School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
Enrico Fermi Institute and Department of Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637, USA.
Nature. 2017 Nov 1;551(7678):89-91. doi: 10.1038/nature24289.
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 discovery 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 (Λ) 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 → He 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.
核聚变的本质是，在初始核和最终核之间的核子重新排列可以释放能量。最近发现了第一个双重魅力重子，它含有两个魅力夸克（c）和一个上夸克（u），质量约为 3621 兆电子伏特（MeV）（质子的质量为 938 MeV），也显示出两个魅力夸克之间约 130 MeV 的大结合能。在这里，我们报告说，这种强大的结合能使夸克重排成为可能，这是一种放热反应，其中两个重子（Λ）发生融合，产生双重魅力重子和一个中子 n（），从而释放 12 MeV 的能量。这种反应是氘氚核聚变反应（DT→He n）的夸克级类似物。两个底夸克（b）之间的结合能（约 280 MeV）要大得多，导致类似的底夸克反应释放出更大的能量，约为 138 MeV。我们建议了一些实验设置，其中两个重夸克重子的融合的高度放热性质可能会显现出来。然而，目前，重底夸克和魅力夸克的极短寿命排除了这种反应的任何实际应用。
