Spin correlations of strongly interacting massive fermion pairs as a test of Bell's inequality

We report the results of the first-time test of the local hidden variable theories (Bell-Clauser-Horne-Shimony-Holt) involving strongly interacting pairs of massive spin 1/2 hadrons from the decay of short-lived (τ<10-21sec ) He2 spin-singlet state, populated in the nuclear reaction H2+H1→He2+n. The novel features of this experiment are (a) the use of an "event body" detector of nearly 100% efficiency to prepare an unbiased sample and (b) a focal-plane polarimeter of full 2πsr acceptance with a random "post selection" of the reference axes. The spin-correlation function is deduced to be Sexp (π/4)=2.83±0.24stat±0.07sys. This result is in agreement with nonlocal quantum mechanical prediction and it violates the Bell-CHSH inequality of |S|≤2 at a confidence level of 99.3%.