Low-energy proton-proton scattering as a test of local hidden-variable theory

Abstract

E I N 8 T E I N , PODOLSKY and ROSEN (1) (EPR) gave an e~ample of a hypothetical experiment capable of testing certain apparently paradoxical predictions of the curren t quantum theory. BELL (2) proved that local hidden-variable theory cannot contain all of the predictions of quantum mechanics. Bell's proof is based on a Bohm (3) variant of the EPR experiment. WINNER (4) analysed and simplified Bell's argument. BOItM (a), BELL (2) and WIGNER (4) used in their analysis of the EPR experiment the example of a pair of spin-one-half particles formed in the singlet state moving in opposite directions. Photons and not spin-one-half particles, however, have unt i l now been used to test quantum mechanics experimentally because of their greater simplicity. BOHM and A~ARANOV (5) analysed the Wu and Shaknow experiment (~) of positron annihilation into two photons as such a test. CLAUSER, H O R N E , SHIMONY and HOLT (7) proposed an experiment using cascade atomic photons, based on Bell's proof, to test local hiddenvariable theory. P~I~S and S~NGER (s), however, argued some time ago that photons could not test the EPR paradox and suggested instead the use of proton-proton scattering. Bo~a and AHARANOV (9), one the other hand, showed that the argument of PIER, S and SINGER WaS incorrect and that photons could be used to test quantum mechanics. Nevertheless BorI~(1~ emphasized recently that nonmassless spin-onehalf particles would be a better test of local hidden-variable theory than photons. Photons are linear combinations of the normal modes of the electromagnetic field over all space which cannot be localized in space by a Lorentz transformation. The hidden variable of the photon could be associated with the non]ocal electromagnetic field. An experiment using nonmassless spin-one-half particles would be very desirable