We analyse the recent claim that a violation of a Bell's inequality has been observed in the B--meson system [A. Go, {\em Journal of Modern Optics} {\bf 51} (2004) 991]. The results of this experiment are a convincing proof of quantum entanglement in B--meson pairs similar to that shown by polarization entangled photon pairs. However, we conclude that the tested inequality is not a genuine Bell's inequality and thus cannot discriminate between quantum mechanics and local realistic approaches.
@article{arxiv.quant-ph/0410122,
title = {Bell's inequality tests: from photons to B-mesons},
author = {A. Bramon and R. Escribano and G. Garbarino},
journal= {arXiv preprint arXiv:quant-ph/0410122},
year = {2009}
}