Temporally Controlled Modulation of Antihydrogen Production and the Temperature Scaling of Antiproton-Positron Recombination

Abstract

We demonstrate temporally controlled modulation of cold antihydrogen production by periodic RF heating of a positron plasma during antiproton-positron mixing in a Penning trap. Our observations have established a pulsed source of atomic antimatter, with a rise time of about 1 s, and a pulse length ranging from 3 to 100 s. Time-sensitive antihydrogen detection and positron plasma diagnostics, both capabilities of the ATHENA apparatus, allowed detailed studies of the pulsing behavior, which in turn gave information on the dependence of the antihydrogen production process on the positron temperature T. Our data are consistent with power law scaling T ÿ1:10:5 for the production rate in the high temperature regime from 100 meV up to 1.5 eV. This is not in accord with the behavior accepted for conventional three-body recombination.

Stimulated decay and formation of antihydrogen atoms

“…for non-correlated plasma [60]. We note that experimental rates have been measured to be different under specific plasma conditions [61].…”

The mechanisms of antihydrogen formationThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at University of Windsor, Windsor, Ontario, Canada on 21–26 July 2008.

“…The presence of the 2-BR mechanism seems to be not supported by the measurement of the maximum H production rate, 440 ± 40 Hz per ATHENA cycle [13], and by the lack of increase in the H production after a laser stimulation [14]. On the contrary, the predominance of the 3-BR mechanism is disproved by two different experiments [15,16] on the temperature dependence of H production. Here we give a new preliminary analysis of the ATHENA data in different experimental conditions to contribute to the understanding of the antihydrogen formation mechanisms.…”

Cold and ultracold Rydberg atoms in strong magnetic fields

“…This was already pointed out in [165] to violate the steady state condition, required to arrive at the recombination rate, Eq.(98). Indeed, recent measurements of the recombination rate in a nested Penning trap [215,222] have found a significant departure from the temperature scaling predicted by Eq. (98), which may arise from the limited antiproton-positron interaction times.…”

“…( 98). Indeed, recent measurements of the recombination rate in a nested Penning trap [215,222] have found a significant departure from the temperature scaling predicted by Eq. ( 98), which may arise from the limited antiproton-positron interaction times.…”