Muon capture on light isotopes measured with the Double Chooz detector

This is the authors' abstract. We don't add key points for this paper.

Using the Double Chooz detector, designed to measure the neutrino mixing angle θ₁₃, the products of μ^- capture on ¹²C,¹³C,¹⁴N, and ¹⁶O have been measured. Over a period of 489.5 days, 2.3×10⁶ stopping cosmic μ^- have been collected, of which 1.8×10⁵ captured on carbon, nitrogen, or oxygen nuclei in the inner detector scintillator or acrylic vessels. The resulting isotopes were tagged using prompt neutron emission (when applicable), the subsequent β decays, and, in some cases, β-delayed neutrons. The most precise measurement of the rate of ¹²C(μ^-,ν)¹²B to date is reported: 6.57_-0.21+0.11×10³0.28em0exs^-1, or (17.35_-0.59+0.35)% of nuclear captures. By tagging excited states emitting γs, the ground state transition rate to ¹²B has been determined to be 5.68_-0.23+0.14×10³0.28em0exs^-1. The heretofore unobserved reactions $¹²C({{μ}}^{{-}},{ν}{α})⁸Li,¹³C({{μ}}^{{-}},{ν}n{α})⁸Li$, and $¹³C({{μ}}^{{-}},{ν}n)¹²B$ are measured. Further, a population of ${β}n$ decays following stopping muons is identified with $5.5{σ}$ significance. Statistics limit our ability to identify these decays definitively. Assuming negligible production of $⁸He$, the reaction $¹³C({{μ}}^{{-}},{ν}{α})⁹Li$ is found to be present at the $2.7{σ}$ level. Limits are set on a variety of other processes.