# Landau–Yang theorem

> selection rule that a massive particle with spin 1 cannot decay into two photons

**Wikidata**: [Q10380297](https://www.wikidata.org/wiki/Q10380297)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Landau–Yang_theorem)  
**Source**: https://4ort.xyz/entity/landau-yang-theorem