Direct Measurement of the Ratio between the Transfer Rates of Muons fromμpandμdAtoms to Xenon in a Gaseous Target of Deuterated Hydrogen

Abstract

The ratio $B$ between the transfer rates ${\lambda }_{\mu p,\mathrm{Xe}}$ and ${\lambda }_{\mu d,\mathrm{Xe}}$ of muons from $\mu p$ and $\mu d$ muonic atoms to xenon has been directly measured by stopping negative muons in a gaseous target containing deuterated hydrogen and small xenon admixtures at a total pressure of 6 atm abs. and at 293 °K. The results were obtained by analyzing the differential time distribution of the decay electrons coming from muons stopped within the gaseous mixture. In this way one gets $B=1.98\mathrm{}\pm 0.12$, which supports the dependence of the transfer rates on the mass of the primary muonic atom within 6%. More precise values for ${\lambda }_{\mu p,\mathrm{Xe}}$ and ${\lambda }_{\mu d,\mathrm{Xe}}$ are also given, i.e., ${\lambda }_{\mu p,\mathrm{Xe}}=(4.53\mathrm{}\pm 0.15)\times {10}^{11}$ ${\sec }^{-1\mathrm{}}$ and ${\lambda }_{\mu d,\mathrm{Xe}}=(2.30\mathrm{}\pm 0.17)\times {10}^{11}$ ${\sec }^{-1\mathrm{}}$. A lower limit for the scattering cross section $\sigma$ of $\mu d$ atoms against xenon is obtained, i.e., $\sigma \ge {10}^{-15\mathrm{}}$ ${\mathrm{cm}}^2$.