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J. Blümlein, A. Freitas, Clemens G. Raab, Kay Schönwald
Abstract
We calculate the complete O(α2) initial state radiation corrections to e+e− annihilation into a neutral vector boson in a direct analytic computation without any approximation. The corrections are represented in terms of iterated incomplete (elliptic) integrals over alphabets of square-root valued letters. Performing the limit s≫me2, we find discrepancies with the earlier results of Ref. [1] and confirm results obtained in Ref. [2] where the effective method of massive operator matrix elements has been used, which works for all but the power corrections in me2/s. In this way, we also confirm the validity of the factorization of massive partons in the Drell-Yan process to O(α2). We add non–logarithmic terms at O(α2) which have not been considered in previous calculations. The final results in the limit s≫me2 can be given in terms of Nielsen integrals.