Spin and Parity Analysis at All Production Angles

Phys. Rev. 133, B428 – Published 27 January 1964
Murray Peshkin


Bohr's symmetry method is applied to an unstable spin-j state X, which is produced in a reaction A+BC+X and then decays according to XD+E. Particles A, B, C, D are assumed to be spinless, and E is either a spinless particle or a gamma ray. Parity is conserved in production, but not necessarily in decay. The angular distribution of E, in the rest system of X, is I(θ)=12ΣaLPL(cosθ), where L<~2j and the polar angle θ is measured from the normal to the production plane. The coefficients aL depend upon the production angle δ and upon the dynamics of the production. It is proved here that the sign of the maximum-complexity coefficient a2j depends only upon the parity of X, and that the magnitude of a2j is not zero but lies between bounds which depend upon j and the parity alone. The implied test for j and the parity has the following advantages: (1) The spin j is equal to half the largest L in I(θ). Addition of a small amount of a higher PL, which always improves the fit, is forbidden by the lower bound of a2j. (2) The bounds of a2j are independent of δ. Any (perhaps biased) average over δ may be performed before expanding I(θ) in the PL. (3) All the data are condensed into a single test quantity a2j, whose statistical error is reliably known.

DOI: http://dx.doi.org/10.1103/PhysRev.133.B428

  • Received 5 September 1963
  • Published in the issue dated January 1964

© 1964 The American Physical Society

Authors & Affiliations

Murray Peshkin

  • Argonne National Laboratory, Argonne, Illinois

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