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

Abstract

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 B 0 → D * − π + π − π + decay relative to the B 0 → D * − π + decay is measured to be B ( B 0 → D * − π + π − π + ) B ( B 0 → D * − π + ) = 2.64 ± 0.04 ( stat ) ± 0.13 ( syst ) . The Cabibbo-suppressed decay B 0 → D * − K + π − π + is observed for the first time, and the measured ratio of branching fractions is B ( B 0 → D * − K + π − π + ) B ( B 0 → 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 B 0 → D * − π + π − π + final state is also performed, and the first observation of the B 0 → ¯¯¯ D 1 ( 2420 ) 0 π + π − decay is reported with the ratio of branching fractions B ( B 0 → ( ¯¯¯ D 1 ( 2420 ) 0 → D * − π + ) π − π + ) B ( B 0 → 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 ( B 0 → ¯¯¯ D 1 ( 2420 ) 0 π − π + ) and B ( ¯¯¯ D 1 ( 2420 ) 0 → D * − π + ) .