Control of Positronium Excitation Laser for the Production of Positive Antihydrogen in GBAR

This summer I assisted the GBAR experiment with several aspects of the laser system used for the excitation of positronium. GBAR (Gravitational Behavior of Antihydrogen at Rest) aims precisely determine how antimatter moves due to the Earth's gravity. At it's core, the premise of this measurement is simple enough that it be described by basic kinematics: A neutral anti-particle is dropped from a known height into free fall, after some known time a signal is detected when it annihilates at one end of a free fall chamber. You may then ask what the gravitational strength of the pull on that particle must have been to have seen a signal at that time. Producing antihydrogen is dicult, generating positive antihydrogen has not been done. Once positive antihydrogen is produced, getting enough events to make a statistically signicant conclusion is a challenge itself. This experiment will test CPT, the weak equivalence principle for antimatter, and could conrm or deny the existence of repulsive gravity (anti-gravity) while developing novel techniques for probing antimatter. Overcoming these challenges opens new doors in antimatter physics and will directly conrm or deny fundamental principles of physics.