Gamow-Teller and dipole transitions to final states in ${}^{13}\mathrm{B}$ were studied via the ${}^{13}\mathrm{C}(t,{}^3\mathrm{He})$ reaction at $E_t=115A$ MeV. In addition to the strong Gamow-Teller transition to the ${}^{13}\mathrm{B}$ ground state, a weaker Gamow-Teller transition to a state at 3.6 MeV was found. This state was assigned a spin-parity of $3/2^{-}$ by comparison with shell-model calculations using the WBP and WBT interactions which were modified to allow for mixing between $n\hslash \omega$ and $(n+2)\hslash \omega$ configurations. This assignment agrees with a recent result from a lifetime measurement of excited states in ${}^{13}\mathrm{B}$. The shell-model calculations also explained the relatively large spectroscopic strength measured for a low-lying $1/2^{+}$ state at 4.83 MeV in ${}^{13}\mathrm{B}$. The cross sections for dipole transitions up to $E_x$$({}^{13}\mathrm{B})=20$ MeV excited via the ${}^{13}\mathrm{C}(t,{}^3\mathrm{He})$ reaction were also compared with the shell-model calculations. The theoretical cross sections exceeded the data by a factor of about 1.8, which might indicate that the dipole excitations are “quenched”. Uncertainties in the reaction calculations complicate that interpretation.

We calculate thermodynamic quantities in symmetric nuclear matter within the self-consistent Green's functions method including three-body forces. The thermodynamic potential is computed directly from a diagrammatic expansion, implemented with the CD-Bonn and Nijmegen nucleon-nucleon potentials and the Urbana three-body forces. We present results for entropy and pressure up to temperatures of 20 MeV and densities of $0.32\hspace{0.5em}{\mathrm{fm}}^{-3}$. While the pressure is sensitive to the inclusion of three-body forces, the entropy is not. The unstable spinodal region is identified and the critical temperature associated to the liquid-gas phase transition is determined. When three-body forces are added we find a strong reduction of the critical temperature, obtaining $T_c\simeq 12\hspace{0.5em}\mathrm{MeV}$.

Fission fragment angular distributions have been measured for the reactions ${}^{11}\mathrm{B}+{}^{204}\mathrm{Pb}$ and ${}^{18}\mathrm{O}+{}^{197}\mathrm{Au}$, both leading to the same compound nucleus ${}^{215}\mathrm{Fr}$ at near barrier energies. The measured fission fragment anisotropies as a function of $E_{\mathrm{c}.\mathrm{m}.}/V_B$ are found to be consistent with the predictions of the standard saddle point statistical model (SSPM) for both the systems, suggesting the absence of entrance channel effects on fission fragment anisotropies even though the entrance channel mass asymmetries for both these systems fall on either side of the Bussinaro-Gallone critical mass asymmetry. The consistency of the present results with SSPM predictions can be understood within the framework of the pre-equilibrium fission model where fission before $K$ equilibration is severely inhibited by the high values of ratios of fission barrier height to nuclear temperature.

We calculate the ground-state energy of cold and dense spin-polarized quark matter with corrections due to correlation energy $(E_{\mathrm{corr}})$. Expressions for $E_{\mathrm{corr}}$ both in the nonrelativistic and ultrarelativistic regimes have been derived and compared with the exchange and kinetic term present in the perturbation series. It is observed that the inclusion of correlation energy does not rule out the possibility of the ferromagnetic phase transition at low density within the model proposed by Tatsumi [Phys. Lett. B489, 280 (2000)]. We also derive the spin stiffness constant in the high-density limit of such a spin-polarized matter.

Landau's Fermi liquid parameters are calculated for non-superfluid pure neutron matter in the presence of a strong magnetic field at zero temperature. The particle-hole interactions in the system, where a net magnetization may be present, are characterized by these parameters in the framework of a multipolar formalism. We use either zero- or finite-range effective nuclear forces to describe the nuclear interaction. Using the obtained Fermi liquid parameters, the contribution of a strong magnetic field on some bulk magnitudes such as isothermal compressibility and spin susceptibility is also investigated.

We prove that any bilinear coupling of a massive spin-$3/2$ field can be brought into a gauge-invariant form suggested by Pascalutsa by means of a nonlinear field redefinition. The corresponding field transformation is given explicitly in a closed form and the implications for chiral effective field theory with explicit Δ(1232) isobar degrees of freedom are discussed.

We show that using parameters consistent with the charge symmetry violating difference between the strong $\mathit{nn}$ and $\mathit{pp}$ scattering lengths provides significant constraints on the calculated amplitude for the $\mathit{dd}\to \alpha {\pi }^0$ reaction.

We have theoretically investigated resonance states in ${}^7\mathrm{He}$ by means of the $\alpha +n+n+n$ microscopic four-cluster model. Low-lying resonance states are searched by solving a $\{{}^6\mathrm{He}(0^{+},2^{+})+n\}+\{{}^5\mathrm{He}({1/2}^{-},{3/2}^{-})+2n(0^{+})\}$ scattering problem by the microscopic $R$-matrix method. Our calculation gives a ${3/2}^{-}$ ground state as well as ${1/2}^{-},{5/2}^{-}$, and the second ${3/2}^{-}$ excited states. For the ${1/2}^{-}$ state, the present calculation gives a broad resonance state in the low-excitation-energy region, $E_x=0.6~1.2$ MeV.

Within the framework of potential scattering theory we derive an analytical two-potential formula for the on-shell partial wave scattering amplitude. This formula embodies a large number of possible applications, including long range Coulomb forces as well as short distance singular potentials. As an example illustrating the use of the formula we analyze the determination of the strong proton-proton scattering $s$-wave phase shift from the experimentally determined Coulomb phase when the one-pion exchange and two-pion exchange chiral potentials are taken into account and analyze the relevant scales of the problem.

The decay of a new $3.2\text{−}\mu \mathrm{s}$, $(4^{-})$ isomeric state at 1298.0 keV has been observed using $\gamma$-ray spectroscopy at the Lohengrin mass spectrometer of the Institut Laue-Langevin. By comparison with theoretical calculations this state was assigned a $\nu 5/2[642]\otimes \nu 3/2[521]$ dominant configuration. Prompt $\gamma$-ray data from a spontaneous fission experiment have also been analyzed allowing the observation of a collective band on top of this isomeric state, the identification of a new band on top of the previously reported ($5^{-}$) isomer of ${}^{156}\mathrm{Nd}$ and the extension of collective bands on top of ($5^{-}$) isomers of the neighboring ${}^{156,158}\mathrm{Sm}$ nuclei. Quasiparticle rotor model calculations reported in this work correctly predict the energies and decay patterns of these bands. A new ($5^{-}$) isomer in ${}^{160}\mathrm{Sm}$ has also been observed. The calculations predict $\nu 5/2[642]\otimes \nu 5/2[523]$ dominant configurations for all these ($5^{-}$) isomers.

The eigenfrequencies of the axial $w$-modes of oscillating neutron stars are studied using the continued fraction method with an equation of state (EOS) partially constrained by the recent terrestrial nuclear laboratory data. It is shown that the density dependence of the nuclear symmetry energy $E_{\mathrm{sym}}(\rho )$ affects significantly both the frequencies and the damping times of these modes. Besides confirming the previously found universal behavior of the mass-scaled eigenfrequencies as functions of the compactness of neutron stars, we explored several alternative universal scaling functions. Moreover, the $w_{\mathit{II}}$-mode is found to exist only for neutron stars having a compactness of $M/R⩾0.1078$ independent of the EOS used.

An excited state of ${}^{22}\mathrm{N}$ unbound with respect to neutron emission was observed in a stripping reaction from a 85 MeV/nucleon ${}^{26}\mathrm{F}$ beam. The observed decay energy of 650(50) keV places the level, which is interpreted to be the first $3^{-}$ state, at an excitation energy of 1.93(22) MeV. Together with the previously measured bound states of ${}^{22}\mathrm{N}$, reduction of the $N=14$ shell gap compared to less neutron-rich nitrogen isotopes at the neutron dripline is observed. Based on the magnitude of the reduction of the shell gap for ${}^{22}\mathrm{N}$, a disappearance of the gap and even a level inversion of the $\nu 1s_{1/2}$ and the $\nu 0d_{5/2}$ levels in the neutron-unbound nucleus ${}^{21}\mathrm{C}$ seems likely.

Recoil-isomer tagging at the Accelerator Laboratory of the University of Jyväskylä has been used to establish the isomeric nature of a known ($7^{-}$) excited state in the doubly odd nucleus ${}^{134}\mathrm{Pm}$. The isomeric state was determined to have a half-life of 20(1) $\mu s$ and was populated from the decay of a $\pi h_{11/2}\otimes \nu h_{11/2}$ band using the ${}^{92}\mathrm{Mo}({}^{54}\mathrm{Fe},2\alpha 3\mathit{pn})$ reaction at 305 and 315 MeV. The isomer decays by a 71-keV transition that provides an intermediate step in linking the established ${}^{134}\mathrm{Pm}$ high-spin level scheme to the lower-spin states observed from the $\beta$ decay of ${}^{134}\mathrm{Sm}$. Electron-conversion analysis for the 71-keV $\gamma$-ray transition reveals that it is of $E1$ character and its small reduced-transition probability suggests that ${}^{134}\mathrm{Pm}$ may have a nuclear shape more rigid than that of the neighboring nuclei.

Radiative processes lead to important corrections to $(e,e^{\text{'}}p)$ experiments. While radiative corrections can be calculated exactly in QED and to a good accuracy also including hadronic corrections, these corrections cannot be included into data analyses to arbitrary orders exactly. Nevertheless consideration of multiphoton bremsstrahlung above the low-energy cutoff is important for many $(e,e^{\text{'}}p)$ experiments. To date, higher-order bremsstrahlung effects concerning electron scattering experiments have been implemented approximately by employing the soft-photon approximation (SPA). In this paper we propose a novel approach to multiphoton emission which partially removes the SPA from $(e,e^{\text{'}}p)$ experiments. In this combined approach one hard photon is treated exactly; and additional (softer) bremsstrahlung photons are taken into account resorting to the soft-photon approximation. This partial removal of the soft-photon approximation is shown to be relevant for the missing-energy distribution for several kinematic settings at MAMI and TJNAF energies.

We evaluate the pion and isobar propagators in cold nuclear matter self-consistently applying a covariant form of the isobar-hole model. Migdal's vertex correction effects are considered systematically in the absence of phenomenological soft form factors. Saturated nuclear matter is modeled by scalar and vector mean fields for the nucleon. It is shown that the short-range dressing of the $\pi N\Delta$ vertex has a significant effect on the pion and isobar properties. Using realistic parameters sets we predict a downward shift of about 50 MeV for the Δ resonance at nuclear saturation density. The pionic soft modes are much less pronounced than in previous studies.

We study photoproduction off nuclei based on a self-consistent and covariant many-body approach for the pion and isobar propagation in infinite nuclear matter. For the first time the $t$-channel exchange of an in-medium pion is evaluated in the presence of vertex correction effects consistently. In particular the interference pattern with the $s$-channel in-medium nucleon and isobar exchange contribution is considered. Electromagnetic gauge invariance is kept as a consequence of various Ward identities obeyed by the computation. Adjusting the set of Migdal parameters to the data set we predict an attractive mass shift for the isobar of about 50 MeV at nuclear saturation density.

The energy of the first excited $2^{+}$ state in ${}^{96}\mathrm{Kr}$ was measured as 241 keV. The nucleus was produced in the fission of ${}^{238}\mathrm{U}$ induced by a 954-MeV ${}^{136}\mathrm{Xe}$ beam and prompt $\gamma$ rays were observed using the clover array CLARA in coincidence with fission products identified with the PRISMA spectrometer. The evolution of the quadrupole collectivity in the Kr isotopes with $N⩾50$ is discussed by comparison with that from the Rb to Mo isotones and with predictions of various theoretical calculations.

The increased interest in more exclusive fission observables has demanded more detailed models. We present here a new computational model, $\mathrm{FREYA}$, that aims to meet this need by producing large samples of complete fission events from which any observable of interest can then be extracted consistently, including arbitrary correlations. The various model assumptions are described and the potential utility of the model is illustrated by means of several novel correlation observables.