Observation of Λ0b → D+pπ−π− and Λ0b → D∗+pπ−π− decays

The multihadron decays Λ0b → D+pπ−π− and Λ0b → D∗+pπ−π− are observed
in data corresponding to an integrated luminosity of 3 fb−1, collected in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV by the LHCb detector. Using the decay Λ0b → Λ+c π+π−π− as a normalisation channel, the ratio of branching fractions is measured to be B(Λ0b → D+pπ−π−)B(Λ0b → Λ+
c π+π−π−) × B(D+ → K−π+π+)B(Λ+c → pK−π+) = (5.35 ± 0.21 ± 0.16) % ,
where the first uncertainty is statistical and the second systematic. The ratio of branching fractions for the Λ0b → D∗+pπ−π− and Λ0b → D+pπ−π− decays is found to be B(Λ0b → D∗+pπ−π−)B(Λ0b → D+pπ−π−) ×(B(D∗+ → D+π0) + B(D∗+ → D+γ))= (61.3 ± 4.3 ± 4.0) % .