CREATION OF A PAIR BY A PHOTON COLLIDING WITH A SHORT FOCUSED LASER-PULSE

The method for the calculation of the probabilities of quantum-electro dynamic effects arising in the interaction of high-energy photons and electrons with a held of a short focused laser pulse is developed. The proposed method is applicable to laser pulses whose durations and foc al radii satisfy the conditions R/lambda much greater than 1 and omega tau much greater than 1 and is based on the summation of the contribu tions of various points of the laser pulse to the probability amplitud e. This paper considers the creation of an e(-)e(+) pair by a photon c olliding with a laser pulse. Spectral-angular and spectral distributio ns of emerging electrons are calculated. It is demonstrated that these distributions radically differ from the distributions characteristic of the case when a plane monochromatic wave is employed as a model of the laser field. This difference is manifested in the broadening of ha rmonics and the appearance of the fine structure of harmonics. The mas s spectrum of e(-)e(+) pairs is calculated.