Simulating Antihydrogen Annihilation Distributions in ASACUSA's Cusp Trap

The hyperfine structure of hydrogen is known very precisely, and if charge, parity and time reversal (CPT) symmetry holds, antihydrogen will have the exact same spectrum. CPT violation may help explain the baryon asymmetry, the mysterious and presently unexplained fact that the universe contains much more matter than antimatter. The Atomic Spectroscopy And Collisions Using Slow Antiprotons (ASACUSA) Collaboration aims to measure the ground state hyperfine structure of antihydrogen in a magnetic field-free region with a precision of 1 ppm. Antiproton and positron plasmas, which are produced further upstream, are combined in the Cusp trap. We use SIMION to simulate antihydrogen trajectories in the spatially varying magnetic field of ASACUSA’s Cusp trap. We use the resulting annihilation distributions as a look-up table in a Python routine which accounts for plasma rotation and thermal velocity distribution. This work allows us to evaluate the antihydrogen ground state annihilation distributions for ranges of plasma properties, helping us to optimize antihydrogen production.