How do they measure quark masses? Quark charges?

  • Context: Graduate 
  • Thread starter Thread starter H_Hernandez
  • Start date Start date
  • Tags Tags
    Charges Measure Quark
Click For Summary

Discussion Overview

The discussion revolves around the measurement of quark masses and charges, particularly in the context of their confinement within baryons like protons and neutrons. Participants explore the implications of quark mass contributions to hadron masses and the complexities involved in defining and measuring these properties.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant notes that while quarks are confined in baryons, the sum of their masses does not equal the mass of the proton, suggesting that interactions contribute significantly to the proton's mass.
  • Another participant suggests searching for "quark mass measurement" for additional resources, indicating that there are many discussions and entries available on the topic.
  • A third participant provides a link to a previous discussion about measuring quark masses, implying that similar questions have been raised in the past.
  • One participant explains that it is possible to compute how the masses of quark-containing particles depend on the quark masses, and that observed hadron masses can be used to infer quark masses. They also mention the complexity of defining quark mass due to confinement.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the specifics of measuring quark masses and charges, and multiple viewpoints and resources are presented without resolution.

Contextual Notes

The discussion highlights the challenges in defining quark mass due to their confinement within hadrons, and the reliance on hadron mass measurements to infer quark properties. There is an acknowledgment of the complexity involved in these measurements.

H_Hernandez
Messages
1
Reaction score
0
Hello,

So, I know quarks are confined in baryons. In a proton, there are "3" quarks, but the sum of their masses is not the mass of the proton. This implies a major fraction of the proton mass comes from interactions. My question is, how then do they measure quark u and d masses? And simmilarily, their charges?
 
Physics news on Phys.org
Google "quark mass measurement". You will get lots of hits, including old entries in this forum.
 
It is possible to compute how the masses of quark-containing particles (such as the proton, neutron, and pion, collectively known as hadrons) depend on the quark masses. Then, the observed values of the hadron masses can be used to determine the quark masses.

For complete details, see

http://pdg.lbl.gov/2012/reviews/rpp2012-rev-quark-masses.pdf

This is a technical document, intended for experts, but I think it's pretty readable nonetheless, and gives a good picture of what physicists actually do to figure these things out. One key point is that, because quarks are confined, their "mass" does not have as clear and simple a definition as it does for unconfined particles such as the electron.
 
  • Like
Likes   Reactions: vanhees71

Similar threads

  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 46 ·
2
Replies
46
Views
8K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 19 ·
Replies
19
Views
2K
  • · Replies 12 ·
Replies
12
Views
4K