Fundamental Physics with Antihydrogen
Antihydrogen—the antimatter equivalent of the hydrogen atom—is of fundamental interest as a test bed for universal symmetries—such as CPT and the Weak Equivalence Principle for gravitation. Invariance under CPT requires that hydrogen and antihydrogen have the same spectrum. Antimatter is of course intriguing because of the observed baryon asymmetry in the universe—currently unexplained by the Standard Model. At the CERN Antiproton Decelerator (AD) , several groups have been working diligently since 1999 to produce, trap, and study the structure and behaviour of the antihydrogen atom. One of the main thrusts of the AD experimental program is to apply precision techniques from atomic physics to the study of antimatter. Such experiments complement the high-energy searches for physics beyond the Standard Model. Antihydrogen is the only atom of antimatter to be produced in the laboratory. This is not so unfortunate, as its matter equivalent, hydrogen, is one of the most well-understood and accurately measured systems in all of physics. It is thus very compelling to undertake experimental examinations of the structure of antihydrogen. As experimental spectroscopy of antihydrogen has yet to begin in earnest, I will give here a brief introduction to some of the ion and atom trap developments necessary for synthesizing and trapping antihydrogen, so that it can be studied.
KeywordsEvaporative Cool Atom Trap Antihydrogen Atom Antiproton Decelerator Antiproton Annihilation
The author would like to thank the editors, Professors Quint and Vogel, for taking the initiative to prepare this volume and for the hard work of editing it. My many colleagues in PS200, ATHENA, and ALPHA are gratefully acknowledged for outstanding collaboration over the years; their names are to be found in the references. I would also like to thank the CERN AD and injector staff for delivering reliable beam over the years, and the members of the other AD and LEAR experiments, past and present, for creating an extremely stimulating working environment at CERN. The authors work has been supported by the Danish National Research Council (SNF, FNU), the Carlsberg Foundation, and the European Research Council.
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