Charged particle spectra from ${\mu }^{-}$ capture on Al

Abstract

Published data on the emission of charged particles following nuclear muon capture are extremely limited. In addition to its interest as a probe of the nuclear response, these data are important for the design of some current searches for lepton flavor violation. This work presents momentum spectra of protons and deuterons following ${\mu }^{-}$ capture in aluminum. It is the first measurement of a muon capture process performed with a tracking spectrometer. A precision of better than 10% over the momentum range of 100--190 MeV/c for protons is obtained; for deuterons of 145--250 MeV/c the precision is better than 20%. The observed partial yield of protons with emission momenta above 80 MeV/c (kinetic energy 3.4 MeV) is $0.0322\pm 0.0007(\text{stat})\pm 0.0022(\text{syst})$ per capture, and for deuterons above 130 MeV/c (4.5 MeV) it is $0.0122\pm 0.0009(\text{stat})\pm 0.0006(\text{syst})$. Extrapolating to total yields gives $0.045\pm 0.001(\text{stat})\pm 0.003(\text{syst})\pm 0.001(\text{extrapolation})$ per capture for protons and $0.018\pm 0.001(\text{stat})\pm 0.001(\text{syst})\pm 0.002(\text{extrapolation})$ for deuterons, which are the most precise measurements of these quantities to date.

arXiv comment16 pages, 13 figures

References in corpus (9)

• Inclusive Charged--Current Neutrino--Nucleus Reactions
• Inclusive Quasi-Elastic Charged-Current Neutrino-Nucleus Reactions
• Mu2e Technical Design Report
• Precise measurement of parity violation in polarized muon decay
• Precision muon decay measurements and improved constraints on the weak interaction
• A Precision Measurement of the Muon Decay Parameters $\rho$ and $\delta$
• Precision planar drift chambers and cradle for the TWIST muon decay spectrometer
• Decay of negative muons bound in ${}^{27}$Al
• A practical way to regularize unfolding of sharply varying spectra with low data statistics

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