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Paper 8 - Theory of the Fermi Interaction

Feynman, R. P. and Gell-Mann, M. (1969) Paper 8 - Theory of the Fermi Interaction. In: The Theory of Beta-Decay. Elsevier , New York, NY, pp. 185-199. ISBN 978-0-08-006509-0.

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The representation of Fermi particles by two-component Pauli spinors satisfying a second order differential equation and the suggestion that in β decay these spinors act without gradient couplings leads to an essentially unique weak four-fermion coupling. It is equivalent to equal amounts of vector and axial vector coupling with two-component neutrinos and conservation of leptons. (The relative sign is not determined theoretically.) It is taken to be “universal”; the lifetime of the μ agrees to within the experimental errors of 2%. The vector part of the coupling is, by analogy with electric charge, assumed to be not renormalized by virtual mesons. This requires, for example, that pions are also “charged” in the sense that there is a direct interaction in which, say, a π^0 goes to π^- and an electron goes to a neutrino. The weak decays of strange particles will result qualitatively if the universality is extended to include a coupling involving a Λ or ∑ fermion. Parity is then not conserved even for those decays like K → 2π or 3π which involve no neutrinos. The theory is at variance with the measured angular correlation of electron and neutrino in He^6, and with the fact that fewer than 10^(-4) pion decay into electron and neutrino.

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Additional Information:© 1969 Elsevier. Received September 16, 1957. The authors have profited by conversations with F. Boehm, A.H. Wapstra, and B. Stech. One of us (M. G. M.) would like to thank R. E. Marshak and E. C. G. Sudarshan for valuable discussions.
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Official Citation:R.P. FEYNMAN and M. GELL-MANN, PAPER 8 - Theory of the Fermi Interaction†, In The Theory of Beta-Decay, edited by C. STRACHAN, Pergamon, 1969, Pages 185-199, ISBN 9780080065090, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:60379
Deposited By: Ruth Sustaita
Deposited On:21 Sep 2015 19:00
Last Modified:10 Nov 2021 22:33

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