Speaker
Description
Although the gravitational interaction between matter and antimatter has been the subject of theoretical speculation since the discovery of the latter in 1928, only recently, for the first time, the ALPHA experiment was able to observe the effects of gravity on antimatter atoms, namely on anti-hydrogen. The experimental strategy is based on the balancing of the gravitational force with the magnetic one and it is conceptually simple: trap and accumulate anti-hydrogen atoms in the desired region, and then slowly release them by lowering the upper and lower magnetic potentials of a vertical trap. The effect of gravity manifests as a difference in the number of annihilation events from the anti-atoms escaping through the top or bottom of the trap. The results confirmed that anti-hydrogen behaves in accordance with gravitational attraction to Earth, ruling out repulsive anti-gravity between anti-hydrogen and the Earth. This measurement gives a test of the weak equivalence principle (WEP), a fundamental principle of Einstein's general theory of relativity, on antimatter. An overview of the experimental setup of the ALPHA experiment and details about the measurement procedure and the data analysis will be given.
