The massless single off-shell scalar box integral — branch cut structure and all-order epsilon expansion

We investigate the single off-shell scalar box integral with massless internal lines in dimensional regularization. A special emphasis is given to higher orders regularization parameter epsilon, its branch cut structure, and kinematic limits. Common representations of introduce superficial cuts, which we eliminate all epsilon expansion. In literature so far a satisfactory solution for this issue only exists up finite order However, calculations at NNLO perturbation theory, are required. paper, present results terms single-valued polylogarithms explicitly determine real imaginary part regions.