Measurements of the branching fractions of Λc+ → pπ−π+, Λc+ → pK−K+, and Λc+ → pπ−K+

The ratios of the branching fractions of the decays Λ+c→pπ−π+, Λ+c→pK−K+, and Λ+c→pπ−K+ with respect to the Cabibbo-favoured Λ+c→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: (Λ+c→pπ−π+)(Λ+c→pK−π+)=(7.44±0.08±0.18)%,(Λ+c→pK−K+)(Λ+c→pK−π+)=(1.70±0.03±0.03)%,(Λ+c→pπ−K+)(Λ+c→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 (Λ+c→pK−π+), the corresponding branching fractions are (Λ+c→pπ−π+)=(4.72±0.05±0.11±0.25)×10−3,(Λ+c→pK−K+)=(1.08±0.02±0.02±0.06)×10−3,(Λ+c→pπ−K+)=(1.04±0.09±0.03±0.05)×10−4, where the final uncertainty is due to (Λ+c→pK−π+).