Beta emission and electron capture bookkeeping
Weak beta channels include n→p+e⁻+ν̄_e, p→n+e⁺+ν_e, and bound-electron capture p+e⁻→n+ν_e within a nucleus.
Key knowledge
Weak beta channels include n→p+e⁻+ν̄_e, p→n+e⁺+ν_e, and bound-electron capture p+e⁻→n+ν_e within a nucleus. They keep A fixed and change the daughter Z by +1 for β⁻, −1 for β⁺ or electron capture. The emitted neutrino/antineutrino carries energy, momentum and lepton quantum numbers; beta electron energies are continuous because the final energy is shared.
Values and equations
β⁻: (A,Z)→(A,Z+1)+e⁻+ν̄_e; β⁺: (A,Z)→(A,Z−1)+e⁺+ν_e; EC: (A,Z)+e⁻→(A,Z−1)+ν_e
- A,Z
- Parent nucleon and proton counts
- e⁻,e⁺
- Electron and positron species
- ν_e,ν̄_e
- Electron-flavor neutrino and antineutrino states
- EC
- Electron-capture channel
Conditions and scope
- These are channel identities inside appropriate nuclei, not assertions that a free proton spontaneously undergoes β⁺ decay. Consistent masses, electron accounting and energy/momentum balance determine whether a specific channel is accessible.
- Rates and allowed/forbidden strengths depend on nuclear weak matrix elements and available phase space; A/Z bookkeeping and positive Q alone do not determine a lifetime or imply individual lepton-flavor conservation during propagation.
Sources · 2
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Introduction to Applied Nuclear Physics: chapter 1 (2012): Section 1.3.2, printed pages 13–14: β⁻, β⁺ and capture identities and A/Z changes. The reversed neutron/proton prose after the displayed β⁻ equation is excluded. Introduction to Applied Nuclear Physics: chapter 7 (2012): Section 7.2.1, printed page 100: three-body continuous beta spectra and capture alternatives; the source's repeated neutron/proton prose reversal is excluded.
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Entry details
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- university-core.1
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