Measurement of eta meson decays into lepton-antilepton pairs
High Energy Physics - Experiment
2013-05-29 v3
Abstract
A search for rare lepton decays of the eta meson was performed using the WASA detector at CELSIUS. Two candidates for double Dalitz decay eta->e+e-e+e- events are reported with a background of 1.3+/-0.2 events. This allows to set an upper limit to the branching ratio of 9.7E-5 (90% CL). The branching ratio for the decay eta->e+e-gamma is determined to (7.8+/-0.5 stat+/-0.8 syst)E-3. An upper limit (90% CL) for the branching ratio for the eta->e+e- decay is 2.7E-5 and a limit for the sum of the eta->mu+mu-mu+mu- and eta->pi+pi-mu+mu- decays is 3.6E-4.
Keywords
Cite
@article{arxiv.0711.3531,
title = {Measurement of eta meson decays into lepton-antilepton pairs},
author = {WASA Collaboration and M. Berłowski and Chr. Bargholtz and M. Bashkanov and D. Bogoslawsky and A. Bondar and H. Calén and F. Cappellaro and H. Clement and L. Demirörs and C. Ekström and K. Fransson and L. Gerén and L. Gustafsson and B. Höistad and G. Ivanov and M. Jacewicz and E. Jiganov and T. Johansson and S. Keleta and I. Koch and S. Kullander and A. Kupść and A. Kuzmin and A. Kuznetsov and I. V. Laukhin and K. Lindberg and P. Marciniewski and R. Meier and B. Morosov and W. Oelert and C. Pauly and H. Pettersson and Y. Petukhov and A. Povtorejko and R. J. M. Y. Ruber and K. Schönning and W. Scobel and R. Shafigullin and B. Shwartz and T. Skorodko and V. Sopov and J. Stepaniak and P. -E. Tegnér and P. Thörngren Engblom and V. Tikhomirov and A. Turowiecki and G. J. Wagner and M. Wolke and A. Yamamoto and J. Zabierowski and I. Zartova and J. Złomańczuk},
journal= {arXiv preprint arXiv:0711.3531},
year = {2013}
}
Comments
9 pages, 10 Postscript figures, uses revtex4.sty, revised version after referee comments; conclusions unchanged