[ExI] Neutrino interaction web

Anders Sandberg anders at aleph.se
Thu Mar 3 23:13:16 UTC 2011

One of the classic simple models of atomic nuclei is the "droplet model" 
by Gamow, Bohr and Wheeler, which just treats them as liquid droplets of 
incompressible fluid with a heck of a surface tension. Insofar this 
model works, it suggests that nuclear matter in its normal state is a 
pretty lousy building material unless you like lumps of stuff.

However, Adrian, I am curious of why you thought a sheet of neutrons 
would stop neutrinos?

Personally I doubt it would work: any interaction would be by the weak 
force, and it is pretty wimpy. Lacking some lepton with the right charge 
the neutrino could not be absorbed by a reaction like n0 + v + e+ -> p+, 
so there might not even be any allowed reaction. But weird things happen 
when you spread out matter in low dimensional structures (think of 
graphenes), so intuitions might be misleading.

Anders Sandberg,
Future of Humanity Institute
Philosophy Faculty of Oxford University 

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