Аннотация:In this Letter the decay B¯¯¯¯0s→J/ψK+K−B¯s0→J/ψK+K− is investigated. Although the J/ψϕJ/ψϕ channel is well known, final states at higher K+K−K+K− masses have not previously been studied. In the K+K−K+K− mass spectrum we observe a significant signal in the f′2(1525)f2′(1525) region as well as a non-resonant component. The ratio of the rate in a K+K−K+K− mass window of ±125±125 MeV around the f′2f2′ relative to that in the J/ψϕJ/ψϕ decay, where ϕ→K+K−ϕ→K+K−, is R=(19.4±1.8±1.0)R=(19.4±1.8±1.0)%. Our sample consists of 0.160.16 fb−1−1 collected with the LHCb detector using 7 TeV pppp collisions.