Quarks in Hadrons: Position Dependence for Pentaquark Stability

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In summary, the conversation covers the topic of pentaquarks and their stability. The speaker presents a theory about the position dependence of a pentaquark's formation, but it is pointed out that this does not make sense due to quark confinement. The concept of asymptotic freedom is also discussed, with the conclusion that it does not apply to hadrons. The conversation ends with a question about the meaning of "hadrons are not massive particle accelerators."
  • #1
BiGyElLoWhAt
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So, I have a question, and maybe we don't have an answer, or maybe it's a simple answer.
I was thinking, and if we have a pentaquark, I'm pretty sure we have to have a quark-antiquark pair (of any color-anticolor) and 3 quarks (one of each color). If, per say, the quark and antiquark were adjacent, I would think it would tend to eject itself from the particle, due to the superposition of the sum of charge appearing as essentially zero to the other 3 quarks. The same would apply to the 3 quarks with respect to the quark-antiquark pair.

When you take into account asymptotic freedom, where the strong force approaches zero as distance approaches zero, any "net" force on these quarks should be negligible. This seems to imply that the quark antiquark pair have another quark inbetween them that they can bond to, to maintain the pentaquark for a ~non-zero amount of time (I know the lifespan was really short). This would also imply that for a stable pentaquark, that the quark-antiquark pair and the quark inbetween would have to be unable to exchange gluons with the environment (otherwise one of them could end up as the same color as an adjacent quark, and be ejceted, effectively causing the pentaquark to decay), or there would have to be simultaneous gluon absorbsion/emission to compensate and maintain its stability (again, I know this particle was highly unstable).

So with this presumable position dependence on the formation of a true pentaquark (contrary to a meson-baryon pair like is also being speculated about), wouldn't this imply a lack of superposition? (i.e. the quarks must be in a certain configuration, and we know their positions relative to each other)

If not, then where is the flaw in this logic? I am apparently missing something.
Thanks in advance.
 
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  • #2
The whole approach does not make sense. Also keep in mind that personal theories are against the forum rules.

"adjacent" doesn't mean anything in hadrons.
BiGyElLoWhAt said:
I would think it would tend to eject itself from the particle
Why?
BiGyElLoWhAt said:
When you take into account asymptotic freedom, where the strong force approaches zero as distance approaches zero
It does not do that.
 
  • #3
mfb said:
The whole approach does not make sense. Also keep in mind that personal theories are against the forum rules. "adjacent" doesn't mean anything in hadrons.
It's not a theory, I'm trying to understand the physics behind it.
Are you saying there is absolutely no position dependance?
mfb said:
Why?
Because quark confinement.
mfb said:
It does not do that.
"In https://www.physicsforums.com/wiki/Physics , asymptotic freedom is a property of some https://www.physicsforums.com/wiki/Gauge_theory that causes bonds between particles to become asymptotically weaker as https://www.physicsforums.com/wiki/Energy increases and https://www.physicsforums.com/wiki/Length_scale decreases."
https://en.wikipedia.org/wiki/Asymptotic_freedom
Perhaps I should have used bond? I feel like bond and force are pretty much inerchangable in this context.[/QUOTE]
 
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  • #4
BiGyElLoWhAt said:
Are you saying there is absolutely no position dependance?
"The position of a quark" is not a meaningful concept. Quarks are not billard balls, they do not have well-defined positions.
BiGyElLoWhAt said:
Because quark confinement.
That does not make sense.

"In https://www.physicsforums.com/wiki/Physics , asymptotic freedom is a property of some https://www.physicsforums.com/wiki/Gauge_theory that causes bonds between particles to become asymptotically weaker as https://www.physicsforums.com/wiki/Energy increases and https://www.physicsforums.com/wiki/Length_scale decreases."
The important point here is "energy increases". Hadrons are not massive particle accelerators.
 
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  • #5
mfb said:
"The position of a quark" is not a meaningful concept. Quarks are not billard balls, they do not have well-defined positions.
I understand that they shouldn't, that was pretty much the point of my spiel.
mfb said:
That does not make sense.
From what I understand, quark confinement is a result of superposition of distant color charges appearing as color neutral to a color charge at some large (in terms of hadrons) distance, and also the fact that the coupling constant increases in distance. Mesons are a result of quark confinement. The superposition of charge was also a high point that I mentioned.
mfb said:
The important point here is "energy increases". Hadrons are not massive particle accelerators.
Let me quote the next line:
"Asymptotic freedom is a feature of https://www.physicsforums.com/wiki/Quantum_chromodynamics (QCD), the https://www.physicsforums.com/wiki/Quantum_field_theory of the https://www.physicsforums.com/wiki/Strong_nuclear_force between https://www.physicsforums.com/wiki/Quarks and https://www.physicsforums.com/wiki/Gluon , the fundamental constituents of nuclear matter." Same wikipedia page as before.

Edit* What does "Hadrons are not massive particle accelerators." mean?
 
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  • #6
BiGyElLoWhAt said:
From what I understand, quark confinement is a result of superposition of distant color charges appearing as color neutral to a color charge at some large (in terms of hadrons) distance
The logic is the opposite - quark confinement makes sure separate objects are color-neutral.
BiGyElLoWhAt said:
and also the fact that the coupling constant increases in distance.
It does not. It increases with decreasing energy.

BiGyElLoWhAt said:
Edit* What does "Hadrons are not massive particle accelerators." mean?
It means you see asymptotic freedom if you look at hadron collisions with ~10 GeV or more energy. Hadrons don't have 10 GeV on their own (not counting the b quark masses).
 

1. What are quarks and hadrons?

Quarks are fundamental particles that make up protons and neutrons, which are known as hadrons. Hadrons are particles that are made up of quarks and are held together by the strong nuclear force.

2. What is the position dependence of quarks in hadrons?

The position dependence of quarks in hadrons refers to the spatial arrangement of quarks within a hadron. This arrangement affects the stability, properties, and interactions of the hadron.

3. What is the significance of studying quarks in hadrons?

Studying quarks in hadrons is important for understanding the fundamental structure of matter and the strong nuclear force. It also helps us to better understand the properties and behavior of hadrons, such as their stability and interactions.

4. What is a pentaquark?

A pentaquark is a type of hadron that is composed of five quarks. It was first theorized in the 1960s but was not observed until 2003. Pentaquarks have since been studied extensively in order to understand their structure and stability.

5. How does the position dependence of quarks affect pentaquark stability?

The position dependence of quarks in pentaquarks plays a crucial role in their stability. If the quarks are arranged in a way that minimizes the strong nuclear force between them, the pentaquark is more likely to be stable. However, if the quarks are arranged in a way that maximizes the force, the pentaquark is more likely to be short-lived and decay quickly.

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