Notes on QED Corrections in Weak Decays

TL;DR

This paper reviews the conceptual aspects of QED corrections in hadronic decays, focusing on infrared logs and their treatment across various decay processes, highlighting ongoing efforts to include structure dependence.

Contribution

It provides a conceptual overview of QED corrections in weak decays, emphasizing infrared log management and illustrating with complex decay cases, including structure effects.

Findings

Infrared sensitive logs are crucial in QED corrections.

Different decay processes require tailored correction approaches.

Including structure dependence remains an ongoing challenge.

Abstract

In these lecture notes the basics of QED corrections to hadronic decays are reviewed with special emphasis on conceptual (e.g. counting and tracking of infrared sensitive logs) rather than numerical aspects. General matters are illustrated for the cases of increased complexity and decreased inclusiveness: $e^+ e^- \to hadrons$, the leptonic decay $\pi^+ \to \ell^+ \bar \nu$ and the semileptonic decay $B \to \pi \ell^+ \bar \nu$. The non-trivial and ongoing efforts of including structure dependence are very briefly outlined.