Science Record

SCIENCE RECORD New Ser. Vol. III, No. 1, 1959

PHYSICS

THE ANGULAR DISTRIBUTION OF THE DECAY PRODUCTS OF HYPERONS*

J. M. Cuen (fkrH#8), T. H. Ho (faite), D. C. Sen (BB) ann H. Y, Tzu (423470)

(Institute of Atomic Energy Research, Academia Sinica)

Experimental facts!"! revealed a large asymmetry of the angular distribution of the decay products of polarized A particles. If the angular distribution of completely polarized A particles in its rest system is proportional to

1 + acosO, (1)

then the experimental value’! of the asymmetry parameter is . \a| 20.73 £0.14, (2)

where 0 is the angle between the spin of the A particle and the momentum of the emitted proton. Lee and Yang"! pointed out that the large value of || strongly suggests the spin of A particle being 4. It is very difficult to reconcile the theoretical result with the experimental value of @, if the spin of the A particle is larger than 4.

Assuming various forms of interaction Hamiltonian, we calculate in this note the angular distribution of hyperon cecay products. The value of @ is not only sensitive to the magnitude of the spin of A, but also valuable in determining the type of interaction Hamiltonian inducing the decay process. It depends on the relative values of interaction constants. Hence, the accurate determination of the value of @ is useful to the determination of the effect of renormalization.

The angular distribution of hyperon decay is discussed phenomenologically first. The hyperon may decay into nucleon and #-meson directly or indirectly through the medium of other fields by way of a series of intermediate

states. It is convemient for the study of hyperon decay process to eliminate all other fields except those of hyperons, nucleons and m-mesons and to

*Received Dec, 10, 1958,

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