The polarized photon distribution function

We employ the LuxQED approach to compute the polarized photon PDF (photon pPDF). This approach expresses the pPDF in terms of the structure functions g₁ and g₂. Different models for the structure functions are employed according to the parameter space region. The resulting pPDF is approximately of the order of x times the unpolarized PDF. The relative uncertainty in the photon pPDF reaches up to $50%$ for x ~ 10⁻³, decreasing to approximately $10%$ for higher values of x. The computation of the photon pPDF will be essential for improving the precision of polarized calculations and will have fundamental implications for studies at the future Electron-Ion Collider (EIC).