First observation of the decay Bc+ to J/psi pi+pi-pi+
  The decay Bc+ --> J/psi pi+pi-pi+ is observed for the first time, using 0.8 fb-1 of pp collisions at sqrt{s}=7 TeV collected by the LHCb experiment. The ratio of branching fractions BR(Bc+ --> J/psi pi+pi-pi+)/BR(B_c+ --> J/psi pi+) is measured to be 2.41+-0.30+-0.33, where the first uncertainty is statistical and the second systematic. The result is in agreement with theoretical predictions. 
LHCb collaboration: R. Aaij, C. Abellan Beteta, B. Adeva, M. Adinolfi,   C. Adrover, A. Affolder, Z. Ajaltouni, J. Albrecht,...
hep-ex