title: Imaginary parts and discontinuities of Wilson line correlators.
abstract: We introduce a notion of position-space cuts of eikonal diagrams, the set of diagrams appearing in the perturbative expansion of the correlator of a set of straight semi-infinite Wilson lines. The cuts are applied directly to the position-space representation of any such diagram and compute its imaginary part to the leading order in the dimensional regulator. Our cutting prescription thus defines a position-space analog of the standard momentum-space Cutkosky rules. Unlike momentum-space cuts which put internal lines on shell, position-space cuts constrain a number of the gauge bosons exchanged between the energetic partons to be lightlike, leading to a vanishing and a non-vanishing imaginary part for space- and timelike kinematics, respectively.
authors.affiliation: Nikhef, Theory Group, Science Park 105, 1098 XG Amsterdam, Netherlands.|ITFA, University of Amsterdam, Science Park 904, 1018 XE Amsterdam, Netherlands.|ITF, Utrecht University, Leuvenlaan 4, 3584 CE Utrecht, Netherlands.
authors.forename: Eric
authors.initials: E
authors.lastname: Laenen
authors.affiliation: Nikhef, Theory Group, Science Park 105, 1098 XG Amsterdam, Netherlands.|Institute for Theoretical Physics, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: Kasper J
authors.initials: KJ
authors.lastname: Larsen
authors.affiliation: Nikhef, Theory Group, Science Park 105, 1098 XG Amsterdam, Netherlands.|ITFA, University of Amsterdam, Science Park 904, 1018 XE Amsterdam, Netherlands.
authors.forename: Robbert
authors.initials: R
authors.lastname: Rietkerk