Quote:
Originally Posted by martillo  CraigD,
The "quarks" with fractional charges are theoretical entities on which the Standard Model" is based but they were never detected isolated experimentally. I mean no particle with fractional charge has ever been detected experimentally.
All detected particles have integer -1, 0 or +1 charge. |
If you mean 'free' quarks have never been detected then this is true,
but the quark model is the only model to correctly predict all the experiments in electron scattering and muon scattering and neutrino scattering experiments that particle physicists have carried out.
Other theories were proposed all failed to correctly predict the results of experiments via these methods.
Also QCD explains why 'free' quarks are never detected and everyone now accepts the quark model because it is the only model that predicts the correct results and it is also mathematically pleasing into the bargain which is always a plus.
Any new model would have a really hard time in agreeing with scattering experiments, I have never came across one but I am willing to give it the benefit of the doubt but comments like 'Have you heard of the new theories ?' are generally annoying because you are not being specific at all never mind enough !! Which causes me to switch off and respond in one sentence answers.
Fractional evidence for the charge comes from the scattering experiments also and from the discovery of 'charmonium' particles.
The evidence is always going to be indirect however as the particles are small.
If this is in some way not satisfying for you, I can't really help you out. Its inherent in the nature of particle physics. That is the field deals with very small hard to detect objects.
Cheers
