A search for $B_{ (s)}^{ 0} \to K_{ S}^{ 0} K^{ *}(892)^{ 0}$ decays is performed using $pp$ collision data, corresponding to an integrated luminosity of $1.0~\text{ fb}^{ -1}$, collected with the LHCb detector at a centre-of-mass energy of $7~\text{ TeV}$. The $B_{ s}^{ 0} \to K_{ S}^{ 0} K^{ *}(892)^{ 0}$ decay is observed for the first time, with a significance of 7.1 standard deviations. The branching fraction is measured to be \begin{ equation*} \mathcal{ B}(B_{ s}^{ 0} \to \bar{ K}^{ 0} K^{ *}(892)^{ 0}) + \mathcal{ B}(B_{ s}^{ 0} \to K^{ 0} \bar{ K}^{ *}(892)^{ 0}) = (16.4 \pm 3.4 \pm 2.3) \times 10^{ -6},\\ \end{ equation*} where the first uncertainty is statistical and the second is systematic. No evidence is found for the decay $B^{ 0} \to K_{ S}^{ 0} K^{ *}(892)^{ 0}$ and an upper limit is set on the branching fraction, $\mathcal{ B}(B^{ 0} \to \bar{ K}^{ 0} K^{ *}(892)^{ 0}) + \mathcal{ B}(B^{ 0} \to K^{ 0} \bar{ K}^{ *}(892)^{ 0}) < 0.96 \ \times 10^{ -6}, $ at $90\,\% $ confidence level. All results are consistent with Standard Model predictions.
Categories: hep-ex