Measurement of eta meson decays into lepton-antilepton pairs

Berlowski, M.; Kullander, S.; Clement, H.; Tegnér, P.-E.; Lindberg, K.; Petukhov, Y.; Morosov, B.; Gustafsson, L.; Ekström, C.; Bondar, A.; Ivanov, G.; Skorodko, T.; Johansson, T.; Calén, H.; Pettersson, H.; Wagner, G. J.; Höistad, B.; Thörngren Engblom, P.; Stepaniak, J.; Oelert, W.; Gerén, L.; Zabierowski, J.; Koch, I.; Shafigullin, R.; Demirörs, L.; Tikhomirov, V.; Laukhin, I. V.; Kuzmin, A.; Sopov, V.; Keleta, S.; Jiganov, E.; Shwartz, B.; Kuznetsov, A.; Wolke, M.; Bashkanov, D.; Zartova, I.; Yamamoto, A.; Scobel, W.; Fransson, K.; Zlománczuk, J.; Turowiecki, A.; Ruber, R.J.M.Y.; Jacewicz, M.; Povtorejko, A.; Pauly, C.; Bargholtz, Chr.; Marciniewski, P.; Meier, R.; Schönning, K.; Cappellaro, F.; Bogolawsky, D.; Kupsc, A.

doi:10.1103/PhysRevD.77.032004

Measurement of eta meson decays into lepton-antilepton pairs

Berlowski, M. ; Bargholtz, C. ; Bashkanov, D. ; Bogolawsky, D. ; Bondar, A. ; Calén, H. ; Cappellaro, F. ; Clement, H. ; Demirörs, L. ; Ekström, C. ; Fransson, K. ; Gerén, L. ; Gustafsson, L. ; Höistad, B. ; Ivanov, G. ; Jacewicz, M. ; Jiganov, E. ; Johansson, T. ; Keleta, S. ; Koch, I. ; Kullander, S. ; Kupsc, A. ; Kuzmin, A. ; Kuznetsov, A. ; Laukhin, I. V. ; Lindberg, K. ; Marciniewski, P. ; Meier, R. ; Morosov, B. ; Oelert, W.FZJ* ; Pauly, C.FZJ* ; Pettersson, H. ; Petukhov, Y. ; Povtorejko, A. ; Ruber, R. J. M. Y. ; Schönning, K. ; Scobel, W. ; Shafigullin, R. ; Shwartz, B. ; Skorodko, T. ; Sopov, V. ; Stepaniak, J. ; Tegnér, P.-E. ; Thörngren Engblom, P. ; Tikhomirov, V. ; Turowiecki, A. ; Wagner, G. J. ; Wolke, M.FZJ* ; Yamamoto, A. ; Zabierowski, J. ; Zartova, I. ; Zlománczuk, J.

2008
Soc. [S.l.]

Physical review / D 77(3), 032004 (2008) [10.1103/PhysRevD.77.032004]

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Please use a persistent id in citations: http://hdl.handle.net/2128/10488 doi:10.1103/PhysRevD.77.032004

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 9.7x10(-5) (90% CL). The branching ratio for the decay eta -> e(+)e(-)gamma is determined to (7.8 +/- 0.5(stat)+/- 0.8(syst))x10(-3) in agreement with world average value. An upper limit (90% CL) for the branching ratio for the eta -> e(+)e(-) decay is 2.7x10(-5) and a limit for the sum of the eta ->mu(+)mu(-)mu(+)mu(-) and eta ->pi(+)pi(-)mu(+)mu(-) decays is 3.6x10(-4).

Keyword(s): 0.893 GeV ; Uppsala CELSIUS Stor ; eta --> 2lepton+ 2lepton- ; eta --> 2muon+ 2muon- ; eta --> 2positron 2electron ; eta --> pi+ pi- muon+ muon- ; eta --> positron electron photon ; eta --> positron electron ; eta: branching ratio ; eta: decay modes ; eta: hadroproduction ; eta: leptonic decay ; eta: semileptonic decay ; experimental results ; lepton: pair production ; magnetic spectrometer: experimental results ; p deuteron --> helium-3 eta ; p deuteron: exclusive reaction ; upper limit

Classification:

Note: Record converted from VDB: 12.11.2012; 9 pages, 10 Postscript figures, uses revtex4.sty, revised version after referee comments; conclusions unchanged

Contributing Institute(s):

Research Program(s):

Physik der Hadronen und Kerne (P53)

Experiment(s):

WASA (Wide Angle Shower Apparatus) at COSY

Appears in the scientific report 2008

Database coverage:
OpenAccess

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