Search for D(s)+ → π+ μ+ μ− and D(s)+ → π− μ+ μ+ Decays

A search for non-resonant D(s)+ → π+ μ+ μ− and D(s)+ → π− μ+ μ+ decays is performed using proton-proton collision data, corresponding to an integrated luminosity of 1.0 fb^−1, at √s = 7 TeV recorded by the LHCb experiment in 2011. No signals are observed and the 90% (95%) confidence level (CL) limits on the branching fractions are found to be B(D+ → π+ μ+ μ−) < 7.3(8.3) x 10^−8, B(Ds+ → π+ μ+ μ−) < 4.1(4.8) x 10^−7, B(D+ → π− μ+ μ+) < 2.2(2.5) x 10^−8, B(Ds+ → π− μ+ μ+) < 1.2(1.4) x 10^−7. These limits are the most stringent to date.