QED Structure Functions: A Systematic Approach

Abstract
The problem of calculating higher-order contributions to QED structure functions is considered. A closed form for any given perturbative order is developed by means of a systematic approach. Analytical formulae for the structure function and its generating function are explicitly computed at the leading log level up to O3). An alternative approach to the calculation of the n-th order contribution to the structure function, particularly useful for numerical applications, is developed. A numerical study of the relevance of third- and fourth-order hard-photon contribution is performed.