All Questions
Tagged with quantum-chromodynamics quantum-field-theory
402
questions
6
votes
1
answer
478
views
Some questions about the BCFW reduction
I am trying to give a fast sketch of what the BCFW reduction does and embed within it some questions at the steps which I don't seem to understand clearly. The first bullet point is sort of a very ...
- 4,561
6
votes
2
answers
1k
views
Feynman rules with helicity states.
Whenever Feynman rules are stated they are always without any mention of the helicities - this I find to be very confusing. How does one introduce and account for that?
Is there an intuitive/simple ...
- 4,619
6
votes
1
answer
591
views
Colour decomposition of $n-$gluon tree amplitude
I have here a $SU(N_c)$ Yang-Mill's theory and let the index $i$, label the $n$-gluons, and $\{k_i, \lambda_i, a_i\}$ be its momenta, helicity and colour index and $\cal{A}_n^{tree/1-loop}(\{k_i, \...
- 4,561
13
votes
1
answer
1k
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Derivation of the effective potential between a quark and an anti-quark
Typically in particle physics books (not in QFT books!) I have often seen this statement that the potential between a heavy quark and its anti-quark can be "empirically" represented as $V(r) = -\frac{...
- 4,619
9
votes
1
answer
1k
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Phase diagram of simplified QCD
Consider QCD with a single generation of massless quarks (u, d). This is probably the simplest variant of QCD which bears some relation to the real world. The theory has the following exact global ...
Squark
9
votes
1
answer
310
views
Why isn't there heterotic holographic QCD?
I think the question speaks for itself... Top-down holographic QCD, like Sakai-Sugimoto, always involves the Type II string. There are one or two papers on hQCD using the Type 0 string. But I can't ...
- 13.1k
4
votes
1
answer
1k
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Online lecture videos on QCD? [duplicate]
I would like to know if there are any online collections of lecture videos on QCD or non-Abelian QFT at a graduate level (at the level of volume 2 of Weinberg's QFT books?)
For example:
In String ...
9
votes
2
answers
566
views
What happens to a single quark in lattice QCD simulations?
I understand that if a pair quark/antiquark, out of the vacuum, tries to separate then the energy increases, another pair is produced, and we finish with two mesons or generically two hadron jets. But ...
- 1,943
2
votes
1
answer
483
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Axion related questions
I have several question regarding axion. Could anyone give me some brief introduction to what is a axion string, axion field and how is this related to fermion zero mode and chiral zero mode?
- 811
5
votes
1
answer
239
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Is the color gauge group spontaneously broken in QCD by the Savvidy vacuum?
One model for confinement in quantum chromodynamics is the Savvidy vacuum. This is a spontaneous symmetry breaking of color gauge symmetry by the gauge fields. The vacuum is divided into Savvidy ...
user2264
4
votes
2
answers
889
views
Polarization of the gluon
I think that, by now, it's understood that the gluon propagator in QCD has a dynamically generated mass. Ok, so my question is the following: where does the extra polarization degree of freedom come ...
- 2,741
9
votes
1
answer
471
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QCD phase diagram in the large N limit
I am sending a couple of questions which seem a bit more specific than others on this site, partially to probe if there is a point in doing so. Not sure what is the range of expertise here, and no way ...
user566