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

TL;DR

This paper explores quark-level analogues of nuclear fusion reactions involving doubly-heavy baryons, revealing potential for reactions with significantly higher energy release due to stronger quark binding energies.

Contribution

It introduces the concept of quark-rearrangement reactions as analogues to nuclear fusion, highlighting the impact of heavy quark binding energies on reaction energetics.

Findings

The $\, ext{Λ}_c ext{Λ}_c o ext{Ξ}_{cc}^{++} ext{n} ext{ reaction has a Q-value of about 12 MeV.

The analogous reaction with bottom quarks has a Q-value of approximately 138 MeV.

Stronger binding energies in bottom quarks lead to larger energy releases in these reactions.

Abstract

The recent discovery by LHCb of the first doubly-charmed baryon $\Xi_{cc}^{++} = ccu$ 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 $DT\to {}^4{\rm He}\,n$. Due to much larger binding energy between two $b$ quarks $\sim 280$ MeV, the analogous reaction with $b$ quarks, $\,\Lambda_b \Lambda_b \to \Xi_{bb}\,N\,$ is expected to have a dramatically larger $Q$-value, $138\pm 12$ MeV.