IPNS Physics Seminar : Dropping Antimatter – The First Result from ALPHA-g


2023/12/18 14:00 – 15:30




藤原真琴 (TRIUMF)






Atomic hydrogen is one of the best studied systems in all of physics. Comparisons between hydrogen with its antimatter counterpart, antihydrogen, provide opportunities to probe some of the most foundational symmetries and principles in modern physics, such as CPT invariance and Einstein’s Equivalence Principle. Nonetheless, unlike hydrogen, antihydrogen does not naturally exist, presenting significant experimental challenges. Over the past decades, the ALPHA collaboration at CERN has developed techniques to synthesize, confine, manipulate and interrogate antihydrogen atoms. While numerous spectroscopic measurements on antihydrogen have been conducted, the study of gravitational effects has remained elusive, primarily due to the extremely weak nature of gravity. After more than a decade of development, the ALPHA-g experiment has now achieved a significant milestone by directly observing Earth’s gravitational influence on the motion of antihydrogen. This result represents an important step towards future precision gravity measurements on antimatter. In this seminar, following a general overview of antihydrogen studies, I will present our first result with the ALPHA-g experiment. I will also discuss our future prospects, including the ambitious HAICU (俳句) project under development at TRIUMF.