High-statistics cross sections and recoil polarizations for the reactions $\gamma +p\to K^{+}+\Lambda$ and $\gamma +p\to K^{+}+{\Sigma }^0$ have been measured at CLAS for center-of-mass energies between 1.6 and $2.3\text{GeV}$. In the $K^{+}\Lambda$ channel we confirm a resonance-like structure near $W=1.9\text{GeV}$ at backward kaon angles. Our data show more complex $s$- and $u$- channel behavior than previously seen, since structure is also present at forward angles, but not at central angles. The position and width change with angle, indicating that more than one resonance is playing a role. Large positive $\Lambda$ polarization at backward angles, which is also energy dependent, is consistent with sizable $s$- or $u$-channel contributions. Presently available model calculations cannot explain these aspects of the data.

How the nucleon magnetic moment originates from the quark spin and orbital motions is an important issue of the nucleon structure. The Gordon decomposition separates the quark vector current and magnetic moment into a spin and an orbital parts. We show that the spin part is related to the quark tensor charge, thus can be determined experimentally and computed reliably by lattice QCD. Knowledge of the spin-orbital structure of the nucleon magnetic moment would also shed light on the nucleon spin problem. As an example, we show that the spin part of the nucleon strangeness magnetic moment ${\mu }_s$ is negative. If the experimental result of a positive ${\mu }_s$ is confirmed, then the orbital motion of strange quarks must be important in the nucleon.

Reaction ${\pi }^{-}p\to {\pi }^0{\pi }^{0}n$ has been measured with high statistics in the beam momentum range $270–750\text{MeV}∕c$. The data were obtained using the Crystal Ball multiphoton spectrometer, which has $93\%$ of $4\pi$ solid angle coverage. The dynamics of the ${\pi }^{-}p\to {\pi }^0{\pi }^{0}n$ reaction and the dependence on the beam energy are displayed in total cross sections, Dalitz plots, invariant-mass spectra, and production angular distributions. Special attention is paid to the evaluation of the acceptance that is needed for the precision determination of the total cross section ${\sigma }_t({\pi }^{-}p\to {\pi }^0{\pi }^{0}n)$. The energy dependence of ${\sigma }_t({\pi }^{-}p\to {\pi }^0{\pi }^{0}n)$ shows a shoulder at the Roper resonance [i.e., the $N\left(1440\right){\frac{1}{2}}^{+}$], and there is also a maximum near the $N\left(1520\right){\frac{3}{2}}^{-}$. It illustrates the importance of these two resonances to the ${\pi }^0{\pi }^0$ production process. The Dalitz plots are highly nonuniform; they indicate that the ${\pi }^0{\pi }^{0}n$ final state is dominantly produced via the ${\pi }^0{\Delta }^0\left(1232\right)$ intermediate state. The invariant-mass spectra differ much from the phase-space distributions. The production angular distributions are also different from the isotropic distribution, and their structure depends on the beam energy. For beam momenta above $550\text{MeV}∕c$, the density distribution in the Dalitz plots strongly depends on the angle of the outgoing dipion system (or equivalently on the neutron angle). The role of the $f_0\left(600\right)$ meson (also known as the $\sigma$) in ${\pi }^0{\pi }^{0}n$ production remains controversial.

Medium spin states of ${}^{95,97}\mathrm{Mo}\left(Z=42,N=53,55\right)$ nuclei have been investigated through the ${}^{82}\mathrm{Se}\left({}^{18}\mathrm{O},xn\right)$ reaction at $E_b=60\text{MeV}$. In ${}^{95}\mathrm{Mo}$, excited states upto $7.5\text{MeV}$ have been studied in the present experiment. A significant modification of the existing level scheme has been suggested. The negative parity level sequence of ${}^{97}\mathrm{Mo}$ has been extended to $8.6\text{MeV}$. The experimental data for both the nuclei have been compared with the theoretical results from shell model and particle rotor model calculations.

The nucleus ${}^{185}\mathrm{Au}$ was populated using the reaction ${}^{159}\mathrm{Tb}\left({}^{30}\mathrm{Si,}4n\right)$${}^{185}\mathrm{Au}$ at $140\text{MeV}$ beam energy. Lifetimes for the $E2$ transitions in $h_{9∕2}$ and $i_{13∕2}$ bands have been measured using recoil distance method. The reduced transition probabilities $B\left(E2\right)$ and transitional quadrupole moments $Q_t$ were extracted using the measured lifetimes. Calculations of quasiparticle Routhians and total Routhian surfaces (TRS) have been performed to investigate the effect of the $\beta$- as well as the $\gamma$-driving properties of these configurations in this nucleus.

The neutron-rich isotope ${}^{218}\mathrm{Bi}$ has been produced in proton-induced spallation of a uranium carbide target at the ISOLDE facility at CERN, extracted from the ion source by the pulsed-release technique and resonant laser ionization, and its $\beta$ decay is studied for the first time. A half-life of $33\left(1\right)\mathrm{s}$ was measured and is discussed in the self-consistent continuum-quasi particle-random-phase approximation framework that includes Gamow-Teller and first-forbidden transitions. A level scheme was constructed for ${}^{218}\mathrm{Po}$, and a deexcitation pattern of stretched $E2$ transitions $8^{+}\to 6^{+}\to 4^{+}\to 2^{+}\to 0^{+}$ to the ground state is suggested. Shell-model calculations based on the Kuo-Herling interaction reproduce the experimental results satisfactorily.

Differential cross sections and a complete set of polarization observables have been measured in the quasielastic ${}^2\mathrm{H}\left(p,n\right)$ reaction at a bombarding energy of $345\text{MeV}$ and laboratory scattering angles of $16°$, $22°$, and $27°$. The data are compared with plane-wave impulse approximation calculations employing an optimal factorization approximation. The agreement between the experimental and theoretical results validates these approximations in the present momentum- and energy-transfer regions. The experimental spin-longitudinal and spin-transverse response functions, $R_L$ and $R_T$, respectively, are deduced from the data. The obtained $R_T$ is consistent with that obtained from the quasielastic electron scattering. The theoretical calculations with the Reid soft core potential give good descriptions for $R_L$ and $R_T$, whereas the latter is slightly underestimated around the quasielastic peak.

The properties of hybrid stars formed by hadronic and quark matter in $\beta$ equilibrium at fixed entropies are described by appropriate equations of state (EOSs) in the framework of relativistic mean-field theory. In this work we include the possibility of neutrino trapped EOS and compare the star properties with the ones obtained after deleptonization, when neutrinos have already diffused out. We use the nonlinear Walecka model for the hadron matter with two different sets for the hyperon couplings and the MIT Bag and the Nambu-Jona-Lasinio (NJL) models for the quark matter. The phase transition to a deconfined quark phase is investigated. Depending on the model and the parameter set used, the mixed phase may or may not exist in the EOSs at high densities. The star properties are calculated for each equation of state. The maximum mass stellar configurations obtained within the NJL have larger masses than the ones obtained within the Bag model. The Bag model predicts a mixed phase in the interior of the most massive stable stars while, depending on the hyperon couplings, the NJL model predicts a mixed phase or pure quark matter. Comparing with neutrino free stars, the maximum allowed baryonic masses for protoneutron stars are $\sim 0.4M_{☉}$ larger for the Bag model and $\sim 0.1M_{☉}$ larger for the NJL model when neutrino trapping is imposed.

Trinucleon longitudinal response functions $R_L(q,\omega )$ are calculated for $q$ values up to $500\text{MeV}∕c$. These are the first calculations beyond the threshold region in which both three-nucleon $\left(3N\right)$ and Coulomb forces are fully included. We employ two realistic $NN$ potentials (configuration space BonnA, $\text{AV}18$) and two $3N$ potentials (UrbanaIX, Tucson-Melborne). Complete final state interactions are taken into account via the Lorentz integral transform technique. We study relativistic corrections arising from first-order corrections to the nuclear charge operator. In addition the reference frame dependence due to our nonrelativistic framework is investigated. For $q⩽350\text{MeV}∕c$ we find that $3N$ forces give effects of between $5\%$ and $10\%$ in the peak region and of $15\%$ in the threshold region at the lowest considered momentum transfer $\left(q=174\text{MeV}∕c\right)$, while the dependence on other theoretical ingredients is small. At $q⩾400\text{MeV}∕c$ relativistic corrections to the charge operator and effects of frame dependence, especially for large $\omega$, become more important. In comparison with experimental data there is generally a rather good agreement. Exceptions are the responses at excitation energies close to threshold, where there exists a large discrepancy with experiment at higher $q$. In the ${}^3\mathrm{He}$ case one finds a much improved agreement with experiment both in the peak region and in the low-$q$–low-$\omega$ region if $3N$ forces are included. However in comparison with the existing data for ${}^3\mathrm{H}$ the inclusion of $3N$ forces appears to have the opposite effect in the peak region.

The $\Lambda \Lambda \text{−}\Xi N\text{−}\Sigma \Sigma$ coupling in ${}_{\Lambda \Lambda }{}^{\phantom{\Lambda }6}\mathrm{He}$ is studied with the $\left[\alpha +\Lambda +\Lambda \right]+\left[\alpha +\Xi +N\right]+\left[\alpha +\Sigma +\Sigma \right]$ model, where the $\alpha$ particle is assumed as a frozen core. We use the Nijmegen soft-core potentials, NSC97e and NSC97f, for the valence baryon-baryon part, and the phenomenological potentials for the $\alpha -B$ parts ($B=N,\Lambda ,\Xi$, and $\Sigma$). We find that the calculated $\Delta B_{\Lambda \Lambda }$ of ${}_{\Lambda \Lambda }{}^{\phantom{\Lambda }6}\mathrm{He}$ for NSC97e and NSC97f are, respectively, 0.6 and $0.4\text{MeV}$ in the full coupled-channel calculation, the results of which are about half in comparison with the experimental data, $\Delta B_{\Lambda \Lambda }^{exp}=1.01\pm {0.20}_{-0.11}^{+0.18}\text{MeV}$. Characteristics of the $S=-2$ sector in the NSC97 potentials are discussed in detail.

Shell model calculations have been performed for low-excitation states in the Zr isotopes between ${}^{90}\mathrm{Zr}$ and ${}^{96}\mathrm{Zr}$ with an emphasis on the $g$ factors and electromagnetic decay rates for the lowest $2^{+}$ and $3^{-}$ states. Overall the $2^{+}$ states are reasonably well described. In contrast, the $3^{-}$ states present a puzzle because the measured $g$ factors imply a single-particle configuration whereas the experimental $E3$ transition rates imply collective structures that cannot be explained by shell model calculations. A consistent description of the $3^{-}$ states in ${}^{90}\mathrm{Zr}$ and ${}^{96}\mathrm{Zr}$ is sought in terms of coupling between the single-particle structure and a collective octupole vibration.

The actinide-based hot fusion reactions with stable projectiles heavier than ${}^{48}\mathrm{Ca}$ are analyzed within the dinuclear system model for compound nucleus formation. The production of the odd superheavy nuclei in the ${}^{48}\mathrm{Ca}$-induced hot fusion reactions is considered. Predictions for several reactions with radioactive beams of ${}^{46}\mathrm{Ar}$, ${}^{47}\mathrm{K}$, and ${}^{50}\mathrm{Ca}$ for the synthesis of heaviest elements are also presented for the future interest.

The transport coefficient of shear viscosity is studied for a hadron matter through microscopic transport model, the ultrarelativistic quantum molecular dynamics (UrQMD), using the Green-Kubo formulas. Molecular-dynamical simulations are performed for a system of light mesons in a box with periodic boundary conditions. Starting from an initial state composed of $\pi ,\eta ,\omega ,\rho ,\varphi$ with a uniform phase-space distribution, the evolution takes place through elastic collisions, production, and annihilation. The system approaches a stationary state of mesons and their resonances, which is characterized by common temperature. After equilibration, thermodynamic quantities such as the energy density, particle density, and pressure are calculated. From such an equilibrated state the shear viscosity coefficient is calculated from the fluctuations of stress tensor around equilibrium using Green-Kubo relations. We do our simulations here at zero net baryon density so that the equilibration times depend on the energy density. We do not include hadron strings as degrees of freedom so as to maintain detailed balance. Hence we do not get the saturation of temperature but this leads to longer equilibration times.

We propose the measurement of the elliptic flow of hadron resonances at the Relativistic Heavy Ion Collider as a tool to probe the amount of hadronic final state interactions for resonances at intermediate and large transverse momenta. This can be achieved by looking at systematic deviations of the measured flow coefficient $v_2$ from the scaling law given by the quark recombination formalism. Our method can be generalized to explore the structure of exotic particles, such as the recently found pentaquark ${\Theta }^{+}\left(1540\right)$.

Existing experimental data for the breakup of ${}^8\mathrm{B}$ at energies from 30 to $1000\text{MeV}∕\text{nucleon}$ on light through heavy targets are analyzed in detail in terms of an extended Glauber model. The predictions of the model are in excellent agreement with independent reaction data (reaction cross sections and parallel momentum distributions for corelike fragments). Final-state interactions have been included in the Coulomb dissociation component. We extract asymptotic normalization coefficients (ANC) from which the astrophysical factor $S_{17}\left(0\right)$ for the key reaction for solar neutrino production, ${}^7\mathrm{Be}\left(p,\gamma \right){}^8\mathrm{B}$, can be evaluated. Glauber model calculations using different effective interactions give consistent, though slightly different results. The differences give a measure of the precision one can expect from the method. The unweighted average of all ANCs extracted leads to $S_{17}\left(0\right)=18.7\pm 1.9\text{eV}\mathrm{b}$. The results of this new analysis are compared with the earlier one. They are consistent with the values from most direct measurements and other indirect methods.

Rotational bands have been studied to high spins in the neutron-deficient ${}^{124,125}\mathrm{Ce}$ nuclei. The nuclei were populated using the ${}^{64}\mathrm{Zn}\left({}^{64}\mathrm{Zn},2p2n\right){}^{124}\mathrm{Ce}$ and ${}^{64}\mathrm{Zn}\left({}^{64}\mathrm{Zn},2pn\right){}^{125}\mathrm{Ce}$ reactions, with a beam energy of $260\text{MeV}$. High-fold $\gamma$-ray coincidence data were collected using the Gammasphere germanium-detector array. The Microball charged-particle detector array was used to provide channel selection. The previously established level structures of both ${}^{124,125}\mathrm{Ce}$ have been extended to high spins $\left(\sim 30\hslash \right)$. In addition, several new bands have been identified. The alignments of pairs of $h_{11∕2}$ neutrons and protons are observed in both nuclei. The alignments are compared to the predictions of Woods-Saxon cranked shell model calculations and to the systematics of $h_{11∕2}$ quasiparticle alignments in neighboring nuclei. The apparent ability of the cranked shell model to explain the $h_{11∕2}$ neutron alignments in ${}^{124,125}\mathrm{Ce}$ highlights the previously reported discrepancies between experiment and theory for the ${}^{128}\mathrm{Ce}$ isotope and, to a lesser extent, ${}^{126}\mathrm{Ce}$.

We investigate truncation schemes to reduce the computational cost of calculating correlations by the generator coordinate method based on mean-field wave functions. As our test nuclei, we take examples for which accurate calculations are available. These include a strongly deformed nucleus, ${}^{156}\mathrm{Sm}$, a nucleus with strong pairing, ${}^{120}\mathrm{Sn}$, the krypton isotope chain which contains examples of soft deformations, and the lead isotope chain which includes the doubly magic ${}^{208}\mathrm{Pb}$. We find that the Gaussian overlap approximation (GOA) for angular-momentum projection is effective and reduces the computational cost by an order of magnitude. Cost savings in the deformation degrees of freedom are harder to realize. A straightforward Gaussian overlap approximation can be applied rather reliably to angular-momentum projected states based on configuration sets having the same sign deformation (prolate or oblate), but matrix elements between prolate and oblate deformations must be treated with more care. We propose a two-dimensional GOA using a triangulation procedure to treat the general case with both kinds of deformation. With the computational gains from these approximations, it should be feasible to carry out a systematic calculation of correlation energies for the nuclear mass table.

We present results from a comprehensive partial-wave analysis of ${\pi }^{\pm }p$ elastic scattering and charge-exchange data, covering the region from threshold to $2.1\text{GeV}$ in the lab pion kinetic energy, employing a coupled-channel formalism to simultaneously fit ${\pi }^{-}p\to \eta n$ data to $0.8\text{GeV}$. Our main result, solution FA02, utilizes a complete set of forward and fixed-$t$ dispersion relation constraints, from threshold to $1\text{GeV}$, and from $t=0$ to $-0.4{(\text{GeV}∕c)}^2$, applied to the $\pi N$ elastic amplitude. A large number of systematic checks have been performed, including fits with no charge-exchange data and other database changes, fits with few or no dispersion relation constraints, and changes to the Coulomb correction scheme. We have also reexamined methods used to extract Breit-Wigner resonance parameters. The quality of fit to both data and dispersion relation constraints is superior to our earlier work. The results of these analyses are compared with previous solutions in terms of their resonance spectra and preferred values for couplings and low-energy parameters, including the $\pi NN$ coupling constant.

We show that the qualitative behavior of the nuclear caloric curve can be inferred from the energy dependence of the isoscaling parameters. Since there are strong indications that the latter are not distorted by the secondary decay of primary hot fragments, in contrast to other observables, this suggests that valuable information on the nuclear caloric curve may be obtained through the analysis presented in this work.

We discuss effective field theory treatments of the problem of three particles interacting via short-range forces. One case of such a system is neutron-deuteron $\left(nd\right)$ scattering at low energies. We demonstrate that in attractive channels the renormalization-group evolution of the $1+2$ scattering amplitude may be complicated by the presence of eigenvalues greater than unity in the kernel. We also show that these eigenvalues can be removed from the kernel by one subtraction, resulting in an equation which is renormalization-group invariant. A unique solution for $1+2$ scattering phase shifts is then obtained. We give an explicit demonstration of our procedure for both the case of three spinless bosons and the case of the doublet channel in $nd$ scattering. After the contribution of the two-body effective range is included in the effective field theory, it gives a good description of the $nd$ doublet phase shifts below deuteron breakup threshold.