2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/50298We present a new estimate of the fine structure constant and the $β$-function of QED at an arbitrary scale. Using the non-perturbative but convergent series expression of the one loop effective action of QED that has been available recently we make a non-perturbative estimate of the running coupling and the $β$-function, and prove the renormalization group invariance of the effective action. The contrast between our result and the perturbative result is remarkable.4 pages, 5 figuresHigh Energy Physics - Theorytext