Does Conservation Hold True for W Boson Spin Changes during Beta Decay?

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Discussion Overview

The discussion revolves around the conservation laws applicable during beta decay, specifically focusing on the changes in quark spin and the role of W bosons in the process. Participants explore theoretical aspects of particle interactions and conservation principles in the context of beta decay.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant asserts that during beta decay, a quark's spin changes and this change is associated with the mass/energy difference being converted into a W boson, referencing E=mc^2 for conservation.
  • Another participant challenges the notion of a real W boson existing in the context of beta decay, stating that the process primarily involves the exchange of a virtual W boson due to the low energies involved.
  • A participant seeks clarification on the correctness of their explanation regarding beta decay.
  • It is noted that while the type of quark changes, the spin itself is not altered, with isospin being the relevant term for the type change.
  • One participant suggests that the spin can change but emphasizes that this is not a strict rule, discussing the implications of different spin components of W bosons on quark spin.

Areas of Agreement / Disagreement

Participants express differing views on the nature of W bosons in beta decay, with some asserting the existence of a real W boson while others argue for the virtual nature of the boson. The discussion remains unresolved regarding the specifics of spin changes and conservation laws.

Contextual Notes

There are limitations in the discussion regarding the definitions of spin and isospin, as well as the conditions under which conservation laws apply. The participants do not fully resolve the mathematical implications of these concepts.

Kiley
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Is this true?:
During beta decay a quarks' spin is changed and the mass/ energy difference is converted to a W boson which quickly decays into an electron/positron and an anti neutrino/neutrino. The mass/ energy is conserved through E=mc^2.
 
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You really cannot say that the W exists in any meaningful manner. The energies involved in beta decay are far below that necessary to create a real W boson. However, the dominant contribution to beta decay is the exchange of a virtual W boson.
 
Thanks for your reply, would the other parts of my explanation be correct?
 
The type of quark is changed, not its spin.

The isospin changes (which is a fancy name for saying the type changes).
 
Awesome, thank you for your reply mfb!
 
I think the spin can also change, but it's not a rule (as there are W bosons with spin component 0 and with spin component +/-1)... the +/-1 should flip the spin of the quark, the 0 should keep it as it is. The spin quantum number though remains the same, for example both d and u-quarks have spin=1/2 (as all quarks and known fundamental fermions) , with components +/-1/2 each. Of course most of the times the spin-components are averaged out in calculations.
 

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