Quark-level analogue of nuclear fusion with doubly-heavy baryons

The recent discovery by LHCb of the first doubly-charmed baryon ${\mathrm{\Xi }}_{cc}^{++}=ccu$ at $3621.40\pm 0.78$ MeV implies a large binding energy $\sim 130$ MeV between the two $c$ quarks. This strong binding enables a quark-rearrangement exothermic reaction $,\Lambda_c \Lambda_c \to \Xi_{cc}^{++},n,$with$Q=12$ MeV, which is a quark-level analogue of deuterium-tritium nuclear fusion reaction $DT\to {}^4\mathrm{H}\mathrm{e}n$. Due to much larger binding energy between two $b$ quarks $\sim 280$ MeV, the analogous reaction with $b$ quarks, ${\mathrm{\Lambda }}_b{\mathrm{\Lambda }}_b\to {\mathrm{\Xi }}_{bb}N$ is expected to have a dramatically larger $Q$-value, $138\pm 12$ MeV.