QFTTopic
S-matrix bootstrap with massless particles in four dimensions
The S-matrix bootstrap finds which scattering outcomes are allowed using only basic principles such as conservation of probability and causality. In four dimensions, massless particles like photons, gravitons and zero-mass pions make the method hard to set up.
Why it matters
Massless particles dominate low-energy physics, so bounds on their scattering constrain the Standard Model's low-energy theory and quantum gravity without knowing the underlying theory.
Review
M. Kruczenski, J. Penedones, B. C. van Rees, Snowmass White Paper: S-matrix Bootstrap, arXiv:2203.02421, 2022. https://arxiv.org/abs/2203.02421 reference checked
Proof
- Signed record
- ec37b6151c82…
- Public log
- Entry 318, in checkpoint 2,123
- Bitcoin date
- Block 969,698, 2026-10-03