Séminaires LAPP
Pair production in light‐by‐light scattering
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Europe/Paris
Auditorium M. Vivargent (LAPP)
Auditorium M. Vivargent
LAPP
Description
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.