Beam-size effect in Bremsstrahlung

Abstract

The smallness of the transverse dimensions of the colliding beams leads to suppression of bremsstrahlung cross section. This beam-size effect was discovered and investigated at INP, Novosibirsk. Different mechanisms of radiation are discussed. Separation of coherent and incoherent radiation is analyzed in detail. For linear collider this suppression affects the whole radiation spectrum. It is shown that objections to the subtraction procedure in \cite{BK2} are groundless.Comment: Plenary talk at the Workshop "Quantum Aspects of Beam Physics", Hiroshima, Japan, January 7-11, 2003. To be pulished in the Proceedings (World Scientific, Singapore