Elementary-Particle Treatment of Muon Capture inO16

Abstract

The rate of the muon-capture process in ${\mathrm{O}}^{16}$ which leads to the $2^{-}$ ground state of ${\mathrm{N}}^{16}$ is calculated treating the initial and final nuclei as "elementary" particles. Nuclear form factors are evaluated on the basis of the conserved-vector-current and partially-conserved-axial-vector-current hypotheses using experimental data on the corresponding beta-decay and inelastic-electron-scattering processes. The resultant calculated rate ${\left[\Gamma \right({\mu }^{-}+{\mathrm{O}}^{16}\left(0^{+}\right)\to {\mathrm{N}}^{16}\left(2^{-}\right)+{\nu }_{\mu }\left)\right]}_{\mathrm{theor}}=(5.8\mathrm{}\pm 2.3)\times {10}^3$ ${\sec }^{-1\mathrm{}}$ is consistent with the measured value ${\left[\Gamma \right({\mu }^{-}+{\mathrm{O}}^{16}\left(0^{+}\right)\to {\mathrm{N}}^{16}\left(2^{-}\right)+{\nu }_{\mu }\left)\right]}_{\mathrm{exper}}=(6.3\mathrm{}\pm 0.7)\times {10}^3$ ${\sec }^{-1\mathrm{}}$ and is to be contrasted with a calculated rate of ${(12\mathrm{}\pm 2)\times 10}^3$ ${\sec }^{-1\mathrm{}}$ obtained on the basis of a nuclear-model impulse-approximation approach.