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Low energy theorem for scalar and vector interactions of a composite spin-1/2 system

S. J. Wallace·Franz Gross·J. A. Tjon
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Abstract

Scalar and vector interactions, with the scalar interaction coupled to a composite spin-1/2 system so as to cause a shift of its mass, are shown to obey a low-energy theorem which guarantees that the second order interaction due to z-graphs is the same as for a point Dirac particle. Off-shell and contact interactions appropriate to the composite system cancel and this is verified in a model of a composite fermion. The result provides a justification for the use of the Dirac equation as it has been in relativistic nuclear scattering and mean field theories.

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S. J. Wallace, Franz Gross, J. A. Tjon. 1994-07-27. Low energy theorem for scalar and vector interactions of a composite spin-1/2 system. https://doi.org/10.1103/physrevlett.74.228

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