Talk:Quantum chromodynamics

Challenges to QCD by others

I can see that there are a number of experts here on the whole topic of QCD and perhaps someone can comment - either here in the discussion or possibly integrated in the body of the article itself - regarding some criticism of QCD that I read about rather recently in a book. The author is trying to present a new theory based on magnetic monopoles (not Dirac monopoles) rather than the Quark-Gluon / color-charge model of QCD, and in the process presents a number of compelling questions about QCD, including (just paraphrasing from what I remember from the book):

• the rise of cross-section for both elastic and inelastic proton-proton scattering
• charge density of the neutron
• tensor force in neucleons
• the presence and location of additional quark-antiquark pairs
• There was also some mathematic proof about gordon-klein (?) being inconsistant
• proton spin crisis
• the fact that the color force is the reverse of all other forces in nature (where the intensity diminishes with the distance or a power thereof- rather than getting stronger when quarks are separated)
• the lack of finding of any particles predicted by QCD like 4-quark, 5-quark, glueballs, etc.

I don't have much of a background in physics at all- I just stumbled on the book at one point and recall that he made a compelling argument against QCD and for his own monopole model, which he claims - quite convincingly- answers all of the questions that he raised against QCD. Frankly, I think that it would be great if we could collect all of the arguments (with refutations) in either a section of the article or in a separate article. Any thoughts would be welcome and appreciated. Thanks, Michael. 209.250.153.11 (talk) 18:50, 11 May 2012 (UTC)

Mathematical Model

As far as I understand this, these are principal fibre bundles on a space-time base space. The fibres in the electrodynamical case are SU(1) (i.e. the unity circle) with sections the electrodynamical vector potentials; In chromodynamics they are SU(3), the sections being tensor potentials with values in complex three-dimensional space, the self-representation of SU(3). So there are three principal fibre bundles: Besides these two there is the tangent (or cotangent) bundle, in which general relativity takes place. If that is so, there is the question: What changes if we change the base space from one cosmological model to another? And how fits unification and grand unification into these mathematical structures? Local symmetries are invariance transformations in the tangent bundle, global ones are transformations in the whole multi-dimensional manifold. — Preceding unsigned comment added by 141.20.6.200 (talk) 10:35, 28 July 2012 (UTC)

New article gluon field and a QCD question

I split content from gluon field strength tensor to gluon field because the two fields are different, and there is lots of literature on these fields, so maybe separate articles could develop the mathematics carefully. We have electromagnetic four-potential and electromagnetic tensor, so why not similarly for the strong interaction? If there are strong (excuse pun) opinions to explain the fields together (as it happened with position and momentum space) then we can always merge.

Concerning the section quantum chromodynamics#Lagrangian: the ${\tilde {\mathbf {G} }}$ seems to be exactly the same as ${\mathcal {A}}$ for the gluon field, so I'm changing the notation, just as an IP did here. Posting here to for others to comment in advance.

Thanks for any corrections highlighted in advance. M∧Ŝc²ħεИ_τlk 21:57, 16 October 2013 (UTC)

Transplant of curvature 2-form expression from this article to gluon field strength tensor

See this cut and paste. This article gives the tensor expression for the Lagrangian and the gluon field strength:

$G_{\mu \nu }^{a}=\partial _{\mu }{\mathcal {A}}_{\nu }^{a}-\partial _{\nu }{\mathcal {A}}_{\mu }^{a}+gf^{abc}{\mathcal {A}}_{\mu }^{b}{\mathcal {A}}_{\nu }^{c}\,,$

which is enough - we don't need the differential forms... M∧Ŝc²ħεИ_τlk 21:18, 20 October 2013 (UTC)

the color connection field and it's gauge symmetry

If we rotate the color axis among a neutrally colored quark group, everything remains as it was for the color connection field is a gauge symmetric field. Some scientists claim that at a large number of rotations some discrepancies might be revealed, and that will help us understand more about gravity and the relationship between the strong and the electroweak force. We have to design that experiment and make sure that in the process we do not cancel out these statistical discrepancies. One proposal is that when different quark groups rotate close to each other, few quarks might briefly become part of the other group or even part with virtual quarks, and especially that virtual quarks aren't totally symmetrical because they occur via complex virtual particle interactions that include the weak force (even indirectly, as not a first direct step of the interaction sequence) with it's broken symmetries.

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Was the proposal of SU(3) in 1965 the final part of QCD

History section not clear on : Was the proposal of SU(3) in 1965 the final part of QCD theory ? Are the calculation methods (eg lattice QCD?) considered part of QCD ? Then it took until quark evidence from SLAC in 1969 for QCD (or quarks?) to be accepted generally ? - Rod57 (talk) 20:03, 2 September 2016 (UTC)

[1] says the QFT of strong interactions (QCD) was 1973. Implies that it wasnt called QCD until 1973 ? - Rod57 (talk) 20:33, 2 September 2016 (UTC)

Lattice QCD

I am not sure that the diagram in this article is correct 45.52.50.120 (talk) 18:31, 27 January 2023 (UTC)

Quark Velocity

I believe near light speed velocity is critical for the creation of mass.

It is necessary for several reasons: 1) to produce a field capable of both building strength and causing a mass effect.

2) to have a special prolonged interaction with passing field intensity calls for motion near the speed of the field.

There used to be many sources of quark speed info but today they seem to be harder to find. I have heard that the speed is within the range of 0.8C and 99.995C .

Bill field pulse (talk) 22:18, 2 February 2024 (UTC)

Do you have a specific change you’d like to make to the article? This is a place for discussing the article, not its subject. OverzealousAutocorrect (talk) 18:58, 26 February 2024 (UTC)

I would like to make a brief statement about quark velocity. Bill field pulse (talk) 21:55, 26 February 2024 (UTC)

Which is..? You refer broadly to the "speed of quarks", but being massive particles they can take on any velocity 0≤v<c. It's not clear what change a "statement about quark velocity" would be. OverzealousAutocorrect (talk) 12:47, 27 February 2024 (UTC)

I would like to say: It is difficult to determine experimentally how quarks move in normal speed protons because to detect quarks requires accelerating protons to speeds which prevent the chromodynamic motion. No particles can move at C hence high nucleon speeds removes speed available for chromodynamic motion. The need for high proton speed is per ref CMS Collaboration physics briefing 13 June 2022 regarding the Large Hadron collider. Bill field pulse (talk) 21:32, 2 March 2024 (UTC)

It is probable that quarks don't undergo much more motion than the overall proton; the proton being the bound state of the three constituent quarks, the three quark momenta must sum to the momentum of the proton, so... Yes, it is difficult to experimentally determine the motion of quarks at low speed, but it doesn't matter much anyway due to their confinement within the proton below an extremely high temperature. OverzealousAutocorrect (talk) 01:42, 3 March 2024 (UTC)

I believe that gravity is a net backward push caused by a passing EM intensity peak however this requires motion in the direction of the EM peak where resistance to C makes the forward push weaker than the gravity direction push. Clearly this would require relativistic speeds. However, I also believe that space does not like to be held steady in a charged state hence cycling at high speed is more stable than slow velocity. This is why I feel quarks move much faster than the proton and it is also why electrons do not clump together with the proton. And why nucleonic attraction has a peak at the proton diameter and getting too close is highly repulsive. Bill field pulse (talk) 19:06, 1 April 2024 (UTC)

Nucleonic attraction peaks at the proton diameter because the residual strong force has to overcome the electromagnetic force, not the other way around; besides you haven't stated exactly what you want to be stated in the article or provided any resources to back up any of your (hard-to-understand) claims. If you wouldn't mind laying out what you want to be changed in a "change X to Y with Z sources" manner, that would be appreciated. OverzealousAutocorrect (talk) 17:58, 2 April 2024 (UTC)