Virtual Compton Scattering on the Proton at High s and Low t

Virtual Compton Scattering (VCS) at low transferred momenta to the proton ($t$) and sufficiently high c.m. energies ($s$) may be used to a) study $Q^2$--dependence of leading $t$--channel exchanges and b) look for onset of scaling behavior with increasing $Q^2$. I discuss the implications for perturbative and nonperturbative QCD and suggest possible experiments.Comment: LaTeX, 7 pages, 3 figures, requires sprocl.sty, psfig.st

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

Monte Carlo generator ELRADGEN 2.0 for simulation of radiative events in elastic ep-scattering of polarized particles

The structure and algorithms of the Monte-Carlo generator ELRADGEN 2.0 designed to simulate radiative events in polarized ep-scattering are presented. The full set of analytical expressions for the QED radiative corrections is presented and discussed in detail. Algorithmic improvements implemented to provide faster simulation of hard real photon events are described. Numerical tests show high quality of generation of photonic variables and radiatively corrected cross section. The comparison of the elastic radiative tail simulated within the kinematical conditions of the BLAST experiment at MIT BATES shows a good agreement with experimental data.Comment: 36 pages, 7 figures, 3 table

Dispersive contributions to e+p/e−pe^+p/e^-p cross section ratio in forward regime

Two-photon exchange (TPE) contributions to elastic electron-proton scattering in the forward regime are considered. The imaginary part of TPE amplitude in these kinematics is related to the DIS nucleon structure functions. The real part of the TPE amplitude is obtained from the imaginary part by means of dispersion relations. We demonstrate that the dispersion integrals for the relevant elastic $ep$-scattering amplitude converge and do not need subtraction. This allows us to make clean prediction for the real part of the TPE amplitude at forward angles. We furthermore compare $e^+p$ and $e^-p$ cross sections which depends on the real part of TPE amplitude, and predict the positron cross section to exceed the electron one by a few per cent, with the difference ranging from 1.4% to 2.8% for electron $lab$ energies in the range from 3 to 45 GeV. We furthermore predict that the absolute value of this asymmetry grows with energy, which makes it promising for experimental tests.Comment: 10 pages, 6 figure

Tuning up the performance of GaAs-based solar cells by inelastic scattering on quantum dots and doping of AlyGa1-ySb type-II dots and AlxGa1-xAs spacers between dots

We used AlGaSb/AlGaAs material system for a theoretical study of photovoltaic performance of the proposed GaAs-based solar cell in which the type-II quantum dot (QDs) absorber is spatially separated from the depletion region. Due to inelastic scattering of photoelectrons on QDs and proper doping of both QDs and their spacers, concentrated sunlight is predicted to quench recombination through QDs. Our calculation shows that 500-sun concentration can increase the Shockley-Queisser limit from 35% to 40% for GaAs single-junction solar cells.Comment: 8 pages, 7 figures; Contributed paper to SPIE Photonics West, San Francisco, CA, USA, February 201