Two Techniques Produce Slow Antihydrogen

Andrew J. Speck

G. Gabrielse

G Gabrielse, A. Speck, C. H. Storry +13 more

G. Gabrielse

Slow antihydrogen is now produced by two different production methods. In Method I, large numbers of H atoms are produced during positron‐cooling of antiprotons within a nested Penning trap (Fig. 1). In a just‐demonstrated Method II, lasers control the production of antihydrogen atoms via charge exchange collisions. Field ionization detection makes it possible to probe the internal structure of the antihydrogen atoms being produced — most recently revealing atoms that are too tightly bound to be well described by the guiding center atom approximation. The speed of antihydrogen atoms has recently been measured for the first time. After the requested overview, the recent developments are surveyed.

J. Fajans

Since 2002, experiments at CERN have been producing slow, but untrapped, antihydrogen. The ultimate goal of these experiments is to test CPT and the gravitational interactions of matter and antimatter. Most schemes to perform CPT and gravity tests require trapped antihydrogen, but trapping antihydrogen is much more difficult than merely synthesizing it. The principle problems that must be solved before we can trap are how to cool the antiprotons, and how to keep them cold during the synthesis process. While we have already learned how to cool antiprotons by ten orders of magnitude, we must cool them by four more orders of magnitude, a scale set by the relative size of the potentials of the antimatter plasmas from which the antiatoms are synthesized compared to the antihydrogen trap well depth. In this talk, I will discuss antihydrogen synthesis and some of the techniques we are developing to control the energy of the resultant antihydrogen.

M. Amoretti, C. Amsler, G. Bonomi +32 more