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

Abstract

Abstract: 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 : B(Λ + c → pπ−π +) B(Λ + c → pK−π+) = (7.44 ± 0.08 ± 0.18)%, B(Λ + c → pK−K+) B(Λ + c → pK−π+) = (1.70 ± 0.03 ± 0.03)%, B(Λ + c → pπ−K+) B(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 worldaverage value for B(Λ + c → pK−π +), the corresponding branching fractions are B(Λ + c → pπ−π +) = (4.72 ± 0.05 ± 0.11 ± 0.25) × 10−3 , B(Λ + c → pK−K+) = (1.08 ± 0.02 ± 0.02 ± 0.06) × 10−3 , B(Λ + c → pπ−K+) = (1.04 ± 0.09 ± 0.03 ± 0.05) × 10−4 ,