Imaginary Parts and Discontinuities of Wilson Line Correlators
Abstract
We introduce a notion of positionspace cuts of eikonal diagrams, the set of diagrams appearing in the perturbative expansion of the correlator of a set of straight semiinfinite Wilson lines. The cuts are applied directly to the positionspace representation of any such diagram and compute its imaginary part to the leading order in the dimensional regulator. Our cutting prescription thus defines a positionspace analog of the standard momentumspace Cutkosky rules. Unlike momentumspace cuts which put internal lines on shell, positionspace cuts constrain a number of the gauge bosons exchanged between the energetic partons to be lightlike, leading to a vanishing and a nonvanishing imaginary part for space and timelike kinematics, respectively.
 Publication:

Physical Review Letters
 Pub Date:
 May 2015
 DOI:
 10.1103/PhysRevLett.114.181602
 arXiv:
 arXiv:1410.5681
 Bibcode:
 2015PhRvL.114r1602L
 Keywords:

 11.15.q;
 11.55.m;
 12.38.Bx;
 Gauge field theories;
 Smatrix theory;
 analytic structure of amplitudes;
 Perturbative calculations;
 High Energy Physics  Theory;
 High Energy Physics  Phenomenology
 EPrint:
 5 pages, 2 figures