We investigate the $p\overrightarrow{p}p\Lambda K^{+}$ and $p\overrightarrow{p}p{\Sigma }^0{K}^{+}$ reactions at beam energies near their thresholds within an effective Lagrangian model, where the strangeness production proceeds via the excitation of $N^{*}\mathrm{}\left(1650\right),$ $N^{*}\mathrm{}\left(1710\right),$ and $N^{*}\mathrm{}\left(1720\right)\mathrm{}$ baryonic resonances. It is found that the $N^{*}\mathrm{}\left(1650\right)\mathrm{}$ resonance dominates both these reactions at near threshold energies. The contributions from this resonance together with the final state interaction among the outgoing particles are able to explain the observed beam energy dependence of the ratio of the cross sections of the two reactions in the near threshold region.

The exclusive production cross sections for $\omega$ and $\phi$ mesons have been measured in proton-proton reactions at $p_{\mathrm{lab}}=3.67\mathrm{}\hspace{0.5em}\mathrm{GeV}/c.\mathrm{}$ The observed $\phi /\omega$ cross section ratio is $(3.8\mathrm{}\pm {0.2}_{-0.9}^{+1.2\mathrm{}})\times {10}^{-3}.$ After phase space corrections, this ratio is enhanced by about an order of magnitude relative to naive predictions based upon the Okubo-Zweig-Iizuka (OZI) rule, in comparison to an enhancement by a factor $\sim 3$ previously observed at higher beam momenta. The modest increase of this enhancement near the production threshold is compared to the much larger increase of the $\phi /\omega$ ratio observed in specific channels of $\overline{p}p$ annihilation experiments. Furthermore, differential cross section results are also presented which indicate that although the $\phi$ meson is predominantly produced from a ${}^3{P}_1$ proton-proton entrance channel, other partial waves contribute significantly to the production mechanism at this beam momentum.

A new measurement of the $p-d$ differential cross section at $E_p=1\mathrm{}\hspace{0.5em}\mathrm{MeV}$ has been performed. These new data and older data sets at energies below the deuteron breakup are compared to calculations using the two-nucleon Argonne $v_{18}$ and the three-nucleon Urbana IX potentials. A quantitative estimate of the capability of these interactions to describe the data is given in terms of a ${\chi }^2$ analysis. The ${\chi }^2$ per datum drastically improves when the three-nucleon interaction is included in the Hamiltonian.

Excited states have been identified in the very neutron-deficient ${}_{55}^{117}{\mathrm{Cs}}_{62}$ nucleus. High-spin spectroscopy has been performed using the Gammasphere array, and the assignment of gamma-ray transitions to ${}^{117}\mathrm{Cs}$ has been made in a separate experiment in which gamma rays were detected in coincidence with x rays and with recoiling evaporation residues. A previously observed sequence of five gamma rays has been extended by 11 transitions, to high spin, and has been identified as the yrast $\pi {(h}_{11/2}\left)\right[550]{1/2}^{-}$ band of ${}^{117}\mathrm{Cs}.$ Two additional bands have been observed and are tentatively assigned to be based on protons in the $\left[404\right]{9/2}^{+}$ and $\left[422\right]{3/2}^{+}$ orbitals. Alignments of pairs of $h_{11/2}$ neutrons and protons are observed in all of the bands. The alignments are compared to cranked Woods-Saxon calculations, and are discussed with respect to the effects of a neutron-proton interaction. Of particular interest are the features of the $\nu {(h}_{11/2}{)}^2$ alignment in the $\pi \left[550\right]{1/2}^{-}$ band and of the $\pi {(h}_{11/2}{)}^2$ alignment in the $\left[422\right]{3/2}^{+}$ band. The frequencies of these alignments can be qualitatively explained only if a neutron-proton interaction is taken into account.

Low-lying dipole excitations in the odd-proton, midshell nucleus ${}^{103}\mathrm{Rh}$ were investigated in photon scattering experiments at the Stuttgart Dynamitron facility using bremsstrahlung beams with end point energies of 4.1 and 2.4 MeV. In total, 106 excited levels, most of them unknown so far, could be observed in the excitation energy range from 1.2 to 4.0 MeV. In addition to 106 transitions to the ground state ${(J}_0^{\pi }{=1/2\mathrm{}}^{-}),$ 20 transitions to the low-lying $J^{\pi }{=3/2\mathrm{}}^{-}$ level at 295 keV and 10 transitions to the $J^{\pi }{=5/2\mathrm{}}^{-}$ state at 357 keV were detected. For 20 photoexcited levels spins could be suggested from the measured angular distribution data. The reduced ground-state transition strengths summed up in the energy range 2–4 MeV amount to $\Sigma g{\Gamma }_0^{\mathrm{red}}=(16.3\mathrm{}\pm 1.9)$ ${\mathrm{m}\mathrm{e}\mathrm{V}/\mathrm{M}\mathrm{e}\mathrm{V}}^3$ corresponding, under the assumption of an electric character for all excitations, to a total excitation strength of $\Sigma B\left(E1\mathrm{}\right)\mathrm{}\uparrow =(15.6\mathrm{}\pm 1.8)\times {10}^{-3}$ $e^2{\mathrm{fm}}^2.$ The fragmentation of the dipole strength and the decay branchings of the photoexcited levels are discussed. The observed feedings of the 295 and 357 keV levels result in a population inversion, the precondition for a possible $\gamma$-ray laser.

The structure of the neutron-rich carbon isotopes ${}^{16,17,19}\mathrm{C}$ has been investigated using one-neutron knockout reactions on a ${}^9\mathrm{Be}$ target at approximately 60 MeV/nucleon. Partial cross sections and associated momentum distributions corresponding to final states of the ${}^{15,16,18}\mathrm{C}$ residues were measured and compared with predictions based on a shell-model theory and an eikonal model of the reaction mechanism. Spectroscopic factors and l-value assignments are given. The ground-state spins of ${}^{17,19}\mathrm{C}$ are ${\frac{3}{2}}^{+}$ and ${\frac{1}{2}}^{+},$ respectively. It is suggested that the accepted one-neutron separation energy for the ground state of ${}^{19}\mathrm{C}$ needs to be revised upwards.

An effective Lagrangian approach for double pion photoproduction and electroproduction on the proton developed by the Valencia group is improved in a covariant relativistic way. We obtain reasonable agreement with available experimental data for charged pion-pair channel from threshold up to 1 GeV. The role of the $D_{13}\mathrm{}\left(1520\right)\mathrm{}$ resonance in this channel as an intermediate state is also discussed. This approach is applied to calculate the ${\pi }^{-}$ inclusive cross section.

We measured the capture-fission excitation functions for the ${}^{32}\mathrm{S}{+}^{181}\mathrm{Ta}$ reaction and the ${}^{38}\mathrm{S}{+}^{181}\mathrm{Ta}$ reaction. (The radioactive ${}^{38}\mathrm{S}$ beam was produced by projectile fragmentation.) In the ${}^{32}\mathrm{S}$-induced reaction, an incomplete fusion component was observed at high energies, with an average linear momentum transfer corresponding to the escape of an $\alpha$ particle. The deduced interaction barrier heights were $130.7\pm 0.3$ and $124.8\pm 0.3\hspace{0.5em}\mathrm{MeV}$ for the ${}^{32}\mathrm{S}$- and ${}^{38}\mathrm{S}$-induced reactions, respectively. No differences between the two reactions were observed beyond a simple shift in the interaction barrier height.

We discuss particle production mechanisms for heavy ion collisions. We present an argument demonstrating how the fluctuations of the number of produced particles in a series of classical emissions can account for Koba-Nielsen-Olesen scaling. We predict rapidity correlations in the particle production in the event-by-event analysis of heavy ion collisions on the rapidity scales of the order of $1/{\alpha }_s.$

The yrast band was significantly extended to ${14}^{+}$ and the γ band to $5^{+}$ in neutron-rich ${}^{118}\mathrm{Pd}$ by measuring the γ-γ-γ coincidences emitted from the spontaneous fission of ${}^{252}\mathrm{Cf}$ with Gammasphere. The first band crossing was observed in the yrast band in ${}^{118}\mathrm{Pd}$ at a frequency of ħω≈0.36 MeV at the starting point of the backbending, which is similar to that found in ${}^{112-116}\mathrm{Pd}.$ The first bandbending in the yrast cascade in ${}^{118}\mathrm{Pd}$ is interpreted to be built on a two $h_{11/2}$ neutron configuration based on its similarity to the yrast bands in even-even ${}^{112-116}\mathrm{Pd}.$ Our result indicates ${}^{118}\mathrm{Pd}$ still maintains a prolate shape. The quasineutron Routhian calculations indicate a lower crossing frequency for the $h_{11/2}$ level.

Emission of intermediate mass fragments (IMFs) $(Z>~3)$ from central collisions of ${}^{40}\mathrm{Ar}{+}^{45}\mathrm{Sc}\mathrm{}\hspace{0.5em}(E/A=35\mathrm{}–115\hspace{0.5em}\mathrm{MeV}),$ ${}^{58}\mathrm{Ni}{+}^{58}\mathrm{Ni}\hspace{0.5em}(E/A=35\mathrm{}–105\hspace{0.5em}\mathrm{MeV}),$ and ${}^{86}\mathrm{Kr}{+}^{93}\mathrm{Nb}\hspace{0.5em}(E/A=35\mathrm{}–95\hspace{0.5em}\mathrm{MeV})$ was studied. For each system, the average number of IMFs per event increased with beam energy, reached a maximum, and then decreased. The beam energy of peak IMF production increased linearly with the combined mass of the system. The number of IMFs emitted at the peak also increased with the system mass. Percolation calculations showed a weaker dependence of the peak beam energy and the number of IMFs on the total mass of the system.

The longitudinal response functions for quasielastic electron scattering on ${}^{12}\mathrm{C},$ ${}^{40}\mathrm{Ca},$ and ${}^{56}\mathrm{Fe}$ have been calculated taking into account relativistic RPA correlations. For these calculations relativistic nonlinear models, providing a good description of ground state properties of finite nuclei, have been used. The effect of the nonlinear terms on the longitudinal response has been discussed.

We have computed the cross section for the process $d(\alpha ,\gamma {)}^6\mathrm{Li}$ at the low energies relevant for primordial nucleosynthesis and comparison with laboratory data. The final state is a six-body wave function generated by the variational Monte Carlo method from the Argonne $v_{18}$ and Urbana IX potentials, including improved treatment of large-particle-separation behavior. The initial state is built up from the $\alpha$-particle and deuteron ground-state solutions for these potentials, with phenomenological descriptions of scattering and cluster distortions. The dominant $E2\mathrm{}$ cross section is in reasonable agreement with the laboratory data. Including center-of-energy and other small corrections, we obtain an $E1\mathrm{}$ contribution which is larger than the measured contribution at 2 MeV by a factor of 7. We calculate explicitly the impulse-approximation $M1\mathrm{}$ contribution, which is expected to be very small, and obtain a result consistent with zero. We find little reason to suspect that the cross section is large enough to produce significant ${}^6\mathrm{Li}$ in the big bang.

Lifetimes have been measured up to the ${22}^{+}$ level in the yrast positive-parity band and up to the ${13}^{-}$ level in the negative-parity band in ${}^{72}\mathrm{Se}$ using the line-shape analysis methods. The $B\left(E2\mathrm{}\right)\mathrm{}$ and $Q_t$ values obtained from these measurements show a prolate shape stabilization along the yrast band with increasing spins. A noncollective behavior is obtained even at the moderate spins for the negative-parity band. These experimental results are compared with theoretical predictions of the EXCITED VAMPIR and the projected shell model.

We extend the relativistic mean field theory model of Sugahara and Toki by adding new couplings suggested by modern effective field theories. An improved set of parameters is developed with the goal to test the ability of the models based on effective field theory to describe the properties of finite nuclei and, at the same time, to be consistent with the trends of Dirac-Brueckner-Hartree-Fock calculations at densities away from the saturation region. We compare our calculations with other relativistic nuclear force parameters for various nuclear phenomena.

The g factors of the $4_1^{+}$ and $6_1^{+}$ states in ${}^{144,148}\mathrm{Nd},$ the $4_1^{+}$ state in ${}^{146}\mathrm{Nd}$ and the $6_1^{+},$ $8_1^{+},$ and ${10}_1^{+}$ states in ${}^{150}\mathrm{Nd}$ have been measured for the first time by projectile Coulomb excitation coupled to the transient field technique. The g factors of the $2_1^{+}$ states of ${}^{144,146,148,150}\mathrm{Nd}$ have been remeasured with high precision. The data clearly indicate that, while ${}^{148,150}\mathrm{Nd}$ are well described by collective excitations, the structure of the low lying levels in the lighter isotopes is dominated by the ${2f}_{7/2}$ neutron configuration.

High-spin states in ${}^{130}\mathrm{Nd}$ were populated in the reaction ${}^{94}\mathrm{Mo}{(}^{40}\mathrm{Ca},2p2n)$ at a beam energy of 180 MeV. The ground-state band has been extended to $I^{\pi }{=(32\mathrm{}}^{+})$ and three side bands were observed for the first time. In addition, a weak band with a large dynamical moment of inertia was found. The moment of inertia of this sequence is similar to those of structures found to be highly deformed in heavier even-even Nd nuclei.

Within the framework of the SU(3) limit of the neutron-proton interacting boson model the matrix elements of the angular momentum and the quadrupole operator between states belonging to the $K=1\mathrm{}$ band are given in closed forms. To obtain the matrix elements analytically, we first derive the extended $\mathrm{U}\mathrm{}\left(6\right)\mathrm{}\supset \mathrm{SU}\mathrm{}\left(3\right)\mathrm{}$ isoscalar factors associated with low-lying bands by using the intrinsic SU(3) states. The extended $\mathrm{U}\mathrm{}\left(6\right)\mathrm{}\supset \mathrm{SU}\mathrm{}\left(3\right)\mathrm{}$ isoscalar factor is defined as the product of the ordinary $\mathrm{U}\mathrm{}\left(6\right)\mathrm{}\supset \mathrm{SU}\mathrm{}\left(3\right)\mathrm{}$ isoscalar factor and the U(6)-reduced matrix element of the one-body boson operator. Using these results, $M1\mathrm{}$ and $E2\mathrm{}$ intraband transition probabilities and the electromagnetic moments in the $K=1\mathrm{}$ band are derived in closed forms.

To identify the states of the $0^{+},$ $2^{+},$ $4^{+},$ and $6^{+}$ two octupole phonon (TOP) multiplet in ${}^{208}\mathrm{Pb}$ and their respective fragmentation inelastic proton, deuteron, and $\alpha$ scattering has been measured in high energy resolution. Quantum numbers and spectroscopic factors of excited states up to 8 MeV are obtained from the ${}^{207}\mathrm{Pb}{\mathrm{}(d,p)\mathrm{}}^{208}\mathrm{Pb}$ transfer reaction with vector polarized deuterons. From the comparison with literature, we conclude that up to $E_x=6\mathrm{}$ MeV, essentially all states are resolved. The data are compared with recent calculations within the quasiparticle phonon model. For the lowest states the calculated energies are in excellent agreement with experiment. The calculated spectrum of $0^{+},$ $2^{+},$ $4^{+},$ and $6^{+}$ states, which includes mixing with the TOP multiplet, is related to experimental states up to excitation energies above twice the excitation energy of the collective $3_1^{-}$ state at $E_x=5230\mathrm{}$ keV. The measured excitation strengths are consistent with the predicted fragmentation of the two octupole phonon states.

Neutrons and isotopically resolved light charged particles have been detected in coincidence with evaporation residues produced in the reaction $E/A=11\mathrm{}\hspace{0.5em}\mathrm{MeV}$ ${}^{60}\mathrm{Ni}{+}^{100}\mathrm{Mo}.$ Multiplicities of evaporated particle-unstable clusters have been determined from correlations in the emission of these light particles. The decay of the short-lived ${}^5\mathrm{He}$ and ${}^8\mathrm{Be}$ ${(E}^{*}=3.04\mathrm{}\hspace{0.5em}\mathrm{MeV})$ states was found to be affected by the Coulomb field of the compound nucleus in accordance with theoretical estimates. The contributions to the measured kinetic-energy distributions of stable fragments from the sequential decay of the unstable clusters was examined. Overall, the contributions from secondary fragments do not greatly influence the spectral shapes and specifically the location of the spectral peaks are not significantly shifted down in energy due to the presence of these secondary fragments. Therefore contrary to the suggestion of Charity et al. [Phys. Rev. C 56, 873 (1997)], the lower peak energy of the experimental $\alpha$-particle spectrum as compared to standard statistical-model calculations cannot be attributed to sequential $\alpha$ particles from ${}^5\mathrm{He}$ and other clusters. Only for the extreme “subbarrier” regions of the $\alpha$-particle, deuteron, ${}^{6,7}\mathrm{Li},$ and ${}^8\mathrm{Be}$ spectra was the sequential contribution found to be dominant. Statistical-model calculations incorporating large initial deformations are shown to provide enhancements in the yield of low-energy fragments which are roughly appropriate for all the detected isotopes. This suggests that the origin of the sub-barrier enhancements may be a result of evaporation from highly deformed systems which are either produced dynamically during the fusion process or by thermal shape fluctuations.