Re: [Phys-l] Relativity Question about spring

[<carmelo@pacific.net.sg>]

Hugh wrote:
> Having not read Scheider's book or looked at the web site Jeff cites, 
> I cannot comment on the context of these remarks, or the further 
> conclusion, but I think Scheider is pushing what we can know too far 
> here. The known masses that he talks about are clearly the masses of 
> the free particles, and so I question the relevance of his comment.

Actually, we are unable to measure the mass of individual neutron or quark while they are in the bounded state, though we can still define it and discuss it. (Gerard't Hooft has classified the mass of quark as follows: Free mass, Constituent mass and Algebraic mass.)

The crux of the problem is a matter of terminology. For example, Peter Galison claims that there are three main subgroups in the particle physics community: experimental physicists, instrument developers and the theoretical physicists; every group speaks in their own specialized language. However, the situation in CERN can be even "worse" when the physicists from many different countries, speak in different "tongue". :-)

Why must some physicists' definition of mass be *absolute* in nature? Can't we visualize the mass of neutron to vary by parts per billion? Can't the mass of proton be continuously changing since the Early Universe? (Reinhold et al., Physical Review Letters, 21 April 2006)

It seems that the terminology "mass of neutron" must be so absolutely fixed according to some physicists or physics educators, that this could be a stumbling block to the Progress in Physics... Hopefully, Hugh, Jeffery and John D will agree..., one day.

Alphonsus