Improved limit on the directly measured antiproton lifetime

Abstract

Continuous monitoring of a cloud of antiprotons stored in a Penning trap for 405 days enables us to set an improved limit on the directly measured antiproton lifetime. From our measurements we extract a storage time of 3.15 × 108 equivalent antiproton-seconds, resulting in a lower lifetime limit of tp > 10.2 a with a confidence level of 68%. This result improves the limit on charge-parity-time violation in antiproton decays based on direct observation by a factor of 7.