The polarized photon distribution function

Abstract

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).