Search for anomalously heavy hydrogen in deep sea water at 4000 m

Abstract

A search was made with a sea water sample taken at a depth of 4000 m for anomalously heavy hydrogen dating from the early Universe. A technique of accelerator mass spectrometry involving a time-of-flight spectrometer was used. A new upper limit for the concentration of heavy particles in hydrogen is set around 4\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}17}$ in the mass range of 5-1600 u at a 95% confidence level.