Search for the rare decay K-s(0) -> mu(+)mu(-)

A search for the decay K-s(0) -> mu(+)mu(-) is performed, based on a data sample of 1.0fb(-1) of pp collisions at root 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(K-S(0) -> mu(+)mu(-)) < 11(9) x 10(-9) at 95 (90)% confidence level. This limit is a factor of thirty below the previous measurement.