Positron Production in Multiphoton Light-by-Light Scattering

Positron Production in Multiphoton Light-by-Light Scattering

A signal of 106 14 positrons above background has been observed in collisions of a low-emittance 46.6-GeV electron beam with terawatt pulses from a Nd:glass laser at 527 nm wavelength in an experiment at the Final Focus Test Beam at SLAC. Peak laser intensities of 1:3 10 W/cm have been achieved corresponding to a value of 0.3 for the parameter = E?=Ecrit where E ? = 2 Elab is the electric eld s...

Positron Production by Laser Light

A signal of positrons above background has been observed in collisions of a low emittance GeV electron beam with terawatt pulses from a Nd glass laser at nm wavelengths in an experiment at the Final Focus Test Beam at SLAC The positrons are interpreted as arising from a two step process in which laser photons are backscat tered to GeV energies by the electron beam followed by a collision be twe...

Light scattering by cubical particle in the WKB approximation

In this work, we determined the analytical expressions of the form factor of a cubical particle in the WKB approximation. We adapted some variables (size parameter, refractive index, the scattering angle) and found the form factor in the approximation of Rayleigh-Gans-Debye (RGD), Anomalous Diffraction (AD), and determined the efficiency factor of the extinction. Finally, to illustrate our form...

Light-by-light scattering in SANC

In this paper we describe the implementation of the QED process γγ → γγ through a fermion loop into the framework of SANC system. The computations of this process takes into account non-zero mass of loop-fermion. We briefly describe additional precomputation modules used for calculation of massive fermion-box diagrams. We present the covariant and helicity amplitudes for this process and also s...

Evidence of Light-by-Light Scattering