Revisiting lifetimes of doubly charmed baryons

We present updated predictions for lifetimes of doubly charmed baryons, within the heavy quark expansion, including available NLO $\alpha_s$ contributions and newly-computed terms in the $1/m_c$ series. Our improved results confirm the expected hierarchy $$\tau(\Xi_{cc}^{+}) < \tau(\Omega_{cc}^{+}) < \tau(\Xi_{cc}^{++}) \,,$$ while the predicted lifetime $\tau(\Xi_{cc}^{++}) = 0.32 \pm 0.05 ^{+0.08}_{-0.07} \,\textrm{ps}$ is consistent with the recent LHCb determination. We provide predictions for the lifetime ratios of the $\Xi_{cc}^{+}$ and $\Omega_{cc}^+$ baryons relative to the $\Xi_{cc}^{++}$ baryon, namely $\tau(\Xi_{cc}^{+})/\tau(\Xi_{cc}^{++})=0.22\pm 0.05\pm 0.04$ and $\tau(\Omega_{cc}^{+})/\tau(\Xi_{cc}^{++})=0.52\pm 0.13^{+0.03}_{-0.02}$.