Caliope: a search for CPT-violation in o-ps

Abstract

CALIOPE, or CP(T) Aberrant Leptons in ortho-Positronium Experiment, is a tabletop search for fundamental symmetry violations, including CP- and CPT-violation, in ortho-positronium (o-Ps). We use a tagged 22Na source adjacent to a cylinder of aerogel to generate o-Ps at the center of a cylindrical array of 24 NaI(Tl) bars. We search for CPT - violating angular correlations in the gamma rays emitted in the decay of o-Ps. With an angular acceptance of 75% of 4π, and the ability to acquire statistics over a longer period of time, CALIOPE will improve upon the limit set by previous experiments. The experimental setup can also be used in a search for CP-violation in o-Ps with the addition of an electromagnet. We describe the design of the experiment, results from a characterization of the systematics for the CPT- and CP-violating measurements, and a demonstration of the DAQ.