Measurement of the lifetime of Ω ⁰_c

Summary

We present a first measurement of the lifetime of the Ω ⁰_c using three independent data samples from two different decay modes. Using a Σ⁻ beam of 340 GeV/c we have obtained clean signals for the Ω ⁰_c decaying into Ξ⁻ K⁻ π⁺ π⁺ and Ω⁻ π⁺ π⁻ π⁺. The short lifetime of the Ω ⁰_c is demonstrated by a clear enhancement of the signals at short decay lengths. Using a continuous maximum-likelihood method we determined the lifetime to be τ_Ω ⁰_c =55 ⁺⁷⁰₋₁₁ (stat) ⁺¹⁸₋₂₃ (syst) fs. This makes the Ω ⁰_c the shortest-living weakly decaying particle observed so far.