Observation of Hyperfine Transitions in Trapped Ground-State Antihydrogen

TL;DR

This paper reports the first observation of hyperfine transitions in trapped ground-state antihydrogen, confirming its properties align closely with hydrogen and demonstrating the ability to study antimatter's magnetic properties.

Contribution

It presents the first experimental detection of hyperfine transitions in trapped antihydrogen, validating theoretical predictions and experimental techniques for antimatter spectroscopy.

Findings

Hyperfine transitions observed in trapped antihydrogen

Transition frequencies match hydrogen within 4 parts in 10^3

Simulations agree with experimental measurements

Abstract

This paper discusses the first observation of stimulated magnetic resonance transitions between the hyperfine levels of trapped ground state atomic antihydrogen, confirming its presence in the ALPHA apparatus. Our observations show that these transitions are consistent with the values in hydrogen to within 4~parts~in~$10^3$. Simulations of the trapped antiatoms in a microwave field are consistent with our measurements.