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Quark-level analogue of nuclear fusion with doubly heavy baryons

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Abstract

The essence of nuclear fusion is that energy can be released by the rearrangement of nucleons between the initial- and final-state nuclei. The recent discovery1 of the first doubly charmed baryon , which contains two charm quarks (c) and one up quark (u) and has a mass of about 3,621 megaelectronvolts (MeV) (the mass of the proton is 938 MeV) also revealed a large binding energy of about 130 MeV between the two charm quarks. Here we report that this strong binding enables a quark-rearrangement, exothermic reaction in which two heavy baryons (Λc) undergo fusion to produce the doubly charmed baryon and a neutron n (), resulting in an energy release of 12 MeV. This reaction is a quark-level analogue of the deuterium–tritium nuclear fusion reaction (DT → 4He n). The much larger binding energy (approximately 280 MeV) between two bottom quarks (b) causes the analogous reaction with bottom quarks () to have a much larger energy release of about 138 MeV. We suggest some experimental setups in which the highly exothermic nature of the fusion of two heavy-quark baryons might manifest itself. At present, however, the very short lifetimes of the heavy bottom and charm quarks preclude any practical applications of such reactions.

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Figure 1: Schematic depiction of quark-level exothermic fusion reactions ΛQΛQΞQQN, where Q, Q {b, c}.
Figure 2: The energy release ΔE in the quark-level fusion reactions ΛQΛQΞQQN, where Q, Q {s, c, b}, plotted against the reduced masses of the doubly heavy diquarks, μred(QQ′).

Change history

  • 30 November 2017

    Please see accompanying Erratum (http://doi.org/10.1038/nature25141). In this Letter, on the right-hand side of the fifth line of equation (2), ‘3He p’ should read ‘4He p’. This error has been corrected online.

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Acknowledgements

We thank A. Gal for calling our attention to refs 17 and 18. We thank V. Belyaev, S. Brodsky, A. Gal and T. Skwarnicki for comments.

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Both authors contributed equally to this work.

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Correspondence to Marek Karliner.

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Reviewer Information Nature thanks G. Miller and S. Stone for their contribution to the peer review of this work.

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Karliner, M., Rosner, J. Quark-level analogue of nuclear fusion with doubly heavy baryons. Nature 551, 89–91 (2017). https://doi.org/10.1038/nature24289

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