CERN experiment weighs antimatter with unprecedented accuracy

CERN experiment weighs antimatter with unprecedented accuracy. Geneva, 28 July 2011. the Japanese-European ASACUSA experiment at CERN ¹ reported a new measurement of the antiproton's mass accurate to about one part in a billion. Precision measurements of the antiproton mass provide an important way to investigate nature's apparent preference for matter over antimatter. "This is a very satisfying result," said Masaki Hori, a project leader in the ASACUSA collaboration. "It means that our measurement of the antiproton's mass relative to the electron is now almost as accurate as that of the proton." Ordinary protons constitute about half of the world around us, ourselves included. With so many protons around it would be natural to assume that the proton mass should be measurable to greater accuracy than that of antiprotons.