We determine the first correction to the quadrupole operator in high-energy QCD beyond the transverse momentum dependent (TMD) limit of Weizsäcker-Williams and linearly polarized gluon distributions. These functions give rise to isotropic, respectively, $\sim \cos 2\varphi$ angular distributions in deep inelastic scattering (DIS) dijet production. On the other hand, the correction produces a $\sim \cos 4\varphi$ angular dependence which is suppressed by one additional power of the dijet transverse momentum scale (squared) $P^2$.

• Received 30 May 2016

DOI:https://doi.org/10.1103/PhysRevD.94.014030