Precision data have been obtained for the elastic scattering of ${}^{17}\mathrm{F}$ on ${}^{12}\mathrm{C}$ and ${}^{14}\mathrm{N}$ at 10 MeV/nucleon to clarify the reaction mechanism for loosely bound nuclei at low energies and to assess the validity of a double-folding procedure to predict optical model potentials for use in indirect methods for nuclear astrophysics. The double-folding procedure incorporates density and energy-dependent effective nucleon-nucleon interactions with realistic densities consistent with experimentally determined asymptotic normalization coefficients. The derived potentials provide an excellent description of the data and point to a complete dominance of absorption at the barrier. A semiclassical analysis in terms of multireflection barrier–internal barrier series expansion of the scattering amplitude shows that only the barrier component survives in the scattering process, pointing to the peripheral character of the reactions.

Proton- and α-induced reactions on ${}^{\mathrm{nat}}$Si have been studied in the energy range from 25 to 65 MeV at the Louvain-la-Neuve cyclotron facility. The measured double-differential cross sections and angle-integrated energy spectra for the production of light charged particles (p, d, t, ${}^3\mathrm{He}$, α) have been compared with the predictions of the nuclear-reaction code TALYS. A full description of the contributing reaction mechanisms is presented, and possible improvements to the calculations are discussed.

We analyze coherent ${\Theta }^{+}\Lambda (1520)$ photoproduction in the $\gamma d$ interaction near the threshold. We demonstrate that the effect of the coherent production becomes manifest in a comparison of the ${\mathit{nK}}^{+}$ invariant mass distribution when the ${\mathit{pK}}^{-}$ system is on the $\Lambda (1520)$ mass. Our model calculations indicate a sizable contribution of resonant and nonresonant background processes in the $\gamma d\to \mathit{np}{K}^{+}{K}^{-}$ reaction that generally exceeds the contribution of the coherent resonance channel. However, we find that coherent ${\Theta }^{+}\Lambda (1520)$ photoproduction is enhanced relative to the background processes in the forward hemisphere of ${\mathit{pK}}^{-}$ pair photoproduction. Moreover, the coherence effect does not depend on the ${\Theta }^{+}$ photoproduction amplitude and is defined by the probabilities of $\Lambda (1520)$ photoproduction and the ${\Theta }^{+}\to \mathit{NK}$ transition. Therefore, this effect may be used as an independent method for studying the production mechanism and properties of ${\Theta }^{+}$.

We study the target normal spin asymmetry for the reaction $\mathit{ep}\to \mathit{ep}$ at electron laboratory energy up to 2 GeV. The asymmetry is proportional to the imaginary part of the reaction scattering amplitude. To estimate the imaginary part of the amplitude we use the unitarity relation and saturate the intermediate hadron states by the proton and resonances from the first, second, and third resonance regions. The resonance electromagnetic transition amplitudes, which are needed to evaluate the asymmetry, are taken from experiment.

By use of the pulsed-beam technique, the lifetimes of the first excited $2^{+}$ states in ${}^{176,178}\mathrm{Os}$ were measured for the first time and the lifetime of the $2_1^{+}$ state in ${}^{180}\mathrm{Os}$ was determined to a greater accuracy. In addition, for ${}^{178}\mathrm{Os}$, a recoil-distance Doppler-shift experiment and an experiment to measure the nuclear deorientation effect that is due to the hyperfine interactions were also performed. The results obtained from this measurement are consistent with the lifetime value extracted by means of the pulsed-beam experiment. As well, the lifetimes of two $I^{\pi }=7$${}^{-}$ isomers in ${}^{180}\mathrm{Os}$ were determined more accurately. Together with previously published data for the even-even osmium isotopes, the newly determined $B(E2,2_1^{+}\to 0_1^{+})$ transition strengths show a maximum value at the $N=104$ midshell. This maximum corresponds to the simple expectation of the $N_{\pi }{N}_{\nu }$ rule of the interacting boson approximation (IBA) but remains to be explained by microscopic models.

The most general spin structures of the spin-1/2 baryon and spinless meson production operator for both photon and nucleon induced reactions are derived from the partial-wave expansions of these reaction amplitudes. The present method provides the coefficients multiplying each spin operator in terms of the partial-wave matrix elements. The result should be useful in studies of these reactions based on partial-wave analyses, especially, when spin observables are considered.

The binary fragmentation of the excited superheavy system of $Z=116$ formed in the reaction 372 MeV ${}^{56}\mathrm{Fe}+{}^{232}\mathrm{Th}$ has been investigated. The fragment masses and kinetic energies were determined through measurement of the fragment velocities by the time-of-flight method. Neutron spectra were measured in coincidence with the fragments at several angles with respect to the fragment direction, which were analyzed to deduce the total as well as the pre-scission neutron multiplicities. We analyzed the correlations between fragment mass and kinetic energy, gated and nongated by the coincidence with neutrons, to learn about the dynamics of the reaction with respect to the two-body exit channels. The events in the near-mass-symmetric valley region appear to receive a significant contribution from the asymmetric mode of fission of the superheavy compound nucleus $Z=116$, which can be due to the influence of the closed proton and neutron shells of $Z=50$ and $N=82$ in the light fragments. From the observed number of pre-scission neutrons, it is inferred that the time scales of the fissionlike reactions leading to near-mass-symmetric splits are rather large, of the order of several times ${10}^{-20}s$. The average number of prompt neutrons emitted in the spontaneous fission of such a superheavy nucleus is $\nu =(12\pm 1)$, as deduced from the neutron measurements.

In order to verify methods of calculating the fission-evaporation competition in reactions used to synthesize new super-heavy nuclei in “cold” $(1n)$ and “hot” $(3n,4n)$ fusion reactions, we present an analysis of existing experimental data on the evaporation-residue cross sections in two selected reactions, ${}^{208}\mathrm{Pb}$(${}^{16}\mathrm{O}$, xn) and ${}^{236}\mathrm{U}$(${}^{12}\mathrm{C}$, xn), for which complementary experimental information necessary to unambiguously calculate the survival probabilities is available: precisely measured fusion excitation functions and saddle-point energies of the fissioning nuclei, deduced from experiments. Standard statistical model calculations, with shell effects accounted for by the Ignatyuk formula, were carried out assuming the ground state shell corrections of Möller et al., and zero shell correction at the saddle configuration (resulting from the presented systematics). Good agreement of the calculated evaporation-residue cross sections with experimental data for different xn reaction channels at low excitation energies leaves no room for modifications of the conventional way of calculating the ${\Gamma }_n/{\Gamma }_f$ ratio, particularly for including into this ratio an additional preexponential factor (such as the Kramers fission hindrance factor or an effective collective factor) significantly different from 1.

We study the correlation characteristics between particles in jets produced in heavy-ion collisions. In the framework of parton recombination we calculate the $\eta$ and $\varphi$ distributions of a pion associated with a trigger particle. The origin of the pedestal in $\Delta \eta$ is related to the longitudinal expansion of the thermal partons that are enhanced by the energy loss of hard partons traversing the bulk medium. The peaks in $\Delta \eta$ and $\Delta \varphi$ are related to the same angular spread of the shower partons in a jet cone. No artificial short- or long-range correlations are put in by hand. A large part of the correlation between hadrons in jets is due to the correlation among the shower partons arising from momentum conservation. Recombination between thermal and shower partons dominates the correlation characterisitics in the intermediate-$p_T$ region.

Laser spectroscopy measurements have been carried out on the neutron-rich tin isotopes with the COMPLIS experimental setup. Using the $5s^{2}5p^{23}{P}_0\to 5s^{2}5p6s{}^3{P}_1$ optical transition, hyperfine spectra of ${}^{126-132}\mathrm{Sn}$ and ${}^{125,127,129-131}\mathrm{Sn}{}^m$ were recorded for the first time. The nuclear moments and the mean square charge radius variation ($\delta \langle r_c^2\rangle$) were extracted. From the quadrupole moment values, these nuclei appear to be spherical. The magnetic moments measured are thus compared with those predicted by spherical basis approaches. From the measured $\delta \langle r_c^2\rangle$, the absolute charge radii of these isotopes were deduced in particular that of the doubly magic ${}^{132}\mathrm{Sn}$ nucleus. The comparison of the results with several mean-field-type calculations have shown that dynamical effects play an important role in the tin isotopes.

An improved quark mass density-dependent model that includes the coupling between the quarks and a nonlinear scalar field is presented. A numerical analysis of solutions of the model is performed over a wide range of parameters. The wave functions of the ground state and the lowest one-particle excited states with even and odd parities are given. The root-mean-squared radius, the magnetic moment, and the ratio between the axial-vector and the vector β-decay coupling constants of the nucleon are calculated. We found that the presented model is successful in describing the properties of the nucleon.

The forward inclusive pion double charge exchange reaction, ${}^{16}\mathrm{O}({\pi }^{-},{\pi }^{+})X$, at $T_0=0.50$ and 0.75 GeV has been studied in the kinematic region where an additional pion production is forbidden by energy-momentum conservation. The experiment was performed with the SKS spectrometer at KEK PS. The measured ratio of double charge exchange cross-section for these energies $\langle d\sigma (0.50\text{GeV})/d\Omega \rangle /\langle d\sigma (0.75\text{GeV})/d\Omega \rangle =1.7\pm 0.2$, disagrees with the value of 7.2 predicted within the conventional sequential single charge exchange mechanism. Possible reasons for the disagreement are discussed in connection with the Glauber inelastic rescatterings.

Two reactions, $\mathit{pp}\to \mathit{ppX}$ and $\mathit{pp}\to p{\pi }^{+}X$, are used to study the $1.47\le M\le 1.680$ GeV baryonic mass range. Three different final states are considered in the invariant masses: $N^{*}$ or ${\Delta }^{+},n{\pi }^{+}$ or $p{\pi }^0$, and $p\eta$. The last two channels are defined by software cuts applied to the missing mass of the first reaction. Several narrow structures are extracted with widths $\sigma (\Gamma )$ varying between 3 and 9 MeV. Some structures are observed in one channel but not in another. Such nonobservation may be due either to the spectrometer momenta limits or to the physics (e.g., no such disintegration channel is allowed from the narrow state considered).

We tentatively conclude that the broad Particle Data Group (PDG) baryonic resonances—$N(1520)D_{13},N(1535)S_{11},\Delta (1600)P_{33},N(1650)S_{11}$, and $N(1675)D_{15}$—are collective states built from several narrow and weakly excited resonances, each having a (much) smaller width than the one reported by PDG.

We adopt the microscopic quasiparticle-phonon model to carry out a systematic study of the low-lying excited $0^{+}$ states observed in large abundance in some deformed nuclei. Through the investigation of the energy levels, the corresponding wave functions, the E0 and E2 transition probabilities, and, especially, the two-nucleon transfer spectroscopic factors, we gain a deep insight into the nature of these states and are able to single the properties shared by all nuclei from the ones induced by the peculiar shell structure of each system.

We present estimates of the mass excess of ${}^{18}\mathrm{Na}$ and properties of some of the low-lying states, using information from the mirror nucleus ${}^{18}\mathrm{N}$ for guidance. We offer explanations for three peaks observed in ${}^{18}\mathrm{Na}\to {}^{17}\mathrm{Ne}+p$ decay.

We employ point form relativistic quantum mechanics to calculate the photoproduction and electroproduction of nucleon resonances. Both the transverse and longitudinal transition amplitudes are computed based on the constituent quark model within the relativistic framework. The obtained results are compared with the calculations of the nonrelativistic approach and of the hypercentral potential model. Relativistic effects and discrepancies among the models are discussed.

The possible existence of four-neutron resonances close to the physical energy region is explored. Faddeev-Yakubovsky equations have been solved in configuration space using realistic nucleon-nucleon interaction models. Complex scaling and analytical continuation in the coupling constant methods were used to follow the resonance pole trajectories, which emerge out of artificially bound tetraneutron states. The final pole positions for four-neutron states lie in the third energy quadrant with negative real energy parts and should thus not be physically observable.

High-resolution nuclear resonance fluorescence experiments (NRF) were performed on ${}^{110,111,112,114,116}\mathrm{Cd}$ at the bremsstrahlung facility of the 4.3-MV Dynamitron accelerator in Stuttgart to study the low-lying dipole strength distributions in these vibrational nuclei. Numerous excited states, most of them previously unknown, were observed in the excitation energy range up to 4 MeV. Detailed spectroscopic information has been obtained on excitation energies, spins, decay widths, decay branchings, and transition probabilities. For states in the even-even isotopes ${}^{110,112,114,116}\mathrm{Cd}$, parities could be assigned from linear polarization measurements. Together with our previous results for ${}^{108,112,113,114}\mathrm{Cd}$ from NRF studies without polarization measurements, systematics was established for the dipole strength distributions of the stable nuclei within the Cd isotopic chain. The results are discussed with respect to the systematics of $E1$ two-phonon excitations and mixed-symmetry states in even-even nuclei near the $Z=50$ shell closure and the fragmentation of these excitation modes in the odd-mass Cd isotopes.

Vector analyzing power $A_n$ is calculated for elastic electron scattering from a variety of spin-zero nuclei at energies from 14 MeV to 3 GeV. Time-reversal symmetry ensures that $A_n$ vanish in the first Born approximation. Therefore $A_n$ depends on Coulomb distortions and can be large for scattering from heavy nuclei. The vector analyzing power is a potential source of systematic error for parity-violation experiments. We find that $A_n=-0.361$ ppm for the kinematics of the parity radius experiment involving 850-MeV electrons scattering at $6^{°}$ from ${}^{208}\mathrm{Pb}$. This is comparable with the parity-violating asymmetry. However, for HAPPEX He involving 3-GeV electrons scattering on ${}^4\mathrm{He}$ we find that $A_n$ is very small.