Discussion Overview
The discussion revolves around the concept of "topological cross section" in experimental quantum physics, particularly its distinction from differential cross section and total cross section. Participants explore definitions, relationships, and implications of these terms within the context of Feynman diagrams and particle interactions.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- Some participants suggest that the topological cross section refers to the total cross section for reactions with a specific number of outgoing lines.
- Others propose a relationship where the total cross section is the sum of the topological cross sections for different numbers of outgoing lines, indicating a focus on visible or charged lines.
- A participant questions the validity of counting only particles exceeding a certain momentum, suggesting it could lead to variability in the cross section value.
- Another participant introduces a definition indicating that the topological cross section is not corrected for possible meson resonances produced in intermediate stages before observing final particles.
- There is a discussion about the nature of Feynman diagrams, with some asserting that all diagrams are topologically different, while others challenge the implications of this statement.
Areas of Agreement / Disagreement
Participants express differing views on the definitions and implications of topological cross sections, with no consensus reached on their exact meaning or relationship to other types of cross sections.
Contextual Notes
Some statements rely on specific interpretations of terms and may depend on the context of particle interactions and Feynman diagram representations. The discussion includes assumptions about the visibility of lines and the impact of momentum thresholds on cross section values.
Every Feynman diagram is topologically different. And every process comes from an infinite number of different Feynman diagrams.