Track processes influence on muonium formation in solid argon

Kinetic equation has been solved analytically for electron density evolution in the positive muon track formed in solid argon. Muon polarization dependence on time due to muonium formation was estimated numerically. The hot (non-thermalized) electrons were shown to contribute to muonium fast formation. Additionally, it was shown that in the case of applied external electric field, the electron mobility estimations on the basis of μSR experiments could contradict to well-known data for thermal mobility. This is due to both electron heating by external electric field and muonium formation in the non-thermalized electron capture by muon.