  The effect of the collinear photon radiation by charged particles is
considered in the second order of the perturbation theory. Double and single
photon radiation is evaluated. The corresponding radiation factors are
obtained. The QED renormalization group approach is exploited in the
next-to-leading order. The results are suited to perform a systematic treatment
of the second order next-to-leading logarithmic radiative corrections to
various processes either analytically or numerically.

High Energy Physics - Phenomenology