Search for the rare decays Bs0→μ+μ− and B0→μ+μ−

A search for the decays Bs0→μ+μ− and B0→μ+μ− is performed with 0.37 fb−1 of pp collisions at s=7 TeV collected by the LHCb experiment in 2011. The upper limits on the branching fractions are B(Bs0→μ+μ−)<1.6×10−8 and B(B0→μ+μ−)<3.6×10−9 at 95% confidence level. A combination of these results with the LHCb limits obtained with the 2010 dataset leads to B(Bs0→μ+μ−)<1.4×10−8 and B(B0→μ+μ−)<3.2×10−9 at 95% confidence level.