Color confinement in high-energy quark knockout

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Discussion Overview

The discussion revolves around the concept of color confinement in quantum chromodynamics (QCD) at ultrahigh energies, specifically in the context of quark knockout events induced by high-energy particles. Participants explore the implications of special relativity and causality on the behavior of the glue field during such interactions, as well as the potential for hadronization in these extreme conditions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant describes color confinement at low energies and questions how it operates at ultrahigh energies, particularly in the context of quark knockout by high-momentum transfer particles.
  • Another participant introduces a simpler analogy involving magnets to question the nature of field line attachment in QCD compared to electromagnetism.
  • A third participant notes that while magnetic charges can be isolated, the dual of color charge does not behave similarly, suggesting a fundamental difference in confinement mechanisms.
  • Another participant argues that color charges behave like magnetic poles and that if a collision is too fast for color lines to reconnect, it would similarly affect magnetic lines, implying that confinement should still occur.

Areas of Agreement / Disagreement

Participants present differing views on the mechanisms of color confinement at ultrahigh energies, with no consensus reached on whether full hadronization occurs in these scenarios. The discussion remains unresolved regarding the implications of special relativity and the behavior of field lines in QCD.

Contextual Notes

Limitations include the dependence on the definitions of confinement and the behavior of field lines in different physical contexts, as well as the unresolved nature of numerical simulations in this energy regime.

nightvidcole
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TL;DR
If a quark is knocked out of a hadron at ultrahigh energies, how does the glue field respond?
At low energies, color is confined because attempting to remove a quark from a hadron will cause a response in the glue field that is often described as "snapping", or more formally, quark-antiquark pair production. However, how does this work at ultrahigh energies, let's say around 10^21 or 10^22 eV - still well below GUT energies? If a 1-10 ZeV electroweak-interacting particle is incident on a hadron and knocks out a quark at high momentum transfer, relativity dictates that the glue field can only respond within a very small distance of the quark's trajectory, due strictly to causality and special relativity. Any response further away from the quark will never be able to "catch up" and pull energy away from the quark since that quark will have departed to a very large distance by the time a light-speed signal can reach it. Given that the QCD coupling constant is suppressed at short length scales, what allows color confinement to operate in this ultrahigh-energy regime? Has anyone run numerical simulations to see if you still get full hadronization even at these ultrahigh energy quark knockouts?
 
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Let's start with a simpler question. If I do this to a magnet and the north and south sides go flying away, what keeps the poles' field lines attached?
 
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Those fields come from a current density - but the analogous thing isn't true for QCD. The dual of the magnetic charge is electric charge - which can be isolated. But whatever the dual of color charge is - it does not at all behave like electric monopoles that can exist independently.
 
But color charges do behave like magnetic poles, in that they are confined - just like magnetic field lines are closed.

If you try and concoct a situation where the collision is "too fast for the color lines to reconnect", it also is too fast for the magnetic lines to reconnect. Since the latter doesn't happen, neither does the former.
 
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