast SD band in ${}^{192}$Hg. Within experimental uncertainties, all four SD bands have equal $Q_0$ values. These results provide constraints on differences in $Q_0$ values between the “identical” SD bands ${}^{194}$Hg(3) and ${}^{192}$Hg(1).

The method of Albergo, Costa, Costanzo, and Rubbino to determine the temperature and free nucleon density of a disassembling hot nuclear source from fragment yields is modified to include the effects of radial collective flow, generated in the system from compression. We find that the freeze-out density increased substantially whereas the extracted temperature is modified only a little.