Effects of collisions on antiprotonic atoms

✍ Scribed by Dezső Horváth

• Publisher: Elsevier Science
• Year: 2005
• Tongue: English
• Weight: 249 KB
• Volume: 233
• Category: Article
• ISSN: 0168-583X
• DOI: 10.1016/j.nimb.2005.03.091

✦ Synopsis

A brief review is given of three experiments at the Antiproton Decelerator at CERN to test CPT invariance which states that particles and antiparticles have identical properties, in particular the same mass and opposite charge. Two experiments, ATHENA and ATRAP aim to study atomic transitions at high precision on antihydrogen, the antiproton-positron atom, as compared to ordinary hydrogen. The third experiment, ASACUSA, performs spectroscopy of antiprotonic helium to measure the charge and mass of the antiproton, at present with the precision of 10 ppb.

Collisions play an important role in these studies. The capture of the antiproton in bound state happens in collisions. Collisions (especially those with foreign atoms) can destroy the freshly formed system, and collisions with the medium or residual gas changes its lifetime and energy levels.