EM vs Neutrino interactions w matter

[BWV]

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? 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]

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?

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.

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?

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.

 

[Orodruin]

the mean free path of neutrinos is 1 light year of lead

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.

 

[e.bar.goum]

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.

Point taken.