This substance was first synthesized by using the LEAR apparatus to launch particles at xenon clusters. The ALPHA project uses minimum-B traps to contain this substance. One can analyze the 1S-2S transitions in this substance's absorption spectrum to confirm the CPT theorem. One method of synthesizing this substance involved collecting radioactive sodium in a Penning trap in the ATRAP and ATHENA experiments. The fact that this substance is (*) rare in the universe is the subject of the baryon asymmetry problem. When one atom of this substance collides with a hydrogen atom, it forms two gamma rays and two pions in an a
This substance was first synthesized by using the LEAR apparatus to launch particles at xenon clusters. The ALPHA project uses minimum-B traps to contain this substance. One can analyze the 1S-2S transitions in this substance's absorption spectrum to confirm the CPT theorem. One method of synthesizing this substance involved collecting radioactive sodium in a Penning trap in the ATRAP and ATHENA experiments. The fact that this substance is (*) rare in the universe is the subject of the baryon asymmetry problem. When one atom of this substance collides with a hydrogen atom, it forms two gamma rays and two pions in an annihilation reaction. For 10 points, name this atom which consists of a single positron orbiting an antiproton, the lightest element of antimatter.
This substance was first synthesized by using the LEAR apparatus to launch particles at xenon clusters.
antihydrogen [or h-bar; accept antimatter until "orbiting", prompt after]