Measurement of the differential branching fraction of the decay Lambda(0)(b) -> Lambda mu(+) mu(-)

The differential branching fraction of the decay Lambda(0)(b) -> Lambda mu(+) mu(-) is measured as a function of the square of the dimuon invariant mass, q(2). A yield of 78 +/- 12 Lambda(0)(b) -> Lambda mu(+) mu(-) decays is observed using data, corresponding to an integrated luminosity of 1.0 fb(-1), collected by the LHCb experiment at a centre-of-mass energy of 7 TeV. A significant signal is found in the q(2) region above the square of the J/psi mass, while at lower-q(2) values upper limits are set on the differential branching fraction. Integrating the differential branching fraction over q(2), while excluding the J/psi and psi(2S) regions, gives a branching fraction of B(Lambda(0)(b) -> Lambda mu(+) mu(-)) = (0.96 +/- 0.16(stat) +/- 0.13(syst) +/- 0.21 (norm)) x 10(-6), where the uncertainties are statistical, systematic and due to the normalisation mode, Lambda(0)(b) -> J/psi Lambda, respectively. (C) 2013 CERN. Published by Elsevier B.V. All rights reserved.