Can the mirror world explain the ortho-positronium lifetime puzzle?
arXiv:hep-ph/0003278 · doi:10.1016/S0370-2693(00)00357-9
Abstract
We suggest that the discrepant lifetime measurements of ortho-positronium can be explained by ortho-positronium oscillations into mirror ortho-positronium. This explanation can be tested in future vacuum experiments.
about 6 pages, Latex, to appear in Phys.Lett.B