Rest Mass of elementary particles.

[gisburnuk]

Can anybody tell me what gives a elementary particle its rest mass? I was under the impression that it is overall the mass of the quarks that gives a elementary particle its rest mass. For example: Lets take for instance two baryon elementary particles, a proton p and a Delta particle Δ+ (type one plus charge). Both have a quark arrangement of uud and have baryon number +1, but Delta has a spin of 3/2 while a proton has a spin of 1/2 and delta has a rest mass of 1232 MeV/c2 and a proton has a rest mass of 938.3 .

So would I be right in saying that elementary particke aquire their mass through spin rather than through their basic quark arrangement?

[swansont]

IIRC the [math]\Delta[/math] is an excited state of the proton, with one of the quarks having the extra angular momentum. The additional mass is due to the energy of excitation.

[gisburnuk]

Okay I follow you, so a delta particle is basically a excited proton which due to its angular spin/momentum acquires the extra mass. The problem I'm having is that the data for these two elementary particles show their 'rest' mass rather than their predicted mass during momentum or movement?

[gisburnuk]

http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

[swansont]

That is the rest mass. The excitation is not from motion - the particle is in a higher energy state due to its internal structure.

 

Hyperphysics is a great site - did you have a particular page in mind? You linked to the index.