First Observation of the Decay B+c→J/ψπ+π−π+

Abstract

The decay B+c→J/ψπ+π−π+ is observed for the first time, using 0.8 fb−1 of pp collisions at √s=7 TeV collected by the LHCb experiment. The ratio of branching fractions B(B+c→J/ψπ+π−π+)/B(B+c→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.