Cross section of the processes e(+) + e(-) -> e(+) + e(-)(gamma), pi(+) + pi(-)(gamma), mu(+) + mu(-)(gamma), gamma plus gamma(gamma) in the energy region 200 MeV <= 2E <= 3 GeV

摘要

The cross section for different processes induced by e(+)e(-) annihilation. in the kinematical limit beta(mu) approximate to beta(pi) = (1 - m(pi)(2)/epsilon(2))(1/2) similar to 1, is calculated taking into account first order corrections to the amplitudes and the corrections due to soft emitted photons, with energy omega <= Delta E <= epsilon in the center of mass of the e(+)e(-) colliding beams. The results are given separately for charge-odd and charge-even terms in the final channels pi(+)pi(-)(gamma) and mu(+)mu(-)(gamma). In case of pions, form factors are taken into account. The differential cross sections for the processes: e(+) + e(-) -> e(+) + e(-)(+gamma), -> pi(+) + pi(-)(gamma), -> mu(+) + mu(-)(gamma), -> gamma + gamma(gamma) have been calculated and the corresponding formulas are given in the ultrarelativistic limit root s/2 = epsilon m mu similar to m pi. For a quantitative evaluation of the contribution of higher order of the perturbation theory, the production of pi(+)pi(-), including radiative corrections. is calculated in the approach of the lepton structure functions. This allows to estimate the precision of the obtained results as better than 0.5% outside the energy region corresponding to narrow resonances. A method to integrate the cross section, avoiding the difficulties which arise from singularities is also described.