Study of J/ψJ/ψ decays into ηK*0K¯*0

We report the first observation of J/ψ→ηK*0K¯*0 decay in a J/ψJ/ψ sample of 58 million events collected with the BESII detector. The branching fraction is determined to be (1.15±0.13±0.22)×10−3(1.15±0.13±0.22)×10−3. The selected signal event sample is further used to search for the Y(2175)Y(2175) resonance through J/ψ→ηY(2175)J/ψ→ηY(2175), Y(2175)→K*0K¯*0. No evidence of a signal is seen. An upper limit of Br(J/ψ→ηY(2175))⋅Br(Y(2175)→K*0K¯*0)<2.52×10−4 is set at the 90% confidence level.