Letter | Published:

Quark-level analogue of nuclear fusion with doubly heavy baryons

Nature volume 551, pages 8991 (02 November 2017) | Download Citation

This article has been updated


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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  • 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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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.

Author information


  1. School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel

    • Marek Karliner
  2. Enrico Fermi Institute and Department of Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637, USA

    • Jonathan L. Rosner


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Both authors contributed equally to this work.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Marek Karliner.

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

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