Production of cold antihydrogen during the positron cooling of antiprotons.

摘要

The production of cold antihydrogen is one of several significant advances made towards a precision comparison of hydrogen and antihydrogen. New and improved accumulation and manipulation techniques make large numbers of electrons, positrons, and antiprotons routinely available for interaction experiments. This has allowed an extensive study of the interaction of antiprotons with positrons in a nested Penning trap to be conducted. Measurements of the rate at which positrons cool the axial motion of antiprotons allow the determination of a fundamental cutoff parameter central to a theoretical description of this process. The theory can then be used to determine parameters important to the recombination of positrons and antiprotons to form anti-hydrogen. Unexpected antiproton cooling and loss is observed in the nested Penning trap, even without positrons being present. This loss, which remains unexplained, has serious consequences for antihydrogen detection schemes based upon the detection of simultaneous positron and antiproton annihilations. Consequently, a completely unambiguous and background free antihydrogen detection method is employed to verify that antihydrogen is produced during the positron cooling of antiprotons.