Influence of a medium on pair photoproduction and bremsstrahlung

by Vladimir N. BAIER (Budker Inst. of Nuclear Physics, Novosibirsk)

Friday 15 Sept 2000, 14:00 → 14:15 Europe/Zurich

TH Auditorium (CERN)

The creation of an electron-positron pair by a photon and the bremsstrahlung of an electron in a medium are considered in the high-energy region, where influence of the multiple scattering on the processes (the Landau-Pomeranchuk-Migdal (LPM) effect) becomes essential. The pair photoproduction probability and bremsstrahlung cross section are calculated with accuracy up to the 'next-to-leading logarithm'. The integral characteristics: the radiation length and the total probability of pair photoproduction are analysed under influence of the LPM effect. Comparison with the recent SLAC experiment, where the LPM effect was observed and investigated, shows perfect agreement between the theory and data.