Next-to-leading order QED/EW contribution to lepton-hadron scattering in a joint QCD and QED/EW factorization approach*

With a large momentum transfer, high energy lepton-hadron scattering induces both QED and QCD radiations.  The QCD factorization systematically takes care of the contributions from collision-induced QCD radiation while contribution from induced QED radiation has been historically corrected by imposing a “radiative correction factor” to the lowest order (LO) cross section in QED coupling.  The “correction” for the simple inclusive deep inelastic scattering (DIS) cross section could be as large as the value of LO cross in some kinematic regime. Recently, a joint factorization approach to evaluate high energy lepton-hadron scattering cross section was proposed to treat both QCD and QED induced radiation equally [1].  In this talk, we will present the first calculation of next-to-leading (NLO) QED contributions to the factorized short-distance hard scattering coefficient to clearly demonstrate how the joint factorization consistently factorize all perturbative collinear sensitivities of partonic scattering into corresponding universal lepton and hadron distributions without the need of any parameters other than the standard factorization scale.  We also discuss the impact of this joint factorization approach on the precision of parity-violating DIS and its reach for physics beyond the standard model [3].

[1]  T. Liu, W. Melnitchouk, J.W. Qiu and N. Sato, JHEP 11, 157 (2021), Phys. Rev. D104, 094033 (2021).