Towards the QED beta function and renormalons at $1/N_f^2$ and $1/N_f^3$

Nicola Andrea Dondi, Gerald V. Dunne, Manuel Reichert +1

We determine the $1/N_f^2$ and $1/N_f^3$ contributions to the QED beta function stemming from the closed set of nested diagrams. At order $1/N_f^2$ we discover a new logarithmic br…