The discussion centers on the interactions of neutrinos and photons with matter, specifically focusing on the differences in their interactions due to the weak and electromagnetic forces. Participants explore the implications of neutrino mass on these interactions and the concept of mean free path in various contexts.
Participants express differing views on the generalization of neutrino mean free paths and the factors influencing them, indicating that multiple competing perspectives remain on the topic.
Limitations include the dependence of neutrino mean free path on energy and the potential implications of neutrino mass on interaction characteristics, which remain unresolved in the discussion.
Yes, sort of. Neutrinos do interact with matter, just not very much (the mean free path of neutrinos is 1 light year of lead). This is because they only interact through the weak interaction, yes.BWV said:basic question- neutrinos pass through matter because they are only subject to the weak interaction whereas photons interact with matter because they are subject to EM?
Not much in terms of interaction strength, but the signatures would be different (this is just kinematics - the recoil would be more). Further, there would be a bunch of other cosmological affects if the neutrino had a 1 GeV mass, and neutrino mixing would look different. Someone who knows more about neutrinos would be able to say more/correct me.BWV said:Does the small mass of the neutrino contribute to this - if there was a neutrino with the mass of a proton how differently would it interact with matter?
e.bar.goum said:the mean free path of neutrinos is 1 light year of lead
Point taken.Orodruin said:This is a statement taken out of context and that has become far too generalised. The mean-free path of neutrinos depend ln the neutrino energy. For example, the Earth is opaque to neutrinos at very high neutrino energies, such as the ultra-high energy neutrinos observed by IceCube.