Magnetic Radius of the Deuteron

The root-mean square radius of the deuteron magnetic moment distribution, $r_{Md}$, is calculated for several realistic models of the $NN$--interaction. For the Paris potential the result is $r_{Md} = 2.312 \pm 0.010$ fm. The dependence of $r_{Md}$ on the choice of $NN$ model, relativistic effects and meson exchange currents is investigated. The experimental value of $r_{Md}$ is also considered. The necessity of new precise measurements of the deuteron magnetic form factor at low values of $Q^2$ is stressed.Comment: 4 pages, RevTe

Relativistic Charge Form Factor of the Deuteron

Relativistic integral representation in terms of experimental neutron-proton scattering phase shifts alone is used to compute the charge form factor of the deuteron $G_{Cd}(Q^2)$. The results of numerical calculations of $|G_{Cd}(Q^2)|$ are presented in the interval of the four-momentum transfers squared $0 \leq Q^2 \leq 35 fm^{-2}$. Zero and the prominent secondary maximum in $|G_{Cd}(Q^2)|$ are the direct consequences of the change of sign in the experimental $^3S_1$- phase shifts. Till the point $Q^2 \simeq 20 fm^{-2}$ the total relativistic correction to $|G_{Cd}(Q^2)|$ is positive and reaches the maximal value of 25% at $Q^2 \simeq 14 fm^{-2}$.Comment: 9 pages, LaTeX, 2 postscript figures, uses wor-sci.sty, epsf.st

Large Logarithms in the Beam Normal Spin Asymmetry of Elastic Electron--Proton Scattering

We study a parity-conserving single-spin beam asymmetry of elastic electron-proton scattering induced by an absorptive part of the two-photon exchange amplitude. It is demonstrated that excitation of inelastic hadronic intermediate states by the consecutive exchange of two photons leads to logarithmic and double-logarithmic enhancement due to contributions of hard collinear quasi-real photons. The asymmetry at small electron scattering angles is expressed in terms of the total photoproduction cross section on the proton, and is predicted to reach the magnitude of 20-30 parts per million. At these conditions and fixed 4-momentum transfers, the asymmetry is rising logarithmically with increasing electron beam energy, following the high-energy diffractive behavior of total photoproduction cross section on the proton.Comment: 10 pages, 6 figures; typos fixed, a reference adde

Scaling and Duality in Semi-exclusive Processes

We discuss extending scaling and duality studies to semi-exclusive processes. We show that semi-exclusive hard pion photoproduction should exhibit scaling behavior in kinematic regions where the photon and pion both interact directly with the same quark. We show that such kinematic regions exist. We also show that the constancy with changing momentum transfer of the resonance peak/scaling curve ratio, familiar for many resonances in deep inelastic scattering, is also expected in the semi-exclusive case.Comment: 8 pages, 4 figures, submitted to Phys.Rev.

Improved radiative corrections for (e,e'p) experiments: Beyond the peaking approximation and implications of the soft-photon approximation

Analysing (e,e'p) experimental data involves corrections for radiative effects which change the interaction kinematics and which have to be carefully considered in order to obtain the desired accuracy. Missing momentum and energy due to bremsstrahlung have so far always been calculated using the peaking approximation which assumes that all bremsstrahlung is emitted in the direction of the radiating particle. In this article we introduce a full angular Monte Carlo simulation method which overcomes this approximation. The angular distribution of the bremsstrahlung photons is reconstructed from H(e,e'p) data. Its width is found to be underestimated by the peaking approximation and described much better by the approach developed in this work.Comment: 11 pages, 13 figure