DGLAP evolution equations

The Dokshitzer–Gribov–Lipatov–Altarelli–Parisi (DGLAP) evolution equations are equations in quantum chromodynamics (QCD) describing the variation of parton distribution functions with varying energy scales.¹ Experimentally observed scaling violation in deep inelastic scattering is important evidence for the correctness of the equations and of QCD in general.¹ The equations were first published in the western world by Guido Altarelli and Giorgio Parisi in 1977, and so are still sometimes called the Altarelli–Parisi equations.² Only later did it become known that an equivalent formula had been published in Russia by Yuri Dokshitzer in 1977,³ and by Vladimir Gribov and Lev Lipatov in 1972.⁴

The DGLAP QCD evolution equations are widely used in global determinations of parton distributions, like those from the Coordinated Theoretical-Experimental Project (CTEQ) or NNPDF collaborations.