0000000000261119
AUTHOR
H. Arenhoevel
Probing hadron structure by real and virtual photons
The importance of subnuclear degrees of freedom in photon absorption and electron scattering by nuclei is discussed. After a short introduction into the basic properties of one-photon processes and a very brief survey on the nuclear response in the various regions of energy and momentum transfers, the particular role of subnuclear degrees of freedom in terms of meson and isobar degrees of freedom is considered. Their importance is illustrated by several reactions on the deuteron which are currently under study at c.w.\ electron machines like MAMI in Mainz.
The quasielastic 2H(e,e'p)n reaction at high recoil momenta
The 2H(e,e'p)n cross section was measured in Hall A of the Thomas Jefferson National Accelerator Facility (JLab) in quasielastic kinematics (x=0.96) at a four-momentum transfer squared, Q^2=0.67 (GeV/c)^2. The experiment was performed in fixed electron kinematics for recoil momenta from zero to 550 MeV/c. Though the measured cross section deviates by 1-2 sigma from a state-of-the-art calculation at low recoil momenta, it agrees at high recoil momenta where final state interactions (FSI) are predicted to be large.
Consistent Treatment of Relativistic Effects in Electrodisintegration of the Deuteron
The influence of relativistic contributions to deuteron electrodisintegration is systematically studied in various kinematic regions of energy and momentum transfer. As theoretical framework the equation-of-motion and the unitarily equivalent S-matrix approaches are used. In a (p/M)-expansion, all leading order relativistic $\pi$-exchange contributions consistent with the Bonn OBEPQ model are included. In addition, static heavy meson exchange currents including boost terms, $\gamma\pi\rho/\omega$-currents, and $\Delta$-isobar contributions are considered. Sizeable effects from the various relativistic two-body contributions, mainly from $\pi$-exchange, have been found in inclusive form fact…