Search for the rare decay K0S→μ+μ−

A search for the decay K0S→μ+μ− is performed, based on a data sample of 1.0 fb−1 of pp collisions at √ s =7 TeV collected by the LHCb experiment at the Large Hadron Collider. The observed number of candidates is consistent with the background-only hypothesis, yielding an upper limit of B(K0S→μ+μ−) < 11(9) × 10−9 at 95 (90)% confidence level. This limit is a factor of thirty below the previous measurement.