THE PROPERTIES OF THE HELIUM-MUONIC ATOMS IN THE ELECTRON EXCITED-STATES AND 4-BODY HELIUM-MUONIC IONS

The properties of muonic (mu(-)) helium (He-3, He-4 and He-infinity) a toms in the electron excited S states (L = 0) are considered. In parti cular, the hyperfine splittings have been calculated for the 1s(mu)2s( e) excited states in the (3)He(2+)mu(-)e(-) and (4)He(2+)mu(-)e(-) ato ms. The bound state spectra in the related four-body (3)He(2+)mu(-)e(- )e(-) and (4)He(2+)mu(-)e(-)e(-) ions are discussed for the first time . It follows from the estimated properties that all such systems have the two-shell (muon-electron) cluster structure. The properties of suc h systems can be found with good accuracy from the general theory of b ound state spectra in the many-shell quasi-atoms (quasi-ions), i.e. wi thout extensive numerical calculations.