Does beta decay change spin orientation?

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SUMMARY

The discussion centers on the spin orientation of protons resulting from neutron beta decay. It establishes that the spin of the resulting proton can be either up or down, influenced by the momenta of the emitted electron and antineutrino. The conservation of total spin is emphasized, with the initial spin of the neutron being +1 and the final state comprising a proton, electron, and electron antineutrino also maintaining a total spin of +1. The helicity of the antineutrino plays a crucial role in determining its spin direction relative to its momentum.

PREREQUISITES
  • Understanding of beta decay processes in particle physics
  • Familiarity with spin and helicity concepts
  • Knowledge of particle interactions involving W bosons
  • Basic principles of conservation laws in quantum mechanics
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  • Research the role of W bosons in weak interactions
  • Study the implications of helicity in particle physics
  • Explore the conservation of angular momentum in beta decay
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Physicists, students of particle physics, and anyone interested in the intricacies of beta decay and spin conservation in quantum mechanics.

jerry mac
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If you have a free neutron viewed from a known frame of reference which is known to be spin up and it decays, is there anything in theory or experiment which indicates whether the remaining proton will be spin up or down? Thanks Jerry
 
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no, the proton can be up or down, depending on the electron and neutrinos' momenta...
 
Thanks for the response. In popular accounts of decay, spin is not usually discussed and I am trying to understand it. I guess in order to emit a w minus particle there would be handedness change internally as the down quark changes into an up quark, but that wouldn't change the overall spin orientation of the nucleon.
 
the spin is conserved... so you don't have to think in terms of the W bosons...
initially you had +1
in the final state you must also have +1
Now the final state consists of the proton, electron and electron antineutrino
some combinations showing the up/down of proton's spin would be: +1_p + 1_e - 1_\nu or -1_p + 1_e + 1_\nu...
Now of course antineutrinos have right handed helicity, and so them having + or - spin depends on their momentum orientation...
If the antineutrino has spin -1, it should also move towards the negative z-axis, if it has +1 it will move towards the positive z-axis (so that the spin and momentum are alligned).
 

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