The giant resonance region from 10 MeV $<E_x<62$ MeV in ${}^{56}\mathrm{Fe}$, ${}^{58}\mathrm{Ni}$, and ${}^{60}\mathrm{Ni}$ has been studied with inelastic scattering of 240 MeV $\alpha$ particles at small angles, including 0°. Most of the expected isoscalar $E0$ and $E2$ strength has been identified below $E_x=40$ MeV. Between 56 and 72% of the isoscalar $E1$ strength has been located in these nuclei. The mass dependence of the giant monopole energy between $A=40$ and 90 is compared to relativistic and nonrelativistic calculations for interactions with compressibility of nuclear matter $K_{\mathrm{NM}}~211–225$ MeV.

Charge form factors for $N=82$ and $N=126$ isotonic nuclei are calculated with the relativistic eikonal approximation, in which the charge density distributions are from the relativistic mean-field theory. The variations of charge form factors with proton number are discussed in detail. It is found that the most sensitive parts of the charge form factors are those around the minimums and maximums. For an increasing proton number, the charge form factors near the extrema have an upward shift. As the protons increase and occupy a new shell, the minimums and maximums of the charge form factors could also have a significant inward shift. The results can be useful for the study of behaviors of valence-proton wave functions for such nuclei as can be considered as a core plus proton(s), and thus the proton-halo phenomenon. In addition, the results can also be useful for future electron-unstable nucleus scattering experiments and provide tests of the reliability of the relativistic mean-field theory for the unstable nuclei.

The excitation function for production of ${}^{262}\mathrm{Bh}$ in the odd-Z-projectile reaction ${}^{208}\mathrm{Pb}$(${}^{55}\mathrm{Mn}$, $n)$ has been measured at three projectile energies using the Berkeley Gas-filled Separator at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. In total, 33 decay chains originating from ${}^{262}\mathrm{Bh}$ and 2 decay chains originating from ${}^{261}\mathrm{Bh}$ were observed. The measured decay properties are in good agreement with previous reports. The maximum cross section of ${540}_{-150}^{+180}$ pb is observed at a lab-frame center-of-target energy of 264.0 MeV and is more than five times larger than that expected based on previously reported results for production of ${}^{262}\mathrm{Bh}$ in the analogous even-Z-projectile reaction ${}^{209}\mathrm{Bi}$(${}^{54}\mathrm{Cr}$, $n)$. Our results indicate that the optimum beam energy in one-neutron-out heavy-ion fusion reactions can be estimated simply using the optimum energy rule proposed by Świątecki, Siwek-Wilczyńska, and Wilczyński.

The lifetimes of α decays of the recently produced isotopes of elements 112, 114, 116, and ${}^{294}118$ and of some decay products are calculated theoretically within the WKB approximation by use of microscopic α-nucleus interaction potentials. We obtain these nuclear potentials by folding the densities of the α and the daughter nuclei with the M3Y effective interaction, supplemented by a zero-range pseudopotential for exchange along with the density dependence. Spherical charge distributions are used for calculating the Coulomb interaction potentials. These calculations provide reasonable estimates for the observed α decay lifetimes and thus provide reliable predictions for other superheavies.

We study the modification of the nucleon-nucleon interaction in a nuclear medium in the scalar isoscalar channel, mediated by the exchange of two correlated (σ channel) or uncorrelated pions. For this purpose we use a standard approach for the renormalization of pions in nuclei. The corrections obtained for the NN interaction in the medium in this channel are of the order of 20% of the free one in average, and the consideration of short-range correlations plays an important role in providing these moderate changes. Yet, the corrections are sizable enough to suggest further studies of the stability and properties of nuclear matter.

Fragment average isospin distributions are investigated within a microcanonical multifragmentation model in different regions of the phase diagram. The results indicate that in the liquid phase $\langle N/Z\rangle$ versus Z is monotonically increasing, in the phase coexistence region it has a rise-and-fall shape, and in the gas phase it is constant. Deviations from this behavior may manifest at low fragment multiplicity as a consequence of mass-charge conservation. Characterization of the “free” and “bound” phase functions of the fragment charge reconfirms the neutron enrichment of the free phase with respect to the bound one irrespectively of the localization of the multifragmentation event in the phase diagram.

The production of light and intermediate-mass nuclides formed in the reaction ${}^1\mathrm{H}+{}^{238}\mathrm{U}$ at 1 GeV was measured at the Fragment Separator at GSI, Darmstadt. The experiment was performed in inverse kinematics, by shooting a 1 A GeV ${}^{238}\mathrm{U}$ beam on a thin liquid-hydrogen target. A total of 254 isotopes of all elements in the range $7\le Z\le 37$ were unambiguously identified, and the velocity distributions of the produced nuclides were determined with high precision. The results show that the nuclides are produced in a very asymmetric binary decay of heavy nuclei originating from the spallation of uranium. All the features of the produced nuclides merge with the characteristics of the fission products as their mass increases.

Potential energy surfaces are calculated by use of the most advanced asymmetric two-center shell model that allows us to obtain shell-and-pairing corrections that are added to the Yukawa-plus-exponential model deformation energy. Shell effects are of crucial importance for the experimental observation of spontaneous disintegration by heavy-ion emission. Results for ${}^{222}\mathrm{Ra}$, ${}^{232}\mathrm{U}$, ${}^{236}\mathrm{Pu}$, and ${}^{242}\mathrm{Cm}$ illustrate the main ideas and show for the first time, for a cluster emitter, a potential barrier obtained by use of the macroscopic-microscopic method.

The caloric curve for mononuclear configurations is studied with a model that allows for both increased surface diffusness and self-similar expansion. The evolution of the effective mass with density and excitation is included in a schematic fashion. The entropies, extracted in a local-density approximation, confirm that nuclei posess a soft mode that is predominately a surface expansion. We also find that the mononuclear caloric curve (temperature versus excitation energy) exhibits a plateau. Thus a plateau should be the expectation with or without a multifragmentationlike phase transition. This conclusion is relevant only for reactions that populate the mononuclear region of phase space.

We analyze the recently proposed charge transfer fluctuations within a finite pseudorapidity space. As the charge transfer fluctuation is a measure of the local charge correlation length, it is capable of detecting inhomogeneity in the hot and dense matter created by heavy-ion collisions. We predict that, going from peripheral to central collisions, the charge transfer fluctuations at mid-rapidity should decrease substantially while the charge transfer fluctuations at the edges of the observation window should decrease by a small amount. These are consequences of having a strongly inhomogeneous matter in which the quark gluon plasma component is concentrated around mid-rapidity. We also show how to constrain the values of the charge correlation lengths in both the hadronic phase and the quark gluon plasma phase by using the charge transfer fluctuations.

We report on the first detailed measurements of electron backscattering from plastic scintillator targets, extending our previous work on beryllium and silicon targets. The scintillator experiment posed several additional experimental challenges associated with charging of the scintillator target, and those challenges are addressed in detail. In addition, we quantitatively compare the energy and angular distributions of this data, and our previous data, with electron transport simulations based on the GEANT4 and PENELOPE Monte Carlo simulation codes. The PENELOPE simulation is found globally to give a superior description of the data. Such information is crucial for a broad array of weak-interaction physics experiments, where electron backscattering can give rise to the dominant detector-related systematic uncertainty.

Neutrino emissivity from neutron star matter with neutral kaon condensate is considered. It is shown that a new cooling channel is opened and that all previously known channels acquire greater emissivity reaching the level of the direct URCA cycle in normal matter.

In a model of relativistic heavy-ion collisions wherein the unconfined quark-gluon plasma is condensed into glass, we derive the Vogel-Fulcher-Tammann cooling law. This law is well known to hold true in condensed matter glasses. The high-energy plasma is initially created in a very hot negative temperature state and cools down to the Hagedorn glass temperature at an ever decreasing rate. The cooling rate is largely determined by the QCD string tension derived from hadronic Regge trajectories. The ultimately slow relaxation time is a defining characteristic of a color glass condensate.

Relativistic and nonrelativistic modern nucleon-nucleon potentials are mapped on a relativistic operator basis using projection techniques. This allows us to compare the various potentials at the level of covariant amplitudes were a remarkable agreement is found. In nuclear matter large scalar and vector mean fields of several hundred MeV magnitude are generated at tree level. This is found to be a model independent feature of the nucleon-nucleon interaction.

The relative γ-ray intensities for the γ-to-ground interband transitions and the γ band $\Delta I=2$ intraband transitions in ${}^{166}\mathrm{Er}$ have been measured with high precision. These intensities have been used to generate interband relative $B(E2)$'s. The results are presented in a Mikhailov plot and are consistent with a cubic polynomial fit at the 0.60% precision level. The significance of the fit is discussed.

The parameters of the nuclear liquid drop model, such as the volume, surface, symmetry, and curvature constants, as well as bulk radii, are extracted from the nonrelativistic and relativistic energy density functionals used in microscopic calculations for finite nuclei. The microscopic liquid drop energy, obtained self-consistently for a large sample of finite, spherical nuclei, has been expanded in terms of powers of $A^{-1/3}$ (or inverse nuclear radius) and the isospin excess (or neutron-to-proton asymmetry). In order to perform a reliable extrapolation in the inverse radius, the calculations have been carried out for nuclei with huge numbers of nucleons, of the order of ${10}^6$. The Coulomb interaction has been ignored to be able to approach nuclei of arbitrary sizes and to avoid radial instabilities characteristic of systems with very large atomic numbers. The main contribution to the fluctuating part of the binding energy has been removed using the Green's function method to calculate the shell correction. The limitations of applying the leptodermous expansion to actual nuclei are discussed. While the leading terms in the macroscopic energy expansion can be extracted very precisely, the higher-order, isospin-dependent terms are prone to large uncertainties due to finite-size effects.

Autocorrelation of two pions produced in heavy-ion collisions at intermediate $p_T$ is calculated in the framework of the recombination model. The differences of the pseudorapidities and azimuthal angles of the two pions are related to the angle between two shower partons in a jet. It is shown how the autocorrelation distribution reveals the properties of the jet cone of the shower partons created by high-$p_T$ partons in hard collisions.

We calculate rapidity and transverse momentum distributions of charmonium formed in high-energy heavy ion collisions from incoherent recombination of charm quarks. The results are very sensitive to the corresponding distributions of the charm quarks, and thus can serve as a probe of the state of matter produced in the heavy ion collision. At one extreme, we generate charm pair momenta directly from pQCD amplitudes, which are appropriate if one can neglect the interaction of the quarks with the medium. At the other extreme, we generate momenta of charm quarks in thermal equilibrium with the expanding medium, appropriate for an extremely strong interaction. Explicit predictions are made for $J/\psi$ formation in Au-Au interactions at the BNL Relativistic Heavy Ion Collider. We find that for the case in that charm quark momenta are unchanged from the pQCD production calculation, both the rapidity and transverse momentum spectra of the formed $J/\psi$ are substantially narrower than would be anticipated in scenarios that do not include the in-medium formation. In particular, the average transverse momentum of the $J/\psi$ will exhibit a nonmonotonic behavior in the progression from pp to pA to AA interactions.

Results of a photon scattering experiment on ${}^{112}\mathrm{Sn}$ using bremsstrahlung with an endpoint energy of $E_0=3.8$ MeV are reported. A $J=1$ state at $E_x=3434(1)$ keV has been excited. Its decay width into the ground state amounts to ${\Gamma }_0=151(17)$ meV, making it a candidate for a $[2^{+}\otimes 3^{-}]1^{-}$ two-phonon state. The results for ${}^{112}\mathrm{Sn}$ are compared with quasiparticle-phonon model calculations as well as the systematics of the lowest lying $1^{-}$ states established in other even-mass tin isotopes. In contrast to findings in the heavier stable even-mass Sn isotopes, no $2^{+}$ states between 2 and 3.5 MeV excitation energy have been detected in the present experiment.

We investigate the evolution of quantal spectra and the corresponding wave functions along the [O(6)-U(5)] ⊃ O(5) transition of the interacting boson model. The model is integrable in this regime, and its ground state passes through a second-order structural phase transition. We show that the whole spectrum as a function of the Hamiltonian control parameter as well as structures of all excited states exhibit rather organized and correlated behaviors, which provide deeper insight into the nature of this transitional path.