The discussion revolves around the concept of a particle's mass and whether it fluctuates, particularly in the context of quantum field theory (QFT) and unstable particles. Participants explore ideas related to mass width, decay width, and the implications of these concepts on particle mass measurements.
Participants express differing views on the interpretation of mass fluctuations, with some focusing on stable versus unstable particles and others introducing concepts like unparticles. The discussion remains unresolved regarding the implications of these concepts on the nature of mass.
There are limitations in the discussion regarding the definitions of terms like "when viewed," which some participants find unclear. Additionally, the relationship between mass width and decay width is not fully explored, leaving some assumptions unaddressed.
It is actually called "decay width".maximdogger said:thanks ..I will look up mass width.
The mass of an "unstable particle" (or more accurately a resonance) is a well-defined number. It's given by the complex pole of its Green's function in (four-)momentum space, i.e., the real part of this pole is the mass and the imaginary part is its decay width, i.e., the inverse mean lifetime.malawi_glenn said:No idea what "when viewed" means.
There is however a concept of mass width in QFT for unstable particles.
Yup.vanhees71 said:The mass of an "unstable particle" (or more accurately a resonance) is a well-defined number. It's given by the complex pole of its Green's function in (four-)momentum space, i.e., the real part of this pole is the mass and the imaginary part is its decay width, i.e., the inverse mean lifetime.
I used that paper when I was starting my phd heheDemystifier said:No, but the mass of "unparticle" fluctuates.
https://arxiv.org/abs/0801.4471