We have measured the production of strange baryons and antibaryons in 340-GeV/c ${\Sigma }^{-}+\mathrm{C}$ and 260-GeV/c $n+\mathrm{C}$ interactions. The single $x_F$ distributions show the expected leading particle effect, and the single $p_t^2$ distributions show a distinct nonthermal behavior. The $x_F$ distributions of Λ-Λ pairs indicate two different phase space distributions for the two coincident baryons. On the other hand two $\overline{\Lambda }\mathrm{’}\mathrm{s}$ show identical distributions. Momentum conservation during the formation process may represent a significant source for the observed behavior.

Nearly degenerate partner bands observed in $A\sim 130$ odd-odd triaxial nuclei are interpreted as a manifestation of chirality in the intrinsic reference frame. A phenomenological approach, based on a core-particle-hole coupling model, has been developed to address the experimental observables. This laboratory-frame model, in which chiral symmetry has been restored, includes a triaxial core, a particle/hole single-particle Hamiltonian, and quadrupole-quadrupole interactions. The optimal model parameters are investigated. The results of the calculations indicate the existence of pairs of $\pi h_{11/2}{\nu }^{-1}{h}_{11/2}$ states with the same spin, parity, and similar excitation energy forming partner bands that are nearly degenerate over a range of spins. These calculated partner bands are consistent with the chiral band interpretation and are in agreement with experimental observations in this region. This model has been applied to excited states in ${}^{132}\mathrm{La},$ which have been studied via the ${}^{123}\mathrm{Sb}{(}^{13}\mathrm{C},4n)$ reaction using γ-ray spectroscopic techniques. In addition to the yrast $\pi h_{11/2}{\nu }^{-1}{h}_{11/2}$ band, the partner band was observed with experimental properties consistent with the same $\pi h_{11/2}{\nu }^{-1}{h}_{11/2}$ configuration. These doublet bands resemble those observed systematically for several $N=75\mathrm{}$ isotones of ${}^{132}\mathrm{La}.$

Over 240 transitions and three new rotational bands have been observed in the well-deformed, odd-odd ${}_{59}^{128}{\mathrm{Pr}}_{69}$ nucleus. The high-spin states were populated in two experiments using the ${}^{92}\mathrm{Mo}{(}^{40}\mathrm{Ca},3pn)$ reaction at beam energies of 170 and 184 MeV. Several structures were confirmed in the former experiment using the Clarion and HyBall arrays with the recoil mass spectrometer at Oak Ridge National Laboratory. Gammasphere, in conjunction with the Microball, were employed in the latter experiment at Argonne National Laboratory to extend the sequences to very high spins. Rotational structures in ${}^{126}\mathrm{Pr}$ were also identified in the $\alpha \mathrm{pn}$ channel of the same reaction. The recent discrepancies of spin assignments for the yrast bands in ${}^{126,128}\mathrm{Pr}$ and the interpretation of the lowest crossing in the $\pi h_{11/2}$ band in ${}^{127}\mathrm{Pr}$ are discussed. An adiabatic crossing of the intruder $i_{13/2}$ neutron with one of the normal-deformed bands in ${}^{128}\mathrm{Pr}$ is observed at high rotational frequency. Experimental trends in the signature inversion phenomenon of the $\pi h_{11/2}\nu h_{11/2}$ bands in the $A\approx 130$ region are defined and prove to be surprisingly irregular with respect to those found in the $\pi h_{11/2}\nu i_{13/2}$ bands of the $A\approx 160$ region.

Low-spin, low energy-levels in ${}^{109,107}\mathrm{Sn}$ have been studied following the $\beta$-decay of a 17-s ${}^{109}\mathrm{Sb}$ and a 4-s ${}^{107}\mathrm{Sb},$ respectively. A number of new transitions and levels are established in ${}^{109}\mathrm{Sn}$ with improved support for spin and parity assignments for previously known states. In addition, the presence of two pairs of levels separated by only 14 keV is confirmed. Four new levels are observed in ${}^{107}\mathrm{Sn},$ three of them are below 1 MeV excitation energy. The structure of these nuclides is discussed, focusing on three-quasiparticle cluster structures, movement of the Fermi level, and extrapolations for the single-neutron levels in ${}^{101}\mathrm{Sn}.$

Excited states in the $N=Z+1\mathrm{}$ nucleus ${}^{73}\mathrm{Kr}$ have been investigated using the ${}^{40}\mathrm{Ca}{(}^{36}\mathrm{Ar},2pn)$ and ${}^{40}\mathrm{Ca}{(}^{40}\mathrm{Ca},\alpha 2pn)$ reactions at 145 and 160 MeV, respectively. $\gamma$ rays were detected using the Gammasphere array and events were recorded in coincidence with charged-particle and neutron detectors. The three previously observed bands were extended to high spin, and a new unfavored positive-parity band has been observed. The alignment characteristics and decay properties of the bands are all consistent with large-deformation prolate rotation, with no clear evidence for oblate bands or shape coexistence. This is quite different from neighboring ${}^{72,74}\mathrm{Kr},$ indicating a strong shape-stabilizing role for the valence neutron. The experimental results are compared to extended total Routhian surface, cranked Nilsson Strutinsky, and cranked relativistic mean-field calculations. The results suggest that the paired calculations lack some important physics. Neutron-proton correlations may be the missing ingredient. There is also evidence for an unusual band crossing in the negative-parity bands, which may indicate the presence of $T=0\mathrm{}$ pairing correlations. At high spin all the models can reproduce the experimental data.

Spallation neutron production in proton induced reactions on Al, Fe, Zr, W, Pb, and Th targets at 1.2 GeV and on Fe and Pb at 0.8 and 1.6 GeV measured at the SATURNE accelerator in Saclay is reported. The experimental double differential cross sections are compared with calculations performed with different intranuclear cascade models implemented in high energy transport codes. The broad angular coverage also allowed the determination of average neutron multiplicities above 2 MeV. Deficiencies in some of the models commonly used for applications are pointed out.

We study selected meson transition processes and associated form factors within a model of QCD based on the Dyson-Schwinger equations truncated to the ladder-rainbow level. The infrared structure of the ladder-rainbow kernel is described by two parameters, the ultraviolet behavior is fixed by the one-loop renormalization group behavior of QCD. The work is restricted to the u and d quark sector and allows a Poincaré-covariant study of the radiative decays $\overrightarrow{\rho }\pi \gamma ,$ $\overrightarrow{\omega }\pi \gamma ,$ and ${\pi }^0\to \gamma \gamma .$ Particular attention is paid to the form factors for the associated transitions ${\gamma }^{*}{\pi }^0\to \gamma ,$ ${\gamma }^{*}{\pi }^0\to {\gamma }^{*},$ ${\gamma }^{*}\overrightarrow{\pi }\rho ,$ and ${\gamma }^{*}\overrightarrow{\rho }\pi .$ The latter two processes are of interest as contributors to meson electroproduction from hadronic targets away from the s-channel resonance region. We use the present QCD model to explore limitations to the assumption that coupling to a t-channel virtual $\overline{q}q$ correlation can be modeled as meson exchange.

The structure of the new nuclides discovered recently in the ${}^{241}\mathrm{Am}{(}^{22}\mathrm{Ne},4n)$ reaction, ${}^{259}\mathrm{Db},$ and its $\alpha$-decay chain are systematically studied in the relativistic mean field (RMF) approach with NL3 and TM1 effective interactions. Both the pairing correlation and deformation are essential to reproduce the experiment $Q_{\alpha }$ values. Large deformations have been predicted for all nuclei in the $\alpha$-decay chain, i.e., $\beta \sim 0.28–\mathrm{0.30.}$ The single-particle levels for both protons and neutrons from the deformed RMF theory are discussed in detail.

New Faddeev-Yakubovsky calculations for light $\Lambda \Lambda$ hypernuclei are presented in order to assess the self-consistency of the $\Lambda \Lambda$-hypernuclear binding-energy world data and the implied strength of the $\Lambda \Lambda$ interaction, in the wake of recent experimental reports on ${}_{\Lambda \Lambda }^{\hspace{0.5em}4}\mathrm{H}$ and ${}_{\Lambda \Lambda }^{\hspace{0.5em}6}\mathrm{He}.$ Using Gaussian soft-core simulations of Nijmegen one-boson-exchange model interactions, the Nijmegen soft-core model NSC97 simulations are found close to reproducing the recently reported binding energy of ${}_{\Lambda \Lambda }^{\hspace{0.5em}6}\mathrm{He},$ but not those of other species. For stranger systems, Faddeev calculations of light $\Lambda \Xi$ hypernuclei, using a simulation of the strongly attractive $\Lambda \Xi$ interactions due to the same model, suggest that ${}_{\Lambda \Xi }^{\hspace{0.5em}6}\mathrm{He}$ marks the onset of nuclear stability for $\Xi$ hyperons.

The contribution of quantum shape fluctuations to inertial properties of rotating nuclei has been analyzed within the self-consistent one-dimensional cranking oscillator model. It is numerically proven that for even-even nuclei the dynamical moment of inertia calculated in a mean field approximation in the rotating frame is equivalent to the Thouless-Valatin moment of inertia. If the contribution of the quantum fluctuations to the total energy is taken into account, the dynamical moment of inertia differs from the Thouless-Valatin value.

The ${}^3\mathrm{H}(\overrightarrow{p},\gamma {)}^4\mathrm{He}$ reaction was studied at incident energies of $E_p=40\mathrm{}$ and 80 keV at the Triangle Universities Nuclear Laboratory (TUNL) using beams from a polarized ion source. The present study was the logical progression of a previous study of the ${}^2\mathrm{H}(\overrightarrow{p},\gamma {)}^3\mathrm{He}$ reaction done by the radiative capture group at TUNL. The angular distributions of the cross section, $\sigma \left(\theta \right),$ and the analyzing power, $A_y\left(\theta \right),$ were measured at incident proton beam energies of 40 keV and 80 keV. In both cases the beam was stopped in the target. The magnetic dipole transition strength was determined from the results of a TME analysis. A comparison of the $M1\mathrm{}$ strength with that seen in similar reactions in the three-nucleon case made it possible to infer the meson-exchange current origin of most of this strength. Previous measurements of the absolute cross section extended down to beam energies of 100 keV. The present study extends the measured cross section data to lower energies and is consistent with the previous results. A parametrization of the astrophysical S factor including both data sets was performed.

Excited states of the nucleus ${}^{79}\mathrm{Br}$ were investigated via the reaction ${}^{76}\mathrm{Ge}{(}^7\mathrm{Li},4n)$ at a beam energy of 35 MeV. Coincidence data of emitted γ rays were measured with an arrangement of six EUROBALL CLUSTER detectors. The $E2\mathrm{}$ bands built on the ${9/2}^{+}$ and ${3/2}^{-}$ states were extended up to $J=37/2\mathrm{}$ at $E\approx 8.8\hspace{0.5em}\mathrm{MeV}.$ The $M1\mathrm{}$ band starting with a ${15/2}^{-}$ state at 2.6 MeV was observed up to $J=(29/2)\mathrm{}$ at $E=6.4\mathrm{}\hspace{0.5em}\mathrm{MeV}.$ Crossover $E2\mathrm{}$ transitions within this band were observed for the first time. Mean lifetimes of 17 levels were deduced using the Doppler-shift-attenuation method. The $M1\mathrm{}$ band can be described within the tilted-axis-cranking model on the basis of the tilted three-quasiparticle configuration $\pi {(g}_{9/2}\left)\hspace{0.5em}\nu {(g}_{9/2}\right)\hspace{0.5em}\nu \mathrm{}\left(\mathrm{fp}\right)\mathrm{}$ which has a triaxial shape. This band appears as a mixed case including contributions of both magnetic and collective rotation.

High-spin states in ${}^{90}\mathrm{Y}$ were populated in the ${}^{82}\mathrm{Se}{(}^{11}\mathrm{B},3n)$ reaction at a beam energy of 37 MeV. γ rays were detected with the spectrometer GASP. The level scheme of ${}^{90}\mathrm{Y}$ was extended up to $J^{\pi }{=(18\mathrm{}}^{+})$ at 9.6 MeV. Mean lifetimes of four levels were determined using the Doppler-shift-attenuation method. The structure of ${}^{90}\mathrm{Y}$ was interpreted in terms of the shell model. The calculations were performed in the model space $\pi {(0f}_{5/2}{,1p}_{3/2}{,1p}_{1/2}{,0g}_{9/2}\left)\nu {(1p}_{1/2}{,0g}_{9/2}{,1d}_{5/2}\right)$ and in an extended space including the $\nu {(0g}_{7/2})$ orbital also. The calculations in the extended model space reveal a correspondence between states in ${}^{90}\mathrm{Y}$ and ${}^{89}\mathrm{Y}.$ Moreover, a combination of the predicted states with $J^{\pi }>~{14}^{\mathrm{}(+)\mathrm{}}$ can be found that reproduces the large experimental $B\left(M1\mathrm{}\right)\mathrm{}$ values of up to about 1 Weisskopf unit.

A phenomenological macroscopic model of the giant dipole resonance (GDR) damping width of cold and hot nuclei with ground-state spherical and near-spherical shapes is developed. The model is based on a generalized Fermi liquid model which takes into account the nuclear surface dynamics. The temperature dependence of the GDR damping width is accounted for in terms of surface and volume components. Parameter-free expressions for the damping width and the effective deformation are obtained. The model is validated with GDR measurements of the following nuclides: ${}^{39,40}\mathrm{K},$ ${}^{42}\mathrm{Ca},$ ${}^{45}\mathrm{Sc},$ ${}^{59,63}\mathrm{Cu},$ ${}^{109-120}\mathrm{Sn},$ ${}^{147}\mathrm{Eu},$ ${}^{194}\mathrm{Hg},$ and ${}^{208}\mathrm{Pb},$ and is compared with the predictions of other models.

NA44 uses a 512-channel Si pad array covering $1.5<\mathrm{}\eta <3.3\mathrm{}$ to study charged hadron production in $158A$ GeV Pb+Pb collisions at the CERN SPS. We apply a multiresolution analysis, based on a discrete wavelet transformation, to probe the texture of particle distributions event by event, allowing a simultaneous localization of features in space and scale. Scanning a broad range of multiplicities, we search for signals of clustering and of critical behavior in the power spectra of local density fluctuations. The data are compared with detailed simulations of detector response, using heavy-ion event generators, and with a reference sample created via event mixing. An upper limit is set on the probability and magnitude of dynamical fluctuations.

$\eta$ meson production in both proton-proton and proton-neutron collisions is investigated within a relativistic meson exchange model of hadronic interactions. It is found that the available cross section data can be described equally well by either the vector or pseudoscalar meson exchange mechanism for exciting the $S_{11}\mathrm{}\left(1535\right)\mathrm{}$ resonance. It is shown that the analyzing power data can potentially be very useful in distinguishing these two scenarios for the excitaion of the $S_{11}\mathrm{}\left(1535\right)\mathrm{}$ resonance.

The linearly polarized γ-ray beam produced by the $\mathrm{HI}\gamma \mathrm{S}$ facility has been used to determine the parity of two previously known dipole excitations in ${}^{88}\mathrm{Sr}.$ The azimuthal asymmetry of γ rays produced in the process of nuclear resonance fluorescence indicated that the dipole state at 4.742 MeV, recently discussed as a new form of $M1\mathrm{}$ excitation, is in fact a $1^{-}$ $\mathrm{}\left(E1\mathrm{}\right)\mathrm{}$ state. The $1^{-}$ state at 4.742 MeV must, therefore, be reconsidered as the $J^{\pi }{=1\mathrm{}}^{-}$ member of the quadrupole-octupole coupled two-phonon multiplet. A second state at 7.535 MeV was also assigned $J^{\pi }{=1\mathrm{}}^{-}.$

The nuclear binding energies for 28 nuclei including several isotopic chains with masses ranging from $A=64\mathrm{}$ to $A=226\mathrm{}$ were evaluated using the Skyrme effective nucleon-nucleon interaction and the extended Thomas-Fermi approximation. The neutron and proton density distributions are assumed in the form of Fermi functions, the parameters of which are determined so as to minimize the total binding energy of any given nucleus. The present study is restricted to quadrupole shapes, but the neutron and proton density distributions are free to have different deformations. A simple expression for the variation of the nuclear energy with the neutron-proton deformation difference is derived.

PHENIX data on $\mathrm{Au}+\mathrm{Au}$ at $\sqrt{s}=130A\hspace{0.5em}\mathrm{GeV}$ suggest that $\overline{p}$ yields may exceed ${\pi }^{-}$ at high $p_{\mathrm{T}}>2\mathrm{}\hspace{0.5em}\mathrm{GeV}/c.\mathrm{}$ We propose that jet quenching in central collisions suppresses the hard PQCD component of the spectra in central $A+A$ reactions, thereby exposing a novel component of baryon dynamics that we attribute to (gluonic) bayron junctions. We predict that the observed $\overline{p}\gtrsim {\pi }^{-}$ and the $p>\mathrm{}{\pi }^{+}$ anomaly at $p_{\mathrm{T}}\sim 2\hspace{0.5em}\mathrm{GeV}/c$ is limited to a finite $p_{\mathrm{T}}$ window that decreases with increasing impact parameter.

In-beam $\gamma$-ray spectroscopic studies of the $N=50\mathrm{}$ nucleus ${}^{92}\mathrm{Mo},$ up to spins of $J\sim 18ħ$ and $E_x\sim 12\hspace{0.5em}\mathrm{MeV},$ are reported using a heavy ion fusion reaction with a ${}^{28}\mathrm{Si}$ beam at an incident energy of 138 MeV on an isotopically enriched ${}^{74}\mathrm{Ge}$ target. Sixteen new transitions belonging to this nucleus have been observed and placed in the decay scheme using the conventional $\gamma -\gamma$ coincidence data. The level scheme derived from these measurements is compared with shell model calculations. The presence of gamma rays with $E_{\gamma }\sim 2\hspace{0.5em}\mathrm{MeV}$ at $J\sim 14ħ$ is indicative of the breaking of the $N=50\mathrm{}$ core. The occurrence of gamma rays with $E_{\gamma }\sim 2\hspace{0.5em}\mathrm{MeV}$ at low spins $\left(J\sim 8ħ\right)$ indicates the excitation of protons across the $Z=38\mathrm{}$ core. This is supported by large-basis shell model calculations. The deduced level scheme exhibits single-particle behavior up to the highest observed spins and excitation energies.