Summary
The transformation properties under time reversal of fundamental quaternion fields and the spin-affine connection in a Riemannian space are shown to lead to an eigenfunction equation whose eigenvalues can be identified with the masses of spinor particles. A one-to-one correspondence is established between the (co-ordinate-dependent) eigenvalues of this equation and a contraction of quaternion and spin-affine connection fields. The identification with theconstant mass of a spinor particle follows only after the coupled nonlinear spinor field equations uncouple, in the asymptotic limit in which the interactions between particles can be assumed to be vanishingly small. In this limit, a generally covariant form of the « free particle » Dirac equation emerges. A necessary part of the derivation is the demonstration of gauge invariance in the generally covariant spinor field equations.
Riassunto
Si dimostra che le proprietà di trasformazione rispetto all’inversione del tempo dci campi quaternionici fondamentali e le connessioni spin-affini in uno spazio di Riemann portano ad una equazione di autofunzioni i cui autovalori possono essere identificati con le masse delle particelle spinoriali. Si stabilisce una corrispondenza biunivoca fra gli autovalori (dipendenti dalle coordinate) di questa equazione ed una contrazione dei campi quaternionici e di connessione spin-affine. L’identificazione con la massacostante di una particella spinoriale segue solo dopo che le equazioni del campo spinoriale non lineari accoppiate si disaccoppiano, nel limite asintotico in cui si può supporre che le interazioni fra le particelle siano trascurabilmente piccole. In questo limite emerge una forma generalmente covariante dell’equazione di Dirac della « particella libera ». Parte necessaria della deduzione è la dimostrazione dell’invarianza di gauge nelle equazioni di campo spinoriali generalmente covarianti.
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References
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Of particular importance, in regard to the special theory of relativity, is the discovery byEinstein andMayer that the four-dimensional proper Lorentz group could be decomposed into the direct product of two two-dimensional spinor groups; thereby establishing a fundamental relationship between spinor fields and Lorentz-covariance. An easily accessible account of this work can be found in P.Roman:The Theory of Elementary Particles, 2nd edition (Amsterdam, 1961), p. 60.
The extension of the description of spinor fields from the Lorentz-covariant formalism into the domain of general relativity was discussed by several authors, during the 1930’s. The article byH. S. Ruse (Proc. Roy. Soc. Edinburgh,57, 97 (1937)) is particularly interesting, especially in reference to the discussion given in this paper A more recent account that also bears on this formalism was given byP. Bergmann (Phys. Rev.,107, 624 (1957)), and by P. A. M. Dirac (Max Planck Festschrift, 1958 (1), p. 339).
In ref. (6) the asterisk (denoting complex conjugation) was mistakingly left off of the transposed matrix (tr). Equation (21) of that paper should read as eq. (13) above.
The operatorɛK (whereK denotes complex conjugation) is the Winger time-reversal operatorW, referred to in earlier publications (1,5).
Note that the formalism in this paper and the last one (6), uses the space-time metric with signature (1 – 1 – 1 – 1) in the limit of a flat space. The earlier papers (which were concerned only with a Lorentz-covariant formalism) used the Minkowski metric. Thus, the pievious expression for the two-component spinor form of the Dirac equation (5) hand the factori in the mass term, while this one does not.
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The research reported in this paper has been supported by the Air Force Cambridge Research Laboratories, Office of Aerospace Research, under contract AF 19(628)-2816.
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Sachs, M. On spinor connection in a riemannian space and the masses of elementary particles. Nuovo Cim 34, 81–92 (1964). https://doi.org/10.1007/BF02725871
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DOI: https://doi.org/10.1007/BF02725871