All Questions
9
questions
9
votes
3
answers
2k
views
Why are gluons massless as their range is finite?
The range of electromagnetic waves and gravitational force is infinity and the particles exchanged during these interactions are photons and gravitons respectively. Both are massless following the ...
1
vote
1
answer
105
views
Why is there still disagreement over the mass of the bottom (or beauty) quark, but none of the others?
Wikipedia (among other places) lists two values for the alleged mass of the B quark, 4.18 and 4.65 GeV.
Only one of the two possible masses listed has a link to another Wiki page explaining the ...
- 4,509
3
votes
2
answers
689
views
What is "Colombia Plot" in reference to lattice QCD?
In High Energy Physics papers, I often see a diagram as shown below:
I am still studying Quantum Field Theory, and I could not understand the only reference I could find about this plot: https://...
0
votes
1
answer
68
views
If quark current masses were equal, processes like $dd \to ss$ would be forbidden?
The QCD lagrangian has a $SU(N_{f})$ vectorial symmetry, which is explicitly broken by the difference in quark current masses. If this symmetry was exact ($m_{u}=m_{d}=m_{s}$...) the charges ...
- 125
3
votes
1
answer
132
views
Why Aren't Hadron Masses More Useful In Determining Standard Model Constant Values?
Some of the most exquisitely precise experimental measurements in all of physics are the masses of the various hadrons.
Consider these examples: the proton mass is known to eleven significant digits. ...
- 3,957
1
vote
1
answer
94
views
Is a quark‘s constituent mass affected by the chiral limit?
The up- and down quark’s constituent mass is usually taken to be around $300\,\text{MeV}\approx \tfrac{1}{3} m_\text{proton}$. Is this quantity affected by the chiral limit, where we let the quarks’ ...
- 2,648
0
votes
0
answers
33
views
Can glueballs, consisting of massles gluons, get a mass without reference to a Higgs field? [duplicate]
Glueballs, the by the standard model predicted combinations of short-lived combinations of massless gluons, have a mass between 1.4 and 5 (MeV). But where is this mass coming from? From interaction ...
3
votes
2
answers
683
views
Are the properties assigned to quarks meaningful?
Suspect this may have been asked before, but can't find it. My question is: If you can never have a free quark, what sense does it make to attribute properties to them, since you can never ...
- 3,856
1
vote
0
answers
85
views
QCD condensate and lepton mass
I read that the QCD U(1) anomaly is caused by the QCD condensate giving rise to quark masses. Does the QCD condensate also give masses to leptons (electron, mu, tau, neutrinos), or are these masses ...
- 1,783