Physicists at the Lawrence Berkeley National Laboratory in California have been forced to withdraw claims that they had discovered two new 'superheavy' elements. The embarrassing U-turn follows several failed attempts to reproduce the original results in further experiments at Berkeley as well as at laboratories in Germany and Japan.

The researchers' claims to have observed two new elements with 118 and 116 protons were made in a 1999 paper published in the journal Physical Review Letters (83, 1104–1107; 1999). The heaviest artificial element previously generated, which was created in Russia, had 114 protons. The lead author of the paper, Victor Ninov, was quoted at the time as saying “we jumped over a sea of instability onto an island of stability that theories have been predicting since the 1970s”.

But the researchers have now been left with wet feet and red faces, and have retracted the paper. Re-analysis of their original data using different software revealed little sign of the much-vaunted element 118. “There are many lessons here and the lab will extract all the value it can from this event,” says Charles Shank, lab director at Berkeley. “The path forward is to learn from the mistakes.”

Other physicists say that they were always sceptical about the claims, pointing out that there was little genuine proof in the original paper. “You could believe or not believe, but physics is not a matter of belief,” says Gottfried Münzenberg, leader of the department of nuclear structure and nuclear chemistry at the German national laboratory for heavy-ion research in Darmstadt.