Paper detail

The strangest lifetime: A bizarre story of $τ(Ω_c^0)$

For a long time it has been established both experimentally and theoretically that $Ω_c^0$ is shortest-lived among the four singly charmed baryons which decay weakly. The situation was dramatically changed in 2018 when LHCb reported a new measurement of the $Ω_c^0$ lifetime using semileptonic $b$-hadron decays. The value is nearly four times larger than the previous world average of $τ(Ω_c^0)$ and it is confirmed by the most recent LHCb measurement with the prompt production. In this viewpoint article, we review the status and point out that heavy quark expansion (HQE) fails to apply to $Ω_c^0$ to the order of $1/m_c^4$. By demanding a sensible HQE for $Ω_c^0$ will lead to a lifetime of $Ω_c^0$ longer than $Λ_c^+$.