We define the new description of the electromagnetic current to hold the current conservation in the momentum-dependent Dirac fields from the Ward identity. To describe the momentum dependence we solve the relativistic Hartree-Fock approximation by using the one-pion exchange. In addition we discuss on contribution from the one-pion exchange current and the core polarization. It is shown that the one-pion exchange current can reduce the convection current in the isovector case, whose value has been too large because of the small effective mass in the usual relativistic Hartree approximation.

We make a critical analysis of the theoretical calculations that lead to predictions of deeply bound kaonic states in nuclei. The model setup, after dropping several important processes and channels, leads unavoidably to an unrealistic deep potential with a very small imaginary part. We review also the experimental results taken as reference for the claim of deeply bound kaons. We suggest that the peaks of the proton spectra come from $K^{-}$ absorption on a pair of nucleons, leaving the rest of the nucleons as spectators. Based on this conjecture, we predict what would happen in other nuclei.

The reaction $\overline{p}p\to \overline{\Lambda }\Lambda \to \overline{p}{\pi }^{+}p{\pi }^{-}$ has been measured with high statistics at a beam momentum of $p_{\overline{p}}=1.637\mathrm{GeV}/c$. The use of a transversely polarized frozen-spin target combined with the self-analyzing property of $\Lambda /\overline{\Lambda }$ decay allows access to unprecedented information on the spin structure of the interaction. The most general spin-scattering matrix can be written in terms of 11 real parameters for each bin of scattering angle; each of these parameters is determined with reasonable precision. From these results, all conceivable spin correlations are determined with inherent self-consistency. Good agreement is found with the few previously existing measurements of spin observables in $\overline{p}p\to \overline{\Lambda }\Lambda$ near this energy. Existing theoretical models do not give good predictions for those spin observables that had not been previously measured.

Techniques developed for handing inverse-power-law potentials in atomic physics are applied to the tensor one-pion exchange potential to determine the regions in which it can be treated perturbatively. In $S,P$, and $D$ waves, the critical values of the relative momentum are less than or of the order of 400 MeV. The Wilsonian renormalization group (RG) is then used to determine the power counting for short-range interaction in the presence of this potential. In the $P$ and $D$ waves, where there are no low-energy bound or virtual states, these interactions have half-integer RG eigenvalues and are substantially promoted relative to naive expectations. These results are independent of whether the tensor force is attractive or repulsive. In the ${}^3{S}_1$ channel, the leading term is relevant, but it is demoted by half an order compared to the counting for the effective-range expansion with only a short-range potential. The tensor force can be treated perturbatively in those $F$ waves and above that do not couple to $P$ or $D$ waves. The corresponding power counting is the usual one given by naive dimensional analysis.

The effects of the spin-orbit component of the particle-hole interaction on nuclear response functions and neutrino mean free path are examined. A complete treatment of the full Skyrme interaction in the case of symmetric nuclear matter and pure neutron matter is given. Numerical results for neutron matter are discussed. It is shown that the effects of the spin-orbit interaction remain small, even at momentum transfer larger than the Fermi momentum. The neutrino mean free paths are marginally affected.

The half-lives against α decay of transuranium nuclei including superheavies are calculated by three methods: a semiempirical formula taking into account the magic numbers of nucleons, the analytical superasymmetric fission model, and the universal curves. The calculations based on $Q$ values determined by using the recently published compilations of atomic masses are compared to the experimental results.

The β decay of the neutron-rich nuclei ${}^{51-53}\mathrm{K}$ has been used to populate bound and unbound states in ${}^{50-53}\mathrm{Ca}$. Measurements of γ rays as well as β-delayed neutrons enabled detailed decay schemes to be established and levels identified in ${}^{50-53}$Ca. A delayed one-neutron emission probability $P_{1n}$ of $63\pm 8$% was determined for the decay of ${}^{51}\mathrm{K}$. A total of seven new γ transitions were observed following the decay of ${}^{51}\mathrm{K}$, and 25 neutron branches were found that enrich the level scheme of ${}^{51}\mathrm{Ca}$. Delayed neutron emission probabilities of $P_{1n}=74.4\pm 9.3$% and $P_{2n}=2.3\pm 0.3$% were determined for the decay of ${}^{52}\mathrm{K}$, and 12 new γ transitions were observed in ${}^{50,51,52}\mathrm{Ca}$. Three new γ transitions were observed in ${}^{52,53}\mathrm{Ca}$ following the β decay of ${}^{53}\mathrm{K}$. New limits on the $P_{1n}$ and $P_{2n}$ values were determined for the β decay of ${}^{53}\mathrm{K}$, and a decay scheme was established for ${}^{53}\mathrm{Ca}$ for the first time. The data obtained here should help clarify the structure of neutron-rich $\mathit{fp}$-shell nuclei around the $N=32\text{−}34$ subshell closures.

For the first time the distribution of nuclear charge of fission products with mass numbers 87, 88, 89, 91, 93, 94, 95, 137, 138, 139, and 140 and their complementary products have been studied for neutron induced fission of ${}^{235}\mathrm{U}$ and ${}^{239}\mathrm{Pu}$ in the energy range from thermal up to 1.2 MeV. The energy dependences of the cumulative yields of ${}^{87}\mathrm{Br}$, ${}^{88}\mathrm{Br}$, ${}^{89}\mathrm{Br}$, ${}^{91}\mathrm{Br}$, ${}^{93}\mathrm{Kr}$, ${}^{94}\mathrm{Rb}$, ${}^{95}\mathrm{Rb}$, ${}^{137}\mathrm{I}$, ${}^{138}\mathrm{I}$, ${}^{139}\mathrm{I}$, and ${}^{140}\mathrm{I}$ have been obtained by delayed neutron measurements. The most probable charge $Z_P(A)$in the appropriate isobaric β-decay chains was estimated. The results were analyzed in terms of the deviation $\Delta Z_P(A^{\text{'}})$ of the most probable charge of isobaric β-decay chains from the unchanged charge distribution before prompt neutron emission (nuclear charge polarization) and they are compared with experimental data of other authors and with predictions from Nethaway's $Z_P$-formula and Wahl's $Z_P$-model. We show that the nuclear charge polarization of primary fission fragments $\langle \Delta Z_P(A^{\text{'}})\rangle$ before prompt neutron evaporation decreases as the excitation energy of the compound nucleus increases. This decrease is more pronounced for fission of ${}^{235}\mathrm{U}$. The energy dependencies of $\Delta Z_P(A^{\text{'}})$ and $\Delta Z_P(Z_P)$ obtained in the present work show an attenuation of the odd-even effects in the charge distribution as the excitation energy of the compound nucleus increases.

We investigate ρ-meson photoproduction in a coupled-channels formulation. It is shown that channel coupling effects are large and account for discrepancies observed in several single-channel treatments.

The phenomenon of superscaling for quasielastic lepton induced reactions at energies of a few GeV is investigated within the framework of the relativistic impulse approximation. A global analysis of quasielastic inclusive electron and charged-current neutrino scattering reactions on nuclei is presented. Scaling and superscaling properties are shown to emerge from both types of processes. The crucial role played by final state interactions is evaluated by using different approaches. The asymmetric shape presented by the experimental scaling function, with a long tail in the region of positive values of the scaling variable, is reproduced when the interaction in the final state between the knockout nucleon and the residual nucleus is described within the relativistic mean field approach. The impact of gauge ambiguities and off-shell effects in the scaling function is also analyzed.

The branching of the $2^{+}\to 0^{+}$ transition in ${}^{92}\mathrm{Sr}$ has been measured to 0.032(4) per ${}^{92}\mathrm{Rb}$ decay. It confirms an earlier measurement which was discarded in nuclear data evaluations because of a contradiction with accepted lower log $\mathit{ft}$ limits. The conflict could be solved assuming that close to half of the decay intensity, mostly as high-energy ground-state transitions, is missing in the decay scheme.

Triple coincidence data from the fission of ${}^{252}\mathrm{Cf}$ were used to deduce the intensity of the proposed “hot” mode in barium channels. $\gamma \text{−}\gamma \text{−}\gamma$ and $\alpha \text{−}\gamma \text{−}\gamma$ fission data were analyzed to find the neutron multiplicity distribution for several binary and ternary charge splits. The binary channels Xe-Ru and Ba-Mo were analyzed, as well as the Ba-α-Zr, Mo-α-Xe, and Te-α-Ru ternary channels. An improved method of analysis was used to avoid many of the complexities associated with fission spectra. With this method, we were unable to confirm the second mode in the either the Ba-Mo or Ba-α-Zr splits.

The extended continuum discretized coupled channel (XCDCC) method is developed to treat reactions where core degrees of freedom play a role. The projectile is treated as a multi-configuration coupled channels system generated from a valence particle coupled to a deformed core which is allowed to excite. The coupled channels initial state breaks up into a coupled channels continuum which is discretized into bins, similarly to the original CDCC method. Core collective degrees of freedom are also included in the interaction of the core and the target, so that dynamical effects can occur during the reaction. We present results for the breakup of ${}^{17}\mathrm{C}$=${}^{16}\mathrm{C}$$+n$ and ${}^{11}\mathrm{Be}$=${}^{10}\mathrm{Be}$$+n$ on ${}^9\mathrm{Be}$. Results show that the total cross section increases with core deformation. More importantly, the relative percentage of the various components of the initial state are modified during the reaction process through dynamical effects. This implies that comparing spectroscopic factors from structure calculations with experimental cross sections requires more detailed reaction models that go beyond the single particle model.

A systematic study on the ground-state structure of He isotopes (including ${}^{10}\mathrm{He}$) is presented through a new method developed on the basis of antisymmetrized molecular dynamics (AMD), the generator coordinate method (GCM), and the stochastic variational method (SVM). In this approach, variational calculations are carried out by means of the GCM with the AMD wave functions produced by means of the SVM. A role of the $t+t$ cluster component is examined with the present method, allowing the wider configuration space containing simultaneously the “$t+t$+valence neutrons” structure and “${}^4\mathrm{He}$+valence neutrons” structure.

We predict transverse and longitudinal momentum spectra and yields of ${\rho }^0$ and ω mesons reconstructed from hadron correlations in C+C reactions at 2 GeV/nucleon. The rapidity and $p_T$ distributions for reconstructable ${\rho }^0$ mesons differs strongly from the primary distribution, while the ω distributions are only weakly modified. We discuss the temporal and spatial distributions of the particles emitted in the hadron channel. Finally, we report on the mass shift of the ${\rho }^0$ due to its coupling to the $N^{*}(1520)$, which is observable in both the dilepton and $\pi \pi$ channel. Our calculations can be compared to the Hades experiment at GSI, Darmstadt.

The ${}^{11}\mathrm{B}$$(d,n)$${}^{12}\mathrm{C}$ reaction was studied using deuteron beams of 120–160 keV to determine the absolute astrophysical $S$ factors and cross sections for the $n_0$ and $n_1$ neutron groups. The slopes of the $S$ factors are consistent with zero for both the $n_0$ and $n_1$ cases. The measured $S$ factor for the sum of both neutron groups at c.m. energies below 135 keV is $S=3180\pm 480$ keV b. A DWBA calculation is able to reproduce the ratio of the $S$ factors found here to those obtained in a recent study of the ${}^7\mathrm{Li}$$(d,n_{0,1})$${}^8\mathrm{Be}$ reaction.

The α decay half-lives of the recently produced isotopes of the 112, 114, 116 and 118 nuclei and decay products have been calculated in the quasi-molecular shape path using the experimental $Q_{\alpha }$ value and a Generalized Liquid Drop Model including the proximity effects between nucleons in the neck or the gap between the nascent fragments. Reasonable estimates are obtained for the observed α decay half-lives. The results are compared with calculations using the Density-Dependent M3Y effective interaction and the Viola-Seaborg-Sobiczewski formulae. Generalized Liquid Drop Model predictions are provided for the α decay half-lives of other superheavy nuclei using the Finite Range Droplet Model $Q_{\alpha }$ and compared with the values derived from the VSS formulae.

The two published literature values [Greenwood et al., Nucl. Phys. A252, 260 (1975) and Gelletly et al., J. Phys. G 11, 1055 (1985)] for absolute primary γ intensities following thermal neutron capture of ${}^{171}\mathrm{Yb}$ differ on average by a factor of 3. We have resolved this conflict in favor of Greenwood et al. by a measurement of primary versus secondary intensities.

We have searched for valence neutron decoupling in ${}^{22}\mathrm{O}$, a phenomenon recently observed in neutron-rich C, B, and lighter O nuclei. From the cross section of the ($d,d^{\text{'}}\gamma$) reaction for the transition between the ground state and the first $2^{+}$ state of ${}^{22}\mathrm{O}$, the neutron and proton deformation parameters have been deduced by distorted wave analysis using and reanalyzing the data of a previous Coulomb excitation measurement. The ratio of the neutron and proton multipole transition matrix elements $M_n/M_p$ compared to the $N/Z$ value has been derived to be around 1. This result indicates that the ${}^{22}\mathrm{O}$ isotope has small and similar neutron and proton deformations, which is consistent with $N=14$ shell closure. Thus, the concept of neutron decoupling does not hold for this nucleus.

We calculate at two-loop order the complex-valued scattering amplitude related to the twice-iterated scalar-isovector boson exchange between nucleons. Compared to the once-iterated boson-exchange amplitude, it shows less dependence on the scattering angle. We calculate also the iteration of the (static) irreducible one-loop potential with the one-boson exchange and find similar features. Together with the irreducible three-boson exchange potentials and the two-boson exchange potentials with vertex corrections, which are also evaluated analytically, our results comprise all nonrelativistic contributions from scalar-isovector boson exchange at one- and two-loop orders. The applied methods can be straightforwardly adopted to the pseudoscalar pion with its spin- and momentum-dependent couplings to the nucleon.