Discussion Overview
The discussion centers around the proton-proton inelastic cross section at MeV energies, exploring the availability of data and theoretical considerations regarding various interactions at these energy levels. Participants examine specific reactions, their thresholds, and cross-sections, while also referencing simulation results.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
- Mathematical reasoning
Main Points Raised
- One participant seeks proton-proton inelastic cross section data specifically in MeV, noting a lack of results in existing databases compared to higher energies.
- Another participant questions whether only elastic scattering occurs at these energies, indicating a lack of familiarity with the interaction.
- A participant suggests that pion production is the first inelastic collision via the strong force at around 150 MeV, but notes a negligible cross-section at this energy.
- Further elaboration on the weak interaction indicates that processes like p+p -> d+positron+neutrino should have no threshold but also a low cross-section.
- Discussion includes potential electromagnetic interactions in inelastic collisions, with a participant proposing a reaction involving photon emission and questioning the comparative cross-sections of various processes.
- A participant shares simulation results from FLUKA, reporting an inelastic scattering length of 9.1E9 cm for proton-proton interactions at 10 MeV, which they find small compared to elastic scattering.
- Another participant corrects the scattering length to 0.16E+10 cm and emphasizes the need for long-range tunneling below the MeV scale, suggesting that the cross-section becomes negligible for simulations.
- There is a discussion about definitions of inelastic interactions in high-energy physics and the relevance of ionization in the context of scattering lengths.
Areas of Agreement / Disagreement
Participants express uncertainty regarding the nature of inelastic collisions at MeV energies, with multiple competing views on the types of interactions that may occur and their respective cross-sections. The discussion remains unresolved with no consensus on the availability of data or the significance of the reported scattering lengths.
Contextual Notes
Participants note limitations in available data and definitions, as well as the dependence on specific energy thresholds and interaction types. The discussion reflects a range of assumptions regarding the interactions involved and the interpretation of simulation results.