TheΛb0→Λc+K+K?π?decay is observed for the first time using a data sample of proton-proton collisions at centre-of-mass energies ofs=7and8TeVcollected by the LHCb detector, corresponding to an integrated luminosity of3fb?1. The ratio of branching fractions between theΛb0→Λc+K+K?π?and theΛb0→Λc+Ds?decays is measured to beB(Λb0→Λc+K+K?π?)B(Λb0→Λc+Ds?)=(9.26±0.29±0.46±0.26)×10?2,where the first uncertainty is statistical, the second systematic and the third is due to the knowledge of theDs?→K+K?π?branching fraction. No structure on the invariant mass distribution of theΛc+K+system is found, consistent with no open-charm pentaquark signature.
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机译：第一次使用质量 - 质子碰撞的数据样本首次观察到λb0→λc+ k + k？π≤衰减。由LHCB检测器的质量中心的质量能量的数据样本相对应为3FBΔ1的集成光度。在λb0→λc+ k + k =πΔ和λb0→λc+ ds之间的分支级分的比率测量为beb（λb0→λc+ k k =πα≤b≤b_）b（λb0→λc+ ds？）= （9.26±0.29±0.46±0.26）×10？2，其中第一个不确定性是统计学，第二系统和第三个是由于有关的知识？→K + k？π？分支级分。没有找到λc+ k +系统的不变质量分布的结构，与没有开放式魅力Pentaquark签名一致。
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