Next-to-Leading Order Computation of Exclusive Diffractive Light Vector Meson Production in a Saturation Framework

We perform the first next-to-leading order computation of the ${\gamma }^{(*)}\to V$ ($\rho ,\varphi ,\omega$) exclusive impact factor in the QCD shock-wave approach and in the most general kinematics. This paves the way to the very first quantitative study of high-energy nucleon and nucleus saturation beyond the leading order for a whole range of small-$x$ exclusive processes, to be measured in $ep$, $eA$, $pp$, and $pA$ collisions at existing and future colliders.

Figure 1

Contributions to the impact factor for the ${\gamma }^{*}\to V$ transition. The gray blobs stand for the external (shock-wave) field while the white blobs denote the distribution amplitudes of the produced vector meson.