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Copernicus
2014-May-13, 06:24 PM
If one was looking for a quark it looks like a point particle. What size, in meters, would be sufficiently small, to look like a point particle, with the current measuring techniques of physics. for example, if the electron were 10^-20 meters, would that look like a point particle. 10^-20 is just a random number I proposed for no particular reason except that it is less than 10^-18 meters which is a number I have noticed is used in literature.

antoniseb
2014-May-13, 08:08 PM
Do you mean what is the maximum size that would be indistinguishable from there being a single point that is the location of the charge (or color charge) of the particle as far as the behavior or effect on other particles? Or are you thinking of some other property of point particles that would be important here?

Copernicus
2014-May-13, 08:19 PM
Do you mean what is the maximum size that would be indistinguishable from there being a single point that is the location of the charge (or color charge) of the particle as far as the behavior or effect on other particles? Or are you thinking of some other property of point particles that would be important here?

The first.

antoniseb
2014-May-13, 08:38 PM
I don't have an answer, but that makes it easier to do a search.

Copernicus
2014-May-13, 08:45 PM
I don't have an answer, but that makes it easier to do a search.

Thanks!

Cougar
2014-May-13, 10:58 PM
It should be remembered that the mass of the quarks contribute almost nothing to the mass of the proton or neutron.

The "size" of a quark is about the same as that of an electron, i.e., less than 10-16 cm.

Search on "Probing Sea Quarks and Gluons - Nuclear Physics" for an informative pdf/powerpoint on the subject (and then some).

ShinAce
2014-May-14, 03:52 AM
Section 3 of the following paper:
http://www.arl.army.mil/arlreports/2001/ARL-TR-2332.pdf

shows the derivation of the 'classical electron radius' and that it implies an electron must travel at 100c. We therefore know the classical idea of a massless shell of charge doesn't work. Its mass would come from electrical potential energy. Therefore, we go with a massive point charge instead.

Copernicus
2014-May-14, 04:27 AM
Section 3 of the following paper:
http://www.arl.army.mil/arlreports/2001/ARL-TR-2332.pdf

shows the derivation of the 'classical electron radius' and that it implies an electron must travel at 100c. We therefore know the classical idea of a massless shell of charge doesn't work. Its mass would come from electrical potential energy. Therefore, we go with a massive point charge instead.

I haven't worked it out yet. But I think you are referring to magnetic moment. I did work out that multiple tori and double tori of size of multiple classical radius could give the correct magnetic moment for the electron, proton, muon, and neutron, but that is just conjecture, and I don't really think that is what is going on anyways since the electron and quarks look like points. I think that the magnetic moment could be modeled from zillions of smaller particles that are on the order of Planck dimensions, but I haven't even tried to do that since there would need to be a way for those zillions of small particles to act as one particle to become a point like particle.

I was just wondering if 10^-20 meters or there abouts would appear to be pointlike.