Cryogenic antiprotons: A 1000‐fold improvement in their measured mass

Long term storage and nondestructive measurements of cryogenic antiprotons has made it possible to obtain antiproton to proton mass ratio 1000 times more accurately than it was measured with exotic atoms. An open access trap design and a self‐shielding solenoid were used to overcome the energetic energy distribution of the antiprotons from the accelerator. (AIP)