Probing strong-field QED in electron-photon interactions

The aim of this workshop is to bring together experts and those interested in measuring QED in the presence of strong fields at and above the Schwinger critical field. It is organised jointly by DESY and the Stanford PULSE institute. The pioneering experiment, E144 at SLAC, measured multi-photon absorption in Compton scattering and e+e- pair production in electron--photon interactions but never reached the Schwinger critical field value. With the advances in laser technology, in particular, new experiments are being considered which should be able to measure non-perturbative QED and its transition from the perturbative regime. This workshop will review the physics case and current theoretical predictions for QED and even effects beyond the Standard Model in the interaction of a high-intensity electron bunch with the strong field of the photons from a high-intensity laser bunch. The world's various electron beam facilities will be reviewed, along with the challenges of producing and delivering laser beams to the interaction region. Possible facilities and sites that could host such experiments will be presented, with a view to experimentally realising the Schwinger critical field during the 2020s. The workshop will have two days of talks, with an informal drinks reception on the evening before and a workshop dinner. The registration fee is 120 Euro and will cover the reception, the lunches, the workshop dinner and coffee breaks during the two days. Posters can be presented during the workshop. In case you are interested please email the title and a short abstract to beate.heinemann@desy.de and matthew.wing@desy.de We thank the Helmholtz foundation and the Moore foundation for their support for the organisation of this event.