The analytic structure and the transcendental weight of the BFKL ladder at NLL accuracy

Understand

We study some analytic properties of the BFKL ladder at next-to-leading logarithmic accuracy (NLLA).

• We use a procedure by Chirilli and Kovchegov to construct the NLO eigenfunctions, and we show that the BFKL ladder can be evaluated order by order in the coupling in terms of certain generalised single-valued multiple polylogarithms recently introduced by Schnetz.
• We develop techniques to evaluate the BFKL ladder at any loop order, and we present explicit results up to five loops.
• Using the freedom in defining the matter content of the NLO BFKL eigenvalue, we obtain conditions for the BFKL ladder in momentum space at NLLA to have maximal transcendental weight.