Where Does the Charge Come From in Electron-Positron Pair Production?

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Discussion Overview

The discussion centers around the origin of charge in the context of electron-positron pair production, exploring the conservation of charge and the conditions under which such pairs can be created. It touches on theoretical implications and the nature of fundamental particles.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • Some participants assert that charge does not come from anywhere, emphasizing that charge is conserved in particle creation processes.
  • Others propose that a neutral photon can create an electron-positron pair, as the total charge remains zero before and after the process.
  • Some participants note that two photons or a photon not in a vacuum are necessary for pair production to conserve both charge and energy/momentum.
  • A later reply highlights the significance of creating charged particles from neutral ones as a profound result of charge conservation, suggesting broader implications for understanding the universe.
  • There is acknowledgment of the complexity of conservation laws, including baryon number and lepton number, and their implications for the nature of fundamental particles.

Areas of Agreement / Disagreement

Participants generally agree on the conservation of charge in the context of pair production, but there are competing views regarding the specific conditions required for such processes, particularly concerning the role of photons and energy conservation.

Contextual Notes

Some assumptions regarding the nature of photons and the conditions for pair production remain unresolved, particularly the requirement of two photons or specific environmental conditions for energy and momentum conservation.

Who May Find This Useful

This discussion may be of interest to those studying particle physics, conservation laws, and the fundamental nature of particles and forces in the universe.

Shervan
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Where do the charge comes in electron-positron pair production
 
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As far as I know, they don't come from anywhere. Charge is simply conserved. Processes which create charged particles must conserve overall charge. This means that a neutral photon can create an electron-positron pair because the total charge before and after the creation process is zero.
 
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Drakkith said:
a neutral photon can create an electron-positron pair
two photons (or a photon not in vaccuum)... otherwise charge may be conserved but not the energy/momentum.
 
ChrisVer said:
two photons (or a photon not in vaccuum)... otherwise charge may be conserved but not the energy/momentum.

Indeed. Thanks for the correction.
 
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Drakkith said:
As far as I know, they don't come from anywhere. Charge is simply conserved. Processes which create charged particles must conserve overall charge. This means that a neutral photon can create an electron-positron pair because the total charge before and after the creation process is zero.
Thanks
 
Just to add, the fact that two charged particles can be created from particles that lack electric charge is a pretty amazing and profound result, even though it flows trivially from conservation of charge. Other conservation laws (e.g. baryon number and lepton number) have some equally profound implications.

Generally speaking, this favors a view of the universe as made of "all purpose stuff" that can be differentiated in various ways according to various laws, as opposed to an atomic/lego like preon kind of conception of the fundamental nature of the universe.
 

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