Beta decay transition: Difference between revisions

Revision as of 13:07, 28 November 2024

Latest revision as of 22:21, 7 June 2025

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: <math>I_i = 0^+ \rightarrow I_f = 0^+ \Rightarrow \Delta I = 0</math>

also <math>\Delta \pi = 0 \Rightarrow</math> parity is conserved: <math>\pi (Y_{\ell\,m}) =(-1)^{\ell}</math>.

: <math>{}^{14}_7 \text{N}^*_{7}</math> = [[excited state]] of N

== Gamow–Teller transition ==

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== Mixed Fermi and Gamow–Teller decay ==

Due to the existence of the 2 possible final states, each β decay is a mixture of the two decay types. This essentially means that some of the time the remaining nucleus is in an excited state and other times the decay is directly to the [[ground state]].

Unlike Fermi transitions, Gamow–Teller transitions occur via an operator that operates only if the initial nuclear wavefunction and final nuclear wavefunction are defined.

The Isospin and Angular Momentum selection rules can be deduced from the operator and the identification of allowed and forbidden decays can be found.<ref>

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The above reaction involves "[[mirror nuclei]]", nuclei in which the numbers of protons and neutrons are interchanged.

One can measure the angular distributions of β particles with respect to the axis of nuclear [[spin polarization]] to determine what the mixture is between the two decay types (Fermi and Gamow–Teller).

The mixture can be expressed as a ratio of matrix elements ([[Fermi's golden rule]] relates transitions to matrix elements)