US particle physicists are inching closer to determining why the Universe exists in its current form, made overwhelmingly of matter.
Physics suggests equal amounts of matter and antimatter should have been made in the Big Bang.
In 2010, researchers at the Tevatron accelerator claimed preliminary results showing a small excess of matter over antimatter as particles decayed.
The team has submitted a paper showing those results are on a firmer footing.
Each of the fundamental particles known has an antimatter cousin, with identical properties but opposite electric charge.