Final results of μp capture rate Λ_S and pseudoscalar coupling g_p

The MuCap experiment is installed on the PSI accelerator that is able to generate enough muons. We present the final results of muon capture on proton μ^- + p → ν_μ + n, which were obtained by the MuCap Collaboration at the Paul Scherrer Institute. The singlet μp capture rate Λ_S is determined as the difference between the lifetimes of μp and μ⁺. Our result is Λ_S = [714.9 ± 5.4(stat) ± 5.1(syst)] s^-1 in excellent agreement with the prediction of chiral perturbation theory Λ_S = (712.7 ± 4.3) s^-1. The induced pseudoscalar coupling constant results as g_p = 8.06 ± 0.48(exp) ± 0.28(th) whereas the predicted value is 8.26 ± 0.23. (authors)