AbstractThe multihadron decays Λb0
Λ
b
0
→ D+pπ−π− and Λb0
Λ
b
0
→ 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 Λb0
Λ
b
0
→ Λc+
Λ
c
+
π+π−π− as a normalisation channel, the ratio of branching fractions is measured to beB(Λb0→Λc0π+π−π−)B(Λb0→D+pπ−π−)×B(Λc0→pK−π−)B(D+→K−π+π+)=(5.35±0.21±0.16)%,
B
Λ
b
0
→
D
+
p
π
−
π
−
B
Λ
b
0
→
Λ
c
0
π
+
π
−
π
−
×
B
D
+
→
K
−
π
+
π
+
B
Λ
c
0
→
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 Λb0
Λ
b
0
→ D*+pπ−π− and Λb0
Λ
b
0
→ D+pπ−π− decays is found to beB(Λb0→D+pπ−π−)B(Λb0→D∗+pπ−π−)×(B(D∗+→D+π0)+B(D∗+→D+γ))=(61.3±4.3±4.0)%.
B
Λ
b
0
→
D
∗
+
p
π
−
π
−
B
Λ
b
0
→
D
+
p
π
−
π
−
×
B
D
∗
+
→
D
+
π
0
+
B
D
∗
+
→
D
+
γ
=
61.3
±
4.3
±
4.0
%
.
</jats:p