Why do particles have mass?
1) they are made from constituents
with mass
- e.g. atoms made from neutrons,
protons, and electrons, less binding energy
but why do constituents have
mass?
2) deus ex machina
- they just are what they are
- spontaneous symmetry breaking
generated by couplings to higgs,
but what determines the couplings?
3) generated by interactions
The masses of light hadrons are mostly
generated by the glue binding the light quarks together, with
small contributions from the bare quark up and down quark masses,
and electromagnetic interactions.
e.g. energy in electromagnetic
fields of a charged particle
e.g. energy in fields binding
together composite systems
e.g. photon mass in a medium
(i.e. n>1, vg<c)
e.g. Higgs field? (see deus
ex machina above)
- dynamical symmetry breaking
e.g. technicolour
