# Handling photons in lattice QCD

- Institution: CERN
- Department: Theory Colloquia
- Speaker: Harvey Meyer
- Year: 2024
- Language: English
- Source: [CERN](https://videos.cern.ch/record/3018393)
- Licence: [CERN](http://copyright.web.cern.ch)
- Who can watch: Teens profiles and older (sources give no ratings; placed by Invisible Network from the source's own words)

I describe some of the computational challenges posed by handling photons in lattice QCD. In Euclidean space, amplitudes containing final-state photons are expressed in terms of hadronic correlation functions with a strong infrared weighting, which are hard to control. Secondly, including electromagnetic corrections in hadronic observables is mandatory once the percent level of precision is reached, and this leads to higher n-point functions that need to be computed efficiently. Thirdly, these corrections also lead to a renormalization of the QCD parameters. Two techniques to overcome these challenges will be described in more detail, the use of coordinate-space methods and choosing an ultraviolet cutoff for the photons that lies well below the lattice cutoff scale. .

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## Lectures

1. [Handling photons in lattice QCD](https://invisiblenetwork.ai/learn/cern/3018393/55a0c805d4d2), 1 h 9 min (CERN's player)