Inverse Beta Decay: Can Free Protons Change to Neutrons?

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Discussion Overview

The discussion centers on the possibility of free protons changing into neutrons through a process involving electron capture, specifically whether this can occur when free protons are bombarded by free electrons. The conversation explores theoretical aspects, detection challenges, and energy considerations related to this particle physics phenomenon.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests that a nuclear proton can capture an inner orbit electron to become a neutron, questioning if free protons can undergo a similar transformation when bombarded by free electrons.
  • Another participant explains that the reverse reaction for a free proton would require specific conditions to meet conservation laws, indicating that such events are not common.
  • A third participant acknowledges the theoretical possibility of the reaction e^{-} + p \rightarrow \nu_e + n but expresses skepticism about its detection due to the challenges of observing neutral particles.
  • One participant notes the role of energy in these interactions, suggesting that low kinetic energy values may lead to the formation of hydrogen atoms instead of free neutrons.
  • A later post raises a question about the conditions for neutrino production, indicating some uncertainty about their properties and the related concepts.

Areas of Agreement / Disagreement

Participants generally agree that while the transformation of free protons to neutrons through electron capture is theoretically possible, it is unlikely and difficult to detect. However, there is no consensus on the specifics of the conditions required for such events or the implications of energy levels.

Contextual Notes

Limitations include the ambiguity in definitions regarding the conditions for neutrino production and the technical difficulties associated with detecting the resulting particles from the proposed reactions.

Dadface
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With this mechanism a nuclear proton can capture an inner orbit electron and change to a neutron with the emisssion of a neutrino.Can this mechanism also operate with free protons if ,say, bombarded by free electrons?I have tried researching this but have found no reference other than a Wiki article which claims that free protons cannot normally be changed to free neutrons by the process of electron capture.To me this implies that it can happen but that such events are rarely observed,possibly due to energy considerations.I will be grateful if someone could clarify this for me and if possible provide a reference.Thank you.
 
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Beta decay of a neutron obtains three particles: proton, electron and an electron neutrino (antineutrino?)

In any case, the reverse reaction for a free proton would require the happenstance of the proton meeting up with an electron and a neutrino at the same time, in just the right way so that all the requisite conservation laws are met. This is what is meant by "not normally".
 
The reaction e^{-} + p \rightarrow \nu_e + n is possible, but I would be suprised if it's actually been detected because of the obvious technical difficulty of detecting two neutral particles in the final state.
 
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Thank you Phrak and jtbell.So it seems that such events may be unlikely and difficult to detect but are theoretically possible.I think energy plays a major part in the event because it seems likely free protons and free electrons at "low" KE values will readily come together to form hydrogen atoms.Also ,if any free neutrons are produced these will be unstable and decay into protons electrons and anti neutrinos.
 
This is how we make neutron stars right.
 
I'm something of a novice at particle Physics; can someone explain to me the conditions and instance of neutrino production? I think they're neutral particles with no mass and near-light speed but I'm not sure...The wikipedia article seems to be somehwat ambiguous on this topic.
 

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