Using 567 pb-1 of data collected with the BESIII detector at a center-of-mass energy of s=4.599 GeV, near the Λc+Λc- threshold, we study the singly Cabibbo-suppressed decays Λc+→pπ+π- and Λc+→pK+K-. By normalizing with respect to the Cabibbo-favored decay Λc+→pK-π+, we obtain ratios of branching fractions: [B(Λc+→pπ+π-)/B(Λc+→pK-π+)]=(6.70±0.48±0.25)%, [B(Λc+→pφ)/B(Λc+→pK-π+)]=(1.81±0.33±0.13)%, and [B(Λc+→pK+Knon-φ-)/B(Λc+→pK-π+)]=(9.36±2.22±0.71)×10-3, where the uncertainties are statistical and systematic, respectively. The absolute branching fractions are also presented. Among these measurements, the decay Λc+→pπ+π- is observed for the first time, and the precision of the branching fraction for Λc+→pK+Knon-φ- and Λc+→pφ is significantly improved.
Bibliographical noteFunding Information:
The BESIII Collaboration thanks the staff of BEPCII, the IHEP computing center, and the supercomputing center of USTC for their strong support. This work is supported in part by National Key Basic Research Program of China under Contract No. 2015CB856700; National Natural Science Foundation of China (NSFC) under Contracts No. 11125525, No. 11235011, No. 11322544, No. 11335008, No. 11425524, No. 11322544, No. 11375170, No. 11275189, No. 11475169, and No. 11475164; the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; the CAS Center for Excellence in Particle Physics (CCEPP); the Collaborative Innovation Center for Particles and Interactions (CICPI); Joint Large-Scale Scientific Facility Funds of the NSFC and CAS under Contracts No. 11179007, No. U1232201, and No. U1332201; CAS under Contracts No. KJCX2-YW-N29 and No. KJCX2-YW-N45; 100 Talents Program of CAS; INPAC and Shanghai Key Laboratory for Particle Physics and Cosmology; German Research Foundation DFG under Collaborative Research Center Contract No. CRC-1044, FOR 2359; Istituto Nazionale di Fisica Nucleare, Italy; Ministry of Development of Turkey under Contract No. DPT2006K-120470; Russian Foundation for Basic Research under Contract No. 14-07-91152; U.S. Department of Energy under Contracts No. DE-FG02-04ER41291, No. DE-FG02-05ER41374, No. DE-FG02-94ER40823, and No. DESC0010118; U.S. National Science Foundation; University of Groningen (RuG) and the Helmholtz Centre for Heavy Ion Research GmbH (GSI), Darmstadt; and WCU Program of National Research Foundation of Korea under Contract No. R32-2008-000-10155-0.
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