3 ms·
Correct me if I'm wrong, but the standard model makes no prediction for the masses of any of the fundamental particles. To my knowledge, they are all input para
by muhbags 8y ago
Correct me if I'm wrong, but the standard model makes no prediction for the masses of any of the fundamental particles. To my knowledge, they are all input parameters. It might put certain bounds on them, but in the end they are all not predicted by the standard model itself.
This is seen as one of the big issues with the standard model, that it does not actually explain a lot of the characteristics of the fundamental particles like their couplings and masses.
- walrus1066 8y agoFor the W & Z bosons, their masses are derived from 3 other 'free parameters' of the SM. The Higgs mass is indeed a free parameter, but the SM wouldn't work of it's mass was greater than 200 GeV or so. The Higgs interacts with other particles of mass, and the strength of interaction is proportional to the Higgs mass, it influences certain processes (like W boson scattering), the rate at which these happen would deviate from experimental observation if Mhiggs was over 200 GeV. That's why the LHC was such a big deal, it reached the energies required for direct observation of sub-200 GeV Higgs, so it would either find the SM Higgs, or rule it out and invalidate the SM. Unfortunately the former seems to have happened. SM free parameters: https://en.m.wikipedia.org/wiki/Standard_Model#Construction_of_the_Standard_Model_Lagrangian https://en.m.wikipedia.org/wiki/Standard_Model#Construction_... Indirect constraints on Higgs mass in SM (a bit technical, slide 6 chart is the key one, strongly influenced specs & mission of the LHC) https://indico.lal.in2p3.fr https://indico.lal.in2p3.fr