Search For Trapped Antihydrogen
Date
2011-1/201Author
Andresen, Gorm B.
Ashkezari, Mohammad D.
Baquero-Ruiz, Marcelo
Bertsche, William
Bowe, Paul D.
Bray, Crystal C.
Butler, Eoin
Cesar, Claudio L.
Chapman, Steven
Charlton, Michael
Fajans, Joel
Friesen, Tim
Fujiwara, Makoto C.
Gill, David R.
Hangst, Jeffrey S.
Hardy, Walter N.
Hayano, Ryugo S.
Hayden, Michael E.
Humphries, Andrew J.
Hydomako, Richard
Jonsell, Svante
J\orgensen, Lars V.
Kurchaninov, Lenoid
Lambo, Ricardo
Madsen, Niels
Menary, Scott
Nolan, Paul
Olchanski, Konstantin
Olin, Art
Povilus, Alexander
Pusa, Petteri
Robicheaux, Francis
Sarid, Eli
Nasr, Sarah Seif El
Silveira, Daniel M.
So, Chukman
Storey, James W.
Thompson, Robert I.
van der Werf, Dirk P.
Wilding, Dean
Wurtele, Jonathan S.
Yamazaki, Yasunori
Metadata
Show full item recordAbstract
We present the results of an experiment to search for trapped antihydrogen atoms with the ALPHA antihydrogen trap at the CERN Antiproton Decelerator. Sensitive diagnostics of the temperatures, sizes, and densities of the trapped antiproton and positron plasmas have been developed, which in turn permitted development of techniques to precisely and reproducibly control the initial experimental parameters. The use of a position-sensitive annihilation vertex detector, together with the capability of controllably quenching the superconducting magnetic minimum trap, enabled us to carry out a high-sensitivity and low-background search for trapped synthesised antihydrogen atoms. We aim to identify the annihilations of antihydrogen atoms held for at least 130 ms in the trap before being released over ~30 ms. After a three-week experimental run in 2009 involving mixing of 10^7 antiprotons with 1.3 10^9 positrons to produce 6 10^5 antihydrogen atoms, we have identified six antiproton annihilation events that are consistent with the release of trapped antihydrogen. The cosmic ray background, estimated to contribute 0.14 counts, is incompatible with this observation at a significance of 5.6 sigma. Extensive simulations predict that an alternative source of annihilations, the escape of mirror-trapped antiprotons, is highly unlikely, though this possibility has not yet been ruled out experimentally.
Citation
Andresen, Gorm B., Mohammad D. Ashkezari, Marcelo Baquero-Ruiz, William Bertsche, et al. 2011. "Search For Trapped Antihydrogen." Physics Letters B, 695(1-4): 95-104