L. Grodzins, with Maurice Goldhaber and A. W. Sunyar, investigated neutrino helicity through correlated nuclear recoil and gamma-ray polarization. Their 1958 result established negative helicity for the neutrinos selected by the experiment.[ref]
Helicity of Neutrinos by Maurice Goldhaber and others. pp.1015–1017: recoil selection and polarization counting
The method combined several physical filters: a polarization-sensitive photon measurement became informative about an unobserved neutrino only through the selected nuclear process and conservation of angular momentum.
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