Is There Anything Smaller Than an Electron Neutrino?

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    Electron Neutrino
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Discussion Overview

The discussion centers around the properties of the electron neutrino, specifically its mass and whether there are particles smaller than it. Participants explore the nature of neutrino mass, oscillations, and the implications of mass eigenstates.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants assert that the electron neutrino has the smallest non-zero mass of all known particles.
  • Others argue that the electron neutrino does not have a well-defined mass, as it is a superposition of three neutrino mass eigenstates, and there is uncertainty regarding whether the lightest neutrino has a non-zero mass.
  • A participant mentions that if the lightest neutrino had zero mass, the determinant of the mass matrix would be zero, which they claim would prevent neutrino oscillations.
  • Another participant challenges this claim, suggesting that oscillations could still occur unless mixing angles are set to zero or mass states are degenerate, which are not guaranteed by a zero determinant.
  • One participant acknowledges a mistake regarding the factors involved in oscillation calculations, indicating a complex understanding of the topic.
  • Questions are raised about the feasibility of setting mixing angles to zero or achieving degenerate mass states.

Areas of Agreement / Disagreement

Participants express differing views on the nature of neutrino mass and oscillations, indicating that the discussion remains unresolved with multiple competing perspectives.

Contextual Notes

There are limitations regarding the definitions of mass eigenstates and the conditions under which neutrino oscillations occur, which are not fully resolved in the discussion.

qsefthuko66
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Do you know a particle smaller than an electron neutrino? An electron neutrino is far by the smallest particle I know! Do you know something smaller than that?
 
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The electron neutrino has the smallest non-zero mass of all known particles.
 
mathman said:
The electron neutrino has the smallest non-zero mass of all known particles.

The electron neutrino doesn't have a well-defined mass. It's a superposition of the three neutrino mass eigenstates, the lightest of which is the lightest know fermion. However, it is not know whether the lightest neutrino has a non-zero mass.
 
Parlyne said:
The electron neutrino doesn't have a well-defined mass. It's a superposition of the three neutrino mass eigenstates, the lightest of which is the lightest know fermion. However, it is not know whether the lightest neutrino has a non-zero mass.

If the lightest neutrino had zero mass, then the determinant of the mass matrix would be 0 and neutrino oscillations would not occur.
 
chrispb said:
If the lightest neutrino had zero mass, then the determinant of the mass matrix would be 0 and neutrino oscillations would not occur.

You are correct that the determinant would be 0; however, I believe that you are incorrect that that would eliminate oscillations. As far as I know, the only ways to prevent oscillations are to set mixing angles to 0 or to make neutrino mass states degenerate. Neither of these possibilities are guaranteed by a 0 determinant.
 
Parlyne said:
You are correct that the determinant would be 0; however, I believe that you are incorrect that that would eliminate oscillations. As far as I know, the only ways to prevent oscillations are to set mixing angles to 0 or to make neutrino mass states degenerate. Neither of these possibilities are guaranteed by a 0 determinant.

Ah, yes, it's not m^2 that factors into the calculation, but delta m^2. My mistake.
 
oh! really is it true the only ways to prevent oscillations are to set mixing angles to 0 or to make neutrino mass states degenerate
 
is it hard to mix them?
 
any idea of mixing angles to 0 or to make neutrino mass states degenerate i think this easy if you have a great trainer...
 

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