Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2002/iii/paper-68/1/b/solution

For physical finite-spin one-particle states, a positive-energy Poincaré group representation is labelled by mass and spin when , or mass and helicity when massless. The individual states also carry their four-momentum and a spin projection. For four-dimensional N=1 supersymmetry, the irreducible labels become , with the superspin, or , with a chosen superhelicity convention. The constituent representation labels are
with the last entry omitted for , and
A required CPT completion of a supermultiplet adds the conjugate labels and conjugates any internal charges.

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