Speed of light measurements using different light source.

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Discussion Overview

The discussion revolves around the measurements of the speed of light using various light sources, particularly focusing on whether electromagnetic radiation can be generated from sources other than electrons, such as protons or neutral pions. The scope includes theoretical considerations and experimental observations related to particle physics and electromagnetic radiation.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant notes that traditional measurements of light speed have primarily involved light sources utilizing electrons, such as lasers and synchrotron radiation.
  • Another participant mentions experiments measuring light speed from the decay of highly relativistic pions, suggesting a different source of electromagnetic radiation.
  • A follow-up question arises regarding whether the pion decay to gamma photons is the only light source not involving electrons.
  • Concerns are raised about the nature of electromagnetic radiation produced by different particles, questioning if there is a fundamental difference in radiation generated by protons, ions, or electrons.
  • One participant clarifies that a neutral pion is a quark-antiquark bound state and discusses the implications of particle-antiparticle annihilation in generating photons.
  • Another participant challenges the classical view that electromagnetic radiation is only produced by charged entities changing velocity, suggesting that quantum mechanics allows for photon production in various decay processes.

Areas of Agreement / Disagreement

Participants express differing views on the nature of electromagnetic radiation from various sources, with no consensus reached on whether there is a significant difference in radiation characteristics based on the type of particle involved.

Contextual Notes

Some statements rely on classical physics interpretations, while others invoke quantum mechanics, indicating a potential gap in assumptions about electromagnetic radiation generation. The discussion also highlights the complexity of particle decay processes and their implications for light speed measurements.

Dilema
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As far as I know all light speed measurements done using light sources that utilized electrons. The nominal light speed measurement used laser which is actually exited electrons. The speed of X-ray radiation from synchrotron used accelerated electrons. The speed of gamma radiation also involved with inhalation of electron and positron. The speed of RF is also involved with electrons modulation in coils and capacitors.

Are there any speed measurements of electromagnetic radiation coming say from oscillated or accelerated protons?
 
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Thanks DaleSpam
 
Following the list provided by DaleSpam , the relativistic pion decay to 2 gamma photons as an electromagnetic source radiation in light speed measuring experiment. Is the only one of this type (namely light source that no electrons involve). Am I correct?
PS.
May be it is not the proper thread but how come a neutral (pion decay into 2 gammas) elementary entity generates electromagnetic radiation? As far as we learned, electromagnetic radiation generates only when charge entity changes its velocity (accelerates or decelerates, see oscillators)
 
Back up a bit.

What makes you think that there is a difference in the type of EM radiation due to these different sources. Do you think EM radiation generated by accelerating protons, ions, etc. is different than those generated by electrons? What is the physics for this difference?

Zz.
 
how come a neutral (pion decay into 2 gammas) elementary entity generates electromagnetic radiation?
A pion is not elementary, it's a quark-antiquark bound state. The Higgs boson is usually assumed to be elementary, but it can also decay into a quark-antiquark pair and from that into 2 gammas. A photon certainly does not 'remember' what type of particle emitted it.
 
Dilema said:
May be it is not the proper thread but how come a neutral (pion decay into 2 gammas) elementary entity generates electromagnetic radiation?
A neutral pion is its own anti-particle, so it always exists as a superposition of the particle and anti-particle. This allows it to annhilate itself and decay into two photons, as happens with other particle-anti-particle annhilations.

Dilema said:
As far as we learned, electromagnetic radiation generates only when charge entity changes its velocity (accelerates or decelerates, see oscillators)
Maybe classically you can justify that statement, but in the quantum world photons are produced in order to conserve energy and momentum in a wide variety of decays.
 

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