The neutron-rich ${}^{169,171,172}\mathrm{Er}$ nuclei were populated by few-neutron transfer reactions between ${}^{170}\mathrm{Er}$ and ${}^{238}\mathrm{U}$ at a near barrier energy. The spectroscopy of these $\mathrm{Er}$ isotopes was studied using prompt $\gamma$ rays correlated with delayed transitions or events involving at least three prompt transitions. The ground-state band of ${}^{172}\mathrm{Er}$ was populated up to spin ${22}^{+}$ at an excitation energy of $5528\mathrm{keV}$. Rotational bands built on the $1∕2^{-}\left[521\right]$, $5∕2^{-}\left[512\right]$, and $7∕2^{+}\left[633\right]$ neutron configurations in ${}^{169,171}\mathrm{Er}$ were extended to substantially higher spins than previously known. The signature splitting observed in these rotational bands is addressed within the framework of the particle-rotor model in terms of triaxiality and Coriolis attenuation. The signature inversion observed in the $5∕2^{-}\left[512\right]$ band is well reproduced by including the triaxial degree of freedom in the calculation. Attenuating the Coriolis interaction in the calculation is found to be necessary to reproduce the signature splitting observed in the $7∕2^{+}\left[633\right]$ band. A similar Coriolis attenuation also is needed to account for the signature splitting as well as the $B\left(M1\right)∕B\left(E2\right)$ ratios in the $7∕2^{+}\left[633\right]$ ground-state band in the neighboring $N=99$ isotones, ${}^{167}\mathrm{Er}$ and ${}^{169}\mathrm{Yb}$.

A careful measurement of the lifetime of the first $2_{T=1}^{+}$ state in ${}^{42}\mathrm{Sc}$ has allowed an accurate experimental test of isospin purity in the $A=42$ isobaric analogs by using the isospin formalism. A lifetime of $69\left(18\right)\mathrm{fs}$ has been determined, giving an isoscalar matrix element of $6.8\left(8\right)\mathrm{W.u.}$ Previous measurements of the lifetimes in the mirror nuclei ${}^{42}\mathrm{Ca}$ and ${}^{42}\mathrm{Ti}$ provided an isoscalar matrix element of $7.1\left(5\right)\mathrm{W.u.}$ which is very close to the presently measured value for ${}^{42}\mathrm{Sc}$.

The evolution of first excited $0^{+}$ states in transitional nuclei of the $N\approx 90$ region is correlated with the structure of the ground band. Iachello’s $X\left(5\right)$ solution for the Bohr-Hamiltonian for axially symmetric prolate nuclei is generalized to the transition path between $X\left(5\right)$ and the rigid-rotor limit using infinite square-well potentials in the quadrupole deformation parameter $\beta$ with boundaries at ${\beta }_M>{\beta }_m⩾0$. Analytical solutions in terms of Bessel functions of first and second kind are derived and describe well the evolutionary trajectory of the studied $0_2^{+}$ states in this mass region.

The nuclear magnetic moment of the nucleus ${}^{59}\mathrm{Cu}$, with one proton and two neutrons outside the closed $N=Z=28$ shells, was measured in an on-line experiment combining $\beta$-NMR with low temperature nuclear orientation and with particle detectors operating at a temperature of about $10\mathrm{K}$. From the data the center frequency $\nu (B_{ext}=0)=209.51\left(22\right)\mathrm{MHz}$ was derived. Using the hyperfine field of $\mathrm{Cu}$ in host iron from the literature the result for the moment is $\mu \left[{}^{59}\mathrm{Cu}\right]=+1.891\left(9\right)$ ${\mu }_N$, which reveals a large deviation from the proton $p_{3∕2}$ single-particle value. This provides strong experimental evidence for a massive shell breaking at ${}^{56}\mathrm{Ni}$.

We report on precision measurements of the elastic cross section for electron-proton scattering performed in Hall C at Jefferson Lab. The measurements were made at 28 distinct kinematic settings covering a range in momentum transfer of $0.4<Q^2<5.5{(\mathrm{GeV}∕c)}^2$. These measurements represent a significant contribution to the world’s cross section data set in the $Q^2$ range, where a large discrepancy currently exists between the ratio of electric to magnetic proton form factors extracted from previous cross section measurements and that recently measured via polarization transfer in Hall A at Jefferson Lab. This data set shows good agreement with previous cross section measurements, indicating that if a heretofore unknown systematic error does exist in the cross section measurements, then it is intrinsic to all such measurements.

A formalism for representing the fully relativistic propagator of the Rarita-Schwinger field in the nuclear medium is developed. Using a convenient basis for expanding the propagator it is shown that it can be represented by 40 energy and momentum dependent quantities which can be decomposed into a $2\times 2$ and a $6\times 6$ matrix. In this way calculations reduce to matrix multiplication. Using the presented formalism the full relativistically covariant contribution of the pion-nucleon loop to the isobar self energy and propagator in isospin-symmetric spin-saturated nuclear medium is computed. Utilizing this propagator the photoabsorption cross section on in-medium nucleons in the isobar region is calculated and the result compared with experimental data.

The rates of the ${}^{18}\mathrm{F}\left(p,\alpha \right){}^{15}\mathrm{O}$ and ${}^{18}\mathrm{F}\left(p,\gamma \right){}^{19}\mathrm{Ne}$ reactions in astrophysical environments depend on the properties of ${}^{19}\mathrm{Ne}$ levels above the ${}^{18}\mathrm{F}+p$ threshold. There are at least eight levels in the mirror nucleus ${}^{19}\mathrm{F}$ for which analogs have not been observed in ${}^{19}\mathrm{Ne}$ in the excitation energy range $E_x=6.4–7.6\mathrm{MeV}$. These levels may significantly enhance the ${}^{18}\mathrm{F}+p$ reaction rates, and thus we have made a search for these levels by measuring the ${}^1\mathrm{H}\left({}^{18}\mathrm{F},p\right){}^{18}\mathrm{F}$ excitation function over the energy range $E_{\mathrm{c.m.}}=0.3–1.3\mathrm{MeV}$. We have identified and measured the properties of a newly observed level at $E_x=7.420\pm 0.014\mathrm{MeV}$, which is most likely the mirror to the $J^{\pi }={\frac{7}{2}}^{+}{}^{19}\mathrm{F}$ level at $7.56\mathrm{MeV}$. We have additionally found a significant discrepancy with a recent compilation for the properties of a ${}^{19}\mathrm{Ne}$ state at $E_x=7.5\mathrm{MeV}$ and set upper limits on the proton widths of missing levels.

The neutron-deficient nucleus ${}^{162}\mathrm{Os}$, produced in the ${}^{106}\mathrm{Cd}\left({}^{58}\mathrm{Ni},2n\right)$ reaction, has been studied using the JUROGAM $\gamma$-ray spectrometer in conjunction with the RITU gas-filled separator and the GREAT focal plane spectrometer. $\gamma$-ray transitions in ${}^{162}\mathrm{Os}$ have been assigned for the first time through the application of the recoil decay tagging technique. The excitation energy of the $2^{+}$ state and the tentative energy of the $8^{+}$ state are discussed in terms of the systematic energy trends as the $N=82$ shell gap is approached.

The recoil-isomer tagging technique has been used to study the isomeric states of nuclei in the vicinity of the $N=50$ shell closure. The nuclei of interest were separated from the projectilelike nuclei and other evaporation residues and transported to the focal plane of a recoil separator. The decay of the tagged isomer was studied at the focal plane using a high-purity Ge detector. The prompt transitions feeding the isomer were detected in an array of Clover Ge detectors placed around the target. The measured half-lives of the $8^{+}$ isomers in ${}^{88}\mathrm{Zr}$ and ${}^{90}\mathrm{Mo}$ are ${1.41}_{(-0.09)}^{(+0.12)}\mu \mathrm{s}$ and ${1.17}_{(-0.07)}^{(+0.19)}\mu \mathrm{s}$, respectively. The corresponding transition probabilities are in reasonable agreement with the predictions of shell model calculations. The systematics of effective charges ($e_p$ and $e_n$) for $N=48$ nuclei are qualitatively understood in these calculations.

A realistic microscopic calculation of the unpolarized quark generalized parton distribution (GPD) $H_q^3$ of the ${}^3\mathrm{He}$ nucleus is presented. In impulse approximation, $H_q^3$ is obtained as a convolution between the GPD of the internal nucleon and the non-diagonal spectral function, describing properly Fermi motion and binding effects. The proposed scheme is valid at low values of ${\Delta }^2$, the momentum transfer to the target, the most relevant kinematical region for the coherent channel of hard exclusive processes. The obtained formula has the correct forward limit, corresponding to the standard deep inelastic nuclear parton distributions, and first moment, giving the charge form factor of ${}^3\mathrm{He}$. Nuclear effects, evaluated by a modern realistic potential, are found to be larger than in the forward case. In particular, they increase with increasing the momentum transfer when the asymmetry of the process is kept fixed, and they increase with the asymmetry at fixed momentum transfer. Another relevant feature of the obtained results is that the nuclear GPD cannot be factorized into a ${\Delta }^2$-dependent and a ${\Delta }^2$-independent term, as suggested in prescriptions proposed for finite nuclei. The size of nuclear effects reaches 8% even in the most important part of the kinematical range under scrutiny. The relevance of the obtained results to study the feasibility of experiments is addressed.

The $0^{+}$ states of ${}^{12}\mathrm{C}$ are considered within the framework of the microscopic three-$\alpha$-cluster model. The main attention is paid to accurate calculation of the width of the extremely narrow near-threshold $0_2^{+}$ state which plays a key role in stellar nucleosynthesis. It is shown that the $0_2^{+}$-state decays by means of the sequential mechanism ${}^{12}\mathrm{C}\to \alpha +{}^8\mathrm{Be}\to 3\alpha$. Calculations are performed for a number of effective $\alpha \text{‐}\alpha$ potentials which are chosen to reproduce both energy and width of ${}^8\mathrm{Be}$. The parameters of the additional three-body potential are chosen to fix both the ground and excited state energies at the experimental values. The dependence of the width on the parameters of the effective $\alpha \text{‐}\alpha$ potential is studied in order to impose restrictions on the potentials.

Effects of in-medium cross sections and of optical potential on preequilibrium emission and on formation of a thermal source are investigated by comparing the results of transport simulations with experimental results from the $p+{}^{197}\mathrm{Au}$ reaction at $6.2–14.6\mathrm{GeV}∕c$. The employed transport model includes light-composite-particle production and allows for inclusion of in-medium particle-particle cross-section reduction and of momentum dependence in the particle optical potentials. Compared to the past, the model incorporates improved parametrizations of elementary high-energy processes. The simulations indicate that the majority of energy deposition occurs during the first $25\mathrm{fm}∕c$ of a reaction. This is followed by a preequilibrium emission and readjustment of system density and momentum distribution toward an equilibrated system. Within different variants of calculations, the best agreement with data, on the $d∕p$ and $t∕p$ yield ratios and on the residue mass and charge numbers, is obtained at the time of about $65\mathrm{fm}∕c$ from the start of a reaction, for simulations employing reduced in-medium cross sections and momentum-dependent optical potentials. By that time, the preequilibrium nucleon and cluster emission, as well as mean field readjustments, drive the system to a state of depleted average density, $\rho ∕{\rho }_0\sim 1∕4–1∕3$ for central collisions, and low-to-moderate excitation, i.e., the region of nuclear liquid-gas phase transition.

Primary and secondary fragment mass and fragment total kinetic energy were measured by the time-of-flight technique in the $12\mathrm{MeV}$ proton induced fission of ${}^{232}\mathrm{Th}$. The average neutron multiplicity was obtained from the difference of the primary fragment mass and the secondary one as a function of mass and total kinetic energy of fission fragments. Simulation calculations were applied for correction of observed fission data affected by instrumental fluctuations in measurements of flight time and kinetic energies of fragments. Anomalous behaviors of the average neutron multiplicity as a function of total kinetic energy in the mass region of $98–107$ for the lighter fragment and $126–135$ for the heavier were observed and they were found to correlate with two fission modes, symmetric and asymmetric fission. The overall trend of the average neutron multiplicity was discussed in terms of the two fission modes. Partition of the total excitation energy between fragment pairs deduced from the neutron multiplicity data was evaluated for each fission mode for the first time.

We study the bulk viscosity of the strange quark matter in the density-dependent quark mass model (DDQM) under the background of self-consistent thermodynamics. The correct formula of the viscosity is derived. We also find that the viscosity in the DDQM is larger by two to three orders of magnitude than that in MIT bag model. We calculate the damping time scale due to the coupling of the viscosity and $r$ mode. The numerical results show that the time scale cannot be shorter than ${10}^{-1}\mathrm{s}$.

We study dynamic polarization potentials for a halo nucleus ${}^6\mathrm{He}$ scattered by a ${}^{12}\mathrm{C}$ target in the eikonal approximation. We use a realistic, six-nucleon wave function of ${}^6\mathrm{He}$ to include both the halo-neutron and the core-nucleon excitations on an equal footing. We discuss the energy dependence of the polarization potential in relation to that of the nucleon-target optical potential. The imaginary part of the polarization potential changes a sign (negative to positive with increasing energy) around the incident energy of $200\mathrm{MeV}∕\mathrm{nucleon}$, which gives different contributions, depending on the energy, to the elastic differential cross section as well as the reaction cross section.

Nearly complete angular distributions of the two-body deuteron photodisintegration differential cross section have been measured using the CEBAF Large Acceptance Spectrometer detector and the tagged photon beam at the Thomas Jefferson National Accelerator Facility. The data cover photon energies between $0.5$ and $3.0\mathrm{GeV}$ and center-of-mass proton scattering angles $10°–160°$. The data show a persistent forward-backward angle asymmetry over the explored energy range, and are well described by the nonperturbative quark gluon string model.

The total absorption spectrometer installed at the GSI on-line mass separator was used to study the $\beta$-decay of the $J^{\pi }=9^{+}$ isomer in ${}^{70}\mathrm{Br}$. The decay energy $Q_{EC}$ of the isomer was found to be $12.19(\pm 7_{\mathrm{stat}}\pm 4_{\mathrm{sys}})\mathrm{MeV}$. By comparing this value with the estimated $Q_{EC}$ value for the ground state of ${}^{70}\mathrm{Br}$, the excitation energy of isomer is found to be $2.23\left(9\right)\mathrm{MeV}$. The latter result removes ambiguities that can be found in literature.

A measurement of the $n\text{−}{}^3\mathrm{He}$ coherent scattering length using neutron interferometry is reported. The result, $b_c=(5.8572\pm 0.0072)\mathrm{fm}$, improves the measured precision of any single measurement of $b_c$ by a factor of eight; the previous world average, $b_c=(5.74\pm 0.04)\mathrm{fm}$, now becomes $b_c=(5.853\pm 0.007)\mathrm{fm}$. Measurements of the $n\text{−}p$, $n\text{−}d$, and $n\text{−}{}^3\mathrm{He}$ coherent scattering lengths have now been performed using the same technique, thus allowing one to extract the scattering length ratios: parameters that minimize systematic errors. We obtain values of $b_{n{}^3\mathrm{He}}∕b_{np}=(-1.5668\pm 0.0021)$ and $b_{nd}∕b_{np}=(-1.7828\pm 0.0014)$. Using the new world average value of $b_c$ and recent high-precision spin-dependent scattering length data also determined by neutron optical techniques, we extract new values for the bound singlet and triple scattering lengths of $b_0=(9.949\pm 0.027)\mathrm{fm}$ and $b_1=(4.488\pm 0.017)\mathrm{fm}$ for the $n\text{−}{}^3\mathrm{He}$ system. The free nuclear singlet and triplet scattering lengths are $a_0=(7.456\pm 0.020)\mathrm{fm}$ and $a_1=(3.363\pm 0.013)\mathrm{fm}$. The coherent scattering cross section is ${\sigma }_c=(4.305\pm 0.007)\mathrm{b}$ and the total scattering cross section is ${\sigma }_s=(5.837\pm 0.014)\mathrm{b}$. Comparisons of $a_0$ and $a_1$ to the only existing high-precision theoretical predictions for the $n\text{−}{}^3\mathrm{He}$ system, calculated using a resonating group technique with nucleon-nucleon potentials incorporating three-nucleon forces, have been performed. Neutron scattering length measurements in few-body systems are now sensitive enough to probe small effects not yet adequately treated in present theoretical models.

We provide for the first time accurate assessments of the consequences of violations of self-consistency in the Hartree-Fock based random phase approximation (RPA) as commonly used to calculate the energy $E_c$ of the nuclear breathing mode. Using several Skyrme interactions we find that the self-consistency violated by ignoring the spin-orbit interaction in the RPA calculation causes a spurious enhancement of the breathing mode energy for spin unsaturated systems. Contrarily, neglecting the Coulomb interaction in the RPA or performing the RPA calculations in the TJ scheme underestimates the breathing mode energy. Surprisingly, our results for the ${}^{90}\mathrm{Zr}$ and ${}^{208}\mathrm{Pb}$ nuclei for several Skyrme type effective nucleon-nucleon interactions having a wide range of nuclear matter incompressibility $(K_{nm}\sim 215–275\mathrm{MeV})$ and symmetry energy $(J\sim 27–37\mathrm{MeV})$ indicate that the net uncertainty $(\delta E_c\sim 0.3\mathrm{MeV})$ is comparable to the experimental one.

High-spin states in ${}^{174}\mathrm{Pt}$ were populated via the ${}^{92}\mathrm{Mo}\left({}^{84}\mathrm{Sr},2p\right)$ and ${}^{92}\mathrm{Mo}\left({}^{84}\mathrm{Sr},2p2n\right)$ reactions. The ground-state band has been extended from $I=14$ to 24 (tentatively 26) and a new side band is observed up to a spin of 21 (tentatively 23). A low-frequency crossing is observed in the latter band at a rotational frequency that is similar to that seen in the ground-state band. The first and second $i_{13∕2}$ neutron alignments are also observed in ${}^{174}\mathrm{Pt}$. Surprisingly, these crossings occur at approximately the same frequency. Total Routhian surface and cranked shell model calculations are used in an attempt to understand this behavior.