Lawrence Berkeley National Laboratory

The ratios of the branching fractions of the decays Λc+ → pπ−π+, Λc+ → pK−K+, and Λc+ → pπ−K+ with respect to the Cabibbo-favoured Λc+ → pK−π+ decay are measured using proton-proton collision data collected with the LHCb experiment at a 7 TeV centre-of-mass energy and corresponding to an integrated luminosity of 1.0 fb−1:ℬ(Λc+→p+)ℬ(Λc+→pK−π+)=(7.44±0.08±0.18)%,ℬ(Λc+→pK−K+)ℬ(Λc+→pK−π+)=(1.70±0.03±0.03)%ℬ(Λc+→pπ−K+)ℬ(Λc+→pK−π+)=(0.165±0.015±0.005)%,where the uncertainties are statistical and systematic, respectively. These results are the most precise measurements of these quantities to date. When multiplied by the world-average value for ℬ(Λc+→pK−π+), the corresponding branching fractions areℬ(Λc+→p+)=(4.72±0.05±0.11±0.25)×10−3,ℬ(Λc+→pK−K+)=(1.08±0.02±0.02±0.06)×10−3,ℬ(Λc+→pπ−K+)=(1.04±0.09±0.03±0.05)×10−4,where the final uncertainty is due to ℬ(Λc+→pK−π+).[Figure not available: see fulltext.].