Chemical Environmental Effects on Muon Transfer Process in Low Pressure Mixture Gases; H2+CO and H2+CO2

A muonic hydrogen atom, which consists of a negative muon and a proton, behaves as an electrically neutral particle. As such, it can approach another nucleus without Coulomb repulsion, allowing the muon to be directly transferred to inner muon levels of the nucleus and form a muonic atom. We studied muonic atom formation via this muon transfer process in two chemical environments; CO and CO2 (CO has one oxygen atom and one triple bond, and CO2 has two oxygen and two double bond), to examine the effects of the environments on muonic atom formation. The muon capture probability and intensity pattern of muonic Xrays for carbon and oxygen atoms were determined through measurement of muonic Xrays emitted after muonic atom formation. By comparing the results of CO and CO2 to each other, we found that the muon capture probabilities and initial muon quantum levels for carbon and oxygen atoms resulting from the muon transfer process do not depend on the chemical environment, though a significant effect of the chemical environmental was observed for the direct muon capture process. The effect of the chemical environmental in muonic atom formation via the muon transfer process is too small to detect statistically significant in our experimental system.