Is the Top Quark Larger than a Proton?

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Discussion Overview

The discussion centers around the size of the top quark in comparison to a proton, exploring whether the top quark could be larger than a proton despite being treated as a point particle. Participants consider the implications of mass and decay properties on the potential size of the top quark.

Discussion Character

  • Exploratory, Debate/contested, Conceptual clarification

Main Points Raised

  • One participant notes that while top quarks have been created and their mass measured, there is no evidence or measurement of their size, raising the question of whether they could be larger than protons.
  • Another participant asserts that it is almost certain that the top quark is smaller than a proton, which contains multiple quarks.
  • A different viewpoint suggests that since quarks cannot exist independently, determining their size is likely very difficult, if not impossible.
  • One participant speculates that the form factor might influence the particle shower produced after the top quark's decay, suggesting that it is likely a point particle, but acknowledges that future measurements from the LHC could provide more clarity.
  • There is a mention of the top quark's Yukawa coupling being very close to unity, which may imply interesting properties related to its size or behavior.

Areas of Agreement / Disagreement

Participants express differing views on the size of the top quark relative to protons, with no consensus reached on whether it could be larger or if it is definitively smaller.

Contextual Notes

The discussion highlights the challenges in measuring the size of quarks, particularly due to their rapid decay and the nature of their existence within protons.

cbd1
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I know that particle accelerators have created and observed top quarks. Also, that they have measured their mass. However, I do not find if we have detected their size (or even attempted to detect their diameter, it would be hard to because they decay so quickly). I find it interesting that a single quark can have more mass than a whole proton. It would be logical to me to assume that the top might actually be larger in diameter than a proton. Note: I understand that we currently treat quarks as "point particles", but I'm concerned with if it could actually be possible that the top be larger than a proton, i.e. do we have proof that they are smaller than a proton?
 
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No measurement has been made, but it is almost certainly smaller than a proton (which contains multiple quarks).
 
Since no quarks can be stand alone, it seems that it would be very difficult, if not impossible, to get a size.
 
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Probably the form factor would have some influence in the shape of the "particle shower" that comes after the decay of the top, so I'd bet that it is pretty a point particle and that, if it is not, the LHC will be able to say.

Now, it is reasonable to suspect that something is going on with the top quark, if only because of its yukawa coupling, 0.98..., very near unity.
 

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