Theory: Four-loop at large-nf: non-singlet structure functions in DIS

by Andrea Pelloni (NIKHEF)

Tuesday 21 Mar 2023, 15:00 → 16:00 Europe/Berlin

SR2

We have calculated the n_f^{^2} and n_f^{^3} contributions to the flavour non-singlet structure functions F_2 and F_L and most recently F_3 in inclusive deep-inelastic scattering at the fourth order in the strong coupling \alpha_s. The coefficient functions have been obtained by computing a very large number of Mellin-N moments using the method of differential equations and then determining the analytic forms in N and Bjorken-x from these. Our new n_f^{^2} terms are numerically much larger than the n3f leading large-nf parts which were already known; they agree with predictions of the threshold and high-energy resummations. I will present the methodology that was developed and used for obtaining these results together with prospects for further developments of this method in the exploration of $n_f$ contributions.