  We calculate the light cone wave functions for a virtual photon to split into
quark-antiquark states, including for the first time quark masses at one loop
accuracy. These wave functions can be used to calculate cross sections for
several precision probes of perturbative gluon saturation at the Electron-Ion
Collider. Using these wave functions we derive, for the first time, the dipole
picture DIS cross sections at one loop for longitudinal and transverse virtual
photons including quark masses. The quark masses are renormalized in the pole
mass scheme, satisfying constraints from the requirement of Lorentz invariance
of the quark Dirac and Pauli form factors.
