On the statistical behaviour of known and unknown elementary particles. Offprint from Physica 7 1940

Pauli, Wolfgang (1900-1958) and Frederick J. Belinfante (1913-91). On the statistical behaviour of known and unknown elementary particles. Offprint from Physica 7 (1940). 177-192pp. 244 x 160 mm. Original printed wrappers, slightly sunned. Very good.

First Edition, Offprint Issue of Pauli and Belinfante's paper on the relation of spin and statistics, which appeared the same year that Pauli published his famous spin-statistics theorem. "While Pauli and Fierz [in their 1939 paper] tried to cope with the extra, negative-energy particles-they especially formulated conditions to suppress these objects . . . Belinfante, a student of Hendrik Kramers's, entered into the fray by applying certain new mathematical methods and physical concepts in the theory of elementary particles; in particular he introduced-instead of the well-known tensor and spin calculus-a different scheme of mathematical quantities, which he called 'undors' and which could describe both integral-spin and half-integral spin fields . . . In the following investigation, 'On the Statistical Behaviour of Known and Unknown Elementary Particles,' (submitted in December 1939 and published in the March 1940 issue of Physica, the article having been written in English, with an abstract in German) Pauli and Belinfante joined forces. They first stated the three postulates which determined the statistics in the relativistic theories of (free) elementary particles, namely:

(I) The energy is always positive,

(II) Observables at different space-time points commute for space-like distances,

(III) There exist two equivalent descriptions of nature, in which the elementary charges have opposite sign, and in which corresponding field quantities transform in the same way under Lorentz transformations.

Pauli and Belinfante then demonstrated that, in the general case of undors having the same rank, postulate (III)-involving Belinfante's charge symmetry would not suffice to determine the statistics of the associated particles; however, the postulates (I) or (II), respectively, would always do" (Mehra & Rechenberg, The Historical Development of Quantum Theory, 6, pp. 960-961).