Search results for "Elastic electron"
showing 10 items of 19 documents
New Measurements of the Transverse Beam Asymmetry for Elastic Electron Scattering from Selected Nuclei
2012
We have measured the beam-normal single-spin asymmetry $A_n$ in the elastic scattering of 1-3 GeV transversely polarized electrons from $^1$H and for the first time from $^4$He, $^{12}$C, and $^{208}$Pb. For $^1$H, $^4$He and $^{12}$C, the measurements are in agreement with calculations that relate $A_n$ to the imaginary part of the two-photon exchange amplitude including inelastic intermediate states. Surprisingly, the $^{208}$Pb result is significantly smaller than the corresponding prediction using the same formalism. These results suggest that a systematic set of new $A_n$ measurements might emerge as a new and sensitive probe of the structure of heavy nuclei.
Binding Behavior of Carbonmonoxide to Gold Atoms on Ag(001)
2020
AbstractThe adsorption behavior of single CO molecules at 4 K bound to Au adatoms on a Ag(001) metal surface is studied with scanning tunneling microscopy (STM) and inelastic electron tunneling spectroscopy (IETS). In contrast to earlier observations two different binding configurations are observed—one on top of a Au adatom and the other one adsorbed laterally to Au on Ag(001). Moreover, IETS reveals different low-energy vibrational energies for the two binding sites as compared to the one for a single CO molecule bound to Ag(001). Density functional theory (DFT) calculations of the adsorption energies, the diffusion barriers, and the vibrational frequencies of the CO molecule on the diffe…
Beam-normal single spin asymmetry in elastic electron scattering off 28Si and 90Zr
2020
We report on a new measurement of the beam-normal single spin asymmetry $A_{\mathrm{n}}$ in the elastic scattering of 570 MeV transversely polarized electrons off $^{28}$Si and $^{90}$Zr at $Q^{2}=0.04\, \mathrm{GeV}^2/c^2$. The studied kinematics allow for a comprehensive comparison with former results on $^{12}$C. No significant mass dependence of the beam-normal single spin asymmetry is observed in the mass regime from $^{12}$C to $^{90}$Zr.
Contributions to the electromagnetic form factors of the deuteron from isobar configurations
1974
A nonrelativistic calculation of the elastic electron deuteron scattering has been performed in which the effects arising from nucleon polarization have been systematically investigated. These effects have been taken into account by admixing isobar configurations into the deuteron wave function. Explicit expressions for the various contributions to the respective deuteron form factors have been given. At higher momentum transfers inclusion of the isobar configurations leads to a substantial increase in the form factors which qualitatively appears to account for at least some of the discrepancies between theory and experiment.
Muonic isotope shifts in the stable Ca nuclei
1978
Abstract Precise isotope shifts of the 2p-1s muonic transition energies for the stable Ca isotopes have been measured. Model-independent radius differences are derived from combined analysis of the present data and elastic electron scattering data. The precise new 48−40 Ca isotope shift disagrees with Hartree-Fock predictions.
High-Precision Determination of the Electric and Magnetic Form Factors of the Proton
2010
New precise results of a measurement of the elastic electron-proton scattering cross section performed at the Mainz Microtron MAMI are presented. About 1400 cross sections were measured with negative four-momentum transfers squared up to Q^2=1 (GeV/c)^2 with statistical errors below 0.2%. The electric and magnetic form factors of the proton were extracted by fits of a large variety of form factor models directly to the cross sections. The form factors show some features at the scale of the pion cloud. The charge and magnetic radii are determined to be r_E=0.879(5)(stat.)(4)(syst.)(2)(model)(4)(group) fm and r_M=0.777(13)(stat.)(9)(syst.)(5)(model)(2)(group) fm.
Zerstörungsfreie Phasenanalyse dünner Oberflächenschichten mittels Konversionselektronen
1987
By use of an appropriate gamma radiation, conversion electrons may be produced by Mossbauer effect also in a depth below the sample surface deeper than the free path for inelastic electron scattering. Because the Mossbauer spectrum of the conversion electrons reflects the local phase composition, the recording of all electrons escaping from the surface allows an integral phase analysis of a layer of some 10–100 nm thickness. If only electrons within a narrow range of energy are recorded, a depth selective phase analysis is possible. The applicability of these two techniques of conversion electron spectroscopy is demonstrated by a few examples concerning oxidation and passivation of steel. C…
Charge and current distributions in elastic electron scattering by 1P shell nuclei
1974
The authors study the charge and magnetic form factors appearing in elastic electron scattering by 1p shell nuclei. The question that the form factors may be obtained from simple nuclear models by simply introducing a scaling factor has been examined using the j-j coupling, the L-S coupling and the intermediate coupling of Cohen-Kurath (CK) resulting from effective interactions. Results for /sup 6/Li, /sup 7 /Li, /sup 9/Be and /sup 13/C are given and the q/sup 2/ dependences of their form factors are compared in the three models and with experiment. The CK scheme gives similar results to the L-S coupling for /sup 6/Li and /sup 7/Li in agreement with experiment, whereas it is intermediate be…
Neutral-current effects in elastic electron-nucleon scattering
1974
Distribution of electric multipole strengths in58Ni
1983
Inelastic electron scattering of 124 and 180 MeV electrons from58Ni has been measured for momentum transfers of 0.4 fm−1≤q≤1.2 fm−1 with an energy resolution of 110 keV. Using DWBA form factors with Tassie transition densities, we have extracted the electric multipole strength forL≤4 residing in 28 discrete states and in the inelastic continuum below 22.5 MeV of excitation.