Discussion Overview
The discussion revolves around the concept of inserting a mass width into the denominator of a propagator in quantum field theory (QFT) and its relation to higher order diagrams in calculations of near resonant cross sections. Participants seek to understand whether this method is equivalent to performing calculations to higher orders or if it is merely an ad hoc approach applicable under certain conditions.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- One participant notes that inserting a mass width in the propagator is typically used to account for unstable decay widths and to avoid problematic poles in calculations.
- Another participant suggests that the equivalence between inserting a mass width and calculating higher order diagrams may be covered in standard QFT texts, recommending Mattuck's work for examples of perturbation expansion.
- A different participant mentions that the relationship may be proportional to contributions from one-loop self-energy diagrams, indicating a connection to experimental data.
- Some participants express uncertainty about the rigor of the treatment in Peskin & Schroeder, noting that while it is suggestive, it may not provide a complete investigation.
- Clarifications are made regarding whether the method of adding mass widths is a general equivalence or an ad hoc method, with some participants questioning its applicability under certain circumstances.
- References to Bailin & Love are made for insights on dimensional regularization and its application to QCD and QED, with a focus on one-loop calculations.
Areas of Agreement / Disagreement
Participants express varying degrees of uncertainty about the equivalence of inserting mass widths and higher order calculations. While some suggest that there are relevant references, no consensus is reached on the rigor or general applicability of the method.
Contextual Notes
Participants mention limitations in the references they have consulted, indicating that some texts may not provide a rigorous treatment of the topic. There is also a noted dependence on the definitions and contexts in which the mass width is applied.