Observation ofΛpmass enhancement in the reactionK−d→Λpπ+π−π−

A study of $\Lambda p$ mass distribution is made from the analysis of bubble-chamber data of the reaction $K^{-}d\to \Lambda p{\pi }^{+}{\pi }^{-}{\pi }^{-}$ at $K^{-}$ beam momenta of 1.45 and 1.65 GeV/c. A statistically significant peak in the $\Lambda p$ mass distribution is observed at $\simeq 2130$ MeV. Another $\Lambda p$ mass peak in the region $\simeq 2195-2210$ MeV is also seen but its statistical significance depends on the choice of the background estimate.