Unstable Particles in Quantum Field Theory
Abstract
In honor of Dave Roper’s \(90^{\mathrm {th}}\) birthday, I present a pedagogical introduction to our modern understanding of unstable particles in Quantum Field Theory, based on the analytic structure of the propagator, with occasional remarks on the Roper resonance. I discuss the mass and decay rate of unstable particles, the Breit–Wigner resonance formulae and width, poles and branch cuts, and pole trajectories. Abstract Published by the Jagiellonian University 2026 authors
Fields of Study & Subjects
Particle physics theoretical and experimental studies
Quantum Chromodynamics and Particle Interactions
Quantum and Classical Electrodynamics
Publication details
- Journal / source
- Acta Physica Polonica B
- Volume
- 57
- Issue
- 2
- Pages
- 1–1
- Publication date
- 10 February 2026
- Language
- EN