  In soft collinear effective theory (SCET) the interaction between high energy
quarks moving in opposite directions involving momentum transfer much smaller
than the center-of-mass energy is described by the Glauber interaction operator
which has two-dimensional Coulomb-like behavior. Here, we determine this
$n$-$\bar{n}$ collinear Glauber interaction operator and consider its
renormalization properties at one loop. At this order a rapidity divergence
appears which gives rise to an infrared divergent (IR) rapidity anomalous
dimension commonly called the gluon Regge trajectory. We then go on to consider
the forward quark scattering cross section in SCET. The emission of real soft
gluons from the Glauber interaction gives rise to the Lipatov vertex. Squaring
and adding the real and virtual amplitudes results in a cancelation of IR
divergences, however the rapidity divergence remains. We introduce a rapidity
counterterm to cancel the rapidity divergence, and derive a rapidity
renormalization group equation which is the Balitsky-Fadin-Kuraev-Lipatov
Equation. This connects Glauber interactions with the emergence of Regge
behavior in SCET.
