Study of B0→D* -^π+π^-π+ and B0→D*-^K+π-^π+ decays

Using proton-proton collision data collected by the LHCb experiment at √s=7 TeV, corresponding to an integrated luminosity of 1.0 fb -1, the ratio of branching fractions of the B0→D* -π+π-π+ decay relative to the B0→D*-π+ decay is measured to be B(B0→D*-π+π-π+) B(B0→D*-π+)=2.64±0.04(stat)±0. 13(syst). The Cabibbo-suppressed decay B0→D*-K +π-π+ is observed for the first time, and the measured ratio of branching fractions is B(B0→D* -K+π-π+)B(B0→D* -π+π-π+)=(6.47±0. 37(stat)±0.35(syst))×10-2. A search for orbital excitations of charm mesons contributing to the B0→D* -π+π-π+ final state is also performed, and the first observation of the B0→D̄1(2420)0π+π- decay is reported with the ratio of branching fractions B(B0→(D̄1(2420)0→D*-π+) π-π+)B(B0→D*-π +π-π+)=(2.04±0.42(stat)±0. 22(syst))×10-2, where the numerator represents a product of the branching fractions B(B0→D̄1(2420)0π -π+) and B(D̄1(2420)0→D*-π+). © 2013 CERN. Published by the American Physical Society under the terms of the.