At how many femtometers does strong force cease to exist?

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Discussion Overview

The discussion revolves around the behavior of the strong force at very short distances, specifically focusing on how it diminishes as one moves away from quarks, measured in femtometers. Participants explore the nature of this force, its decay rate, and the mathematical representation of its strength over distance.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant states that at 2.5 femtometers from a quark, the strong force significantly loses power, but questions at what distance it becomes completely negligible.
  • Another participant notes that there is no exact point where the force becomes zero, but it decreases rapidly and becomes irrelevant compared to other forces, such as the electromagnetic force, at just a few femtometers away.
  • A participant inquires about the mathematical rate at which the strong force drops off, seeking an equation to describe this behavior.
  • One participant suggests that the strong force may fall off like exp(-r/r0)/r for long distances, where r0 is approximately 1.5 femtometers.
  • Another participant expresses confusion about the notation used in the equation and seeks clarification.
  • A participant clarifies that the strength of the strong force is proportional to the function e^(-r/r0)/r and provides a link to a plot illustrating this relationship.
  • Further discussion includes confirmation of the axes in the provided graph, with emphasis on the shape of the graph rather than the specific numerical values on the y-axis.

Areas of Agreement / Disagreement

Participants generally agree that the strong force does not reach exactly zero but decreases rapidly with distance. However, there is no consensus on the exact distance at which it becomes negligible or on the precise mathematical representation of its decay.

Contextual Notes

Limitations include potential misunderstandings of notation and the dependence on the definition of the strong force's strength, as well as the unresolved nature of the mathematical representation discussed.

Rorkster2
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At 2.5 femtometer away from a quark the strong force is said to significantly loose power and become insignificant. At how many femtometers does the strong force completely loose any amount of tug?
 
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As usual, there is no single point where it gets exactly 0. But the force is decreasing so quickly that it gets completely irrelevant (and small compared to the electromagnetic force, for example) just some femtometers away.
 
mfb said:
As usual, there is no single point where it gets exactly 0. But the force is decreasing so quickly that it gets completely irrelevant (and small compared to the electromagnetic force, for example) just some femtometers away.

Ok. Is their any known way to find out the rate in which the force drops off? I.e. an equation of some sort?
 
Someone may correct me on this, but I think for long distances it should fall off roughly like exp(-r/r0)/r, where r0 is the Compton wavelength of the pion, which is about 1.5 femtometers.
 
@The_Duck I looked that up to find out what it ment and google didn't return anything.
 
In case the problem is notation, it means that at a distance r the strength of the strong force should be proportional to the function

[tex]\frac{e^{-r/r_0}}{r}[/tex]

where r0 is 1.5 femtometers. Here's a plot of this behavior: http://www.wolframalpha.com/input/?i=plot+exp(-r/1.5)/r,+r=0..10
In the plot, the x-axis is the distance in femtometers and the y-axis is proportional to the strength of the strong force
 
Ahh thanks a lot. In the graph the x-axis is length in femtometers and would Y be the strength? I'm pretty sure I get it I just want to be sure
 
Yes. Just keep in mind that the numbers on the y-axis don't mean anything; it's the shape of the graph that is meaningful.
 
The_Duck said:
Yes. Just keep in mind that the numbers on the y-axis don't mean anything; it's the shape of the graph that is meaningful.

You have rightfully earned the title the duck. Thank you
 

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