ISOTOPE DEPENDENCE OF PARTICLE-DECAY RATES OF MUONIC MOLECULAR-IONS (DHE-3,4-MU)J=1 BELOW (D-MU)(1S-)HE-3,4 THRESHOLD

Rates of particle-emitting decay of the resonant state of the muonic molecular ion (dHemu)J=1 lying below the (dmu)1s-He threshold can decay to the d-Hemu scattering state. The resonant state is estimated by scattering calculations with the non-adiabatic coupled-rearrangement-channel method. Strong isotope dependence of the decay rates of (dHe-3mu)J=1 and (dHe-4mu)J=1 is predicted, though the calculated radiative decay rates of the states are almost the same. In (dHe-3mu)J=1, the particle decay width is three times larger than the radiative decay width, while the two types of decay widths are almost the same in (dHe-4mu)j=1. This results in a strong hindrance of the branching ratio of the radiative decay of (dHe-3mu)J=1 compared with the case of (dHe-4mu)J=1. This is consistent with a recent observation of the radiative decay of the two molecular states.