Improved limits on nuebar emission from mu+ decay
Abstract
We investigated mu+ decays at rest produced at the ISIS beam stop target. Lepton flavor (LF) conservation has been tested by searching for \nueb via the detection reaction p(\nueb,e+)n. No \nueb signal from LF violating mu+ decays was identified. We extract upper limits of the branching ratio for the LF violating decay mu+ -> e+ \nueb \nu compared to the Standard Model (SM) mu+ -> e+ nue numub decay: BR < 0.9(1.7)x10^{-3} (90%CL) depending on the spectral distribution of \nueb characterized by the Michel parameter rho=0.75 (0.0). These results improve earlier limits by one order of magnitude and restrict extensions of the SM in which \nueb emission from mu+ decay is allowed with considerable strength. The decay \mupdeb as source for the \nueb signal observed in the LSND experiment can be excluded.
Cite
@article{arxiv.hep-ex/0302017,
title = {Improved limits on nuebar emission from mu+ decay},
author = {B. Armbruster and I. M. Blair and B. A. Bodmann and N. E. Booth and G. Drexlin and J. A. Edgington and C. Eichner and K. Eitel and E. Finckh and H. Gemmeke and J. Hössl and T. Jannakos and P. Jünger and M. Kleifges and J. Kleinfeller and W. Kretschmer and R. Maschuw and C. Oehler and P. Plischke and J. Reichenbacher and C. Ruf and M. Steidl and J. Wolf and B. Zeitnitz},
journal= {arXiv preprint arXiv:hep-ex/0302017},
year = {2009}
}
Comments
10 pages, including 1 figure, 1 table