Experimental study ofμ-atomic andμ-molecular processes in pure helium and deuterium-helium mixtures

Abstract

We present experimental results of $\ensuremath{\mu}$-atomic and $\ensuremath{\mu}$-molecular processes induced by negative muons in pure helium and helium-deuterium mixtures. The experiment was performed at the Paul Scherrer Institute (Switzerland). We measured relative intensities of muonic x-ray $K$ series transitions in ${(\ensuremath{\mu}^{3,4}\mathrm{He})}^{*}$ atoms in pure helium as well as in helium-deuterium mixtures. The $d\ensuremath{\mu}^{3}\mathrm{He}$ radiative decay probabilities for two different helium densities in ${\mathrm{D}}_{2}+^{3}\mathrm{He}$ mixture were also determined. Finally, the ${q}_{1s}^{\mathrm{He}}$ probability for a $d\ensuremath{\mu}$ atom formed in an excited state to reach the ground state was measured and compared with theoretical calculations using a simple cascade model.