The ingredients of cold antihydrogen: Simultaneous confinement of antiprotons and positrons at 4 K

Low energy antiprotons and cold positrons are stored together and observed to interact for the first time. The particles and the nested Penning trap t hat confines them are cooled to 4.2 K, within a vacuum better than 5 x 10(- 17) Torr. The simultaneous confinement clearly demonstrates the potential o f a nested Penning trap for the production of cold antihydrogen. Contaminan t ions play a deleterious role, and we observe a surprising coupling betwee n the positron and antiproton accumulation mechanisms. (C) 1999 Published b y Elsevier Science B.V. All rights reserved.