We study experimentally observable signals for nonlinear QCD dynamics in deep inelastic scattering (DIS) at small Bjorken variable $x$ and moderate virtuality $Q^2$, by quantifying differences between the linear Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution and nonlinear evolution with the Balitsky-Kovchegov equation. To remove the effect of the parametrization freedom in the initial conditions of both equations, we first match the predictions for the DIS structure functions $F_2$ and $F_{\mathrm{L}}$ from both frameworks in a region in $x$, $Q^2$ where both frameworks should provide an accurate description of the relevant physics. The differences in the dynamics are then quantified by the deviations when one moves away from this matching region. For free protons we find that the differences in $F_2$ remain at a few-percent level, while in $F_{\mathrm{L}}$ the deviations are larger, up to 10% at the Electron Ion Collider (EIC) and 40% at the Large Hadron-electron Collider (LHeC) kinematics. With a heavy nucleus the differences are up to 10% in $F_2$, and can reach 20% and 60% in $F_{\mathrm{L}}$ for the EIC and the LHeC, respectively.

• Received 29 March 2022
• Accepted 13 May 2022

DOI:https://doi.org/10.1103/PhysRevD.105.114017

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Published by the American Physical Society