Recent experimental data indicate that in the ternary cold fission of ${}^{252}\mathrm{Cf}$ the energy of the first excited state of the accompanying light cluster ${}^{10}\mathrm{Be}$ is decreased by an amount ranging between $\approx$ 6 and 26 keV. A model is proposed to calculate the shift of the vibrational $2_1^{+}$ state in ${}^{10}\mathrm{Be}$ when its heavy companions are the even-even nuclei ${}^{146}\mathrm{Ba}$ and ${}^{96}\mathrm{Sr}.$ The stiffness parameters of the $\beta$ vibrations are calculated within the self-consistent Hartree-Fock method with BCS pairing correlations taken into account, and their change is determined by the interaction of the light cluster with the heavy fragments. The results point to a dependence of the shift magnitude and signature on the relative distance between the three clusters and their mutual orientation. Eventually it is the anharmonic perturbation of the spherical vibrator which is responsible for obtaining a negative energy shift of the $2_1^{+}$ state.

High-spin states were populated in ${}^{80}\mathrm{Sr}$ with the reaction ${}^{58}\mathrm{Ni}{(}^{28}\mathrm{Si},\alpha 2p),$ using a 130 MeV ${}^{28}\mathrm{Si}$ beam from the 88-Inch Cyclotron at LBNL. Gamma rays were detected with Gammasphere, and evaporated alphas and protons were detected with the Microball. The level scheme has been extended, and angular distributions of many of the transitions have been measured. A portion of the data was taken using a backed target, allowing lifetime measurements. No evidence for band termination was found in the spin range studied, but a cranking model analysis indicates possible shape evolution at higher spin.

Baryons containing two heavy quarks are treated in the Born-Oppenheimer approximation. The Schrödinger equation for the two-center Coulomb plus harmonic oscillator potential is solved by the method of the ethalon equation at large intercenter separations. Asymptotical expansions for the energy term and wave function are obtained in analytical form. Using those formulas, the energy spectra of doubly heavy baryons with various quark compositions are calculated analytically.

We study nuclear matter and finite nuclei in terms of the quark mean field (QMF) model, in which we describe the nucleon using the constituent quark model. The meson mean fields, in particular the $\sigma$ meson, created by other nucleons act on quarks inside a nucleon and change the nucleon properties in nuclear medium. The QMF model predicts an increasing size of the nucleon as well as a reduction of the nucleon mass in the nuclear environment. The present model is applied to study the properties of finite nuclei after fixing all the parameters by the nuclear matter properties, and it is found to give satisfactory results on the nuclear properties.

We analyze the radiative correction to high energy elastic electron-proton scattering of polarized electrons. We show that if the approximations inherent in the calculations developed by Tsai and given in the work of Mo and Tsai which have been used in the analysis of almost all experimental data pertaining to medium and high energy elastic electron scattering for the past three decades are maintained, then the same radiative correction applies both in the case of initially polarized and unpolarized electrons.

We have unambiguously characterized the deexcitation of the 228.5-keV $T_{1/2}=4.7\mathrm{}-s$ isomer in ${}^{80}\mathrm{Y}$ as an $M3\mathrm{}$ transition. This result determines, in conjunction with other experimental data, the spin and parity of the 228.5-keV isomer and the ${}^{80}\mathrm{Y}$ ground state as $1^{-}$ and $4^{-},$ respectively.

A realistic determination of fission saddle-point shapes requires an exploration of a sufficiently large deformation space so that all a priori reasonable candidates for saddle-point shapes are included in the calculation. Until now no calculation has explored in a proper way a deformation space that is sufficiently complete to determine realistic fission saddle-point shapes. Here we calculate a five-dimensional grid of 1020000 deformation points. We find that the fission fragments that result from the breakup of the nucleus in some situations have already established their identity at the saddle point.

High-spin states in ${}^{177}\mathrm{Ta}$ have been studied using the ${}^{170}\mathrm{Er}{(}^{11}\mathrm{B},4n)$ reaction. New intrinsic states have been observed corresponding to 3-, 5-, and 7-quasiparticle high-$K$ structures. Rotational bands built on most of the 3- and 5-quasiparticle states and some transitions above the 7-quasiparticle states have been identified. Several isomers have been found, the longest lived being the ${\frac{49}{2}}^{-},$ 7-quasiparticle state with a meanlife of 192 $\mu \mathrm{s}.$ Configurations for the observed intrinsic states have been assigned on the basis of $g_K$ values, alignments, and decay properties. While the properties of most of the bands are consistent with their proposed configurations, the behavior of some, including the one built on $K^{\pi }={\frac{21}{2}}^{-}$ 3-quasiparticle isomer, is not well understood. Multiquasiparticle blocking calculations based on the Lipkin-Nogami method, are in good agreement with the excitation energies of the experimentally observed states and all the predicted states close to the yrast line up to spin $\frac{49}{2}$ have been observed experimentally. The calculations predict the existence of a 9-quasiparticle ${\frac{67}{2}}^{-}$ yrast trap at $\sim 8.5\hspace{0.5em}\mathrm{MeV}.$

The effect of shadowing on the early state of ultrarelativistic heavy ion collisions is investigated along with transverse energy and hard process production, specifically Drell-Yan, $J/\psi ,$ and Υ production. We choose several parton distributions and parametrizations of nuclear shadowing, as well as the spatial dependence of shadowing, to study the influence of shadowing on relevant observables. Results are presented for Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=200\mathrm{}$ GeV and Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.5\mathrm{}$ TeV.

A quasiparticle description of the thermodynamics of deconfined matter, reproducing both the perturbative limit and nonperturbative lattice QCD data at finite temperature, is generalized to finite chemical potential. By a flow equation resulting from Maxwell’s relation, the equation of state is extended from zero to nonzero quark densities. The impact of the massive strange flavor is considered and implications for cold, charge-neutral deconfined matter in $\beta$ equilibrium in compact stars are given.

We show that incomplete absorption in ${}^{90}\mathrm{Zr}(\alpha ,{\alpha }_0)$ scattering is responsible for the spectacular dip observed in the backward excitation function at low energy ${(E}_{\alpha }\simeq$ 25 MeV), which we interpret as a destructive interference effect between the barrier and internal wave contributions to the scattering amplitude. Because of this transparency, an optical potential, which is in line with the higher energy data, can be extracted with good accuracy. The real part of this potential is found to support several rotational bands; the properties of the states of the first Pauli-allowed band, with $N=16,$ in particular the electromagnetic transition rates between the first states, are in good agreement with those of the states of the experimental ${}^{94}\mathrm{Mo}$ ground state band, suggesting that $\alpha$-cluster structure is still an important feature in the $A=90\mathrm{}$ region.

The ${}^3{S}_1{-}^3{D}_1$ mixing angle for nucleon-nucleon scattering ${\epsilon }_1$ is calculated to next-to-next-to-leading order in an effective field theory with perturbative pions. Without pions, the low energy theory fits the observed ${\epsilon }_1$ well for momenta less than ∼50 MeV. Including pions perturbatively significantly improves the agreement with data for momenta up to ∼150 MeV with one less parameter. Furthermore, for these momenta the accuracy of our calculation is similar to an effective field theory calculation in which the pion is treated nonperturbatively. This gives phenomenological support for a perturbative treatment of pions in low energy two-nucleon processes. We explain why it is necessary to perform spin and isospin traces in d dimensions when regulating divergences with dimensional regularization in higher partial wave amplitudes.

The temperature dependent BCS equations are modified in order to include the contribution of the continuum single particle states. The influence of the continuum upon the critical temperature corresponding to the phase transition from a superfluid to a normal state and upon the behavior of the excitation energy and of the entropy is discussed.

Isoscalar monopole density vibrations in spherical nuclei with a sharp surface are studied in a nonlinear hydrodynamical approach. The frequency shift of the one- and two-phonon excitations due to nonlinear terms is obtained. The frequencies of one- (two-) phonon giant isoscalar monopole resonances calculated in the nonlinear hydrodynamic theory increase by $\approx 2\%(8\%)\mathrm{}$ in heavy nuclei and by $\approx 14–18\%$ (50%) in light nuclei compared to the linear approximation. The frequency shift is a function of both the mass number A and the parameters of the nucleon-nucleon interaction.

Limitations of the quasiparticle random phase approximation (QRPA) are studied within an exactly solvable model, with a two body interaction of Fermi type. A special attention is paid to the violation of the Pauli exclusion principle (PEP) in solving the QRPA equation. A comparison of the exact solution, obtained by the diagonalization of a schematic nuclear Hamiltonian and those obtained within the standard QRPA, the renormalized QRPA, the QRPA with pertubative treatment of the PEP, and the QRPA with exact consideration of the PEP, is presented. The agreement quality is judged in terms of the quasiparticle number operator matrix elements in the ground state and in the first excited states, of the $\beta$ transition amplitudes, of the Ikeda sum rule, and of the nuclear matrix element for the double $\beta$ decay. We have found that by restoring the PEP, the QRPA solutions are considerably stabilized and a better agreement with the exact solution is obtained.

We investigate nuclear matter on a cubic lattice. An exact thermal formalism is applied to nucleons with a Hamiltonian that accommodates on-site and next-neighbor parts of the central, spin-, and isospin-exchange interactions. We describe the nuclear matter Monte Carlo methods which contain elements from shell model Monte Carlo methods and from numerical simulations of the Hubbard model. We show that energy and basic saturation properties of nuclear matter can be reproduced. Evidence of a first-order phase transition from an uncorrelated Fermi gas to a clustered system is observed by computing mechanical and thermodynamical quantities such as compressibility, heat capacity, entropy, and grand potential. We compare symmetry energy and first sound velocities with literature and find reasonable agreement.

Finite-range coupled channel calculations of proton-induced reactions on ${}^6\mathrm{He}$ have been performed below the ${}^6\mathrm{He}$ three-body breakup threshold, assuming that the $\alpha$ particle core is inert. The coupling scheme included all transitions between open channels and therefore no imaginary parts of the interaction potentials were used. The calculations have revealed a complicated dynamics of the ${p+}^6\mathrm{He}$ interaction at the chosen energy, with couplings to all open channels being important to generate the final cross sections. The total absorption from the elastic ${p+}^6\mathrm{He}$ channel depends on the details of the interactions employed in the three-body model of ${}^6\mathrm{He}$ and shows a strong correlation with the r.m.s. radius of ${}^6\mathrm{He}.$ The role of the exchange mechanisms was investigated within the framework of the distorted-wave Born approximation. It was found that both the triton exchange ${}^6\mathrm{He}{(p,}^4\mathrm{He})t$ and two-neutron ${}^6\mathrm{He}{\mathrm{}(p,t)\mathrm{}}^4\mathrm{He}$ direct transfer mechanisms produce comparable cross sections. The investigation of the radiative capture ${}^6\mathrm{He}(p,\gamma {)}^7\mathrm{Li}$ in the potential model shows strong suppression of the $E1\mathrm{}$ transition because of the destructive interference between the external and internal contributions to the reaction amplitude and the absorption in the incident channel.

The relative ${}^4\mathrm{He}$ and ${}^5\mathrm{He}$ ternary fission yields were determined from a careful analysis of the energy distribution of $\alpha$ spectra from a new measurement with a ${}^{252}\mathrm{Cf}$ source and from published data on ${}^{252}\mathrm{Cf}$ and ${}^{235}\mathrm{U}\mathrm{}(n,f).$ The kinetic energies of the ${}^5\mathrm{He}$ and ${}^4\mathrm{He}$ ternary particles were found to be approximately 11 and 16 MeV, respectively. ${}^5\mathrm{He}$ particles contribute 10–20 % to the total alpha yield with the remainder originating from ${}^4\mathrm{He}$ accompanied fission.

We present analytic expressions of the Coulomb interaction between spherical and deformed nuclei which are valid for all separation distances. We demonstrate their significant deviations from commonly used formulas in the region inside the Coulomb radius, and show that they remove various shortcomings of the conventional formulas.

Lifetimes of levels in ${}^{80}\mathrm{Rb}$ have been measured using the Doppler shift attenuation method. The high-spin states have been populated through the ${}^{55}\mathrm{Mn}{(}^{28}\mathrm{Si},2pn)$ reaction at 90 MeV. Collective enhancement was observed in the $B\left(E2\mathrm{}\right)\mathrm{}$ values of the two most strongly populated bands, while the $B\left(M1\mathrm{}\right)\mathrm{}$ values of the yrast band exhibit a large alternating pattern. Transition quadrupole moments were deduced from $E2\mathrm{}$ transition strengths and compared with those predicted by Woods-Saxon cranking calculations.