B. Zeidman

Bio: B. Zeidman is an academic researcher from Argonne National Laboratory. The author has contributed to research in topics: Neutron & Nuclear reaction. The author has an hindex of 10, co-authored 20 publications receiving 345 citations.

Two-body photodisintegration of the Deuteron up to 2.8 GeV

Abstract: Measurements were performed for the photodisintegration cross section of the deuteron for photon energies from 1.6 to 2.8 GeV and center-of-mass angles from 37° to 90°. The measured energy dependence of the cross section at θ_(cm)=90° is in agreement with the constituent counting rules.

Neutron-excess dependence of fusion-Ni+Sn

Abstract: Excitation functions (${E}_{\mathrm{lab}}=235\ensuremath{-}320$ MeV) for producing nuclei close to the compound system (evaporation residues) were measured for $^{58,64}\mathrm{Ni}$+ $^{112\ensuremath{-}124}\mathrm{Sn}$, corresponding to a 20% variation in the compound-nucleus neutron number. A dramatic, order-of-magnitude increase was observed in the maximum cross section as a function of the compound-nucleus neutron neutron excess. The subbarrier energy dependence of the cross sections is well described by an optical-model calculation, but not by the frequently used parabolic approximation.

Fission following fusion of Ni+Sn.

Abstract: Excitation functions for fission were measured for $^{58,64}\mathrm{Ni}$ beams incident on the even $^{112\ensuremath{-}124}\mathrm{Sn}$ targets at energies extending from well below to about 1.5 times the Coulomb barrier. Fission was identified by kinematic coincidence between fission fragments. Angle integrated fission cross sections were obtained from angular distributions taken at several energies for all systems. From these and the previously measured cross sections for evaporation residues, we obtain the total fusion cross sections and fission probabilities over the energy range $150\ensuremath{\lesssim}{E}_{\mathrm{c}.\mathrm{m}.}\ensuremath{\lesssim}240$ MeV. The competition between particle evaporation and fission in the compound nuclei is compared to statistical model calculations. A good description of the data for all 14 systems is achieved with the use of a single set of parameters. The model includes fission barriers with finite range and nuclear diffuseness effects, and partial-wave distributions for fusion that are qualitatively consistent with those from microscopic reaction model calculations. The fusion excitation functions are analyzed in terms of the dynamical fusion model of Swiatecki et al. Within this model we extract new values for the "extra-push" parameters.

Two-body disintegration of the deuteron with 0.8-1.8 GeV photons.

Abstract: The differential cross section for the reaction 2H(γ,p)n has been measured at several center-of-mass angles ranging from 50° to 143° for photon energies between 0.8 and 1.8 GeV. The experiment was performed at the SLAC-NPAS facility with the use of the 1.6 GeV/c spectrometer to detect the high energy protons produced by a bremsstrahlung beam directed at a liquid deuterium target. Contributions from concurrent disintegration by the residual electron beam were determined by measuring the proton yield without the Cu photon radiator. At angles not very far from 90°, the energy dependence of the cross sections is consistent with predictions of scaling using counting rules for constituent quarks. At least one theoretical calculation based on a meson-baryon picture of the reaction is able to reproduce the magnitude and energy dependence of the 90° cross section. The angular distribution exhibits a large enhancement at backward angles at the higher energies.

Sub-barrier fusion of two nuclei

Abstract: In 1980 the anomalous sub-barrier fusion of two massive atomic nuclei was discovered. The author examines the experimental findings that the cross sections for sub-barrier fusion far exceed simple quantum tunnelling expectations, and the magnitude of the excess fusion is particularly sensitive to the valence structure of the collision partners. The phenomenon is interpreted as one which occurs when intrinsic degrees of freedom of the dinuclear system couple to the tunnelling degree of freedom. Several models, developed during the period from 1983-5, serve to illustrate the salient features of coupling-aided barrier penetration. The author discusses the nature of the couplings and the underlying dynamics, focusing attention on the quasi-elastic channels (inelastic scattering and nucleon transfer). Results of studies on quasi-elastic scattering and of the fusion partial-wave distributions, completed during the past three years, are then presented.

Nuclei beyond the proton drip-line

Abstract: ▪ Abstract The proton drip-line defines the limit at which nuclei become unbound to the emission of a proton from their ground states. Low-Z nuclei lying beyond this limit only exist as short-lived resonances and cannot be detected directly. The location of the drip-line constrains the path of nucleosynthesis in explosive astrophysical scenarios such as novae and X-ray bursters, and consequently controls the rate of energy generation. In higher-Z regions of the drip-line, the potential energy barrier resulting from the mutual electrostatic interaction between the unbound proton and the core can cause nuclei to survive long enough to be detected. This review describes the recent major advances in the study of these exotic nuclei. Particular emphasis is placed on understanding the phenomenon of proton radioactivity and the unique insights it offers into the structure of nuclei lying beyond one of nature's fundamental limits to stability.

Inclusive quasielastic electron-nucleus scattering

Abstract: This paper presents a review on the field of inclusive quasielastic electron-nucleus scattering. It discusses the approach used to measure the data and includes a compilation of data available in numerical form. The theoretical approaches used to interpret the data are presented. A number of results obtained from the comparison between experiment and calculation are then reviewed. The analogies to, and differences from, other fields of physics exploiting quasielastic scattering from composite systems are pointed out.

The Deuteron: Structure and Form Factors

Abstract: Diplon, deuton, deuteron: under different names, the nucleus of deuterium, or diplogen, has been the subject of intense studies since its discovery in 1932. As the only two-nucleon bound state, its properties have continuously been viewed as important in nuclear theory as the hydrogen atom is in atomic theory. Yet, ambiguities remain in the relativistic description of this system and the two-nucleon picture is incomplete: meson exchange and nucleon excitation into resonances should be considered in the deuteron description. The question of rare configurations where the two nucleons overlap and loose their identity is still under debate. We are still looking for the elusive effects of quarks in the nuclear structure.

The conditions for the synthesis of heavy nuclei

Abstract: In parallel to the attempts to synthesize the heaviest nuclei, systematic studies have been made to obtain better understanding of the reaction aspects. The most comprehensive data have been taken for nearly mass-symmetric massive systems. They combine high Coulomb forces in the entrance channel with evaporation-residue cross sections which are high enough to be easily detectable. With these systems, rather cold compound nuclei can be produced, and even radiative fusion was observed. While one of the most salient features of the thoroughly studied fusion of light and medium-heavy systems is the enhanced sub-barrier fusion, the massive systems exhibit a considerable deficit of fusion above the expected potential barrier. This hindrance to fusion may be attributed to the dynamical evolution of the composite system which may lead to immediate reseparation. The experimental data reveal that the hindrance to fusion is strongly influenced by the nuclear structure of the reaction partners. The high fission competition in the evaporation cascade of fissile excited compound systems as deduced from measured evaporation-residue cross sections is compared with the expectations of the statistical model. Experimental evidence is presented.