关键词: VEPP2000, SND; , 正负电子, 电子分宽度

Abstract: A search for the rare decay η′→e+e- has been performed with the SND detector at the VEPP-2000 e+e-  collider. The inverse reaction e+e-→η′  and η′ five decay chains have been used for this search. The upper limit Γ_η′→e+e-＜0.002 eV at the 90% confidence level has been set. A sensitivity of SND in a search for η→e+e- decay has been studied. For this purpose a data sample with an integrated luminosity of 108 nb^-1 collected in the centerofmass energy range 520580 MeV was analyzed. No background events for the reaction e+e-→η with decay η→π0π0π0 have been found. In the absence of background, a sensitivity to B(η→e+e-) of 10^-6 can be reached during two weeks of VEPP-2000 operation.

Key words: EPP-2000, SND, e+e-, η′, η, electronic width