2025

Tevio, Mirja; Lappi, Tuomas; Mäntysaari, Heikki; Paukkunen, Hannu

We formulate the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution of the Deep Inelastic Scattering (DIS) structure functions F2 and FL at next to leading order in αs (NLO) directly in terms of the structure functions rather than parton distributions (PDFs). We call this the physical basis approach. In practice, we first express the NLO quark singlet and gluon PDFs in terms of the structure functions F2 and FL in momentum space. Employing these expressions in the DGLAP evolution, we arrive at the evolution equations for F2 and FL in the physical basis. We demonstrate how one is free from defining a factorization scale and scheme when using the physical basis evolution equations. We also discuss the process of applying the NLO physical basis to global analysis of LHC cross sections.