First observation of the decay Bc+→J/ψπ +π -π +

Abstract

The decay Bc+→J/ψπ +π -π + is observed for the first time, using 0.8fb -1 of pp collisions at √s=7TeV collected by the LHCb experiment. The ratio of branching fractions B(Bc+→J/ψπ +π -π +)/ B(Bc+→J/ψπ +) is measured to be 2.41±0.30±0. 33, where the first uncertainty is statistical and the second is systematic. The result is in agreement with theoretical predictions. © 2012 CERN.