Comments on arXiv:1011.3046 "Muon Capture Constraints on Sterile Neutrino Properties"

Understand

It has been very recently reported (McKeen, Pospelov, arXive:1011.3046) that the parameter region suggested for an explanation of the neutrino oscillation results from the LSND, KARMEN and MiniBooNE experiments in terms of the production and radiative decay of a heavy neutrino ($\nu_h$) can be ruled out based on the measurements of the radiative muon capture (RMC) on hydrogen.

• We calculate limits on mixing strength between the $\nu_h$ and $\nu_\mu$ by using results of this experiment, and find out that they essentially disagree with the reported bounds.
• For the $\nu_h$ with mass 60 MeV our limit is worse by a factor of 5, while for 90 MeV it is worse by about two orders of magnitude.
• We also noticed the wrong behavior of the reported limit curve in the low mass region.