Muon Transfer to Low Z Elements

Abstract

A negative muon, captured in a mixture of natural hydrogen with a small amount of another gas of atomic number Z, forms a muonic hydrogen or a muonic Z atom in an excited state. In the deexcitation process, muonic X rays are emitted. Because the cascade time is very short (of the order of 10^–12 s at 10 bar), they appear promptly with regard to the incoming muon. After deexcitation of the (μp)* system (in about 10^–10s), which occurs essentially by collisions, ¹ the (up) is atom can then disappear by muon decay with an associated rate λ₀, by formation of a pup mesomolecule (λ_pp), or by transferring the muon to deuterium (λ_d) or to the Z element (λ_pz). The total disappearance rate of the up atom, λ is then:

$$\lambda = {\lambda _{0}} + {\lambda _{{pp}}} + {\lambda _{d}} + {\lambda _{{pZ}}}$$

((1))