Satire about the search for a theory of everything in physics, sometimes about the strand-spaghetti model.
10 September 2011
No mass calculation
The strand model, though my favorite, lacks a good explanation for particle masses. It does explain certain mass ratios, but it does not explain the absolute mass values. We should help on this topic.
Aren't they experimental data? I think such things as charges and masses are just experimental data, and the other things, like energy levels, scattering amplitudes are calculable from them. All theories must be phenomenological and must contain experimental data.
Besides, SM is a renormalizable theory - it contains wrong mass terms that are corrected in course of calculations ;-)
A theory is a scientific guess of how a given body will behave in different conditions. The force in equations may change, the initial conditions too, but the body mass may not. Good (final) theory covers all possible forces and initial conditions but it has the same external parameter - the body mass. This mass comes together with the other experimental data to compare so if you have a theory which is beautiful but disagrees with those, you have at best a beautiful mathematical construction, not a physical theory.
As a minimum, the theory should give a hint about the difference between the mass of the top and the mass of the rest of particles. Of course it is arguable, as the quotient top/charm is not very horrible when compared to charp/up. But the value =1 (or 0.995 if you prefer) of the top yukawa coupling puts it in a different status.
For instance, you could have a symmetry protecting the other particles. Any in a 84 or 42 irrep of some group would do. Some other objects from sugra and m-theory also provide 84 slots, but nobody has given any use.
Aren't they experimental data? I think such things as charges and masses are just experimental data, and the other things, like energy levels, scattering amplitudes are calculable from them. All theories must be phenomenological and must contain experimental data.
ReplyDeleteBesides, SM is a renormalizable theory - it contains wrong mass terms that are corrected in course of calculations ;-)
Anybody who claims to have a final theory must explain particle masses. The final theory is not allowed to be phenomenological - it is final!
ReplyDeleteA theory is a scientific guess of how a given body will behave in different conditions. The force in equations may change, the initial conditions too, but the body mass may not. Good (final) theory covers all possible forces and initial conditions but it has the same external parameter - the body mass. This mass comes together with the other experimental data to compare so if you have a theory which is beautiful but disagrees with those, you have at best a beautiful mathematical construction, not a physical theory.
ReplyDeleteAs a minimum, the theory should give a hint about the difference between the mass of the top and the mass of the rest of particles. Of course it is arguable, as the quotient top/charm is not very horrible when compared to charp/up. But the value =1 (or 0.995 if you prefer) of the top yukawa coupling puts it in a different status.
ReplyDeleteFor instance, you could have a symmetry protecting the other particles. Any in a 84 or 42 irrep of some group would do. Some other objects from sugra and m-theory also provide 84 slots, but nobody has given any use.
In the latest version of the strand model I found a proposal by Schiller for calculating masses. But I am not sure it really solves the problem.
ReplyDelete