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 $1\mathrm{/}{m}_c$ series. Our improved results confirm the expected hierarchy $$\tau ({\mathrm{\Xi }}_{cc}^{+})<\tau ({\mathrm{\Omega }}_{cc}^{+})<\tau ({\mathrm{\Xi }}_{cc}^{++}),$$ while the predicted lifetime $\tau ({\mathrm{\Xi }}_{cc}^{++})=0.32\pm 0.05_{-0.07}^{+0.08}\text{ps}$ is consistent with the recent LHCb determination. We provide predictions for the lifetime ratios of the ${\mathrm{\Xi }}_{cc}^{+}$ and ${\mathrm{\Omega }}_{cc}^{+}$ baryons relative to the ${\mathrm{\Xi }}_{cc}^{++}$ baryon, namely $\tau ({\mathrm{\Xi }}_{cc}^{+})\mathrm{/}\tau ({\mathrm{\Xi }}_{cc}^{++})=0.22\pm 0.05\pm 0.04$ and $\tau ({\mathrm{\Omega }}_{cc}^{+})\mathrm{/}\tau ({\mathrm{\Xi }}_{cc}^{++})=0.52\pm 0.13_{-0.02}^{+0.03}$.