High Precision for Hard Processes (HP2 2026)

Towards NNLO QED corrections to radiative return processes

Not scheduled

20m

Speakers

Mr Thomas Dave (University of Liverpool)Mr Pau Petit Rosas (University of Liverpool) William Torres Bobadilla (Universidad de Salamanca)

Description

We present the analytic calculation of the two-loop QED corrections to the process $e^+e^-\to\gamma\gamma^*\to \pi^+\pi^- (\mu^+\mu^-)$, focusing on the initial-state radiation contribution, where the energetic photon is emitted from the leptonic line. The calculation is performed retaining the full dependence on all kinematic invariants, without resorting to small-mass approximations. This work is motivated by the current lack of NNLO theoretical predictions for low-energy radiative-return experiments and aims to improve the theoretical precision needed to better understand the persistent tension between experimental measurements and theoretical predictions.