Speaker
Description
The ALPHA (Antihydrogen Laser Physics Apparatus) collaboration has performed several precision tests of fundamental symmetries through laser and microwave spectroscopy of atomic transitions in the antihydrogen atom [1, 2, 3]. Since typically only around only twenty antihydrogen atoms are trapped per experimental cycle, in these experiments antihydrogen atoms are accumulated [4] over time scales ranging from tens of minutes to many hours. The temperature of the positrons used to synthesise antihydrogen is thought to be the current limitation to the antihydrogen trapping rate. Here we present sympathetic cooling of large, dense positron plasmas to temperatures below 7 K using laser cooled Be+ ions [5,6] in a Penning trap used for antihydrogen synthesis. Our experimental methodology, and the current limitations of sympathetic cooling will be presented. The factor of 2.5 decrease in temperature compared to our typical positron plasmas will likely result in a significant increase in the amount of trappable antihydrogen, facilitating improvements in future measurements.
References
[1] ALPHA Collaboration, Nature 557, 71-75 (2018).
[2] ALPHA Collaboration, Nature 548, 66-69 (2017). [3] ALPHA Collaboration, Nature 561, 211-215 (2018).
[4] ALPHA Collaboration, Nat. Commun. 8, 681 (2017).
[5] ALPHA collaboration, Nat. Commun. 12, 6139 (2021).
[6] B. M. Jelenkovic et al., Phys. Rev. A 67, 063406 (2003).
