Pair production in light‐by‐light scattering

par Dr Thomas Koffas

mardi 2 févr. 2010, 11:00 → 12:00 Europe/Paris

Auditorium M. Vivargent (LAPP)

Quantum electrodynamics (QED) has been tested extensively in the weak field regime where the perturbative methods lead to results that agree to a fantastic accuracy with the measured data. When approaching the critical QED field (~1016 V/cm) non‐linear effects (both multi‐photon and vacuum polarization) become prominent and the application of these techniques is of limited use and the different processes can be treated only within a semiclassical theoretical frame. One such effect is the production of e+e‐ pairs in lightby‐ light scattering observed by the E‐144 experiment at the Stanford Linear Accelerator Center (SLAC). The data can be viewed as a manifestation of the multi‐photon version of the Breit‐Wheeler process. Alternatively they can also be interpreted as a direct evidence of the “sparking of the vacuum”, a phenomenon predicted more than 70 years ago but eluded experimental verification until the time of this experiment.

Slides ThomasKoffas02022010.pdf